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Group A streptococcus (GAS) is a pathogen typically transmitted through respiratory droplets and skin contact, causing an estimated 700 million mild non-invasive infections worldwide each year. There are approximately 650 000 infections that progress to severe invasive infections, even resulting in death. Therefore, the ability to detect GAS rapidly, accurately and in real time is important. Herein, we developed a nanozyme linked multi-array gas driven sensor (NLMAGS) to point-of-care testing of GAS within 2 h. The NLMAGS demonstrated excellent performance as it combined the advantages of nanozyme techniques, immunoassay techniques, and 3D printing techniques. Platinum- and palladium-rich nanozyme particles (Au@Pt@PdNPs) were synthesized and used to label monocloning antibodies as detection probes. Magnetic beads were labeled with monocloning antibodies as capture probes to establish a double-antibody sandwich immunoassay for the detection of GAS. The sandwich immune complex can catalyze the H2O2 substrate and produce O2. GAS quantification can be achieved by measuring the distance that the O2 pushes the ink drops forward in the sensor. Under optimized conditions, the NLMAGS quantitatively detected 24 spiked samples with a limit of detection (LOD) of 62 CFU mL−1, which was 5 times lower than that of ELISA (334 CFU mL−1). A strong correlation with the conventional ELISA was found (r = 0.99, P < 0.001). In comparison, the traditional lateral flow immunoassay based on Au@Pt@PdNPs-mAb2 (Au@Pt@PdNPs-LFIA) had a LOD of 104 CFU mL−1, which was significantly higher than that of NLMAGS. The NLMAGS demonstrated excellent sensitivity to GAS. The intra- and inter-assay precisions of the sensor were below 15%. Overall, the established NLMAGS has promising potential as a rapid and quantitative method for detecting GAS and can also be used to detect various pathogens. [ABSTRACT FROM AUTHOR]

Simple Summary: Cytokines are substances important in the regulation of the immune system. The cytokine interleukin-6 (IL-6) is important for the normal function of the immune system and also plays a pathogenic role in multiple diseases such as chronic inflammation, autoimmunity cancer, sepsis, and cardiovascular disease. A new immunoregulatory mechanism is described. Proteolytic degradation of serum albumin generates immunoregulatory neo-structures, one of which has the capacity to induce IL-6, Il-6-inducing factor, IL-6IF. The serum concentration of this factor is significantly increased in advanced stages of colon cancer and is associated with cancer-specific survival of the patients. IL-6IF is immunogenic, resulting in the production of autoantibodies with the capacity to inhibit IL-6IF-induced IL-6 synthesis. The specificity of these autoantibodies, using the single B-cell technique, enables the production of human monoclonal antibodies, which therapeutically can be used to specifically inhibit pathological IL-6 production, leaving IL-6 for the normal function of the immune system intact. Background: Interleukin-6 is dysregulated in multiple pathological conditions, e.g., cancer and inflammatory diseases. Aim: To investigate new mechanisms for the regulation of pathological IL-6 production. Methods: PBMCs (peripheral blood mononuclear cells) stimulated by cancer serum factors or specific peptides produce interleukin-6 (IL-6). Immunoregulatory albumin neo-structures and peptides were identified with 2D gel electrophoresis and MALDI-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry) analyses. Il-6 and albumin neo-structures were determined by ELISA (enzyme-linked immunosorbent assay). Results: Conformational changes in normal serum albumin by proteolytic degradation generates an IL-6-inducing neo-structure, IL-6-inducing factor (IL-6IF). This neo-structure is immunogenic which results in the production of autoantibodies. IL-6 production induced by IL-6IF and cancer patient sera is inhibited by specific antibodies. The serum concentration of IL-6IF is significantly higher in advanced cancer stages, and its presence is significantly correlated with the survival of the patients. Conclusions: A new mechanism for the induction IL-6 synthesis is presented. Based on this mechanism, the pathological IL-6 production related to enhanced proteolytic activity can be diagnosed and selectively inhibited by specific antibodies. Such antibodies were identified and purified. Thus, the neo-structure, inducing pathological IL-6 production, associated with a reduced survival of cancer patients, can be selectively removed by the therapeutic administration of antibodies leaving the function of IL-6 needed for the normal activity of the immune system intact. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is a complex multi-organ autoimmune disease marked by the production of autoantibodies against nuclear structures, formation of immune complexes, and chronic inflammation triggered by their tissular deposition. SLE is characterized by alternating periods of relapse and remission and each flare has the potential to cause new organ damage related to either the disease process or the medication toxicity. Despite remarkable progress across its multiple domains, SLE is still an area with many unmet needs, calling for innovative and practical solutions. The efforts of the drug development programme in lupus have led to considerable growth in the last decade, owing to the approval of belimumab, anifrolumab, and voclosporin. The increasing understanding of the pathogenesis of the disease has enabled the exploration of novel therapeutic strategies. New discoveries in the intricate cytokine kaleidoscope of lupus have made the concept of targeted therapy an attractive and promising research focus. JAK inhibitors are oral targeted therapies approved for a wide variety of diseases across the Rheumatology, Gastroenterology, Dermatology, and Haematology fields. Multiple JAKis are currently being investigated in SLE. This paper aims to summarize existing data coming from both clinical trials and case reports regarding the use of JAK inhibitors in SLE. [ABSTRACT FROM AUTHOR]

Japanese spotted fever is an emerging rickettsiosis caused by Rickettsia japonica and is characterized by high fever, rash, and eschar formation. Other symptoms are often vague and nonspecific and include headaches, nausea, vomiting, and myalgia. We present a case of a 46-year-old woman with Japanese spotted fever, complicated by transient bilateral sensorineural hearing loss and presenting cutaneous IgM/IgG immune complex vasculitis. The patient was admitted with a history of several days of high fever, generalized skin erythema, and hearing impairment. Laboratory findings revealed thrombocytopenia and elevated liver enzyme and C-reactive protein levels. Pure-tone audiometry revealed bilateral sensorineural hearing loss, and a skin biopsy revealed leukocytoclastic vasculitis with deposition of C3 and IgM on the vessel walls. Under the tentative diagnosis of rickettsiosis, scrub typhus, or Japanese spotted fever, the patient was treated with minocycline, and her symptoms improved within approximately 10 days. A definitive diagnosis was made on the basis of a serological test showing increased antibody levels against Rickettsia japonica. Japanese spotted fever can cause transient sensorineural hearing loss, a rare complication that presents with cutaneous IgM/IgG immune complex vasculitis. [ABSTRACT FROM AUTHOR]

Les vascularites sont définies par une inflammation des endothéliums vasculaires, elles sont rares et de diagnostic difficile. Cet article n'évoquera que les vascularites primitives non infectieuses, comme cela est fait dans la nomenclature internationale de Chapel Hill dont la deuxième version impose le remplacement des dénominations éponymes des maladies par des expressions en lien avec leur mécanisme physiopathologique ou leurs caractéristiques histologiques. Cette nomenclature des vascularites prend en compte la taille des vaisseaux et les mécanismes physiopathologiques qui, dans l'atteinte des petits et moyens vaisseaux, sont des mécanismes immunologiques. Il s'agit d'une part des vascularites à dépôts de complexes immuns, comprenant les vascularites cryoglobulinémiques, les vascularites à dépôts d'IgA, les vascularites urticariennes hypocomplémentémiques (maladie de McDuffie) et les vascularites à Acs anti-membrane basale glomérulaire (maladie de Goodpasture), et d'autre part des vascularites à Acs anticytoplasme des polynucléaires neutrophiles (ANCA pour Anti-Neutrophil Cytoplasmic Antibodies), qui comprennent la granulomatose avec polyangéite (ex-syndrome de Wegener), la granulomatose à éosinophiles avec polyangéite (ex-syndrome de Churg et Strauss) et la polyangéite microscopique. Dans cet article, les mécanismes physiopathologiques de ces vascularites immunologiques et les outils biologiques seront développés, permettant aux biologistes de participer au diagnostic de ces maladies rares et fréquemment sévères. Vasculitis is defined by inflammation of the vascular endothelium, it is rare and difficult to diagnose. This article will only discuss primary non-infectious vasculitis, as is done in the international nomenclature of Chapel Hill, the second version of which aimed to replace the eponymous names of diseases with expressions related to their pathophysiological mechanism or their histological characteristics. This nomenclature of vasculitis takes into account the size of the vessels and the pathophysiological mechanisms which, in the involvement of small and medium-sized vessels, are immunological mechanisms. These are first, vasculitis with immune complex deposition, including cryoglobulinemic vasculitis, vasculitis with IgA deposits, hypocomplementemic urticarial vasculitis (McDuffie's disease) and vasculitis with anti-glomerular basement membrane Abs (Goodpasture's disease), and second, vasculitis with anti-neutrophil cytoplasmic Abs (ANCA), including granulomatosis with polyangiitis (formerly Wegener's syndrome), eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss syndrome) and microscopic polyangiitis. In this article, the pathophysiological mechanisms of these immunological vasculitides and the biological diagnostic tools will be developed, allowing biologists to participate in the diagnosis of these rare and frequently severe diseases. [ABSTRACT FROM AUTHOR]

