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Hepatitis B is an infectious disease resulting from infection with the hepatitis B virus. Chronic hepatitis B (CHB) is characterized by prolonged inflammation in the liver, the development of fibrosis, liver cirrhosis and hepatocellular carcinoma. Factors of the immune system play a critical role in the pathogenesis of CHB. Thanks to chemokines, immune cells migrate to the site of inflammation to implement their effector functions. The CX3CL1/Fractalkine chemokine is the only member of the CX3C family of chemokines with unique structural and functional properties. Its receptor CX3CR1 is expressed mainly on the surface of cytotoxic effector lymphocytes such as NK cells, TNK and cytotoxic T lymphocytes. The purpose of our study was to analyze the content of CX3CL1/Fractalkine in the blood plasma of patients with CHB and the analysis of this chemokine with liver fibrosis. The concentration of CX3CL1/Fractalkine was determined in the blood plasma of patients with CHB using a multiplex assay based on xMAP technology. Blood plasma from patients with chronic viral hepatitis C (CHC) and autoimmune liver diseases (AILD) was used as a comparison group. The control group consisted of healthy individuals. For statistical analysis of data, nonparametric statistics methods were used: Kruskal–Wallis test, Spearman correlation coefficient ROC-analysis. It was shown a reduced level of CX3CL1/Fractalkine in patients with CHB compared with the control group (p = 0.0003) and with the comparison groups of CHC (p 0.0001) and AILD (p = 0.0005). A reduced concentration of CX3CL1/Fractalkine was shown in the blood plasma of CHB patients with initial fibrosis (p = 0.0092) and severe fibrosis/cirrhosis (p = 0.0009), while in patients with severe fibrosis/cirrhosis, a significantly reduced level of this chemokine was established compared with the initial degree of liver fibrosis (p = 0.0081). Correlation analysis revealed a highly significant inverse relationship between the severity of liver fibrosis and the content of CX3CL1/Fractalkine in the blood plasma of patients with CHB (Spearman r = –0.33; p = 0.02). Thus, the chemokine CX3CL1/Fractalkine is included in the immunopathogenesis of CHB; its reduced content is characteristic only of CHB and does not change in other chronic liver diseases. It is involved in the processes of liver fibrosis during infection with the hepatitis B virus. The concentration of the chemokine CX3CL1/Fractalkine depends on the stage of liver fibrosis in CHB, and a decrease in the level of CX3CL1/Fractalkine in the blood plasma can serve as a negative factor in the development of CHB.

Relevance. Hemorrhagic fever with renal syndrome (HFRS) is a natural focal viral infection with a high probability of severe course, the possibility of death, a long recovery period after infection, low effectiveness of therapy and vaccine prevention. In the Russian Federation, HFRS is most often caused by the Puumala orthohantavirus. The aim of the study — to evaluate the immunophenotypic composition of lymphocytes and cytokine profile in the blood of patients with hemorrhagic feverwith renal syndrome in comparison with acute respiratory viral infections and with the prospect of developing immunological criteria for early diagnosis of HFRS. Matherials and Methods. There were examined the blood of 24 patients with a verified diagnosis of HFRS who were hospitalized in the infectious diseases department of the Samara Medical University Clinics and admitted in the first days of the disease, 18 patients with acute respiratory viral infections of established etiology, as well as 15 healthy people. Results and Discussion. Analysis of the results of lymphocyte phenotyping and cytokine levels in the blood revealed that the percentage of B lymphocytes in the blood was 12.6 %, cytotoxic CD8+ T lymphocytes expressing the activating lectin receptor NKG2D (CD3+CD8+CD314+), 25 %, regulatory T cells with CD3+CD4+FoxP3+ phenotypes 7.8 % and CD3+CD8+FoxP3+ 9.5 %, as well as IL-6 24 pg/ml, TNFß 55 pg/ml, IL-10 11.3 pg/ml with high diagnostic significance, judging by the results of ROC analysis, indicates in favor of GLPS, but not ARVI. Conclusion. The results obtained can be used as criteria for early immunodiagnosis of HFRS. The development of a new hypothesis on the mechanism of CD8+ immunological memory formation may contribute to the discovery of new potential targets for HFRS immunotherapy and the creation of new principles for the production of vaccine preparations for the prevention of this disease.

Aim. To develop and evaluate the effectiveness of complex therapy of vulvar lichen sclerosus (VLS), considering the clinical and immunological variant (CIV) of the disease. Materials and methods. A randomized prospective study included 292 patients 20-70 years old with different CIVs of the VLS course: atrophic (n=101), sclerosing (n=154), scleroatrophic (n=37), as well as 35 females with VLS in the comparison group of the same age category. Based on the clinical, immunological, and morphological features of the VLS course, a complex anti-relapse therapy was developed, the effectiveness of which was evaluated after a year of follow-up in comparison with the standard of care (SoC) of patients (from the comparison group) based on the number of disease relapses and the results of the Vulvar Quality of Life Index Questionnaire (VQLI) survey of women with vulvar diseases. Results. In patients with the sclerosing variant of VLS, short courses of topical glucocorticoids during exacerbations are justified; in patients with the scleroatrophic variant – topical calcineurin inhibitors, in the atrophic variant – a protein-peptide complex from porcine blood leukocytes (vaginal suppositories and cream-balsam with lanolin) containing interleukin-1, 6, tumor necrosis factor α, transforming growth factor, macrophage migration inhibitory factor. Patients with any variant of VLS are instructed to follow household and hygienic recommendations, use emollients daily, take prophylactic doses of vitamins A, E, and D to correct its deficiency or insufficiency, as well as use local enzyme therapy, as indicated, aimed at preventing or treatment of cicatricial changes. Local estrogens were prescribed only to women with genitourinary menopausal syndrome in the peri- and postmenopausal period. The developed complex anti-relapse therapy of VLS showed greater clinical efficacy compared to SoC: 3.7-fold decrease in episodes of disease exacerbation, as well as a significant (p=0.001) 1.3-fold decrease in the negative effect of VLS on the QoL of patients in the main clinical group (15.4 points according to the VQLI assessment – a mild effect on QoL) compared to SoC with the average score of 27.6, which corresponded to a strong negative effect of the disease on QoL. Conclusion. The results of the study support the distinction of VLS CIVs and the need to consider their features when choosing an effective therapy for the disease. Properly selected complex, supportive therapy of VLS can significantly increase the QoL of patients, minimize the number of relapses, and prevent the development of complications, including, probably, the risk of malignant transformation.

Abstract Background The role of pathogen genotype in determining disease severity and immunopathology has been studied intensively in microbial pathogens including bacteria, fungi, protozoa and viruses but is poorly understood in parasitic helminths. The medically important blood fluke Schistosoma mansoni is an excellent model system to study the impact of helminth genetic variation on immunopathology. Our laboratory has demonstrated that laboratory schistosome populations differ in sporocyst growth and cercarial production in the intermediate snail host and worm establishment and fecundity in the vertebrate host. Here, we (i) investigate the hypothesis that schistosome genotype plays a significant role in immunopathology and related parasite life history traits in the vertebrate mouse host and (ii) quantify the relative impact of parasite and host genetics on infection outcomes. Methods We infected BALB/c and C57BL/6 mice with four different laboratory schistosome populations from Africa and the Americas. We quantified disease progression in the vertebrate host by measuring body weight and complete blood count (CBC) with differential over a 12-week infection period. On sacrifice, we assessed parasitological (egg and worm counts, fecundity), immunopathological (organ measurements and histopathology) and immunological (CBC with differential and cytokine profiles) characteristics to determine the impact of parasite and host genetics. Results We found significant variation between parasite populations in worm numbers, fecundity, liver and intestine egg counts, liver and spleen weight, and fibrotic area but not in granuloma size. Variation in organ weight was explained by egg burden and intrinsic parasite factors independent of egg burden. We found significant variation between infected mouse lines in cytokine levels (IFN-γ, TNF-α), eosinophils, lymphocytes and monocyte counts. Conclusions This study showed that both parasite and host genotype impact the outcome of infection. While host genotype explains most of the variation in immunological traits, parasite genotype explains most of the variation in parasitological traits, and both host and parasite genotypes impact immunopathology outcomes. Graphical Abstract

