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Co-occurrence of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and IgA nephropathy (IgAN) is extremely uncommon. To date, only a few case reports have described such patients. Here, we describe the clinical presentation, pathologic features, treatment response, and outcome data of five patients with the rare form of co-existing AAV and IgAN and compared the characteristics of these patients to AAV patients with pauci-immune glomerulonephritis (n = 10) and IgAN patients (n = 10) that were selected as controls by stratified random sampling. In addition, we summarize all the previously reported cases of AAV and IgAN. In total, including the current study, 16 AAV/IgAN overlap cases were reported. Our five patients with the coexistence of AAV and IgAN were younger than the ten AAV patients with pauci-immune glomerulonephritis (22.6 ± 8.2 years versus 48.9 ± 15.7 years, respectively, P = 0.004). Histologically, they had a significantly lower percentage of glomeruli with fibrous crescents compared with AAV patients (0.0% versus 4.0%, P = 0.038). Compared with ten IgAN patients, our five AAV/IgAN patients had higher levels of ESR (P = 0.032) and CRP (P = 0.031). After accepting treatment with a combination of steroid and immunosuppressants, all patients showed a positive response to therapy, except for one patient in our cohort and another previously reported patient. We described the clinical presentation, pathologic features, treatment response, and outcome data of five patients with overlapping AAV and IgAN. They had mild glomerular pathological lesions and a positive response to aggressive immunosuppressive therapy. They were quite similar to pauci-immune AAV patients in clinical features, except for younger age. They had a lower percentage of glomeruli with fibrous crescents compared with AAV patients. In contrast to IgAN patients, they had higher levels of ESR and CRP. The mechanism of the coexistence of IgAN and AAV needs further study.

Studies have highlighted a critical role for autophagy in the regulation of multiple cytokines. Autophagy inhibits the release of interleukin (IL)-1 family cytokines, including IL-1α, IL-1β and IL-18, by myeloid cells. This, in turn, impacts the release of other cytokines by myeloid cells, as well as other cells of the immune system, including IL-22, IL-23, IL-17 and interferon-γ. Here, we assessed the impact of genetic depletion of the autophagy gene Atg7 in myeloid cells on acute and chronic inflammation. In a model of acute lipopolysaccharide-induced endotoxemia, loss of autophagy in myeloid cells resulted in increased release of proinflammatory cytokines, both locally and systemically. By contrast, loss of Atg7 in myeloid cells in the Lyn−/− model of lupus-like autoimmunity resulted in reduced systemic release of IL-6 and IL-10, with no effects on other cytokines observed. In addition, Lyn−/− mice with autophagy-deficient myeloid cells showed reduced expression of autoantibodies relevant to systemic lupus erythematosus, including anti-histone and anti-Smith protein. In vitro, loss of autophagy, through pharmacological inhibition or small interfering RNA against Becn1, inhibited IL-10 release by human and mouse myeloid cells. This effect was evident at the level of Il10 messenger RNA expression. Our data highlight potentially important differences in the role of myeloid cell autophagy in acute and chronic inflammation and demonstrate a direct role for autophagy in the production and release of IL-10 by macrophages.

Cell viability is an important release criterion in the manufacturing of cell therapy products. Low cell viability can have significant impact on product quality and manufacturing efficiency. Counterflow centrifugation technology has been applied to the manufacturing of cell therapy products, to enable cell separation based on size and density. This study evaluated the utility of counterflow centrifugation technology for dead cell removal to improve cell viability of the final product.Jurkat cell cultures with low and high dead cell burden were subjected to counterflow centrifugal elutriation to determine the correlation between process parameters (e.g., flow rate, centrifugal force) and processing outcomes (i.e., cell recovery and viability). Subsequently, the optimized parameters were applied to dead cell elutriation using expanded T cells and freshly isolated human amniotic epithelial cells (hAECs). The efficiency of dead cell removal, cell function and post-thaw viability were compared.Elutriation using a low flow rate allowed better control of viable cell recovery from both low and high dead cell burden cultures of Jurkat cells. The viability of T cells and hAECs was improved by counterflow centrifugal processing, from 80.67% ± 2.33 to 94.73% ± 1.19 and 79.19% ± 5.35 to 90.34% ± 3.59, respectively. Processing increased the proliferation rate of T cells, while the metabolic activity of hAECs was unchanged.Counterflow centrifugal elutriation can be added as an integrated step to the automated wash-and-concentrate protocol for cell manufacturing to remove dead cells and improve cell viability of the final product.

Data on anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) are limited in children. This study is to determine the clinical features and outcomes of childhood-onset AAV. A retrospective study was performed on patients who were diagnosed with AAV before 18 years old in Xiangya Hospital. Their medical records were analyzed by retrospective review. Sixteen patients were diagnosed with AAV before 18 years old in the past 9 years, with an average age of 13.3 ± 3.3 years and 13 of them were female. There were 15 patients with microscopic polyangiitis (MPA) and 1 with Wegener’s granulomatosis. The interval between onset of disease and diagnosis of AAV was 2 (1.5–3) months. Most patients (15/16, 93.8%) had multi-organ involvement, and all patients had renal involvement with 7 (43.8%) patients requiring dialysis at presentation. Eleven patients underwent a renal biopsy, of which mixed class and sclerotic class were the most two common histological types. All patients received immunosuppressive therapy for induction therapy including intravenous administrations of methylprednisolone (MP) pulse therapy for 8 patients. 8 patients (50%) achieved remission after induction therapy. After a median follow-up of 46.3 ± 36.1 months, nine (56.3%) patients progressed to end-stage renal disease (ESRD) and 5 (31.3%) patients died. Childhood-onset AAV showed similar clinical and pathological features compared to those of adults, except that it usually occurs in girls. The most commonly involved organ was the kidney, and it had a high risk of progression to ESRD. Early diagnosis and initiation of appropriate immunomodulatory therapy would be important to improve outcomes.