Hepatitis E virus (HEV) infection, one of the most common forms of hepatitis worldwide, is often associated with extrahepatic, particularly renal, manifestations. However, the underlying mechanisms are incompletely understood. Here, we report the development of a de novo immune complex-mediated glomerulonephritis (GN) in a kidney transplant recipient with chronic hepatitis E. Applying immunostaining, electron microscopy, and mass spectrometry after laser-capture microdissection, we show that GN develops in parallel with increasing glomerular deposition of a non-infectious, genome-free and non-glycosylated HEV open reading frame 2 (ORF2) capsid protein. No productive HEV infection of kidney cells is detected. Patients with acute hepatitis E display similar but less pronounced deposits. Our results establish a link between the production of HEV ORF2 protein and the development of hepatitis E-associated GN in the immunocompromised state. The formation of glomerular IgG-HEV ORF2 immune complexes discovered here provides a potential mechanistic explanation of how the hepatotropic HEV can cause variable renal manifestations. These findings directly provide a tool for etiology-based diagnosis of hepatitis E-associated GN as a distinct entity and suggest therapeutic implications. It's poorly understood how renal manifestations develop in HEV infection in patients. Here, the authors observe glomerular accumulation of the viral protein ORF2 in complex with host IgG in immunocompromised patients with chronic or acute HEV infection who developed glomerulonephritis. [ABSTRACT FROM AUTHOR]

Chronic antibody-mediated rejection in kidney transplantation is a common cause of graft loss in the late post-transplant period. In this process, the role of the classical complement activation pathway is crucial due to the formation of immune complexes between donor-specific antibodies (DSAs) and donor antigens and the attachment of the C1q complement fragment. This study aimed to determine the levels of circulating C1q immunocomplexes (CIC-C1q) and complement activation (CH50), in sensitized kidney transplant recipients (KTRs). In this cross-sectional study we used serum samples from KTRs with de novo or preformed DSAs (n = 14), KTRs without DSAs (n = 28), and 22 subjects with no history of chronic kidney disease (controls). C1q immunocomplexes and CH50 concentration in serum were measured with the enzyme immunoassay (EIA) kit MicroVue CIC-C1q (Quidel, Athens, OH, USA) and EIA kit MicroVue CH50 (Quidel, OH, USA), respectively. Higher concentrations of CIC-C1q was observed in KTRs with DSAs in comparison with controls and with KTRs with no DSAs (6.8 ± 2.7 and 4.8 ± 1.9 vs. 5.0 ± 1.2 μg Eq/mL, respectively, p < 0.01). We found no difference in CIC-C1q between KTRs with no DSAs and controls. CIC-C1q levels were positively correlated with DSA titer. CH50 levels were decreased in KTRs with DSAs in comparison with controls and KTRs with no DSAs (39 ± 15 vs. 68 ± 40 and 71 ± 34 U Eq/mL, respectively, p < 0.01). There was no difference in CH50 between DSA-negative KTRs and controls. Kidney transplant recipients with DSAs had increased serum levels of C1q immunocomplexes and increased classical pathway complement activation. [ABSTRACT FROM AUTHOR]

Unlike most other picornaviruses, foot-and-mouth disease (FMD) intact virions (146S) dissociate easily into small pentameric subunits (12S). This causes a dramatically decreased immunogenicity by a mechanism that remains elusive. Here, we present the high-resolution structures of 12S (3.2 Å) and its immune complex of a single-domain antibody (VHH) targeting the particle interior (3.2 Å), as well as two 146S-specific VHHs complexed to distinct sites on the 146S capsid surface (3.6 Å and 2.9 Å). The antigenic landscape of 146S is depicted using 13 known FMD virus-antibody complexes. Comparison of the immunogenicity of 146S and 12S in pigs, focusing on the resulting antigenic sites and incorporating structural analysis, reveals that dissociation of 146S leads to structural alteration and destruction of multiple epitopes, resulting in significant differences in antibody profiles/lineages induced by 12S and 146S. Furthermore, 146S generates higher synergistic neutralizing antibody titers compared to 12S, whereas both particles induce similar total FMD virus specific antibody titers. This study can guide the structure-based rational design of novel multivalent and broad-spectrum recombinant vaccines for protection against FMD. Foot-and-mouth disease vaccine efficacy is reduced when full virion 146S dissociates into pentameric 12S subunit. Here, the authors elucidate the molecular basis of this compromised immunogenicity by comparing antigenicity, humoral immunogenicity and structures of 146S and 12S particles. [ABSTRACT FROM AUTHOR]

Identifying antibodies that neutralize specific antigens is crucial for developing effective immunotherapies, but this task remains challenging for many target antigens. The rise of deep learning-based computational approaches presents a promising avenue to address this challenge. Here, we assess the performance of a deep learning approach through two benchmark tests aimed at predicting antibodies for the receptor-binding domain of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. Three different strategies for constructing input sequence alignments are employed for predicting structural models of antigen-antibody complexes. In our initial testing set, which comprises known experimental structures, these strategies collectively yield a significant top-ranked prediction for 61% of cases and a success rate of 47%. Notably, one strategy that utilizes the sequences of known antigen binders outperforms the other two, achieving a precision of 90% in a subsequent test set of ~1,000 antibodies, balanced between true and control antibodies for the antigen, albeit with a lower recall of 25%. Our results underscore the potential of integrating deep learning methods with single B cell sequencing techniques to enhance the prediction accuracy of antigen-antibody interactions. [ABSTRACT FROM AUTHOR]

Changes in the immune status and the content of blood transport components reflect adaptations in the human body in response to adverse factors, showcasing the organism's adaptive capabilities and functional state. In this study, we aimed to determine the features of the immune system and levels of transport components of the blood system in residents of the Arctic of the Russian Federation. Methods: The peripheral venous blood of 191 residents of the Arctic of the Russian Federation (Murmansk Oblast) aged 21–55 analyzed comprehensively. Blood was sampled from the ulnar vein on an empty stomach in the morning. The hemogram, phagocytic activity of neutrophils, lymphocyte content with CD3, CD4, CD8, CD10, CD19, CD16, CD71, CD25, HLA‐DR and CD95 phenotypes, concentrations of cytokines: TNF‐α, IFN‐γ, IL‐6, IL‐10, extracellular receptor pool: sCD71, sCD62L, sApo‐1/Fas, sFasL, circulating immune complexes (CIC) and blood transport components: haptoglobin (Hp), transferrin, IgM, IgG, IgA, IgE (immunoglobulins M, G, A and E) low‐density lipoproteins (LDL), and high density lipoprotein (HDL) were evaluated. The results were analyzed using descriptive statistics and comparative, factorial, and regression analyses. Results: Residents of the Murmansk Oblast exhibit a high prevalence of erythrocytosis (62.3%), thrombocytosis (25.0%), leukocytosis (20.1%), and increased hemoglobin (Hb) concentrations (42.5%), coupled with a significantly decreased level of active phagocytes (47.6%). A significantly decreased level of lymphocytes with phenotypes CD3 (92.4%), CD4 (40.4%), CD71 (62.3%) was revealed, coupled with the activation of lymphocytes with phenotypes CD16 (50.1%), CD8 (37.5%), CD19 (15.9%) and increased concentrations of pro‐inflammatory IFN‐γ (47.9%), IL‐6 (33.3%), and TNF‐α (20.1%). Elevated levels of sCD71 (56.6%), sCD62L (32.1%), sApo‐1/Fas (22.1%), sFasL (10.2%), and autoantibodies to double‐stranded DNA (57.1%), RNA (10.4%), and oLDL (oxidized‐modified LDL) (16.3%) were recorded in residents of the Murmansk Oblast. Arctic residents showed elevated concentrations of Hp (63.3%), IgM (63.9%), IgA (42.4%), IgE (18.8%), LDL (24.9%), and a decreased level of HDL (21.1%) owing to an ApoA‐I ligand deficiency (58.1%). Elevated levels of Hp in the blood are associated with increased erythrocyte aggregation frequency, T‐lymphocyte activation, and increased concentration of free receptors of the extracellular pool. Increased IgM and IgA levels in the blood are attributed to the need to bind components of the extracellular receptor pool sCD71, sCD62L, sApo‐1/Fas, sFasL and are associated with decreased levels lymphocyte with CD8 and CD16 phenotypes. The humoral immune response in Arctic residents is triggered when the cellular component of immunity is under strain which compounded by ineffective clearance of metabolic byproducts owing to imbalanced LDL and HDL lipid transport complexes. Conclusions: The immune system of Arctic residents is characterized by excessive cytotoxic activity of lymphocytes and increased concentrations of pro‐inflammatory cytokines, free forms of receptors of the extracellular pool, and autoantibodies. The change in the content of transport components of the blood system is directed at maintaining homeostasis by exhibiting antioxidant, anti‐inflammatory, and immunoregulatory properties. [ABSTRACT FROM AUTHOR]