Type I interferons (IFN-Is) are important players in the immunopathogenesis of systemic lupus erythematosus (SLE). Pathogenic events in patients with SLE are potent triggers of IFN-I induction, yet IFN-I may induce or initiate the immunopathogenesis leading to these events. Because blocking IFN-I is effective in some clinical manifestations of SLE patients, concerns about the efficacy of anti-IFN-I therapy in patients with lupus nephritis remain. Tissues from kidney biopsies of patients with lupus nephritis revealed infiltration of various immune cells and activation of inflammatory signals; however, their correlation with renal damage is not clear, which raises serious concerns about how critical the role of IFN-I is among the potential contributors to the pathogenesis of lupus nephritis. This review addresses several issues related to the roles of IFN-I in SLE, especially in lupus nephritis, including (1) the contribution of IFN-I to the development and immunopathogenesis of SLE; (2) evidence supporting the association of IFN-I with lupus nephritis; (3) therapies targeting IFN-I and IFN-I downstream signaling molecules in SLE and lupus nephritis; (4) findings challenging the therapeutic benefits of anti-IFN-I in lupus nephritis; and (5) a perspective associated with anti-IFN-I biologics for lupus nephritis treatment. In addition to providing clear pictures of the roles of IFN-I in SLE, especially in lupus nephritis, this review addresses the lately published observations and clinical trials on this topic.

Gyrovirus (GyV) is small, single-stranded circular DNA viruses that has recently been assigned to the family Anelloviridae. In the last decade, many GyVs that have an apparent pan-tropism at the host level were identified by high-throughput sequencing (HTS) technology. As of now, they have achieved global distribution. Several species of GyVs have been demonstrated to be pathogenic to poultry, particularly chicken anemia virus (CAV), causing significant economic losses to the global poultry industry. Although GyVs are highly prevalent in various birds worldwide, their direct involvement in the etiology of specific diseases and the reasons for their ubiquity and host diversity are not fully understood. This review summarizes current knowledge about GyVs, with a major emphasis on their morphofunctional properties, epidemiological characteristics, genetic evolution, pathogenicity, and immunopathogenesis. Additionally, the association between GyVs and various diseases, as well as its potential impact on the poultry industry, have been discussed. Future prevention and control strategies have also been explored. These insights underscore the importance of conducting research to establish a virus culture system, optimize surveillance, and develop vaccines for GyVs.

The adverse outcomes of fungal infection in mammalian hosts depend on the complex interactions between the host immune system and pathogen virulence-associated traits. The main clinical problems arise when the host response is either too weak to effectively eliminate the pathogen or overly aggressive, resulting in host tissue damage rather than protection. This article will highlight current knowledge regarding the virulence attributions and mechanisms involved in the dual-sided role of the host immune system in the immunopathogenesis of the thermally dimorphic fungus Talaromyces marneffei through the lens of the damage response framework (DRF) of microbial pathogenesis model.

The aim of the review is to give a brief characteristic of cell cultures obtained from mammalian tissues and to consider the current possibilities and prospects for their use in virology. The analysis of the literature data presented in the main databases, such as Web of Science, PubMed, Scopus, Elsevier, Google Scholar and RSCI (as of July 2023), indicates that various types of cell cultures are currently used in virological studies. The use of cell culture has a number of advantages over other in vitro and in vivo methods of virological research. The review provides numerous examples on the development of new methods of obtaining cell cultures for the cultivation of viruses. Among them are sensitive and reporter cell systems, the design of which can be a promising tool for diagnostics of existing and new unknown viral infections. Cell cultures are characterized as potential in vitro models in virology for developing new diagnostic test-systems and antiviral drugs. An important area of cell cultures application is their use as a substrate for the production of culture-derived vaccines. Another aspect of the cell cultures application is also highlighted, such as the study of the effect of the viruses on the host immune system or the mechanisms of immunopathogenesis of viral infections. It is concluded that the use of cell cultures remains currently and in the near future one of the most important methods in practical virology and in scientific research.

Abstract Communications between immune cells are essential to ensure appropriate coordination of their activities. Here, we observed the infiltration of activated macrophages into the joint-footpads of chikungunya virus (CHIKV)-infected animals. Large numbers of CD64+MHCII+ and CD64+MHCII- macrophages were present in the joint-footpad, preceded by the recruitment of their CD11b+Ly6C+ inflammatory monocyte precursors. Recruitment and differentiation of these myeloid subsets were dependent on CD4+ T cells and GM-CSF. Transcriptomic and gene ontology analyses of CD64+MHCII+ and CD64+MHCII- macrophages revealed 89 differentially expressed genes, including genes involved in T cell proliferation and differentiation pathways. Depletion of phagocytes, including CD64+MHCII+ macrophages, from CHIKV-infected mice reduced disease pathology, demonstrating that these cells play a pro-inflammatory role in CHIKV infection. Together, these results highlight the synergistic dynamics of immune cell crosstalk in driving CHIKV immunopathogenesis. This study provides new insights in the disease mechanism and offers opportunities for development of novel anti-CHIKV therapeutics.

Objectives: Chronic diarrhoea and severe wasting associated with HIV infection were first described in East African patients as slim disease (SD) in 1985. The main histological features are flattening of the villi (villous atrophy) and crypt hyperplasia (elongated crypts), i.e., HIV enteropathy (HIVE). Selective loss of mucosal clusters of differentiation 4 (CD4)+ T helper (Th)17+ lymphocytes is the immunological hallmark of HIVE. This review explores (i) the historical background of HIVE and SD, (ii) the relationship between gut mucosal CD4+ Th17+ and intestinal-resident intra-epithelial gamma delta (IRIE) T lymphocytes in pathogenesis of HIVE, (iii) the role of cytokines in regulation of intestinal epithelial proliferation, and (iv) the role of antiretroviral therapy in HIVE. Methods: Recent studies have highlighted the role of IRIE T lymphocytes, mostly CD8+, in regulating gut epithelial regeneration. CD4+Th17+ and IRIE T cells are necessary to maintain intestinal barrier integrity and mucosal antimicrobial immune defence. However, the immunological cross-talk between such lymphocyte sub-sets culminating in HIVE is uncertain. We undertook a narrative literature review under the headings ‘HIVE’, ‘SD’, and 'Highly active antiretroviral therapy (HAART). Relevant studies were located using the electronic search engines Google Scholar and PubMed from 1984 to 2022. Results: Depletion of Th17+ cells in the lamina propria, attributed to low-level viraemia, is accompanied by concomitant increase in the density of gut mucosal IRIE T lymphocytes in AIDS. The latter express a broad range of cytokines (interferon-gamma, tumor necrosis factor-alpha, interleukin-17) and chemokines e.g., keratinocyte growth factor, post exposure to HIV-infected cells. Keratinocyte growth factor induces epithelial proliferation mainly in the crypts, leading to functional immaturity of enterocytes, reduced gut absorptive surface area and malabsorption in animal experiments. Of note, the absence of IRIE T cells is associated with a reduction in epithelial cell turnover. Patients with HIVE receiving early HAART show enhanced expression of mucosal repair genes and improvement of gut symptoms. Conclusion: Multiple lines of enquiry suggest HIVE is directly related to HIV infection and is a consequence of perturbations in mucosal CD4+Th17+ and IRIE T lymphocytes. The pathological result is enterocyte immaturity and dysfunction. SD whose main features are malabsorption, diarrhoea and weight loss, is a severe clinical expression of HIVE. A better understanding of immuno-pathogenesis of HIVE opens a window of opportunity for the potential use of immunotherapy in HIV disease and other T cell-mediated enteropathies.