There are a few studies that reported sex disparities in clinical features, pathological features and outcomes among ANCA-associated vasculitis (AAV) patients, but studies focusing on sex-specific differences of myeloperoxidase (MPO)-AAV patients are scarce. Therefore, the purpose of this study was to analyze sex differences in clinicopathological features and outcomes of MPO-AAV. Patients diagnosed with MPO-AAV in Xiangya Hospital from January 2010 to June 2021 were included in the study and separated into female and male groups. The differences in clinical manifestations, laboratory parameters, pathological features and prognosis between the two groups were retrospectively analyzed. Three hundred and sixty-six patients were included and divided into female group (n = 176) and male group (n = 190). The age of the male group was 62.41 ± 10.49 years, significantly higher than that of the female group (58.69 ± 16.39, p = 0.011). Compared with the female group, the male group had a shorter duration of disease, higher levels of hemoglobin, eosinophil count, proteinuria, serum C4, and lower levels of serum globulin, serum IgG and serum IgM (p

Background Myeloperoxidase ANCA-associated vasculitis is a major cause of ESKD. Efficacy of anti-CD20 mAb treatment was tested in a mouse model of the disease. Methods MPO immunization induced anti-MPO autoimmunity, and a subnephritogenic dose of sheep anti-mouse GBM globulin triggered GN. Results Anti-CD20 mAb treatment increased the numbers and immunomodulatory capacity of MPO-specific T regulatory cells (Tregs) and attenuated T cell-mediated and humoral anti-MPO autoimmunity and GN. Disabling of Tregs negated the therapeutic benefit of anti-CD20 treatment. The mechanism of enhancement of Treg activity could be attributed to anti-CD20 mAb effects on inducing B cell apoptosis. Administering anti-CD20 mAb-induced apoptotic splenocytes to mice developing anti-MPO GN was as effective as anti-CD20 mAb treatment in inducing Tregs and attenuating both anti-MPO autoimmunity and GN. A nonredundant role for splenic macrophages in mediating the anti-CD20 mAb-induced immunomodulation was demonstrated by showing that administration of anti-CD20 mAb ex vivo-induced apoptotic splenocytes to unmanipulated mice attenuated autoimmunity and GN, whereas deletion of splenic marginal zone macrophages prevented anti-CD20 mAb-induced immunomodulation and treatment efficacy. Six days after administering anti-CD20 mAb to mice with murine anti-MPO GN, cell-mediated anti-MPO responses and GN were attenuated, and Tregs were enhanced, but ANCA levels were unchanged, suggesting humoral autoimmunity was redundant at this time point. Conclusions Collectively, these data suggest that, as well as reducing humoral autoimmunity, anti-CD20 mAb more rapidly induces protective anti-MPO Treg-mediated immunomodulation by splenic processing of anti-CD20-induced apoptotic B cells.

Objective: To analyze the role of serum sortilin in coronary artery calcification (CAC) and cardiovascular and cerebrovascular events (CCE) in maintenance hemodialysis (MHD) patients. Methods: One hundred eleven patients with MHD ≥3 months were included in this study. The general data, clinical features, hematological data, and medication history of the patients were recorded. Eighty-five cases were examined by vascular color Doppler ultrasound, cardiac color Doppler ultrasound, lateral lumbar radiography, and coronary artery calcification score. The patients were followed up for a median time of 45 months. The primary endpoint was CCE or death from a vascular event, and the role of sortilin in this process was analyzed. Results: Among 85 MHD patients, 51 cases (60.00%) had different degrees of CAC. There were significant differences in diabetes, dialysis time, serum phosphorus, calcium-phosphorus product, medical history of phosphate binders, sortilin, and carotid artery plaque between 4 different degrees of calcification groups (p < 0.05). Logistic regression analysis showed that diabetes (OR = 5.475; 95% CI: 1.794–16.71, p = 0.003), calcium-phosphorus product (OR = 2.953; 95% CI: 1.198–7.279, p = 0.019), and sortilin (OR = 1.475 per 100 pg/mL; 95% CI: 1.170–1.858, p = 0.001) were independent risk factors for CAC. During the follow-up, 28 cases of 111 patients (25.23%) suffered from CCE. There were significant differences in CCE between mild, moderate, and severe CAC groups and noncalcification groups (p < 0.05). Cox regression analysis showed that diabetes mellitus (HR 3.424; 95% CI: 1.348–8.701, p = 0.010), CAC (HR 5.210; 95% CI: 1.093–24.83, p = 0.038), and serum sortilin (HR = 8.588; 95% CI: 1.919–38.43, p = 0.005) were independent risk factors for CCE. Besides, we proposed a cutoff value of 418 pg/mL for serum sortilin level, which was able to predict the occurrence of CCE with 75.0% sensitivity and 71.9% specificity. The area under the curve was 0.778 (95% CI: 0.673–0.883). Conclusion: Sortilin is newly found to be independently associated with CAC and CCE in MHD patients.