IgA nephropathy (IgAN) is characterized by immune-mediated glomerulonephritis, with the accumulation of galactose-deficient IgA1 (Gd-IgA1) in the glomeruli and increased levels of circulating Gd-IgA1 and Gd-IgA1-containing immune complexes. An incomplete understanding of the underlying mechanisms and differences in clinical and pathological features between individuals and ethnicities has contributed to the lack of established treatments for IgAN. A tumor necrosis factor (TNF) family member, a proliferation-inducing ligand (APRIL), is a crucial cytokine essential for the generation and survival of plasma cells. Recent studies demonstrated that APRIL is a pivotal mediator in the production of Gd-IgA1 in IgAN. As our understanding of the autoimmune pathogenesis underlying IgAN has improved, various pharmacological therapeutic targets, including APRIL antagonists, have emerged. Preliminary results showed that APRIL-targeting agents effectively reduced proteinuria and Gd-IgA1 levels without significantly increasing adverse events, indicating their potential as novel therapeutic agents for IgAN. In the present review, we discuss the current understanding of the role of APRIL in the pathogenesis of IgAN and novel therapeutic strategies focusing on APRIL-targeting agents for IgAN. APRIL inhibitors may offer new hope to patients with IgAN. [ABSTRACT FROM AUTHOR]

Introduction: An event of increasing interest during host-pathogen interactions is the polarization of patrolling/naive monocytes (MOs) into macrophage subsets (MФs). Therapeutic strategies aimed at modulating this event are under investigation. Methods: This review focuses on the mechanisms of induction/development and profile of MФs polarized toward classically proinflammatory (M1) or alternatively anti-inflammatory (M2) phenotypes in response to bacteria, fungi, parasites, and viruses. Results and discussion: It highlights nuclear, cytoplasmic, and cell surface receptors (pattern recognition receptors/PPRs), microenvironmental mediators, and immune signaling. MФs polarize into phenotypes: M1 MФs, activated by IFN-γ, pathogen-associated molecular patterns (PAMPs, e.g. lipopolysaccharide) and membrane-bound PPRs ligands (TLRs/CLRs ligands); or M2 MФs, induced by interleukins (ILs-4, -10 and -13), antigen-antibody complexes, and helminth PAMPs. Polarization toward M1 and M2 profiles evolve in a pathogen-specific manner, with or without canonicity, and can vary widely. Ultimately, this can result in varying degrees of host protection or more severe disease outcome. On the one hand, the host is driving effective MФs polarization (M1 or M2); but on the other hand, microorganisms may skew the polarization through virulence factors to increase pathogenicity. Cellular/genomic reprogramming also ensures plasticity of M1/M2 phenotypes. Because modulation of polarization can occur at multiple points, new insights and emerging perspectives may have clinical implications during the inflammation-to-resolution transition; translated into practical applications as for therapeutic/vaccine design target to boost microbicidal response (M1, e.g. triggering oxidative burst) with specifics PAMPs/IFN-γ or promote tissue repair (M2, increasing arginase activity) via immunotherapy. Plain Language Summary: Monocytes are white blood cells (leukocytes) that help fight off various types of aggressive agents, including microorganisms (bacteria, fungi, viruses, and parasites), and help maintain the healthy balance of the human body. These cells differentiate into specific macrophages in tissues such as the lungs, heart, liver, skin, and brain. The present review focuses on the peculiar cellular properties that macrophages can acquire during the human immune response to infectious diseases. In this regard, it is discussed that macrophages are didactically divided into M1 and M2 subtypes. The first subtype (M1) is responsible for fighting pathogens and causing inflammation. The second subtype (M2) is mainly responsible for healing and repairing damaged tissue. Current knowledge shows that although both subtypes are involved in the same immune response aimed at protecting the human body, these M1 and M2 profiles have different characteristics that have implications for therapeutic measures such as developing specific drugs or vaccines to balance the immune response against a given pathogen and promote a complete cure of the disease. Alongside the therapeutic impacts, this review also looks at the characteristics that allow aggressive microorganisms to counteract the immune response developed by these M1 and M2 cell profiles. It highlights how exactly there can be greater protection or detriment to the human host against a given microorganism when there is a predilection to develop a more abundant immune response from one of the two profiles (M1 or M2). [ABSTRACT FROM AUTHOR]

The gut microbiota can play an important role in enhancing the host's complex immune system. In this regard, many studies indicate that probiotics consumption has a beneficial impact on alterations in the composition of the gut microbiota. Our previous study demonstrated that the oral administration of Lacticaseibacillus rhamnosus HDB1258 (HDB1258) enhances immune cell activity and alters the composition of gut microbiota in C57BL/6 mice, thereby showing its potential as a novel immunostimulatory ingredient. Therefore, this clinical trial assessed the effects of HDB1258 on human natural killer (NK) cell activity and changes in gut microbiota. It also investigated the correlation between gut microbiota and NK cell activity following HDB1258 supplementation. Participants (n = 71) were randomized into placebo and HDB1258 groups, and NK cell activity and gut microbiota were investigated at baseline (week 0) and endline (week 8). The present study showed that HDB1258 significantly increased NK cell activity and resulted in positive regulatory effects on the gut microbial balance in subjects compared to the placebo group. HDB1258 affected the gut microbial balance by inducing the growth of beneficial bacteria such as Lactococcus and Sutterella. Especially, the changes in Escherichia–Shigella composition were negatively correlated with the changes in NK cell activity after HDB1258 consumption. There was also a positive correlation between the NK cell activity in the HDB1258 group and the composition of Prevotella 9 and Adlercreutzia. These findings suggest that HDB1258 may improve the host's intestinal environment by regulating gut bacteria related to immune response and promote NK cell activation. This study was registered at clinical research information service (CRIS: KCT0008204). [ABSTRACT FROM AUTHOR]

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The CCL2–CCR2 axis is involved in lupus nephritis, however the precise roles in the mechanisms by which different pathological lesions develop after glomerular immune complex deposition remain elusive. Previously, we demonstrated that genetic CCR2 inhibition induced a histological switch from glomerular endocapillary hypercellularity to wire‐loop lesions in murine lupus nephritis. This study aimed to clarify the CCL2–CCR2 axis‐mediated cellular mechanism in the formation of these different pathological lesions. We injected MRL/lpr mouse‐derived monoclonal IgG3 antibody‐producing hybridomas, 2B11.3 or B1, into wild‐type (WT) mice to selectively induce glomerular endocapillary hypercellularity or wire‐loop lesions. The expression of chemokine and chemokine receptors was analyzed using RT‐quantitative PCR and/or immunofluorescence. We found 2B11.3 caused glomerular endocapillary hypercellularity in WT mice with glomerular infiltration of larger numbers of CCR2‐expressing macrophages and neutrophils phagocyting immune complex, whereas B1 induced wire‐loop lesions. In glomerular endocapillary hypercellularity, CCL2 was identified as the ligand involved in the CCR2‐positive cell infiltration; it was expressed by glomerular endothelial cells and macrophages. Notably, 2B11.3‐induced glomerular endocapillary hypercellularity converted to wire‐loop lesions with reduced glomerular macrophage and neutrophil infiltration in CCL2‐deficient (Ccl2−/−) mice similarly observed in Ccr2−/− mice. Moreover, this histological conversion was also observed when both glomerular macrophage and neutrophil infiltration were inhibited in anti‐Ly6G antibody‐treated Ccr5−/− mice but not when only glomerular macrophage infiltration was inhibited in Ccr5−/− mice or when only glomerular neutrophil infiltration was inhibited in anti‐Ly6G antibody‐treated WT mice. In contrast, B1 injection caused wire‐loop lesions in Ccl2−/− and Ccr2−/− mice, as observed in WT mice. Moreover, 2B11.3 induced CCL2 from glomerular endothelial cells to a larger extent than B1 when injected into Ccr2−/− mice. In conclusion, the CCL2–CCR2 axis determines whether glomerular endocapillary hypercellularity or wire‐loop lesions develop by regulating glomerular infiltration of phagocytic cells: macrophages and neutrophils. © 2024 The Pathological Society of Great Britain and Ireland. [ABSTRACT FROM AUTHOR]