Helicobacter pylori infection is a well-established risk factor for the development of gastric cancer (GC). Understanding the immunopathogenesis underlying this association is crucial for developing effective preventive and therapeutic strategies. This narrative review comprehensively explores the immunopathogenesis of H. pylori-induced GC by delving into several key aspects, emphasizing the pivotal roles played by H. pylori virulence factors, including cytotoxin-associated gene A (cagA) and vacuolating cytotoxin A (vacA), blood group antigen-binding adhesin (babA), and sialic acid binding adhesin (sabA). Moreover, the review focuses on the role of toll-like receptors (TLRs) and cytokines in the complex interplay between chronic infection and gastric carcinogenesis. Finally, the study examines the association between H. pylori evasion of the innate and adaptive immune response and development of GC. A comprehensive understanding of the immunopathogenesis of H. pylori-induced GC is essential for designing targeted interventions to prevent and manage this disease. Further research is warranted to elucidate the intricate immune responses involved and identify potential therapeutic targets to improve patient outcomes.

Toxoplasma gondii (T. gondii) is a cosmopolitan protozoan parasite in humans and animals. It infects about 30 % of the human population worldwide and causes potentially fatal diseases in immunocompromised hosts and neonates. For this study, five English-language databases (ScienceDirect, ProQuest, Web of Science, PubMed, and Scopus) and the internet search engine Google Scholar were searched. This review was accomplished to draw a global perspective of what is known about the pathogenesis of T. gondii and various factors affecting it. Virulence and immune responses can influence the mechanisms of parasite pathogenesis and these factors are in turn influenced by other factors. In addition to the host's genetic background, the type of Toxoplasma strain, the routes of transmission of infection, the number of passages, and different phases of parasite life affect virulence. The identification of virulence factors of the parasite could provide promising insights into the pathogenesis of this parasite. The results of this study can be an incentive to conduct more intensive research to design and develop new anti-Toxoplasma agents (drugs and vaccines) to treat or prevent this infection. In addition, further studies are needed to better understand the key agents in the pathogenesis of T. gondii.

Introduction: Periodontitis is one of the most prevalent diseases occurring worldwide, and is caused by an imbalance of host immunological defenses and microbiome profile which occurs in the oral cavity. This imbalance leads to irregularity and uncontrolled activities of immune cells, resulting in over-reactivity of periodontopathogens and tissue destruction. To alleviate periodontitis, exact targeting of specific events involving particular cells could be a potential application of immunomodulatory agents. Phytochemical drug development targeting specific immunopathogenesis events could be a promising complementary, alternative approach to periodontal therapy. Objectives: This review aimed to explore various events involving a variety of cells in the immunopathogenesis of periodontitis in order to determine potential specific immunomodulation targets for future development of effective phytochemical drugs. Results: Immunopathogenesis of periodontitis contributes significantly to the disease onset and resolution. Various events occur during the disease development, which involve a variety of immune cells and mediators. Among these, neutrophils, cytokines and lymphocytes, especially Th17 cells, were reported to be the most relevant components in the disease pathogenesis. These components affect the initial responses to periodontopathogens, inhibit oxidative stress formation, control intercellular communication to enhance inflammation, and promote effector cells’ migration to induce alveolar bone resorption. Several phytochemical drugs were developed to cure periodontitis, however, the development of phytochemical immunomodulatory drugs to target specific events has not been realized. Conclusion: This review concluded that development of phytochemical immunomodulatory drugs to target particular events generated by neutrophils, pro-inflammatory cytokines and lymphocytes has tremendous potential to regulate and modulate the immunopathogenesis of periodontitis.

Mycosis fungoides (MF) is the most common subtype of Cutaneous T-Cell Lymphoma (CTCL). Patients with Skin of Color (SOC) may be disproportionately impacted by MF due to delayed diagnoses, limited research, and treatment differences. In this graphical review, we provide an overview of MF immunopathogenesis and demonstrate how it manifests differently in SOC patients. We also provide our hypothesis for why the disease process can result in a myriad of clinical presentations in SOC patients. Last, we provide a summary of current treatment options, highlighting ongoing clinical trials and opportunities to include SOC patients to promote health equity.

Cutaneous T-cell lymphoma (CTCL) serves as an umbrella term for numerous lymphomas that reside in or recirculate through the skin. One such systemic lymphoma is Sézary Syndrome (SS). Although SS is not as common in Skin of Color (SOC), minority patients presenting with the condition do have a different presentation than their White counterparts. In this graphical review, we provide an overview of SS immunopathogenesis and varying presentations. Additionally, a summary of current treatment options is provided, highlighting ongoing clinical trials and opportunities to include SOC patients to promote health equity. SOC patients often have poorer prognosis due to biological differences and health disparities resulting in delayed diagnosis. This exemplifies the potential advantages and promising solutions of precision medicine implementation. To this end, the impact and benefits of precision medicine are summarized.

SARS-CoV-2, responsible for COVID-19, shares 79% and 50% of its identity with SARS-CoV-1 and MERS-CoV, respectively. It uses the same main cell attachment and entry receptor as SARS-CoV-1, which is the ACE-2 receptor. However, key residues in the receptor-binding domain of its S-protein seem to give it a stronger affinity for the receptor and a better ability to hide from the host immune system. Like SARS-CoV-1 and MERS-CoV, cytokine storms in critically ill COVID-19 patients cause ARDS, neurological pathology, multiorgan failure, and increased death. Though many issues remain, the global research effort and lessons from SARS-CoV-1 and MERS-CoV are hopeful. The emergence of novel SARS-CoV-2 variants and subvariants raised serious concerns among the scientific community amid the emergence of other viral diseases like monkeypox and Marburg virus, which are major concerns for healthcare settings worldwide. Hence, an updated review on the comparative analysis of various coronaviruses (CoVs) has been developed, which highlights the evolution of CoVs and their repercussions.

Ankylosing spondylitis (AS) is a chronic inflammatory disorder characterized by inflammatory back pain and bony fusion of vertebral joints. Genetic associations and environmental factors have been proposed to explain the immunopathogenesis of AS. In the past few years, there have been major advances in understanding T cell dysfunction in AS. Clinically, targeting interleukin-17A, a major cytokine secreted by T helper 17 cells, has been approved for treating patients with active AS. Non-coding RNAs (ncRNAs) are RNA transcripts that do not translate into proteins. The ncRNAs regulate both innate and adaptive immunity and participate in the pathogenesis of autoimmune diseases, including AS. The main purpose of this article is to review the up-to-date studies investigating the aberrant expression of ncRNAs in T cells from patients with AS and to summarize their roles in its pathogenesis. After searching PubMed for studies published between January 2013 and June 2024, nine studies investigating the expression of ncRNAs in AS T cells were included. We found that aberrantly expressed ncRNAs in AS T cells could cause abnormal cytokine release, cell signaling abnormalities, and dysregulated cell proliferation and death, which contribute to the immunopathogenesis of AS. We discussed some limitations of these studies and suggested several research fields for further investigation.

African swine fever (ASF) caused by the African swine fever virus (ASFV) is a fatal and highly contagious disease of domestic pigs characterized by rapid disease progression and death within 2 weeks. How the immune cells respond to acute ASFV infection and contribute to the immunopathogenesis of ASFV has not been completely understood. In this study, we examined the activation, apoptosis, and functional changes of distinct immune cells in domestic pigs following acute infection with the ASFV CADC_HN09 strain using multicolor flow cytometry. We found that ASFV infection induced broad apoptosis of DCs, monocytes, neutrophils, and lymphocytes in the peripheral blood of pigs over time. The expression of MHC class II molecule (SLA-DR/DQ) on monocytes and conventional DCs as well as CD21 expression on B cells were downregulated after ASFV infection, implying a potential impairment of antigen presentation and humoral response. Further examination of CD69 and ex vivo expression of IFN-γ on immune cells showed that T cells were transiently activated and expressed IFN-γ as early as 5 days post-infection. However, the capability of T cells to produce cytokines was significantly impaired in the infected pigs when stimulated with mitogen. These results suggest that the adaptive cellular immunity to ASFV might be initiated but later overridden by ASFV-induced immunosuppression. Our study clarified the cell types that were affected by ASFV infection and contributed to lymphopenia, improving our understanding of the immunopathogenesis of ASFV.