Platelet-to-lymphocyte ratio (PLR) has recently been investigated as a new inflammatory marker in many inflammatory diseases, including systemic lupus erythematosus and immunoglobulin A vasculitis. However, there were very few reports regarding the clinical role of PLR in patients with anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis. This study was thus undertaken to investigate the relationship between inflammatory response and disease activity in Chinese patients with myeloperoxidase-anti-neutrophil cytoplasmic antibody (MPO-ANCA) associated vasculitis. Furthermore, we evaluated whether PLR predicts the progression of end stage of renal disease (ESRD) and all-cause mortality.The clinical, laboratory and pathological data, and the outcomes of MPO-ANCA associated vasculitis patients were collected. The Spearman correlation coefficient was computed to examine the association between 2 continuous variables. Cox regression analysis was used to estimate the association between PLR and ESRD or all-cause mortality.A total of 190 consecutive patients with MPO-ANCA associated vasculitis were included in this study. Baseline PLR was positively correlated with CRP (PLR is positively correlated with CRP and ESR. Furthermore, PLR may independently predict the risk of ESRD.

Objectives ANCA-associated vasculitis (AAV) is an autoimmune disease characterized by small blood vessel inflammation, commonly affecting the kidneys and respiratory tract. It is unclear why the incidence of this condition increases with age. Previous studies in a passive antibody transfer system in aged mice have implicated innate effectors. To test the hypothesis that autoimmunity to myeloperoxidase (MPO), an autoantigen responsible for AAV, increases with age, anti-MPO autoimmunity was studied in murine models of active autoimmunity and disease induced by cellular immunity. Methods Young (8 weeks) and aged (either 15 or 22 months) mice were immunized with whole proteins or peptides from ovalbumin, as a model foreign antigen, or MPO protein or peptides. Mice were subjected to a model of active anti-MPO glomerulonephritis. Cellular and humoral immune responses, and tissue inflammation were assessed. Results While cellular immunity to ovalbumin was diminished in aged mice, cellular autoimmunity to MPO and its immunodominant CD4+ and CD8+ T cell epitopes was increased after immunization with either MPO peptides or whole MPO protein, assessed by peptide and antigen-specific production of the pro-inflammatory cytokines IFN-γ and IL-17A. MPO-ANCA titres were not increased in aged mice compared with young mice. In experimental anti-MPO glomerulonephritis, cell-mediated injury was increased, likely due to CD4+ and CD8+ T cells, innate immunity and the increased vulnerability of aged kidneys. Conclusion Heightened cellular immunity to MPO develops with ageing in mice and may contribute to the increased incidence and severity of AAV in older people.

Background Antiglomerular basement membrane (anti-GBM) disease is associated with HLA-DRB1*1501 (the major predisposing genetic factor in the disease), with α3127-148 as a nephritogenic T and B cell epitope. Although the cause of disease remains unclear, the association of infections with anti-GBM disease has been long suspected. Methods To investigate whether microbes might activate autoreactive T and B lymphocytes via molecular mimicry in anti-GBM disease, we used bioinformatic tools, including BLAST, SYFPEITHI, and ABCpred, for peptide searching and epitope prediction. We used sera from patients with anti-GBM disease to assess peptides recognized by antibodies, and immunized WKY rats and a humanized mouse model (HLA-DR15 transgenic mice) with each of the peptide candidates to assess pathogenicity. Results On the basis of the critical motif, the bioinformatic approach identified 36 microbial peptides that mimic human α3127-148. Circulating antibodies in sera from patients with anti-GBM recognized nine of them. One peptide, B7, derived from Actinomyces species, induced proteinuria, linear IgG deposition on the GBM, and crescent formation when injected into WKY rats. The antibodies to B7 also targeted human and rat α3127-148. B7 induced T cell activation from human α3127-148-immunized rats. T cell responses to B7 were detected in rats immunized by Actinomyces lysate proteins or recombinant proteins. We confirmed B7's pathogenicity in HLA-DR15 transgenic mice that developed kidney injury similar to that observed in α3135-145-immunized mice. Conclusions Sera from patients with anti-GBM disease recognized microbial peptides identified through a bioinformatic approach, and a peptide from Actinomyces induced experimental anti-GBM GN by T and B cell crossreactivity. These studies demonstrate that anti-GBM disease may be initiated by immunization with a microbial peptide.