Introduction: Erythema nodosum (EN) is the most common form of panniculitis. EN can be idiopathic or secondary to an underlying systemic disease, infection, drug use, or tumor. CD5-positive diffuse large B-cell lymphoma (CD5+ DLBCL) is a relapsed and refractory lymphoma, and further understanding of its pathology is required. We report a case of newly diagnosed CD5+ DLBCL with concomitant EN. Within the scope of our search, there were no reports of CD5+ DLBCL complicated with EN. Case Presentation: A 79-year-old woman experienced swelling, warmth, redness, and pain in both legs and a mass lesion on the right side of the back at almost the same time. The respective lesions were diagnosed as EN and CD5+ DLBCL by biopsy. With chemotherapy, the lymphoma and EN improved in parallel courses. The patient has completed scheduled chemotherapy, and there has been no recurrence of swelling in the legs or mass on the right side of the back. Discussion: The lymphoma and EN developed simultaneously and followed a parallel clinical course after chemotherapy, suggesting that EN was a paraneoplastic symptom of CD5+ DLBCL. Recognizing and treating underlying malignancies in patients presenting with EN is crucial. [ABSTRACT FROM AUTHOR]

Introduction: Despite progress in our understanding of disease pathogenesis for systemic autoimmune rheumatic diseases (SARD), these diseases are still associated with high morbidity, disability, and mortality. Much of the strongest evidence to date implicating environmental factors in the development of autoimmunity has been based on well-established, large, longitudinal prospective cohort studies. Methods: Herein, we review the current state of knowledge on known environmental factors associated with the development of SARD and potential areas for future research. Results: The risk attributable to any particular environmental factor ranges from 10-200%, but exposures are likely synergistic in altering the immune system in a complex interplay of epigenetics, hormonal factors, and the microbiome leading to systemic inflammation and eventual organ damage. To reduce or forestall the progression of autoimmunity, a better understanding of disease pathogenesis is still needed. Conclusion: Owing to the complexity and multifactorial nature of autoimmune disease, machine learning, a type of artificial intelligence, is increasingly utilized as an approach to analyzing large datasets. Future studies that identify patients who are at high risk of developing autoimmune diseases for prevention trials are needed. [ABSTRACT FROM AUTHOR]

Neuroimmune interactions are essential for the development of neuropathic pain, yet the contributions of distinct immune cell populations have not been fully unraveled. Here, we demonstrate the critical role of B cells in promoting mechanical hypersensitivity (allodynia) after peripheral nerve injury in male and female mice. Depletion of B cells with a single injection of anti-CD20 monoclonal antibody at the time of injury prevented the development of allodynia. B cell–deficient (muMT) mice were similarly spared from allodynia. Nerve injury was associated with increased immunoglobulin G (IgG) accumulation in ipsilateral lumbar dorsal root ganglia (DRGs) and dorsal spinal cords. IgG was colocalized with sensory neurons and macrophages in DRGs and microglia in spinal cords. IgG also accumulated in DRG samples from human donors with chronic pain, colocalizing with a marker for macrophages and satellite glia. RNA sequencing revealed a B cell population in naive mouse and human DRGs. A B cell transcriptional signature was enriched in DRGs from human donors with neuropathic pain. Passive transfer of IgG from injured mice induced allodynia in injured muMT recipient mice. The pronociceptive effects of IgG are likely mediated through immune complexes interacting with Fc gamma receptors (FcγRs) expressed by sensory neurons, microglia, and macrophages, given that both mechanical allodynia and hyperexcitability of dissociated DRG neurons were abolished in nerve-injured FcγR-deficient mice. Consistently, the pronociceptive effects of IgG passive transfer were lost in FcγR-deficient mice. These data reveal that a B cell–IgG–FcγR axis is required for the development of neuropathic pain in mice. Editor's summary: B cells contribute to the pathogenesis of neuropathic pain, but the exact mechanisms remain elusive. Lacagnina et al. report increased immunoglobulin G (IgG) in the dorsal root ganglia (DRGs) of mice after peripheral nerve injury (PNI) and patients with chronic pain. Passive transfer of IgG from injured wild-type mice elicited allodynia in PNI mice without B cells (muMT) that were otherwise protected from allodynia. Mice lacking the Fc gamma receptor (FcγR) were also protected from allodynia, and this receptor was necessary for the development of hyperexcitability in DRG neurons upon PNI. The identified B cell–IgG–FcγR axis could help to develop alternative treatment avenues for neuropathic pain. —Daniela Neuhofer [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is a chronic, heterogeneous, systemic autoimmune disease characterized by autoantibody production, complement activation, and immune complex deposition. SLE predominantly affects young, middle-aged, and child-bearing women with episodes of flare-up and remission, although it affects males at a much lower frequency (female: male; 7:1 to 15:1). Technological and molecular advancements have helped in patient stratification and improved patient prognosis, morbidity, and treatment regimens overall, impacting quality of life. Despite several attempts to comprehend the pathogenesis of SLE, knowledge about the precise molecular mechanisms underlying this disease is still lacking. The current treatment options for SLE are pragmatic and aim to develop composite biomarkers for daily practice, which necessitates the robust development of novel treatment strategies and drugs targeting specific responsive pathways. In this communication, we review and aim to explore emerging therapeutic modalities, including multiomics-based approaches, rational drug design, and CAR-T-cell-based immunotherapy, for the management of SLE. [ABSTRACT FROM AUTHOR]

Abstract\nSUMMARYAluminum salt-based adjuvants like alum, alhydrogel and Adju-Phos are by far the most favored clinically approved vaccine adjuvants. They have demonstrated excellent safety profile and currently used in vaccines against diphtheria, tetanus, pertussis, hepatitis B, anthrax etc. These vaccinations cause minimal side effects like local inflammation at the injection site. Aluminum salt-based adjuvants primarily stimulate CD4+ T cells and B cell mediated Th2 immune response leading to generate a robust antibody response. In this review article, we have compiled the role of physio-chemical role of the two commonly used aluminum salt-based adjuvants alhydrogel and Adju-Phos, and the effect of surface properties, buffer composition, and adjuvant dosage on the immune response. After being studied for almost a century, researchers have come up with various mechanism by which these aluminum adjuvants activate the immune system. Firstly, we have covered the initial works of Glenny and his “repository effect” which paved the work for his successors to explore the involvement of cytokines, chemokines, recruitment of innate immune cells, enhanced antigen uptake by antigen presenting cells, and formation of NLRP3 inflammasome complex in mediating the immune response. It has been reported that aluminum adjuvants activate multiple immunological pathways which synergistically activates the immune system. We later discuss the recent developments in nanotechnology-based preparations of next generation aluminum based adjuvants which has enabled precise size control and morphology of the traditional aluminum adjuvants thereby manipulating the immune response as per our desire.Aluminum salt adjuvants like alum, aluminum hydroxide gel, and aluminum phosphate have been regularly used in vaccine formulations to potentiate the immune response. Despite being discovered nearly a century ago by Alexander Glenny, the cellular and molecular mechanism behind the working of these adjuvants is still elusive. In this article, we review the advances made in understanding the mechanism of action of these adjuvants. Firstly, we cover the “repository theory” put forward by Glenny, and gradually review the role of innate and adaptive immune cells, immune complexes, and different immunological pathways in aluminum adjuvant orchestrated immune response. We also take a dig into the role of physio-chemical parameters like surface properties, buffer composition and adjuvant dosage of aluminum adjuvants in eliciting an immune response. Finally, we discuss the advances made by nano-preparations of aluminum adjuvants and their diverse physio-chemical properties as well as hypothesize their probable mechanism of action. [ABSTRACT FROM AUTHOR]

Nucleotide-binding domain and leucine-rich repeat (NLR) proteins play crucial roles in immunity against pathogens in both animals and plants. In solanaceous plants, activation of several sensor NLRs triggers their helper NLRs, known as NLR-required for cell death (NRC), to form resistosome complexes to initiate immune responses. While the sensor NLRs and downstream NRC helpers display diverse genetic compatibility, molecular evolutionary events leading to the complex network architecture remained elusive. Here, we showed that solanaceous NRC3 variants underwent subfunctionalization after the divergence of Solanum and Nicotiana, altering the genetic architecture of the NRC network in Nicotiana. Natural solanaceous NRC3 variants form three allelic groups displaying distinct compatibilities with the sensor NLR Rpi-blb2. Ancestral sequence reconstruction and analyses of natural and chimeric variants identified six key amino acids involved in sensor-helper compatibility. These residues are positioned on multiple surfaces of the resting NRC3 homodimer, collectively contributing to their compatibility with Rpi-blb2. Upon activation, Rpi-blb2-compatible NRC3 variants form membrane-associated punctate and high molecular weight complexes, and confer resistance to the late blight pathogen Phytophthora infestans. Our findings revealed how mutations in NRC alleles lead to subfunctionalization, altering sensor-helper compatibility and contributing to the increased complexity of the NRC network. Author summary: Plants utilize complex immune systems to fend off invading pathogens. The nucleotide-binding domain and leucine-rich repeat (NLR) proteins function as intracellular immune receptors and play major roles in plant immunity. In solanaceous plants, several sensor NLRs form a complex genetic network with helper NLRs called NRCs (NLR-required for cell death) to trigger immune responses. However, the evolution of genetic compatibility between sensor NLRs and NRCs was unclear. Here, we showed that NRC3, one of the NRC subgroups in solanaceous plants, underwent subfunctionalization after the Solanum-Nicotiana divergence, altering the NRC network in Nicotiana. Using natural, chimeric, and reconstructed ancestral NRC variants, we mapped six critical residues on multiple protein surfaces of NRC3 contributing to subfunctionalization. These findings reveal how mutations in NRC alleles lead to subfunctionalization, altering sensor-helper NLR compatibility and increasing the complexity of plant immune systems. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by loss of tolerance to nuclear antigens. The formation of autoantibodies and the deposition of immune complexes trigger inflammatory tissue damage that can affect any part of the body. In most cases, SLE is a complex disease involving multiple genetic and environmental factors. Despite advances in the treatment of SLE, there is currently no cure for SLE and patients are treated with immunosuppressive drugs with significant side effects. The elucidation of rare monogenic forms of SLE has provided invaluable insights into the molecular mechanisms underlying systemic autoimmunity. Harnessing this knowledge will facilitate the development of more refined and reliable biomarker profiles for diagnosis, therapeutic monitoring, and outcome prediction, and guide the development of novel targeted therapies not only for monogenic lupus, but also for complex SLE. [ABSTRACT FROM AUTHOR]