Aim to evaluate the pathogenetic role of T-lymphocytes carrying the natural killer marker CD56 in hemorrhagic fever with renal syndrome (HFRS). Material and methods. The study group included 65 patients with HFRS receiving the inpatient treatment in the Clinics of SamSMU, and 15 healthy people were chosen for the control group. The following examinations were scheduled for all patients in the different stages of the disease: a clinical blood test, flow cytometry with a given set of monoclonal antibodies, enzyme-linked immunosorbent assay of blood serum to determine the cytokine profile. For statistical analysis we used the SPSS v.23 software. Results. The percentage of CD3+ CD56+ NKT blood content in comparison with those for cells of innate immunity (neutrophil granulocytes, monocytes, natural killers) and lymphocytes of adaptive immune response, as well as the level of cytokines in the blood serum showed that in polyuric and convalescent periods, the number of these cells significantly increases and remains closely embedded in correlations with other components of the immune system. Conclusion. A new hypothesis has been proposed to interpret the role of NKT in the development of the immune response in HFRS.

Alopecia areata (AA) is an autoimmune-mediated disorder in which the proximal hair follicle (HF) attack results in non-scarring partial to total scalp or body hair loss. Despite the growing knowledge about AA, its exact cause still needs to be understood. However, immunity and genetic factors are affirmed to be critical in AA development. While the genome-wide association studies proved the innate and acquired immunity involvement, AA mouse models implicated the IFN-γ- and cytotoxic CD8+ T-cell-mediated immune response as the main drivers of disease pathogenesis. The AA hair loss is caused by T-cell-mediated inflammation in the HF area, disturbing its function and disrupting the hair growth cycle without destroying the follicle. Thus, the loss of HF immune privilege, autoimmune HF destruction mediated by cytotoxic mechanisms, and the upregulation of inflammatory pathways play a crucial role. AA is associated with concurrent systemic and autoimmune disorders such as atopic dermatitis, vitiligo, psoriasis, and thyroiditis. Likewise, the patient’s quality of life (QoL) is significantly impaired by morphologic disfigurement caused by the illness. The patients experience a negative impact on psychological well-being and self-esteem and may be more likely to suffer from psychiatric comorbidities. This manuscript aims to present the latest knowledge on the pathogenesis of AA, which involves genetic, epigenetic, immunological, and environmental factors, with a particular emphasis on immunopathogenesis.

Plasmodium falciparum and Plasmodium vivax are two major species of malaria that can establish a focus of infection in millions of individuals per year. Principally, this occurs in the tropical and subtropical regions of the world where malaria is endemic due to the ubiquity of the disease vector, the Anopheles mosquitos. Malaria takes the lives of thousands of infected individuals as the progression of disease symptoms having fatal consequences. This disease mainly affects children and pregnant women which poses a great public health concern. It is also a global economic burden from the millions of international dollars are aliquoted for research yearly. This review looks to discuss the pathogenesis of malaria, various host immune responses, the development of clinical immunity in reinfected individuals, and the effects that the presence of one species may have on the pathogenesis and disease outcome of another malarial species in co-infected individuals. Overall, this manuscript aims to provide an understanding of malarial infection and the differing host immune mechanisms of previously exposed individuals compared to those of naïve individuals in environments where malaria is of high prevalence. These highlights indicate a need for further research in order to better understand host-species and species-species interactions so that proper therapeutics and vaccinations may be developed as to not inhibit the beneficial effects species may have on one another in mixed species interactions as well as to aid in the development of clinical immunity.

The aim of the work is to determine the relationship between the levels of cytokines of proinflammatory and anti-inflammatory action during the clinical course of hemorrhagic fever with renal syndrome (HFRS) and the previously described characteristics of the phenotypic composition of blood lymphocytes in disease of various severity. Materials and methods. 65 patients with a serologically verified diagnosis of HFRS were under observation. The control group included 15 conditionally healthy people. Determination of cytokines in the blood of patients with HFRS was carried out by the enzyme immunoassay method at the different stages of the disease. The phenotypic composition of blood lymphocytes was assessed by flow cytofluorimetry. Results. At the different stages of the disease, there was a quantitatively different increase in the content of cytokines in the blood associated with cytotoxic immune reactions (IL-12, IFN, TNFa, TNF), as well as IL-10 and IL-6 correlated with each other in severe cases, against the background of a drop in blood levels of IL-4 and IL-1. In the moderate course of HFRS, correlations of IL-12 and IL-4 with NKG2D+ CTL, the relationship of IL-12 with almost all other cytokines, and the correlation of CD8+ Treg with IL-6 and TNF levels were observed. In severe cases, the formation of a complex that included interconnected IL-6 and IL-10 correlating with the number of NKG2D+ CTL, CD8+ Treg, NKT was noted. Conclusion. The pathogenetically significant mechanism of HFRS is realized with the predominant participation of cytokines of the cellular immune response and IL-6, correlatively associated with NKG2D+ CTL, CD8+ Treg, NKT, which, in case of a favorable outcome, contribute to the active formation of a pool of CD8+ memory cells, disrupted presumably by excessive secretion of IL-10.

Tina Bhutani,1,* Jason E Hawkes2,* 1Psoriasis and Skin Treatment Center, Department of Dermatology, University of California at San Francisco, San Francisco, CA, USA; 2Department of Dermatology, University of California at Davis, Sacramento, CA, USA*Both authors contributed equally to this paperCorrespondence: Dr. Jason E Hawkes, Email hawkes3@gmail.comAbstract: Generalized pustular psoriasis is a rare presentation of psoriatic disease and is characterized by the acute onset of diffuse superficial pustules on the skin. These pustules can often coalesce, forming what’s known as ‘lakes of pus’ that are most often seen on the trunk and on skin folds. GPP flares are often accompanied by systemic symptoms, including fever, malaise, and edema. The interleukin (IL)-36 pathway plays a central role in the development of GPP, although several other genes may be associated. The rarity of GPP makes its diagnosis challenging and it could be mistaken for an infectious condition or other types of pustular psoriasis, including unstable forms of plaque psoriasis that may present with pustules. Performing a thorough skin examination and obtaining a detailed history are vital to exclude these differential diagnoses. Incorrect or late diagnosis, inadequate or delayed treatment, and lack of specialist referrals may contribute to increased disease severity and can have a debilitating impact on patients’ quality of life. In this podcast, two US-based dermatologists discuss the clinical characteristics of GPP, highlight the central role of IL-36 in immunopathogenesis, and share practical approaches to recognizing and diagnosing the disease.Keywords: Diagnosis, generalized pustular psoriasis, genetics, immunopathogenesis, interleukin-36 pathway, quality of life

Atopic dermatitis (AD) is a recurrent, chronic, inflammatory, itchy skin disorder that affects up to 20% of the pediatric population and 10% of the adult population worldwide. Onset typically occurs early in life, and although cardinal disease features are similar across all ages, different age groups and ethnicities present distinct clinical characteristics. The disease imposes a significant burden in all health-related quality of life domains, both in children and adults, and a substantial economic cost both at individual and national levels. The pathophysiology of AD includes a complex and multifaceted interplay between the impaired dysfunctional epidermal barrier, genetic predisposition, and environmental contributors, such as chemical and/or biological pollutants and allergens, in the context of dysregulated TH2 and TH17 skewed immune response. Regarding the genetic component, the loss of function mutations encoding structural proteins such as filaggrin, a fundamental epidermal protein, and the more recently identified variations in the epidermal differentiation complex are well-established determinants resulting in an impaired skin barrier in AD. More recently, epigenetic factors have facilitated AD development, including the dysbiotic skin microbiome and the effect of the external exposome, combined with dietary disorders. Notably, the interleukin (IL)-31 network, comprising several cell types, including macrophages, basophils, and the generated cytokines involved in the pathogenesis of itch in AD, has recently been explored. Unraveling the specific AD endotypes, highlighting the implicated molecular pathogenetic mechanisms of clinically relevant AD phenotypes, has emerged as a crucial step toward targeted therapies for personalized treatment in AD patients. This review aims to present state-of-the-art knowledge regarding the multifactorial and interactive pathophysiological mechanisms in AD.