Identification of risk factors for treatment resistance and relapse would be crucial to personalization therapy in patients with myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (MPO-AAV). Current evidence with regard to the risk factors for treatment resistance and relapse remains limited and inconclusive. We aimed to assess the predictors for treatment resistance and relapse in a single-center cohort of Chinese patients with MPO-AAV in this study. In total, 184 patients with MPO-AAV were included. Treatment resistance occurred in 64 (34.9%) of 184 patients and was positively associated with lung involvement (odds ratio [OR] 3.581, 95% CI 1.137-11.278, p = 0.029) and the initial serum creatinine level (OR 1.004, 95% CI 1.001-1.007, p = 0.010) and was negatively associated with platelet (OR 0.992, 95% CI 0.987-0.998, p = 0.007) and serum C3 levels (OR 0.998, 95% CI 0.996-0.999, p = 0.004). Relapse occurred in 29 (24.17%) of 120 patients in whom remission was achieved and was independently associated with lung involvement (hazard ratio [HR] 4.595, 95% CI 1.272-16.599, p = 0.020) and cardiovascular involvement (HR 3.689, 95% CI 1.237-11, p = 0.019,). The serum globulin was demonstrated to be negatively associated with relapse independently (HR 0.876; 95% CI 0.806-0.953; p = 0.002). This retrospective study of MPO-AAV patients in a single Chinese center suggests that treatment resistance was positively associated with lung involvement and the initial serum creatinine level and was negatively associated with platelet and serum C3 levels. Lung involvement and cardiovascular involvement were associated with an increased risk of relapse, while the higher serum globulin was demonstrated to be in association with a decreased risk of relapse.

Chronic kidney disease (CKD) leads to significant morbidity and mortality worldwide. Glomerulonephritis (GN) is the second leading cause of CKD resulting in end stage renal failure. The most severe and rapidly progressive type of GN is characterized by glomerular crescent formation. The current therapies for crescentic GN, which consist of broad immunosuppressive drugs, are partially effective, non-specific, toxic and cause many serious side effects including infections, cancer, and cardiovascular problems. Therefore, new and safer therapies are needed. Human amniotic epithelial cells (hAECs) are a type of stem cell which are isolated from the placenta after birth. They represent an attractive and novel therapeutic option for the treatment of various inflammatory conditions owing to their unique and selective immunosuppressive ability, as well as their excellent safety profile and clinical applicability. In this review, we will discuss the immunopathogenesis of crescentic GN, issues with currently available treatments and how hAECs offer potential to become a new and harmless treatment option for this condition.

In their recent publication, Kuczma and colleagues have provided evidence that advances the relationship between naive T cells, T cell anergy and T regulatory cells. Their findings strengthen the understanding of how these T cell subsets function in relation to self and microbiota-derived epitopes to promote and maintain peripheral tolerance to self and mucosal antigens.

Anti-myeloperoxidase nephritogenic autoimmunity induces severe glomerulonephritis. To assess the therapeutic potential of monoclonal antibodies targeting T helper (Th) subset differentiation determining cytokines, we studied a murine model of anti-myeloperoxidase glomerulonephritis. The temporal participation of T helper subsets was determined by quantitating gene expression of CD4+ T-cells isolated from nephritic kidneys and cytokine production by lymphocytes from nodes draining myeloperoxidase immunization sites. Th17 cytokines (IL-17A and IL-6) rose rapidly but declined as autoimmunity matured when Th1 cytokines (IL-12 and TNF) predominated. Therefore, T helper subset participation in anti-myeloperoxidase autoimmunity is biphasic, with Th17 early and Th1 late. To confirm the functional relevance of this biphasic pattern, we compared systemic anti-myeloperoxidase autoimmunity in wild type, Th17 deficient and Th1 deficient mice. Early, Th1 deficient mice developed similar autoimmunity and glomerulonephritis to wild type mice. However, Th17 deficient mice had significantly reduced anti-myeloperoxidase autoimmunity. In late autoimmunity, Th1 deficient mice developed reduced autoimmunity and were protected from anti-myeloperoxidase glomerulonephritis. The therapeutic potential of these findings were demonstrated by neutralizing monoclonal antibodies. Targeting IL-23p19 attenuated early Th17 dominated anti-myeloperoxidase autoimmunity and glomerulonephritis but not late phase disease. Targeting IL-12p35 attenuated late phase Th1 dominated anti-myeloperoxidase autoimmunity and glomerulonephritis but not early autoimmunity or glomerulonephritis. Targeting both T helper subsets with an anti-IL-12p40 monoclonal antibody was effective during both early and late phases of anti-myeloperoxidase glomerulonephritis. Thus, definition of dominant T helper differentiating subsets in anti-myeloperoxidase glomerulonephritis by renal CD4+ T-cell cytokine gene expression allows effective proper phase monoclonal antibody treatment of anti-myeloperoxidase glomerulonephritis.

BACKGROUND: Myeloperoxidase (MPO)-ANCA–associated GN is a significant cause of renal failure. Manipulating autoimmunity by inducing regulatory T cells is potentially a more specific and safer therapeutic option than conventional immunosuppression. METHODS: To generate MPO-specific regulatory T cells, we used a modified protein-conjugating compound, 1-ethyl-3-(3′dimethylaminopropyl)-carbodiimide (ECDI), to couple the immunodominant MPO peptide (MPO(409–428)) or a control ovalbumin peptide (OVA(323–339)) to splenocytes and induced apoptosis in the conjugated cells. We then administered MPO- and OVA-conjugated apoptotic splenocytes (MPO-Sps and OVA-Sps, respectively) to mice and compared their effects on development and severity of anti-MPO GN. We induced autoimmunity to MPO by immunizing mice with MPO in adjuvant; to trigger GN, we used low-dose antiglomerular basement membrane globulin, which transiently recruits neutrophils that deposit MPO in glomeruli. We also compared the effects of transferring CD4(+) T cells from mice treated with MPO-Sp or OVA-Sp to recipient mice with established anti-MPO autoimmunity. RESULTS: MPO-Sp but not OVA-Sp administration increased MPO-specific, peripherally derived CD4(+)Foxp3(−) type 1 regulatory T cells and reduced anti-MPO autoimmunity and GN. However, in mice depleted of regulatory T cells, MPO-Sp administration did not protect from anti-MPO autoimmunity or GN. Mice with established anti-MPO autoimmunity that received CD4(+) T cells transferred from mice treated with MPO-Sp (but not CD4(+) T cells transferred from mice treated with OVA-Sp) were protected from anti-MPO autoimmunity and GN, confirming the induction of therapeutic antigen-specific regulatory T cells. CONCLUSIONS: These findings in a mouse model indicate that administering apoptotic splenocytes conjugated with the immunodominant MPO peptide suppresses anti-MPO GN by inducing antigen-specific tolerance.