Cell-surface receptors form the front line of plant immunity. The leucine-rich repeat (LRR)-receptor-like kinases SOBIR1 and BAK1 are required for the functionality of the tomato LRR-receptor-like protein Cf-4, which detects the secreted effector Avr4 of the pathogenic fungus Fulvia fulva. Here, we show that the kinase domains of SOBIR1 and BAK1 directly phosphorylate each other and that residues Thr522 and Tyr469 of the kinase domain of Nicotiana benthamiana SOBIR1 are required for its kinase activity and for interacting with signalling partners, respectively. By knocking out multiple genes belonging to different receptor-like cytoplasmic kinase (RLCK)-VII subfamilies in N. benthamiana:Cf-4, we show that members of RLCK-VII-6, −7, and −8 differentially regulate the Avr4/Cf-4-triggered biphasic burst of reactive oxygen species. In addition, members of RLCK-VII-7 play an essential role in resistance against the oomycete pathogen Phytophthora palmivora. Our study provides molecular evidence for the specific roles of RLCKs downstream of SOBIR1/BAK1-containing immune complexes. Cell-surface receptors form the front line of plant immunity. Here, the authors show that the RLP co-receptors SOBIR1 and BAK1 directly phosphorylate each other, leading to activation of the immune receptor complex in which RLCKs are differentially required for production of reactive oxygen species that play a role in resistance against Phytophthora palmivora. [ABSTRACT FROM AUTHOR]

Kidney complications can occur due to infective endocarditis, one of which is glomerulonephritis. Most often, an immune complex or complement‐mediated glomerulonephritis is seen on kidney biopsy. In a minor subset of cases, pauci‐immune glomerulonephritis may be present. Most often, such patients will demonstrate the presence of antineutrophil cytoplasmic antibodies (ANCA) on serologic testing. A growing number of cases of ANCA‐associated glomerulonephritis due to Bartonella endocarditis have been reported. This type of endocarditis can present diagnostic difficulties given that these patients are often culture negative. Herein, we report a challenging case of ANCA‐negative pauci‐immune glomerulonephritis showing florid crescents on biopsy that was associated with Bartonella endocarditis. [ABSTRACT FROM AUTHOR]

This article discusses the pathogenesis of IgA nephropathy (IgAN), a kidney disease characterized by the presence of immunodeposits containing IgA, IgG, and C3 in the glomeruli. The article highlights the role of abnormal O-glycosylation of IgA1 in the development of IgAN, as well as the genetic factors and cytokines involved in this process. It also explores the formation of pathogenic immune complexes consisting of galactose-deficient IgA1 bound by IgG autoantibodies, which contribute to kidney injury. The article concludes by emphasizing the need for further research in genomics and glycomics to inform the development of new therapeutic approaches for IgAN. [Extracted from the article]

The main pathological features of Alzheimer’s disease (AD) include the cytotoxic extracellular accumulation of the amyloid beta (Aβ) plaques and intracellular neurofibrillary tangles. The Aβ plaques are responsible for cholinergic dysfunction and dementia in AD patients. Immunoglobulin G (IgG) and Aβ form an immune complex that activates neuroglia, clearing Aβ from the brain. Various Aβ-based therapeutic strategies have been proposed to reduce Aβ production, inhibit Aβ aggregation, and increase Aβ clearance. New medicines, such as aducanumab and donanemab, which are human IgG1 monoclonal antibodies, reduce cognitive impairment in patients with AD by decreasing the amount of Aβ plaques. Despite the considerable advantages of these agents, some disadvantages have also been reported, including Aβ-related imaging abnormalities, anaphylaxis, high cost, and contradictory results. Moreover, donanemab has delivered contradictory outcomes in improving recognition and performance in AD. However, although not fully proven yet, fewer side effects are reported for donanemab compared to aducanumab. Therefore, this review aims to explore the research background, compare the mechanism of action, and understand the advantages and disadvantages of aducanumab and donanemab. As a result, these medicines with maximum effectiveness and safety, yet fewer side effects, could be developed for future treatment and references. [ABSTRACT FROM AUTHOR]

Plants' complex immune systems include nucleotide-binding domain and leucine-rich repeat-containing (NLR) proteins, which help recognize invading pathogens. In solanaceous plants, the NRC (NLR required for cell death) family includes helper NLRs that form a complex genetic network with multiple sensor NLRs to provide resistance against pathogens. However, the evolution and function of NRC networks outside solanaceous plants are currently unclear. Here, we conducted phylogenomic and macroevolutionary analyses comparing NLRs identified from different asterid lineages and found that NRC networks expanded significantly in most lamiids but not in Ericales and campanulids. Using transient expression assays in Nicotiana benthamiana, we showed that NRC networks are simple in Ericales and campanulids, but have high complexity in lamiids. Phylogenetic analyses grouped the NRC helper NLRs into three NRC0 subclades that are conserved, and several family-specific NRC subclades of lamiids that show signatures of diversifying selection. Functional analyses revealed that members of the NRC0 subclades are partially interchangeable, whereas family-specific NRC members in lamiids lack interchangeability. Our findings highlight the distinctive evolutionary patterns of the NRC networks in asterids and provide potential insights into transferring disease resistance across plant lineages. Nucleotide-binding domain and leucine-rich repeat-containing required for cell death networks have differing degrees of complexity across asterids. [ABSTRACT FROM AUTHOR]

Summary: The prevalence of allergies has been globally escalating. While allergies could appear at any age, they often develop in early life. However, the significant knowledge gap in the field is the mechanisms by which allergies affect certain people but not others. Investigating early factors and events in neonatal life that have a lasting impact on determining the susceptibilities of children to develop allergies is a significant area of the investigation as it promotes the understanding of neonatal immune system that mediates tolerance versus allergies. This review focuses on the research over the recent 10 years regarding the potential maternal factors that influence offspring allergies with a view to food allergy, a potentially life‐threatening cause of anaphylaxis. The role of breast milk, maternal diet, maternal antibodies, and microbiota that have been suggested as key maternal factors regulating offspring allergies are discussed here. We also suggest future research area to expand our knowledge of maternal–offspring interactions on the pathogenesis of food allergy. [ABSTRACT FROM AUTHOR]

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Introduction: Erythema nodosum (EN) is the most common form of panniculitis. EN can be idiopathic or secondary to an underlying systemic disease, infection, drug use, or tumor. CD5-positive diffuse large B-cell lymphoma (CD5+ DLBCL) is a relapsed and refractory lymphoma, and further understanding of its pathology is required. We report a case of newly diagnosed CD5+ DLBCL with concomitant EN. Within the scope of our search, there were no reports of CD5+ DLBCL complicated with EN. Case Presentation: A 79-year-old woman experienced swelling, warmth, redness, and pain in both legs and a mass lesion on the right side of the back at almost the same time. The respective lesions were diagnosed as EN and CD5+ DLBCL by biopsy. With chemotherapy, the lymphoma and EN improved in parallel courses. The patient has completed scheduled chemotherapy, and there has been no recurrence of swelling in the legs or mass on the right side of the back. Discussion: The lymphoma and EN developed simultaneously and followed a parallel clinical course after chemotherapy, suggesting that EN was a paraneoplastic symptom of CD5+ DLBCL. Recognizing and treating underlying malignancies in patients presenting with EN is crucial.