Behcet’s disease (BD) is a chronic multi-systemic disease characterized by relapsing-remitting oral ulcers, genital ulcers, ocular inflammatory involvements, and numerous other systemic features. Ocular involvements are quite common in BD and may cause severe tissue damage and potentially blindness. Even though the pathogenesis of BD remains ambiguous, growing evidences have shown that genetic factors, environmental triggers and immunological abnormalities play significant roles in its development and progression. Novel biotherapies targeting IFN-γ, TNF-α and interleukins have been used in recent years. In this review, we mainly pay attention to the ocular involvement of BD, and discuss the current understanding of mechanisms and advances in therapeutic approaches, especially novel biologics. Finally, we discuss the management in patients with pregnancy.

IntroductionKawasaki disease (KD) is an acute febrile illness primarily affecting children and characterized by systemic inflammation and vasculitis that can lead to coronary artery complications. The aim of this study was to gain a comprehensive understanding of immune dysregulation in KD.MethodsTo this end, we employed integration of single-cell RNA sequencing (scRNA-Seq) and bulk RNA sequencing (bulk RNA-Seq) data. Furthermore, we conducted flow cytometry analysis for a cohort of 82 KD patients.ResultsOur analysis revealed significant heterogeneity within immune cell populations in KD patients, with distinct clusters of T cells, B cells, and natural killer (NK) cells. Importantly, CD4+ naïve T cells in KD patients were found to predominantly differentiate into Treg cells and Th2 cells, potentially playing a role in the excessive inflammation and vascular damage characteristic of the disease. Dysregulated signaling pathways were also identified, including the mTOR signaling pathway, cardiomyopathy pathway, COVID-19 signaling pathway, and pathways involved in bacterial or viral infection.DiscussionThese findings provide insights into the immunopathogenesis of KD, emphasizing the importance of immune cell dysregulation and dysregulated signaling pathways. Integration of scRNA-Seq and bulk RNA-Seq data offers a comprehensive view of the molecular and cellular alterations in KD and highlights potential therapeutic targets for further investigation. Validation and functional studies are warranted to elucidate the roles of the identified immune cell types and pathways in KD pathogenesis and to develop targeted interventions to improve patient outcomes.

ABSTRACT Canine distemper virus (CDV) causes systemic infection resulting in severe and often fatal disease in a large spectrum of animal host species. The virus is closely related to measles virus and targets myeloid, lymphoid, and epithelial cells, but CDV is more virulent and the infection spreads more rapidly within the infected host. Here, we aimed to study the pathogenesis of wild-type CDV infection by experimentally inoculating ferrets with recombinant CDV (rCDV) based on an isolate directly obtained from a naturally infected raccoon. The recombinant virus was engineered to express a fluorescent reporter protein, facilitating assessment of viral tropism and virulence. In ferrets, this wild type-based rCDV infected myeloid, lymphoid, and epithelial cells, and the infection resulted in systemic dissemination to multiple tissues and organs, especially those of the lymphatic system. High infection percentages in immune cells resulted in depletion of these cells both from circulation and from lymphoid tissues. The majority of CDV-infected ferrets reached their humane endpoints within 20 d and had to be euthanized. In that period, the virus also reached the central nervous system in several ferrets, but we did not observe the development of neurological complications during the study period of 23 d. Two out of 14 ferrets survived CDV infection and developed neutralizing antibodies. We show for the first time the pathogenesis of a non-adapted wild type-based rCDV in ferrets. IMPORTANCE Infection of ferrets with recombinant canine distemper virus (rCDV) expressing a fluorescent reporter protein has been used as proxy to understand measles pathogenesis and immune suppression in humans. CDV and measles virus use the same cellular receptors, but CDV is more virulent, and infection is often associated with neurological complications. rCDV strains in current use have complicated passage histories, which may have affected their pathogenesis. Here, we studied the pathogenesis of the first wild type-based rCDV in ferrets. We used macroscopic fluorescence to identify infected cells and tissues; multicolor flow cytometry to determine viral tropism in immune cells; and histopathology and immunohistochemistry to characterize infected cells and lesions in tissues. We conclude that CDV often overwhelmed the immune system, resulting in viral dissemination to multiple tissues in the absence of a detectable neutralizing antibody response. This virus is a promising tool to study the pathogenesis of morbillivirus infections.

Abstract Immune dysregulation has been identified as a critical cause of the most common types of cardiovascular diseases (CVDs). Notably, the innate and adaptive immune responses under physiological conditions are typically regulated with high sensitivity to avoid the exacerbation of inflammation, but any dysregulation can probably be associated with CVDs. In this respect, progranulin (PGRN) serves as one of the main components of the regulation of inflammatory processes, which significantly contributes to the immunopathogenesis of such disorders. PGRN has been introduced among the secreted growth factors as one related to wound healing, inflammation, and human embryonic development, as well as a wide variety of autoimmune diseases. The relationship between the serum PGRN and TNF-α ratio with the spontaneous bacterial peritonitis constitute one of the independent predictors of these conditions. The full-length PGRN can thus effectively reduce the calcification of valve interstitial cells, and the granulin precursor (GRN), among the degradation products of PGRN, can be beneficial. Moreover, it was observed that, PGRN protects the heart against ischemia-reperfusion injury. Above all, PGRN also provides protection in the initial phase following myocardial ischemia-reperfusion injury. The protective impact of PGRN on this may be associated with the early activation of the PI3K/Akt signaling pathway. PGRN also acts as a protective factor in hyperhomocysteinemia, probably by down-regulating the wingless-related integration site Wnt/β-catenin signaling pathway. Many studies have further demonstrated that SARS-CoV-2 (COVID-19) has dramatically increased the risks of CVDs due to inflammation, so PGRN has drawn much more attention among scholars. Lysosomes play a pivotal role in the inflammation process, and PGRN is one of the key regulators in their functioning, which contributes to the immunomodulatory mechanism in the pathogenesis of CVDs. Therefore, investigation of PGRN actions can help find new prospects in the treatment of CVDs. This review aims to summarize the role of PGRN in the immunopathogenesis of CVD, with an emphasis on its treatment.

To date, despite significant advances in the study of the immunopathogenesis of chronic hepatitis C (CHC), many open questions remain in the diagnosis, prediction and course of treatment. In the context of the study of this infection, the Toll-like gene family of innate immune system receptors (TLRs) is of considerable interest. The article analyzes and summarizes the data of professional scientific sources on the role of the TLR-4 gene in the functioning of the natural human immune system, as well as Asp299Gly polymorphism of this gene in the immunopathogenesis of CHC. The relevance of the study is due to the fact that the innate immune system is crucial in the primary protection of the macroorganism from pathogens, the recognition of which largely depends on the TLRs receptor gene family, and genetic analysis is a modern and promising direction in personalized medicine. The importance of determining genetic markers lies in the fact that regardless of age and other factors of the external and internal environment, they carry information about the predisposition to various diseases, which can be used in the formation of a genetic passport. The data concerning the influence of the Asp299Gly polymorphism of the TLR4 gene on the immunopathogenesis of CHC are contradictory and require further investigation. An in-depth study of this issue will improve the therapeutic and diagnostic tactics of this disease based on a comprehensive assessment of the features of the immune response, which are caused by the carriage of the indicated polymorphism in the human genome.

Candida auris has globally emerged as a multidrug-resistant fungus linked to healthcare-associated outbreaks. There is still limited evidence on its virulence, pathogenicity determinants, and complex host–pathogen interactions. This study analyzes the in vivo fungal behaviour, immune response, and host–pathogen interactions upon C. auris infection compared to C. albicans and C. parapsilosis in G. mellonella. This was performed by immunolabelling fungal structures and larval plasmatocytes and using a quantitative approach incorporating bioinformatic morphometric techniques into the study of microbial pathogenesis. C. auris presents a remarkably higher immunogenic activity than expected at its moderate degree of tissue invasion. It induces a greater inflammatory response than C. albicans and C. parapsilosis at the expense of plasmatocyte nodule formation, especially in non-aggregative strains. It specifically invades the larval respiratory system, in a pattern not previously observed in other Candida species, and presents inter-phenotypic tissue tropism differences. C. auris filaments in vivo less frequently than C. albicans or C. parapsilosis mostly through pseudohyphal growth. Filamentation might not be a major pathogenic determinant in C. auris, as less virulent aggregative phenotypes form pseudohyphae to a greater extent. C. auris has important both interspecific and intraspecific virulence and phenotype heterogeneity, with aggregative phenotypes of C. auris sharing characteristics with low pathogenic species such as C. parapsilosis. Our work suggests that C. auris owns an important morphogenetic plasticity that distinguishes it from other yeasts of the genus. Routine phenotypic identification of aggregative or non-aggregative phenotypes should be performed in the clinical setting as it may impact patient management.