Autoreactivity to myeloperoxidase (MPO) causes anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), with rapidly progressive glomerulonephritis. Here, we show that a Staphylococcus aureus peptide, homologous to an immunodominant MPO T-cell epitope (MPO409–428), can induce anti-MPO autoimmunity. The peptide (6PGD391–410) is part of a plasmid-encoded 6-phosphogluconate dehydrogenase found in some S. aureus strains. It induces anti-MPO T-cell autoimmunity and MPO-ANCA in mice, whereas related sequences do not. Mice immunized with 6PGD391–410, or with S. aureus containing a plasmid expressing 6PGD391–410, develop glomerulonephritis when MPO is deposited in glomeruli. The peptide induces anti-MPO autoreactivity in the context of three MHC class II allomorphs. Furthermore, we show that 6PGD391–410 is immunogenic in humans, as healthy human and AAV patient sera contain anti-6PGD and anti-6PGD391–410 antibodies. Therefore, our results support the idea that bacterial plasmids might have a function in autoimmune disease., Autoreactivity to myeloperoxidase (MPO) causes autoimmune vasculitis and severe glomerulonephritis. Here, Ooi et al. show that a Staphylococcus aureus plasmid encodes a peptide that is homologous to an immunodominant MPO epitope and induces anti-MPO autoimmunity and glomerulonephritis in mice.

Idiopathic membranous nephropathy (IMN) is an organ-specific autoimmune disease of the kidney glomerulus. It may gradually progress to end-stage renal disease (ESRD) characterized by increased proteinuria, which leads to serious consequences. Although substantial advances have been made in the understanding of the molecular bases of IMN in the last 10 years, certain questions remain largely unanswered. To define the transcriptomic landscape at single-cell resolution, we analyzed kidney samples from 6 patients with anti-PLA2R positive IMN and 2 healthy control subjects using single-cell RNA sequencing. We then identified distinct cell clusters through unsupervised clustering analysis of kidney specimens. Identification of the differentially expressed genes (DEGs) and enrichment analysis as well as the interaction between cells were also performed. Based on transcriptional expression patterns, we identified all previously described cell types in the kidney. The DEGs in most kidney parenchymal cells were primarily enriched in genes involved in the regulation of inflammation and immune response including IL-17 signaling, TNF signaling, NOD-like receptor signaling, and MAPK signaling. Moreover, cell-cell crosstalk highlighted the extensive communication of mesangial cells, which infers great importance in IMN. IMN with massive proteinuria displayed elevated expression of genes participating in inflammatory signaling pathways that may be involved in the pathogenesis of the progression of IMN. Overall, we applied single-cell RNA sequencing to IMN to uncover intercellular interactions, elucidate key pathways underlying the pathogenesis, and identify novel therapeutic targets of anti-PLA2R positive IMN.

The molecular mechanisms underlying renal damage of IgA nephropathy (IgAN) remain incompletely defined. Here, single-cell RNA sequencing (scRNA-seq) was applied to kidney biopsies from IgAN and control subjects to define the transcriptomic landscape at single-cell resolution. We presented a comprehensive scRNA-seq analysis of human renal biopsies from IgAN. We showed for the first time that IgAN mesangial cells displayed increased expression of several novel genes including MALAT1, GADD45B, SOX4, and EDIL3, which were related to cell proliferation and matrix accumulation. The overexpressed genes in tubule cells of IgAN were mainly enriched in inflammatory pathways including TNF signaling, IL-17 signaling, and NOD-like receptor signaling. Furthermore, we compared the results of 4 IgAN patients with the published scRNA-Seq data of healthy kidney tissues of three human donors in order to further validate the findings in our study. The results also verified that the overexpressed genes in tubule cells from IgAN patients were mainly enriched in inflammatory pathways including TNF signaling, IL-17 signaling, and NOD-like receptor signaling. The receptor-ligand crosstalk analysis revealed potential interactions between mesangial cells and other cells in IgAN. IgAN patients with overt proteinuria displayed elevated genes participating in several signaling pathways compared with microproteinuria group. It needs to be mentioned that based on number of mesangial cells and other kidney cells analyzed in this study, the results of our study are preliminary and needs to be confirmed on larger number of cells from larger number of patients and controls in future studies. Therefore, these results offer new insight into pathogenesis and identify new therapeutic targets for IgAN.