An immunochromatographic test system based on the indirect competitive format has been developed for the rapid control of cyanotoxin microcystin-LR (MC-LR) in drinking water. To increase the assay sensitivity, a hydroquinone-based reduction of silver ions on the surface of gold nanoparticles as part of the immune complexes formed on the immunochromatographic membrane has been carried out. This stage allows for the enhancement of the colouration in test strip zones. The developed test system is characterised by an instrumental limit of detection of 0.05 ng/mL, a cut-off of 0.5 ng/mL, and a working range of the detectable concentrations of 0.08–0.42 ng/mL. The assay duration was 17 min. The applicability of the test system for MC-LR detection in drinking water is demonstrated. The assay recoveries vary from 90% to 120%. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is a complex autoimmune disorder characterized by a spectrum of hypersensitivity reactions, encompassing Type II, Type III, and Type IV responses. Firstly, RA is marked by Type II hypersensitivity reactions driven by autoantibodies, such as rheumatoid factor (RF) and anti-(cyclic) citrullinated protein antibodies (ACPAs). These autoantibodies serve not only as serological markers for RA but also actively participate in inflammation, bone erosion, and clinical outcomes, with concurrent activation of the complement system involving C1q, C3, and C5 components specifically linked to RA progression and bone damage. Secondly, RA exhibits traits of Type III hypersensitivity, marked by the formation of immune complexes inciting inflammatory reactions. Immunoglobulin G (IgG) autoantibodies like RF and ACPA play pivotal roles in immune complex formation and the ensuing inflammatory responses. RA also demonstrates Type IV hypersensitivity propelled by CD4+ T cells, encompassing T helper 1 (Th1) and Th17 subsets. Th1 cells release interferon (IFN)-γ, promoting proinflammatory cytokines, while Th17 cells secrete IL-17, IL-22, and granulocyte-macrophage colony-stimulating factor (GM-CSF), contributing to synovial inflammation, bone and cartilage damage, and angiogenesis. RA concurrently exhibits features of Type II, Type III, and Type IV hypersensitivity. It is crucial to comprehend the presence and complex interplay of hypersensitivity responses and specific immune cell subsets in RA to create precise and efficient therapeutic approaches for the management of this incapacitating autoimmune condition. Thus, in this review, we aim to provide a comprehensive overview of the hypersensitivity features of RA.

Abstract Background Vaccine development against tuberculosis remains a global health imperative, necessitating robust immunogenicity and safety profiles. Nanoparticle-based delivery systems offer promising avenues to enhance vaccine efficacy while ensuring tolerability. This study explores the utilization of chitosan micelles as a delivery platform for immune complex vaccination against tuberculosis. Leveraging two key antigens of Mycobacterium tuberculosis, namely HspX and Mpt51, known for their relevance in latent tuberculosis and its co-infection with the human immunodeficiency virus, immune complexes were synthesized in vitro using antibodies raised against these antigens. The immune complexes were then conjugated onto chitosan micelles, characterized for their physicochemical properties, and evaluated for their biocompatibility and immunogenicity. Results Chitosan nanoparticles conjugated with either antigen or its immune complexes were synthesized as micelles and physicochemical characterizations confirm the formation of micelles without altering the polymer composition. These immune complex-conjugated chitosan micelles were found to be safe, exhibiting no significant hemolytic and cytotoxic activity even at a higher concentration of 400 µg/ml. Peripheral blood mononuclear cells upon stimulation with immune complex-conjugated chitosan micelles showed enhanced cellular uptake and one to two-fold increased expression of key immune markers—interferon gamma and CD-86. Conclusions These findings underscore the potential of chitosan nanoparticles as a versatile delivery platform for immune complex vaccination against tuberculosis. While limitations exist, such as including only two markers of immune modulation, this study lays a foundation for future investigations into immune complex vaccine potential in animal models. In conclusion, chitosan micelles carrying immune complexes of HspX and Mpt51 tuberculosis antigens exhibit promising immunogenicity, highlighting their potential as a platform for multi-antigenic vaccine components warranting further in vivo studies.

Type I hypersensitivity, also known as classical allergy, is mediated via allergen‐specific IgE antibodies bound to type I FcR (FcεRI) on the surface of mast cells and basophils upon cross‐linking by allergens. This IgE‐mediated cellular activation may be blocked by allergen‐specific IgG through multiple mechanisms, including direct neutralization of the allergen or engagement of the inhibitory receptor FcγRIIb which blocks IgE signal transduction. In addition, co‐engagement of FcεRI and FcγRIIb by IgE‐IgG‐allergen immune complexes causes down regulation of receptor‐bound IgE, resulting in desensitization of the cells. Both, activation of FcεRI by allergen‐specific IgE and engagement of FcγRIIb by allergen‐specific IgG are driven by allergen‐binding. Here we delineate the distinct roles of antibody affinity versus avidity in driving these processes and discuss the role of IgG subclasses in inhibiting basophil and mast cell activation. [ABSTRACT FROM AUTHOR]

Summary Antibodies are able to up‐ or downregulate antibody responses to the antigen they bind. Two major mechanisms can be distinguished. Suppression is most likely caused by epitope masking and can be induced by all isotypes tested (IgG1, IgG2a, IgG2b, IgG3, IgM, and IgE). Enhancement is often caused by the redistribution of antigen in a favorable way, either for presentation to B cells via follicular dendritic cells (IgM and IgG3) or to CD4+ T cells via dendritic cells (IgE, IgG1, IgG2a, and IgG2b). IgM and IgG3 complexes activate complement and are transported from the marginal zone to follicles by marginal zone B cells expressing complement receptors. IgE–antigen complexes are captured by CD23+ B cells in the blood and transported to follicles, delivered to CD8α+ conventional dendritic cells, and presented to CD4+ T cells. Enhancement of antibody responses by IgG1, IgG2a, and IgG2b in complex with proteins requires activating FcγRs. These immune complexes are captured by dendritic cells and presented to CD4+ T cells, subsequently helping cognate B cells. Endogenous feedback regulation influences the response to booster doses of vaccines and passive administration of anti‐RhD antibodies is used to prevent alloimmunization of RhD‐negative women carrying RhD‐positive fetuses. [ABSTRACT FROM AUTHOR]

IgA nephropathy (IgAN) is considered the most common primary glomerulonephritis worldwide with a predilection for Asian-Pacific populations and relative rarity in those of African descent. Perhaps 20%-50% of patients progress to kidney failure. The pathogenesis is incompletely understood. Mesangial deposition of immune complexes containing galactose-deficient IgA1 complexed with anti-glycan IgG or IgA antibodies results in mesangial cell activation and proliferation, inflammatory cell recruitment, complement activation, and podocyte damage. Diagnosis requires a biopsy interpreted by the Oxford criteria. Additional pathologic features include podocytopathy, thrombotic microangiopathy, and C4d staining. Biomarkers predicting adverse outcomes include proteinuria, reduced GFR, hypertension, and pathology. Acceptable surrogate endpoints for therapeutic trials include ongoing proteinuria and rate of eGFR decline. The significance of persisting hematuria remains uncertain. The mainstay of therapy is supportive, consisting of lifestyle modifications, renin-angiotensin inhibition (if hypertensive or proteinuric), sodium-glucose-transporter 2 inhibition (if GFR reduced or proteinuric), and endothelin-receptor antagonism (if proteinuric). Immunosuppression should be considered for those at high risk after maximal supportive care. Corticosteroids are controversial with the most positive results observed in Chinese. They carry a high risk of serious side effects. Similarly, mycophenolate may be most effective in Chinese. Other immunosuppressants are of uncertain benefit. Tonsillectomy appears efficacious in Japanese. Active areas of investigation include B-cell inhibition with agents targeting the survival factors BAFF and APRIL and complement inhibition with agents targeting the alternate pathway (Factors B and D), the lectin pathway (MASP-2), and the common pathway (C3 and C5). Hopefully soon, the who and the how of immunosuppression will be clarified, and kidney failure can be forestalled. [ABSTRACT FROM AUTHOR]

The most characteristic feature of membranous nephropathy (MN) is the presence of subepithelial electron dense deposits and the consequential thickening of the glomerular basement membrane. There have been great advances in the understanding of the destiny of immune complexes in MN by the benefit of experimental models represented by Heymann nephritis. Subepithelial immune complexes are formed in situ by autoantibodies targeting native autoantigens or exogenous planted antigens such as the phospholipase A2 receptor (PLA2R) and cationic BSA respectively. The nascent immune complexes would not be pathogenic until they develop into immune deposits. Podocytes are the major source of autoantigens in idiopathic membranous nephropathy. They also participate in the modulation and removal of the immune complexes to a large extent. The balance between deposition and clearance is regulated by a wide range of factors such as the composition and physicochemical properties of the immune complexes and the complement system. Complement components such as C3 and C1q have been reported to be precipitated with the deposits whereas a complement regulatory protein CR1 expressed by podocytes is involved in the phagocytosis of immune complexes by podocytes. Podocytes regulate the dynamic change of immune complexes which is disturbed in membranous nephropathy. To elucidate the precise fate of the immune complexes is essential for developing more rational and novel therapies for membranous nephropathy. [ABSTRACT FROM AUTHOR]