Background: Oral lichen planus is a chronic inflammatory condition that only involves in the oral cavity and is mediated by the cellular immune system. The etiology of OLP is unclear but autoreactive T lymphocytes are considered to play an important role in the development of OLP. Factors like stress and psychological anxiety have been associated with OLP but their roles in the development of OLP is yet explored. Purpose: To describe stress-induced OLP immunopathogenesis and therapeutic potential. Reviews: In the early stages, the mechanism of OLP involves the expression of keratinocyte antigens or exposure to an antigen in the form of self-peptide or heat shock protein (HSP). HSP90 is the most expressed heat shock protein in the basal layer of keratinocytes and plays a role in recruitment of cellular immune cells through the production of cytokines due to TLR2/4 and CD91 activation, inflammatory cell migration due to 4 integrin activation, and increased antigen presentation due to HSP90-peptide binding to MHC class I/II. Stress as a physiological response triggers the release of the hormone cortisol from the adrenal cortex and catecholamine hormones such as epinephrine/ adrenaline and norepinephrine/noradrenaline from the adrenal medulla. Catecholamines increase the migration of T lymphocyte cells through the interaction of integrins and integrin ligands on the endothelium through the expression of 2-integrin after binding to adrenergic receptors on the cell membrane. Conclusion: Oral lichen planus is a chronic inflammatory condition caused by various factors where stress increases the migration of T lymphocyte cells on the side that expresses self-peptides and antigens through the interaction of immune cells with catecholamines. Topical nonselective beta blockers can be supporting therapy in reducing pain and size of OLP lesions.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a contagious respiratory virus that is the cause of the coronavirus disease 2019 (COVID-19) pandemic which has posed a serious threat to public health. COVID-19 is characterized by a wide spectrum of clinical manifestations, ranging from asymptomatic infection to mild cold-like symptoms, severe pneumonia or even death. Inflammasomes are supramolecular signaling platforms that assemble in response to danger or microbial signals. Upon activation, inflammasomes mediate innate immune defense by favoring the release of proinflammatory cytokines and triggering pyroptotic cell death. Nevertheless, abnormalities in inflammasome functioning can result in a variety of human diseases such as autoimmune disorders and cancer. A growing body of evidence has showed that SARS-CoV-2 infection can induce inflammasome assembly. Dysregulated inflammasome activation and consequent cytokine burst have been associated with COVID-19 severity, alluding to the implication of inflammasomes in COVID-19 pathophysiology. Accordingly, an improved understanding of inflammasome-mediated inflammatory cascades in COVID-19 is essential to uncover the immunological mechanisms of COVID-19 pathology and identify effective therapeutic approaches for this devastating disease. In this review, we summarize the most recent findings on the interplay between SARS-CoV-2 and inflammasomes and the contribution of activated inflammasomes to COVID-19 progression. We dissect the mechanisms involving the inflammasome machinery in COVID-19 immunopathogenesis. In addition, we provide an overview of inflammasome-targeted therapies or antagonists that have potential clinical utility in COVID-19 treatment.

Alopecia areata is an autoimmune disease characterized by non-scarring hair loss with preservation of the hair follicle. Hair loss in alopecia areata can be either focal with the appearance of clearly defined foci of alopecia, or diffuse or complete hair loss in any area of the skin where hair follicles are present. Data on the role of food allergy in the development of alopecia areata and the nature of the sensitization spectrum are extremely scarce. Objective: to study the features of the spectrum of sensitization to food and pollen (cross-reacting) allergens in patients with alopecia areata.The study involved patients with alopecia areata (n = 17), who were divided into groups according to age: group 1 — children (n = 9) and group 2 — adults (n = 8). All patients underwent a specific allergological examination: collection of an allergic history, skin prick testing with food and pollen allergens (Allergopharma, Germany).Analysis of the spectrum of sensitization to food allergens in patients with alopecia areata revealed features depending on their age. Thus, in the group of sick children, the highest frequency of sensitization to whole chicken eggs, food cereals, yeast, soybeans and cow's milk proteins was noted. In the group of sick adults, the most significant food allergens were: egg protein, rye flour, oats. Among the pollen allergens in the first group of patients, the most common allergens were a mixture of weed and grass pollen, in the second group, a mixture of meadow grass pollen. All patients, taking into account allergological testing, were administered an individual elimination diet with the exclusion of causally significant allergens, taking into account crossreacting allergens. The elimination effect was assessed 2 months after the start of the elimination diet. 70% of patients showed a clinical improvement, i.e., the growth of vellus was noted (vellus depigmented hair) in the foci of alopecia, as well as terminal pigmented hair. Complete regression of alopecia foci occurred on average within 3-6 months from the start of therapy.The sensitization to food and pollen (cross-reacting) allergens in patients with alopecia areata and the positive effect of the elimination diet revealed in our study well supports the role of food allergy in the development of this disorder. Therefore, the study of the causal relationship between food allergy and alopecia areata is of particular relevance and creates prerequisites for the discovery of new diagnostic and therapeutic options.

Introduction. The immunopathogenesis of the novel coronavirus infection COVID-19 is usually associated with the development of imbalance in the immune response to its causative agent, SARS-CoV-2 virus (Coronaviridae: Coronavirinae: Betacoronavirus: Sarbecovirus). This is manifested, in particular, by interferons’ (IFNs) deficiency at the beginning of the disease followed by hyperproduction of pro-inflammatory cytokines. The virus causes a decrease in IFN types I (α/β) and III (λ) levels; changes in IFN type II (γ) are less studied. In this regard, it is relevant to assess the functional bioactive IFN (interferon status) in COVID-19. The aim of the study was to assess the antiviral potential of the body by testing the biologically active IFNs in COVID-19. Material and methods. We used biological serum samples of COVID-19 patients taken in the acute phase (110 patients on the 1–5 days of the disease) and during rehabilitation (47 patients during 1–3 months after the disease onset). Assessment of interferon status was performed according to the technique developed by the authors and described earlier. Results. The IFN status of patients with COVID-19 in the acute period and in the phase of post-infection rehabilitation was studied during the observation period. It was found that SARS-CoV-2 causes a pronounced inhibition of biological activity of IFN types I and II compared to the reference values by more than 20 and 7 times, respectively. During the post-COVID period, incomplete recovery of the IFN system activity was registered, which proceeded very slowly. No cases of reaching physiological indicators of interferon status were identified during the observation period. Conclusion. The obtained data on deficiency of the functional biologically active IFN confirm the hypothesis about the predominant role of impaired IFN production of different types in the immunopathogenesis of the novel coronavirus infection.

The immune response to invading pathogens is characterized by the rapid establishment of a complex network of cellular interactions and soluble signals. The correct balancing of activating and regulating pathways and tissue-homing signals determines its effectiveness and persistence over time. Emerging viral pathogens have always represented a great challenge to the immune system and an often uncontrolled/imbalanced immune response has been described (e.g. cytokine storm, immune paralysis), contributing to the severity of the disease. Several immune biomarkers and cell subsets have been identified as major players in the cascade of events leading to severe diseases, highlighting the rationale for host-directed intervention strategy. There are millions of immunocompromised pediatric and adult patients worldwide (e.g. transplant recipients, hematologic patients, subjects with primary immune-deficiencies), experiencing an impaired immune reactivity, due to diseases and/or to the medical treatments. The reduced immune reactivity could have two paradoxical non-exclusive effects: a weak protective immunity on one hand, and a reduced contribution to immune-mediated pathogenetic processes on the other hand. In these sensitive contexts, the impact of emerging infections represents a still open issue to be explored with several challenges for immunologists, virologists, physicians and epidemiologists. In this review, we will address emerging infections in immunocompromised hosts, to summarize the available data concerning the immune response profile, its influence on the clinical presentation, the possible contribution of persistent viral shedding in generating new viral variants with improved immune escape features, and the key role of vaccination.