Glucocorticoid-induced leucine zipper (GILZ) mimics many of the anti-inflammatory effects of glucocorticoids, suggesting it as a point of therapeutic intervention that could bypass GC adverse effects. We previously reported that GILZ down-regulation is a feature of human SLE, and loss of GILZ permits the development of autoantibodies and lupus-like autoimmunity in mice. To further query the contribution of GILZ to protection against autoimmune inflammation, we studied the development of the lupus phenotype in Lyn-deficient (Lyn-/-) mice in which GILZ expression was genetically ablated. In Lyn-/- mice, splenomegaly, glomerulonephritis, anti-dsDNA antibody titres and cytokine expression were exacerbated by GILZ deficiency, while other autoantibody titres and glomerular immune complex deposition were unaffected. Likewise, in patients with SLE, GILZ was inversely correlated with IL23A, and in SLE patients not taking glucocorticoids, GILZ was also inversely correlated with BAFF and IL18. This suggests that at the onset of autoimmunity, GILZ protects against tissue injury by modulating pro-inflammatory pathways, downstream of antibodies, to regulate the cycle of inflammation in SLE.

In antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides (AAV), the two major target antigens of ANCA are proteinase 3 (PR3) and myeloperoxidase (MPO). Evidence is accumulating that there are distinct differences between patients with PR3-AAV and those with MPO-AAV. In the present study, the clinicopathological features and prognosis of patients with PR3-AAV and MPO-AAV from a single center in China were retrospectively analyzed. A total of 212 Chinese patients with AAV were recruited in the present study; 189/212 (89.15%) patients were classified as having MPO-AAV and 23/212 (10.85%) patients as having PR3-AAV. Compared with those in the PR3-AAV group, patients in the MPO-AAV group were older and less frequently had ear, nose and throat or ophthalmic involvement. MPO-AAV patients had higher levels of serum creatinine and proteinuria at baseline. No significant difference was observed with regard to the pathological changes of the glomeruli and tubulointerstitium between the two groups. The probability of developing end-stage renal disease was significantly higher in patients with MPO-AAV compared with that in patients with PR3-AAV. There was no significant difference in the one-year patient survival rate between the two groups. However, differences in certain clinical characteristics and outcomes were observed between MPO-AAV and PR3-AAV patients. A large national investigation of AAV is required to confirm the concept that PR3-AAV and MPO-AAV are distinct disease entities.

Autoimmune diseases such as type 1 diabetes and systemic lupus erythematosus are chronic inflammatory diseases caused by immune system dysfunction. When immune cells such as T cells and B cells recognize self-antigens, this can lead to cellular and tissue destruction. Multiple causes of autoimmune diseases have been suggested, such as genetic predisposition, molecular mimicry, and importantly, a loss in numbers and/or function of regulatory T cells. Regulatory T cells (or Tregs) are a subset of CD4+ T cells essential for functional cellular immunity. They play an important role in preventing the induction of autoimmunity through various mechanisms, including, but not limited to, the secretion of immunosuppressive cytokines such as IL-10 and TGF-β. Their indispensability in protection against autoimmunity can be demonstrated in cases of immune dysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome, where loss of Treg function results in severe autoimmunity and even death. Furthermore, a decrease in numbers of functional Tregs and/or loss of Treg function is often been implicated in the pathogenesis of autoimmune diseases. Consequently, there has been increased interest in the use of Tregs in immunotherapy (whether polyclonal or antigen-specific) to treat autoimmune diseases such as systemic lupus erythematosus. Recent studies have shown that antigen-specific Tregs are important for protection against autoimmune disease. In a paradigm shifting study, utilizing the model autoimmune disease, Goodpasture’s, it was found that antigen-specific Tregs dominantly suppressed pro-inflammatory autoreactive conventional T cells and protected from disease. Therefore, there are now efforts to increase the numbers of antigen-specific Tregs to treat autoimmune diseases. One such way is to genetically engineer antigen-specific Tregs. Studies using animal models of disease and Jurkat cell lines have shown potential for the genetic engineering of antigen-specific Tregs for antigen-specific disease suppression. These Tregs can be conferred with antigen specificity through the use of lentiviral vectors containing specific T cell receptor (TCR) sequences. The use of antigen-specific Tregs as therapeutics in autoimmunity could also be applied to systemic lupus erythematosus (SLE), a chronic inflammatory autoimmune disease estimated to affect 1 in 1000 people. SLE is a highly heterogenous disease with a number of target autoantigens such as double-stranded DNA and the Smith (Sm) antigen. Patients present with different disease manifestations, including, but not limited to, lupus nephritis, malar rash, and neuropsychiatric lupus. Amongst the autoantigens, the Sm antigen is most specific for SLE; and, autoreactivity to the Sm antigen is associated with worse prognosis, in particular a strong predisposition to develop lupus nephritis. Furthermore, there is a strong HLA association in anti-Sm + SLE patients, suggesting a dominant T cell directed response in these patients. Current treatments for SLE involve the use of corticosteroids and immunosuppressive agents. However, long-term intake of these medications can lead to severe side effects such as increased risks of infection and drug toxicity. Due to the importance of antigen-specific Tregs in protecting against autoimmune disease, there is now the potential to develop antigen-specific Tregs for use as treatment for SLE.