Atopic dermatitis (AD) is a common allergic inflammatory skin condition marked by severe itching, skin lichenification, and chronic inflammation. AD results from a complex immune response, primarily driven by T lymphocytes and environmental triggers, leading to a disrupted epidermal barrier function. Traditional treatments, such as topical corticosteroids, have limitations due to long-term side effects, highlighting the need for safer alternatives. Here, we aimed to show that Agrimonia coreana extract (ACext) can be used in treating AD-related dermatologic symptoms. ACext could inhibit CRAC (Calcium Release-Activated Calcium) channel activity, reducing Orai1/CRAC currents and decreasing intracellular calcium signaling. This inhibition was further confirmed by the reduced IL-2 levels and T cell proliferation upon ACext treatment. In a mouse model of AD, ACext significantly ameliorates symptoms, improves histological parameters, and enhances skin barrier function, demonstrating its potential for treating AD. [ABSTRACT FROM AUTHOR]

Background: Immunoglobulin (Ig) glycosylation modulates the immune response and plays a critical role in ageing and diseases. Studies have mainly focused on IgG glycosylation, and little is known about the genetics and epidemiology of IgA glycosylation. Methods: We generated, using a novel liquid chromatography-mass spectrometry method, the first large-scale IgA glycomics dataset in serum from 2423 twins, encompassing 71 N- and O-glycan species. Results: We showed that, despite the lack of a direct genetic template, glycosylation is highly heritable, and that glycopeptide structures are sex-specific, and undergo substantial changes with ageing. We observe extensive correlations between the IgA and IgG glycomes, and, exploiting the twin design, show that they are predominantly influenced by shared genetic factors. A genome-wide association study identified eight loci associated with both the IgA and IgG glycomes (ST6GAL1, ELL2, B4GALT1, ABCF2, TMEM121, SLC38A10, SMARCB1, and MGAT3) and two novel loci specifically modulating IgA O-glycosylation (C1GALT1 and ST3GAL1). Validation of our findings in an independent cohort of 320 individuals from Qatar showed that the underlying genetic architecture is conserved across ancestries. Conclusions: Our study delineates the genetic landscape of IgA glycosylation and provides novel potential functional links with the aetiology of complex immune diseases, including genetic factors involved in IgA nephropathy risk. [ABSTRACT FROM AUTHOR]

Lymphocytes are important for protective immunity against infections and cancers, and dysregulation of the immune system may lead to systemic lupus erythematosus (SLE). Metabolic adaptation regulates the fate of lymphocytes. The immune microenvironment is vital role in both SLE and gynecological malignancies. The disruption of the immune microenvironment in SLE is one of the key factors leading to disease occurrence. Overactive autoimmunity indices the body to attack its own tissues, leading to the formation of immune complexes that further trigger tissue damage and inflammation. This imbalance in the immune microenvironment affects the progression of SLE and may also indirectly affect the occurrence of gynecological cancers. For gynecological cancers, immune cells, cytokines, and chemokines in the tumor microenvironment jointly comprise a complex network, and their interactions determine cancer growth, invasion, and metastasis. Mendelian randomization analysis revealed that SLE does not have a statistically significant causal effect on the risk of common cancers of the female reproductive system such as cervical, endometrial, and ovarian cancers in the European population. However, the odds ratio < 1 in the inverse variance weighted results suggest the potential of SLE as a protective factor for endometrial cancer. [ABSTRACT FROM AUTHOR]

Background: Metabolic dysregulation following sepsis can significantly compromise patient prognosis by altering immune-inflammatory responses. Despite its clinical relevance, the exact mechanisms of this perturbation are not yet fully understood. Methods: Single-cell RNA sequencing (scRNA-seq) was utilized to map the immune cell landscape and its association with metabolic pathways during sepsis. This study employed cell-cell interaction and phenotype profiling from scRNA-seq data, along with pseudotime trajectory analysis, to investigate neutrophil differentiation and heterogeneity. By integrating scRNA-seq with Weighted Gene Co-expression Network Analysis (WGCNA) and machine learning techniques, key genes were identified. These genes were used to develop and validate a risk score model and nomogram, with their efficacy confirmed through Receiver Operating Characteristic (ROC) curve analysis. The model's practicality was further reinforced through enrichment and immune characteristic studies based on the risk score and in vivo validation of a critical gene associated with sepsis. Results: The complex immune landscape and neutrophil roles in metabolic disturbances during sepsis were elucidated by our in-depth scRNA-seq analysis. Pronounced neutrophil interactions with diverse cell types were revealed in the analysis of intercellular communication, highlighting pathways that differentiate between proximal and core regions within atherosclerotic plaques. Insight into the evolution of neutrophil subpopulations and their differentiation within the plaque milieu was provided by pseudotime trajectory mappings. Diagnostic markers were identified with the assistance of machine learning, resulting in the discovery of PIM1, HIST1H1C, and IGSF6. The identification of these markers culminated in the development of the risk score model, which demonstrated remarkable precision in sepsis prognosis. The model's capability to categorize patient profiles based on immune characteristics was confirmed, particularly in identifying individuals at high risk with suppressed immune cell activity and inflammatory responses. The role of PIM1 in modulating the immune-inflammatory response during sepsis was further confirmed through experimental validation, suggesting its potential as a therapeutic target. Conclusion: The understanding of sepsis immunopathology is improved by this research, and new avenues are opened for novel prognostic and therapeutic approaches. [ABSTRACT FROM AUTHOR]

Researchers have developed a new PROTAC degrader called L18I that targets Bruton's tyrosine kinase (BTK) for the treatment of autoimmune diseases. In experiments using lupus and diffuse alveolar hemorrhage (DAH) disease models, L18I effectively reduced lupus symptoms and showed inhibitory effects on B-cell activation and TLR signaling pathways. The article also discusses the potential use of L18I as a targeted drug for the treatment of DAH, a condition characterized by bleeding in the lungs. L18I was found to decrease immune cell infiltration and reduce the production of inflammatory cytokines, suggesting it could be a safer and more effective alternative to current therapies for DAH. [Extracted from the article]

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulopathy in our adult population and is associated with a high lifetime risk of kidney failure. Recent years have succeeded in describing the pathogenesis of IgAN at the molecular level, where immune complexes containing specific galactose deficient IgA1 play an essential role. The gold standard in the diagnosis of IgAN remains renal biopsy followed by determination of a prognostic score using the Oxford classification. A fundamental goal in the management of patients with IgAN is to optimize supportive therapy involving active lifestyle modification and renoprotective medications. The reno-protective drug menu has recently been expanded to include effective sodium-glucose cotransporter 2 inhibitors (SGLT2i), and additional agents are on the way. However, despite maximal supportive therapy, a wide range of patients remain at high risk of disease progression and require the deployment of immunomodulatory drugs. To date, however, we do not have high potency agents that are well tolerated and safe. This has led to the initiation of many studies to target the inflammatory process at different pathogenetic levels. In this article, we summarize the current standards in the treatment of IgAN and present new promising options in the management of this disease. [ABSTRACT FROM AUTHOR]

Immune complex (IC)-driven formation of neutrophil extracellular traps (NETs) is a major contributing factor to the pathogenesis of autoimmune diseases including systemic lupus erythematosus (SLE). Exogenous recombinant human serpin B1 (rhsB1) can regulate NET formation; however, its mechanism(s) of action is currently unknown as is its ability to regulate IC-mediated NET formation and other neutrophil effector functions. To investigate this, we engineered or posttranslationally modified rhsB1 proteins that possessed specific neutrophil protease inhibitory activities and pretreated isolated neutrophils with them prior to inducing NET formation with ICs derived from patients with SLE, PMA, or the calcium ionophore A23187. Neutrophil activation and phagocytosis assays were also performed with rhsB1 pretreated and IC-activated neutrophils. rhsB1 dose-dependently inhibited NET formation by all three agents in a process dependent on its chymotrypsin-like inhibitory activity, most likely cathepsin G. Only one variant (rhsB1 C344A) increased surface levels of neutrophil adhesion/activation markers on IC-activated neutrophils and boosted intracellular ROS production. Further, rhsB1 enhanced complement-mediated neutrophil phagocytosis of opsonized bacteria but not ICs. In conclusion, we have identified a novel mechanism of action by which exogenously administered rhsB1 inhibits IC, PMA, and A2138-mediated NET formation. Cathepsin G is a well-known contributor to autoimmune disease but to our knowledge, this is the first report implicating it as a potential driver of NET formation. We identified the rhsB1 C334A variant as a candidate protein that can suppress IC-mediated NET formation, boost microbial phagocytosis, and potentially impact additional neutrophil effector functions including ROS-mediated microbial killing in phagolysosomes. [ABSTRACT FROM AUTHOR]