Psoriasis is a chronic disabling complex inflammatory disorder prevalent worldwide with environmental and genetic components that involve predominantly skin in addition to nails and joints associated with various systemic comorbidities having periods of exacerbations and remissions. Psoriasis is characterized by hyper-proliferation as well as abnormal differentiation of epidermal keratinocytes and lymphocyte infiltration (mainly T cells) with resultant inflammatory cytokines and chemokines. Immunological and genetic studies over the last decade have identified genetic susceptibility risk alleles, molecular, cellular and immunological mechanisms involved in immunopathogenesis of psoriasis. The current disease model emphasizes the role of aberrant Th1 and Th17 responses regulated by a complex network of different cytokines, including TNF-α, IL-17 and IL-23; signal transduction pathways downstream to the cytokine receptors; and various activated transcription factors, including NF-κB, interferon regulatory factors and signal transducer and activator of transcriptions. Cytokines targeting biologics (IL-17, IL-23 and TNFα) therapies have revolutionized the management of severe skin disease having beneficial effects on joints and systemic inflammation of psoriasis as well. Further better understanding of immunopathogenesis of psoriasis will pave way for precision medicine based on specific immunopathogenic targets in a given phenotype of disease. Complex interplay of psoriasis with associated comorbidities is also a future area of research for overall better patient management and to improve their quality of life.

Coronavirus Disease 2019 (COVID-19) happened due to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. It is the third coronavirus causing a pandemic. Cases of COVID-19 have increased rapidly. Epidemiological studies show droplets as a medium of transmission of this virus. The high rate of transmission and the death rate create urgency on the management of COVID-19. Unfortunately, until now there is no definitive therapy for the SARS-CoV-2 virus. Several potential therapies, including antivirals, immunomodulatory agents, convalescent plasma transfusions, and supportive therapies such as vitamin D supplementation, have been applied in the management of COVID-19. As a hormone, vitamin D has an immunomodulatory effect used in supportive therapy for various immune-related diseases and respiratory system infections. The immunomodulatory effects of vitamin D are strengthening the physical barrier (cell junction), the specific immune system (adaptive immunity), and the non-specific immune system (innate immunity). Vitamin D is known to suppress pro-inflammatory cytokines and increase the production of anti-inflammatory cytokines. In addition, vitamin D also performs as a substantial part in the induction of ACE2 receptors which gives a weighty influence on pathogenesis of COVID-19. Vitamin D deficiency can amplify the risk of infections including COVID-19. Presently, clinical trials of vitamin D supplementation and COVID-19 are limited. This literature review further examined the role of vitamin D supplementation in COVID-19.

Multiple sclerosis is an autoimmune treatable but not curable disease. There are a multiplicity of medications for multiple sclerosis therapy, including a class entitled disease-modifying drugs that are mainly indicated to reduce the number and severity of disease relapses. Not all patients respond well to these therapies, and minor to severe adverse effects have been reported. Vitamin D, called sunshine vitamin, is being studied as a possible light at the end of the tunnel. In this review, we recapitulated the similar immunopathogenesis of multiple sclerosis and experimental autoimmune encephalomyelitis, the immunomodulatory and neuroprotective potential of vitamin D and the state-of-art concerning its supplementation to multiple sclerosis patients. Finally, based on our and other groups’ experimental findings, we analyzed the need to consider the relevance of the route and the different time-point administration aspects for a more rational indication of this vitamin to multiple sclerosis patients.

Age/autoimmunity-associated B cells (ABCs) are a novel B cell subpopulation with a unique transcriptional signature and cell surface phenotype. They are not sensitive to BCR but rely on TLR7 or TLR9 in the context of T cell-derived cytokines for the differentiation. It has been established that aberrant expansion of ABCs is linked to the pathogenesis of systemic autoimmune diseases such as systemic lupus erythematosus. Recently, we and other groups have shown that increased ABCs is associated with rheumatoid arthritis (RA) disease activity and have demonstrated their pathogenic role in RA, indicating that targeting specific B cell subsets is a promising strategy for the treatment of inflammatory arthritis. In this review, we summarize the current knowledge of ABCs, focusing on their emerging role in the pathogenesis of inflammatory arthritis. A deep understanding of the biology of ABCs in the context of inflammatory settings in vivo will ultimately contribute to the development of novel targeted therapies for the treatment of inflammatory arthritis.

Summary: Human monkeypox is a viral zoonotic smallpox-like disease caused by the monkeypox virus (MPXV) and has become the greatest public health threat in the genus Orthopoxvirus after smallpox was eradicated. The host immune response to MPXV plays an essential role in disease pathogenesis and clinical manifestations. MPXV infection leads to skin lesions with the genital area as the main feature in the current outbreak and triggers a strong immune response that results in sepsis, deep tissue abscess, severe respiratory disease, and injuries to multiple immune organs. Emerging evidence shows that the immunopathogenesis of MPXV infection is closely associated with impaired NK-cell function, lymphopenia, immune evasion, increased antibodies, increased blood monocytes and granulocytes, cytokine storm, inhibition of the host complement system, and antibody-dependent enhancement. In this overview, we discuss the immunopathology and immunopathogenesis of monkeypox to aid the development of novel immunotherapeutic strategies against monkeypox.

Abstract Introduction Human brucellosis is a zoonotic bacterial disease with up to 500,000 new cases each year. The major evasion mechanisms from the host immune system by Brucella are restraint of complement pathway and Toll‐like receptors signaling pathways, interference with efficient antigen presentation to CD4‐positive T lymphocytes, selective subversion of autophagy pathways, inhibition of dendritic cell stimulation, inhibition of autophagolysosomal fusion, and macrophage apoptosis. Many molecular and cellular pathways contribute to brucellosis that microRNAs have a vital function in the immunopathogenesis of this disease. In this regard, these molecules apply for their roles by modulating various events like inflammatory reactions and immune defense. Recently, in the case of immunity to human brucellosis, it has been shown that microRNAs play an important role in immunity against these bacteria. Methods and Results In this study, we tried to review the immune defense and immunopathogenesis of Brucella infection and highlight the current knowledge of the microRNAs in infected cells by Brucella pathogens. The recent findings suggest that the regulation of microRNAs expression is impaired during brucellosis infection, which may contribute to disease progression or inhibition by modulating immune responses against this pathogen. Conclusions The interplay between miRNAs and Brucella pathogens and the underlying process required comprehensive examination to unravel the novel therapeutic or diagnostic approaches.

Inflammatory bowel disease (IBD) is a typical immune-mediated chronic inflammatory disorder. Following the industrialization and changes in lifestyle, the incidence of IBD in the world is rising, which makes health concerns and heavy burdens all over the world. However, the pathogenesis of IBD remains unclear, and the current understanding of the pathogenesis involves dysregulation of mucosal immunity, gut microbiome dysbiosis, and gut barrier defect based on genetic susceptibility and environmental triggers. In recent years, autophagy has emerged as a key mechanism in IBD development and progression because Genome-Wide Association Study revealed the complex interactions of autophagy in IBD, especially immunopathogenesis. Besides, autophagy markers are also suggested to be potential biomarkers and target treatment in IBD. This review summarizes the autophagy-related genes regulating immune response in IBD. Furthermore, we explore the evolving evidence that autophagy interacts with intestinal epithelial and immune cells to contribute to the inflammatory changes in IBD. Finally, we discuss how novel discovery could further advance our understanding of the role of autophagy and inform novel therapeutic strategies in IBD.