Epidemiological studies suggest that the Bacillus Calmette-Guérin (BCG) vaccine may have protective effects against coronavirus disease 2019 (COVID-19); and, there are now more than 15 ongoing clinical trials seeking to determine if BCG vaccination can prevent or reduce the severity of COVID-19 (1). However, the mechanism by which BCG vaccination can induce a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specific T cell response is unknown. Here, in silico, we identify 8 BCG derived peptides with significant sequence homology to either SARS-CoV-2 NSP3 or NSP13 derived peptides. Using an in vitro co-culture system, we show that human CD4+ and CD8+ T cells primed with a BCG derived peptide developed enhanced reactivity to its corresponding SARS-CoV-2 derived peptide. As expected, HLA differences between individuals meant that not all persons developed immunogenic responses to all 8 BCG derived peptides. Nevertheless, all of the 20 individuals that were primed with BCG derived peptides developed enhanced T cell reactivity to at least 7 of 8 SARS-CoV-2 derived peptides. These findings provide a mechanistic basis for the epidemiologic observation that BCG vaccination confers protection from COVID-19; and supports the use of BCG vaccination to induce cross-reactive SARS-CoV-2 specific T cell responses.

BackgroundRapidly progressive glomerulonephritis caused by antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is typically characterized as pauci-immune glomerulonephritis. However, immune complex (IC) deposition in the glomerulus has been reported in a growing number of studies. Here, we assess the presence of glomerular immune deposits alongside renal outcome in myeloperoxidase (MPO)-ANCA associated glomerulonephritis (MPO-ANCA GN).MethodsClinical and histopathologic characteristics of 97 patients with MPO-ANCA GN classified by renal biopsy from January 2008 to December 2019 were extracted retrospectively from electronic medical records. The extent of immune deposits in the kidney (C3, C4, C1q, IgA, IgG, IgM) at diagnosis were analyzed by immunofluorescence (IF). Patients were followed up for a median period of 15 months. The response to treatment and outcomes of renal and histological lesion changes were also assessed.ResultsIn our study, 41% (40/97) of patients showed positive IF (≥2+) for at least one of the six immunoglobulin or complement components tested. Patients with IC deposits showed higher levels of serum creatinine (p=0.025), lower platelet counts (p=0.009), lower serum complement C3 (sC3) (≤790 ml/L) (p=0.013) and serum IgG (p=0.018) than patients with pauci-immune (PI) deposition at diagnosis. End-stage renal disease was negatively associated with eGFR (HR 0.885, 95% CI 0.837 to 0.935, pConclusionIn conclusion, patients with immune complex deposits in the kidney showed less platelet count, lower sC3 and sIgG levels, and higher serum creatinine levels. Patients with low sC3 at initial and with continued low sC3 during the treatment displayed a trend toward poorer kidney survival. Moreover, the IC group showed a worse renal outcome than the PI group, further enforcing the present strategy of introducing complement targeted therapies in AAV.

The physiological role of T cell anergy induction as a key mechanism supporting self-tolerance remains undefined, and natural antigens that induce anergy are largely unknown. In this report, we used TCR sequencing to show that the recruitment of CD4+CD44+Foxp3−CD73+FR4+ anergic (Tan) cells expands the CD4+Foxp3+ (Tregs) repertoire. Next, we report that blockade in peripherally-induced Tregs (pTregs) formation due to mutation in CNS1 region of Foxp3 or chronic exposure to a selecting self-peptide result in an accumulation of Tan cells. Finally, we show that microbial antigens from Akkermansia muciniphila commensal bacteria can induce anergy and drive conversion of naive CD4+CD44-Foxp3− T (Tn) cells to the Treg lineage. Overall, data presented here suggest that Tan induction helps the Treg repertoire to become optimally balanced to provide tolerance toward ubiquitous and microbiome-derived epitopes, improving host ability to avert systemic autoimmunity and intestinal inflammation.

BACKGROUND: Antiglomerular basement membrane (anti-GBM) disease is associated with HLA-DRB1*1501 (the major predisposing genetic factor in the disease), with α3(127–148) as a nephritogenic T and B cell epitope. Although the cause of disease remains unclear, the association of infections with anti-GBM disease has been long suspected. METHODS: To investigate whether microbes might activate autoreactive T and B lymphocytes via molecular mimicry in anti-GBM disease, we used bioinformatic tools, including BLAST, SYFPEITHI, and ABCpred, for peptide searching and epitope prediction. We used sera from patients with anti-GBM disease to assess peptides recognized by antibodies, and immunized WKY rats and a humanized mouse model (HLA-DR15 transgenic mice) with each of the peptide candidates to assess pathogenicity. RESULTS: On the basis of the critical motif, the bioinformatic approach identified 36 microbial peptides that mimic human α3(127–148). Circulating antibodies in sera from patients with anti-GBM recognized nine of them. One peptide, B7, derived from Actinomyces species, induced proteinuria, linear IgG deposition on the GBM, and crescent formation when injected into WKY rats. The antibodies to B7 also targeted human and rat α3(127–148). B7 induced T cell activation from human α3(127–148)-immunized rats. T cell responses to B7 were detected in rats immunized by Actinomyces lysate proteins or recombinant proteins. We confirmed B7’s pathogenicity in HLA-DR15 transgenic mice that developed kidney injury similar to that observed in α3(135–145)-immunized mice. CONCLUSIONS: Sera from patients with anti-GBM disease recognized microbial peptides identified through a bioinformatic approach, and a peptide from Actinomyces induced experimental anti-GBM GN by T and B cell crossreactivity. These studies demonstrate that anti-GBM disease may be initiated by immunization with a microbial peptide.