IgA nephropathy (IgAN) is considered to be an autoimmune disease characterized by the formation of IgA1-containing immune complexes in the circulation and glomerular immunodeposits. Extensive research has identified multiple genetic, immunological, and environmental factors contributing to disease development and progression. The pathogenesis of IgAN is considered a multifactorial process involving the formation of immune complexes wherein aberrantly O-glycosylated IgA1 is recognized as an autoantigen. Consequently, the clinical presentation of IgAN is highly variable, with a wide spectrum of manifestations ranging from isolated microscopic hematuria or episodic macroscopic hematuria to nephrotic-range proteinuria. Whereas some patients may exhibit a slowly progressive form of IgAN, others may present with a rapidly progressive glomerulonephritis leading to kidney failure. Development of the treatment for IgAN requires an understanding of the characteristics of the pathogenic IgA1-containing immune complexes that enter the glomerular mesangium and induce kidney injury. However, not all details of the mechanisms involved in the production of galactose-deficient IgA1 and immune-complex formation are fully understood. Here, we review what we have learned about the characteristics of nephritogenic IgA1 in the half-century since the first description of IgAN in 1968. [ABSTRACT FROM AUTHOR]

Audiovestibular dysfunction in patients with systemic lupus erythematosus has been underestimated for decades. Systemic lupus erythematosus can affect both the auditory and vestibular systems simultaneously. Several potential pathophysiological mechanisms behind systemic lupus erythematosus-related audiovestibular dysfunction have been proposed, including antibody-mediated immune responses, cell-mediated cytotoxicity, immune complex deposition in microvessels, central involvement in the audiovestibular pathway, and ototoxicity from medications used in systemic lupus erythematosus treatment. Currently available tests to evaluate audiovestibular function in systemic lupus erythematosus patients are neither specific nor sensitive. Nevertheless, there is no consensus regarding the efficacy of treatments for audiovestibular dysfunction in such patients. In this systematic review, we electronically searched the PubMed, Embase, ClinicalKey, Web of Science, and ScienceDirect platforms to find eligible articles. The first inspection date was on 29 December 2023 and the final update search date was on 11 June 2024. Further, we rated the quality of the included articles with Newcastle–Ottawa Scale. Based upon the aforementioned systematic review process, we have summarized the currently available evidence on the characteristics, pathophysiology, examination, and treatment of audiovestibular dysfunction related to systemic lupus erythematosus. Furthermore, we have proposed a specific steroid treatment protocol to manage audiovestibular dysfunction related to systemic lupus erythematosus. Audiovestibular dysfunction related to systemic lupus erythematosus may be responsive to adequate treatments, potentially allowing for reversibility if the disease is recognized and managed in a timely manner. Therefore, to provide clinically relevant evidence to clinicians, we have organized this literature review article to summarize the available evidence on the characteristics, pathophysiology, examination, and treatment of audiovestibular dysfunction in patients with systemic lupus erythematosus. Finally, based on our modified steroid treatment protocol, we would like to provide a new treatment strategy to clinicians to manage systemic lupus erythematosus-related audiovestibular dysfunction. [ABSTRACT FROM AUTHOR]

Tissue repair and regeneration have long been a focus of research, with growing evidence highlighting the role played by immunomodulation. The repair of tissue cells can be significantly promoted through the localized immunomodulation of tissues. Hydrogels are increasingly used in this field due to their biocompatibility, versatility, and relative ease of fabrication. This Review highlights the critical role of inflammation and immune development in the complex process of tissue repair after injury, highlighting the dynamic interactions between immune cells that ultimately influence the outcome of tissue healing. We also summarize the precise functions of immune cells and their responses in various tissue injury scenarios, which are critical for harnessing the full potential of immunomodulatory strategies to promote tissue repair. We discuss recent advances in drug-carrying hydrogels, which offer promising avenues for tissue regeneration with precise control of the immune environment for constructive tissue repair. Further advances in our understanding of the mechanisms driving inflammation and immune cell behavior during tissue injury are expected to foster the development of increasingly effective hydrogel-based immunomodulatory strategies to promote tissue repair and regeneration. [ABSTRACT FROM AUTHOR]

Innate immunity is essential for the host against pathogens, cancer, and autoimmunity. The innate immune system encodes many sensor, adaptor, and effector proteins and relies on the assembly of higher-order signaling complexes to activate immune defense. Recent evidence demonstrates that many of the core complexes involved in innate immunity are organized as liquid-like condensates through a mechanism known as phase separation. Here, we discuss phase-separated condensates and their diverse functions. We compare the biochemical, structural, and mechanistic details of solid and liquid-like assemblies to explore the role of phase separation in innate immunity. We summarize the emerging evidence for the hypothesis that phase separation is a conserved mechanism that controls immune responses across the tree of life. The discovery of phase separation in innate immunity provides a new foundation to explain the rules that govern immune system activation and will enable the development of therapeutics to treat immune-related diseases properly. The discovery of liquid-liquid phase separation as a new form of regulation in innate immunity offers potential for future therapeutic strategies. Wang and Zhou explore recent advances that begin to address the main questions in the field and highlight the functions and principles of phase separation controlling innate immunity. [ABSTRACT FROM AUTHOR]

Background: Hyperactive neutrophil extracellular traps (NETs) formation plays a crucial role in active severe systemic lupus erythematosus (SLE). However, what triggers the imbalance in dysregulated NETs formation in SLE is elusive. Transfer RNA-derived small RNAs (tsRNAs) are novel non-coding RNAs, which participate in various cellular processes. We explore the role of tsRNAs on NETs formation in SLE. Methods: We analyzed the levels of NETs DNA and platelet-derived extracellular vesicles (pEVs) from 50 SLE patients and 20 healthy control subjects. The effects of pEVs on NETs formation were evaluated by using immunofluorescence assay and myeloperoxidase-DNA PicoGreen assay. The regulatory mechanism of pEVs on NETs formation and inflammatory cytokines production were investigated using an in vitro cell-based assay. Results: Increased circulating NETs DNA and pEVs were shown in SLE patients and were associated with disease activity (P < 0.005). We demonstrated that SLE patient-derived immune complexes (ICs) induced platelet activation, followed by pEVs release. ICs-triggered NETs formation was significantly enhanced in the presence of pEVs through Toll-like receptor (TLR) 8 activation. Increased levels of tRF-His-GTG-1 in pEVs and neutrophils of SLE patients were associated with disease activity. tRF-His-GTG-1 interacted with TLR8 to prime p47phox phosphorylation in neutrophils, resulting in reactive oxygen species production and NETs formation. Additionally, tRF-His-GTG-1 modulated NF-κB and IRF7 activation in neutrophils upon TLR8 engagement, resulting IL-1β, IL-8, and interferon-α upregulation, respectively. Conclusions: The level of tRF-His-GTG-1 was positively correlated with NETs formation in SLE patients; tRF-His-GTG-1 inhibitor could efficiently suppress ICs-triggered NETs formation/hyperactivation, which may become a potential therapeutic target. Plain English summary: Neutrophils and platelets are key members in the immunopathogenesis of SLE. EVs play a key role in intercellular communication. Abnormal NETs formation promotes vascular complications and organ damage in SLE patients. tsRNA is a novel regulatory small non-coding RNA and participates in diverse pathological processes. Herein, we showed that SLE patient-derived ICs activates platelets directly, followed by intracellular tRF-His-GTG-1 upregulation, which is loaded into pEVs. The pEV-carried tRF-His-GTG-1 could interact with TLR8 in neutrophils, followed by activation of the downstream signaling pathway, including p47phox-NOX2-ROS, which causes NETs enhancement, while IRF7 promotes the expression of IFN-α. The tRF-His-GTG-1 inhibitor could suppress efficiently SLE ICs-induced NETs formation and pEVs primed NETs enhancement. This study offers new molecular machinery to explain the association between the platelets-derived tsRNAs, pEVs, and hyperactive NETs formation in lupus. tRF-His-GTG-1 may serve as a potential therapeutic target and help to advance our understanding of tsRNAs in SLE pathogenesis. [ABSTRACT FROM AUTHOR]

Over the course of evolution, many proteins have undergone adaptive structural changes to meet the increasing homeostatic regulatory demands of multicellularity. Aminoacyl tRNA synthetases (aaRS), enzymes that catalyze the attachment of each amino acid to its cognate tRNA, are such proteins that have acquired new domains and motifs that enable non-canonical functions. Through these new domains and motifs, aaRS can assemble into large, multi-subunit complexes that enhance the efficiency of many biological functions. Moreover, because the complexity of multi-aminoacyl tRNA synthetase (mARS) complexes increases with the corresponding complexity of higher eukaryotes, a contribution to regulation of homeostatic functions in multicellular organisms is hypothesized. While mARS complexes in lower eukaryotes may enhance efficiency of aminoacylation, little evidence exists to support a similar role in chordates or other higher eukaryotes. Rather, mARS complexes are reported to regulate multiple and variegated cellular processes that include angiogenesis, apoptosis, inflammation, anaphylaxis, and metabolism. Because all such processes are critical components of immune homeostasis, it is important to understand the role of mARS complexes in immune regulation. Here we provide a conceptual analysis of the current understanding of mARS complex dynamics and emerging mARS complex roles in immune regulation, the increased understanding of which should reveal therapeutic targets in immunity and immune-mediated disease. [ABSTRACT FROM AUTHOR]