ABSTRACT Relapsing fever, caused by diverse Borrelia spirochetes, is prevalent in many parts of the world and causes significant morbidity and mortality. To investigate the pathoetiology of relapsing fever, we performed a high-throughput screen of Borrelia-binding host factors using a library of human extracellular and secretory proteins and identified CD55 as a novel host binding partner of Borrelia crocidurae and Borrelia persica, two agents of relapsing fever in Africa and Eurasia. CD55 is present on the surface of erythrocytes, carries the Cromer blood group antigens, and protects cells from complement-mediated lysis. Using flow cytometry, we confirmed that both human and murine CD55 bound to B. crocidurae and B. persica. Given the expression of CD55 on erythrocytes, we investigated the role of CD55 in pathological B. crocidurae-induced erythrocyte aggregation (rosettes), which enables spirochete immune evasion. We showed that rosette formation was partially dependent on host cell CD55 expression. Pharmacologically, soluble recombinant CD55 inhibited erythrocyte rosette formation. Finally, CD55-deficient mice infected with B. crocidurae had a lower pathogen load and elevated proinflammatory cytokine and complement factor C5a levels. In summary, our results indicate that CD55 is a host factor that is manipulated by the causative agents of relapsing fever for immune evasion. IMPORTANCE Borrelia species are causative agents of Lyme disease and relapsing fever infections in humans. B. crocidurae causes one of the most prevalent relapsing fever infections in parts of West Africa. In the endemic regions, B. crocidurae is present in ~17% of the ticks and ~11% of the rodents that serve as reservoirs. In Senegal, ~7% of patients with acute febrile illness were found to be infected with B. crocidurae. There is little information on host-pathogen interactions and how B. crocidurae manipulates host immunity. In this study, we used a high-throughput screen to identify host proteins that interact with relapsing fever-causing Borrelia species. We identified CD55 as one of the host proteins that bind to B. crocidurae and B. persica, the two causes of relapsing fever in Africa and Eurasia. We show that the interaction of B. crocidurae with CD55, present on the surface of erythrocytes, is key to immune evasion and successful infection in vivo. Our study further shows the role of CD55 in complement regulation, regulation of inflammatory cytokine levels, and innate immunity during relapsing fever infection. Overall, this study sheds light on host-pathogen interactions during relapsing fever infection in vivo.

Immunoglobulin A vasculitis (IgAV), formerly known as Henoch-Schönlein purpura, is the most common systemic vasculitis in children, characterized by diverse clinical manifestations with a wide spectrum ranging from isolated cutaneous vasculitis to systemic involvement. The incidence of IgAV is geographically and ethnically variable, with a prevalence in autumn and winter, suggesting a driving role that genetic and environmental factors play in the disease. Although IgAV has a certain degree of natural remission, it varies widely among individuals. Some patients can suffer from severe renal involvement and even progress to end-stage renal disease. Its pathogenesis is complex and has not been fully elucidated. The formation of galactose-deficient IgA1 (Gd-IgA1) and related immune complexes plays a vital role in promoting the occurrence and development of IgAV nephritis. In addition, neutrophil activation is stimulated through the binding of IgA to the Fc alpha receptor I expressed on its surface, resulting in systemic vascular inflammation and tissue damage. Starting from the epidemiological characteristics, this article will review the role of immunological factors such as Gd-IgA1, autoantibodies, circulating immune complexes, complement system, cellular immunization, and the contributions of environmental and genetic factors in the pathogenesis of IgAV, and conclude with the major biomarkers for IgAV.

Summary: The presence of anti-citrullinated protein autoantibodies (ACPA) is a hallmark feature of rheumatoid arthritis (RA), which causes chronic joint destruction and systemic inflammation. Based on ACPA status, RA patients can be sub-grouped into two major subsets: ACPA-positive RA (ACPA+ RA) and ACPA-negative RA (ACPA– RA). Accumulating evidence have suggested that ACPA+ RA and ACPA– RA are two distinct disease entities with different underlying pathophysiology. In contrast to the well-characterized pathogenic mechanisms of ACPA+ RA, the etiology of ACPA– RA remains largely unknown. In this review, we summarized current knowledge about the primary drivers of ACPA– RA, particularly focusing on the serological, cellular, and molecular aspects of immune mechanisms. A better understanding of the immunopathogenesis in ACPA– RA will help in designing more precisely targeting strategies, and paving the road to personalized treatment. In addition, identification of novel biomarkers in ACPA– RA will substantially promote early treatment and improve the outcomes.

Adult-onset Still’s disease (AOSD) is a rare disease affecting multiple systems and organs with unknown etiology, and the clinical symptoms are usually described as spiking fever, arthritis, evanescent salmon-pink eruptions, lymphadenopathy, splenomegaly, and other manifestations. The laboratory indicators are not specific, often presenting as increased leukocyte counts and neutrophil percentage, elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), hyperferritinemia, and increased inflammatory factors. ANA, ENA, and RF are negative. According to those unspecific clinical presentations and laboratory findings, infection, tumor, connective tissue disease, and other diseases must be ruled out before diagnosis. The diagnosis of AOSD is a great challenge for clinicians. The mechanism of AOSD pathogenesis is complicated and still being studied. There is a new opinion that atypical persistent skin eruptions (APSEs) with specific histological manifestations are unique for AOSD, and APSEs might be on a spectrum with classical evanescent eruptions. Studies on APSEs showed that IL-1β and IFN-γ are strongly correlated with the pathogenesis of necrosis keratinocytes in APSEs. IL-1β is strongly involved in inflammatory disease when it is abnormal, and plays an important role in the pathogenesis of neutrophil dermatosis. In the early stage of AOSD, skin lesions appear to be evanescent urticaria-like eruptions accompanied by fever, and only neutrophils infiltrate around the blood vessels in the dermis pathologically. As the course of the disease progresses, IL-1β is gradually released. Through the stimulation of other inflammatory factors and the influence of unknown factors, IL-1β gradually infiltrates into the stratum corneum and finally accumulates around the necrotic keratinocytes of the stratum corneum. However, the detailed mechanism is still unknown. IFN-γ could play a pro-inflammatory or regulatory role in some disorders. IL-1β can enhance the expression of IFN-γ, and IFN-γ can cause keratinocyte apoptosis by activating the autocrine of caspase. Also, several pieces of evidence indicate that adaptive immunity is also involved in the pathogenesis of AOSD. Increased α-soluble receptors of IL-2 may suggest T-cell activation and proliferation in AOSD patients. Increased IL-4- and IFN-γ-producing T cells were found in active AOSD and related to disease severity. Frequencies of Treg cells in AOSD were significantly lower and were inversely correlated with disease severity. According to these, more and more researchers have reached a consensus that AOSD is a disease at the crossroads of innate immunity and autoimmunity. In this review, we will provide a comprehensive insight into AOSD, describing research progress and the immunological mechanism contribution to the disease. In the meantime, different treatment options and the efficacy and safety of various biologic agents are also discussed. A further understanding of AOSD requires closer cooperation among doctors from different departments, and this review will provide a new idea for diagnosis and therapeutic options.

(1) Introduction: Psoriasis is a chronic, immune-mediated disease that negatively impacts patients’ quality of life and predisposes them to cardiovascular or metabolic diseases. This paper aims to summarize the knowledge structure and future directions in psoriasis research by means of bibliometrics. (2) Material and methods: The Thomson Reuters Web of Science database was interrogated using preestablished keywords. A list of the top 100 most cited articles focusing solely on psoriasis was compiled and analyzed. VOSviewer software was used to assess and visualize collaboration networks, citation, co-citation and co-wording analysis, and bibliographic coupling. (3) Results: The articles were written by 902 authors from 20 countries and were published in 31 journals. The United States was at the forefront of this field. Griffiths, CEM had the most citations, while the most prolific institution was Rockefeller University, New York City. Pathogenesis, especially key-pathogenic factors, immune pathways, and epidemiology were the most discussed topics. Work published in the last decade focused on the use of biologics. Keywords such as “quality of life”, “efficacy”, and “necrosis-factor alpha” have been widely used. (4) Conclusion: Research interest regarding psoriasis is high, leading to the rapid development of this field. Treatment modalities, especially novel-targeted therapies, immune pathways, and an integrative approach to such cases are receiving great interest and represent research hotspots in the future.