Neutrophil-to-lymphocyte ratio (NLR) has been recently reported to be a promising inflammatory marker to assess systemic inflammation in many disorders. However, there are only a few studies looking at NLR in patients with myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This study was thus undertaken to explore the relationship between NLR at diagnosis with inflammatory response and disease activity among MPO-AAV patients in a single Chinese center. Furthermore, we evaluated whether NLR could predict the renal prognosis and patient outcome. 188 patients with MPO-AAV were included in this study. Baseline NLR was positively correlated with CRP (r = 0.404, P

The prospects for complement-targeted therapy in ANCA-associated vasculitis have been enhanced by a recent clinical trial in which C5a receptor 1 (C5aR1) inhibition safely replaced glucocorticoids in induction treatment. C5aR1 primes neutrophils for activation by anti-neutrophil cytoplasmic antibody (ANCA) and is therefore required in models of glomerulonephritis induced by anti-myeloperoxidase antibody. Although humoral and cellular autoimmunity play essential roles in ANCA-associated vasculitis, a role for C5aR1 in these responses has not been described. Here, we use murine models to dissect the role of C5aR1 in the generation of anti-myeloperoxidase autoimmunity and the effector responses resulting in renal injury. The genetic absence or pharmacological inhibition of C5aR1 results in reduced autoimmunity to myeloperoxidase with an attenuated Th1 response, increased Foxp3 + regulatory T cells and reduction in generation of myeloperoxidase-ANCA. These changes are mediated by C5aR1 on dendritic cells, which promotes activation, and thus myeloperoxidase autoimmunity and glomerulonephritis. We also use renal intravital microscopy to determine the effect of C5aR1 inhibition on ANCA induced neutrophil dysfunction. We found that myeloperoxidase-ANCA induce neutrophil retention and reactive oxygen species burst within glomerular capillaries. These pathological behaviors are abrogated by C5aR1 inhibition. Thus, C5aR1 inhibition ameliorates both autoimmunity and intra-renal neutrophil activation in ANCA-associated vasculitis.

Dendritic cells (DCs) are thought to form a dendritic network across barrier surfaces and throughout organs, including the kidney, to perform an important sentinel function. However, previous studies of DC function used markers, such as CD11c or CX3CR1, that are not unique to DCs. Here, we evaluated the role of DCs in renal inflammation using a CD11c reporter mouse line and two mouse lines with DC-specific reporters, Zbtb46-GFP and Snx22-GFP. Multiphoton microscopy of kidney sections confirmed that most of the dendritically shaped CD11c+ cells forming a network throughout the renal interstitium expressed macrophage-specific markers. In contrast, DCs marked by Zbtb46-GFP or Snx22-GFP were less abundant, concentrated around blood vessels, and round in shape. We confirmed this pattern of localization using imaging mass cytometry. Motility measurements showed that resident macrophages were sessile, whereas DCs were motile before and after inflammation. Although uninflamed glomeruli rarely contained DCs, injury with nephrotoxic antibodies resulted in accumulation of ZBTB46+ cells in the periglomerular region. ZBTB46 identifies all classic DCs, which can be categorized into two functional subsets that express either CD103 or CD11b. Depletion of ZBTB46+ cells attenuated the antibody-induced kidney injury, whereas deficiency of the CD103+ subset accelerated injury through a mechanism that involved increased neutrophil infiltration. RNA sequencing 7 days after nephrotoxic antibody injection showed that CD11b+ DCs expressed the neutrophil-attracting cytokine CXCL2, whereas CD103+ DCs expressed high levels of several anti-inflammatory genes. These results provide new insights into the distinct functions of the two major DC subsets in glomerular inflammation.

Myeloperoxidase (MPO) anti-neutrophil cytoplasmic Ab (ANCA)–associated vasculitis results from autoimmunity to MPO. IL-17A plays a critical role in generating this form of autoimmune injury but its cell of origin is uncertain. We addressed the hypothesis that IL-17A–producing γδ T cells are a nonredundant requisite in the development of MPO autoimmunity and glomerulonephritis (GN). We studied MPO-ANCA GN in wild type, αβ, or γδ T cell–deficient (C57BL/6, βTCR−/−, and δTCR−/− respectively) mice. Both T cell populations played important roles in the generation of autoimmunity to MPO and GN. Humoral autoimmunity was dependent on intact αβ T cells but was unaffected by γδ T cell deletion. Following MPO immunization, activated γδ T cells migrate to draining lymph nodes. Studies in δTCR−/− and transfer of γδ T cells to δTCR−/− mice show that γδ T cells facilitate the generation of anti-MPO autoimmunity and GN. δTCR−/− mice that received IL-17A−/− γδ T cells demonstrate that the development of anti-MPO autoimmunity and GN are dependent on γδ T cell IL-17A production. Finally, transfer of anti-MPO CD4+ T cell clones to naive δTCR−/− and wild type mice with planted glomerular MPO shows that γδ T cells are also necessary for recruitment of anti-MPO αβ CD4+ effector T cells. This study demonstrates that IL-17A produced by γδ T cells plays a critical role in the pathogenesis of MPO-ANCA GN by promoting the development of MPO-specific αβ T cells.