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Antineutrophilic cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a condition characterized by vessel inflammation and may have a variety of etiologies. Among these, cocaine and its common adulterant, levamisole, have been described to contribute to the development of AAV with distinct cutaneous manifestations. Classically, these manifestations involve purpuric or necrotic lesions involving the ears, nose, and extremities. However, we present a case of cocaine-induced AAV presenting with violaceous nodules on the dorsal hands in order to demonstrate that this condition may not always present with retiform purpura and skin necrosis., (© 2024 the International Society of Dermatology.)

Background and objectives : The initial symptom that triggers granulomatosis with polyangiitis (GPA) diagnosis is rarely ocular. We describe a case with a single ocular lesion identified as probable GPA due to proteinase 3 (PR3)-antineutrophil cytoplasmic antibody (ANCA)-positivity according to the diagnostic criteria of the Ministry of Health in Japan; the lesion repeatedly worsened. Materials and methods : A 25-year-old female visited the Department of Ophthalmology, Asahi General Hospital, with upper eyelid swelling and conjunctival and episcleral hyperemia of the left eye. Both hordeolum and eyelid cellulitis were suspected, as the condition was resistant to treatment with antibiotic eye drops. Episcleritis was suspected due to localized hyperemia in the upper part of the eye. Upon treatment with antibacterial agents and steroid eye drops, the swelling and the hyperemia repeatedly worsened every week. Results : Blood samples were positive for PR3-ANCA, and GPA with an isolated ocular lesion was considered. After oral steroid treatment, the patient had no recurrence for 4 years. There was no systemic involvement in the upper respiratory tract, lungs, or kidneys. Conclusions : Diagnosing GPA with ocular symptoms as initial manifestations is challenging. GPA should be considered in treatment-resistant eyelid, orbital, and episcleral lesions, even at a young age.

Background: The indirect immunofluorescence assay (IIFA) utilizing antineutrophil cytoplasmic antibodies (ANCA) is widely used as a diagnostic test for autoimmune vasculitis. The presence of antinuclear antibodies (ANA) might lead to a misleading interpretation of ANCA. This study aims to explore the impact of the presence of ANA on the interpretation of ANCA., Methods: This retrospective research examined samples negative for antiMPO and antiPR3 ANCA by IIFA and explored correlations between the ANA-IIFA results and the ANCA interpretation frequencies. Our analysis involved the use of suitable statistical methods, including Chi-square and kappa statistics., Results: Up to 75.2% of the ANCA-IIFA-positive samples exhibited a positive p-ANCA pattern when using the ethanol-fixed substrate, with c-ANCA positivity at 24.8%. In the ANA-IIFA-positive samples, ~77.3% displayed p-ANCA patterns on ethanol-fixed substrates. A comparison between the ANA-IIFA titers and the p-ANCA results revealed that p-ANCA positivity was notably more common in samples with higher titers, and this correlation was found to be statistically significant., Conclusion: Positive ANA results by IIFA tests are linked to a higher incidence of p-ANCA interpretation, particularly in cases with higher titer patterns. This insight aids laboratories in establishing effective workflows to investigate potential p-ANCA interference., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Myeloperoxidase (MPO) is a pro-oxidant enzyme mainly found in the azurophilic granules of neutrophils. It not only displays a key role in the intracellular microbial killing process but also contributes to the extracellular clearance of several pathogens. This study aimed to detect MPO in cutaneous leukocytoclastic vasculitis (LCV) using immunohistochemistry. We retrospectively collected 22 confirmed cases of skin LCV diagnosed in our pathology department over 11 years (2012-2023). Immunohistochemistry was performed using anti-myeloperoxidase antibody (Leica clone 59A5) on the LeicaBond MAX automated system, following manufacturer's instructions. Two pathologists assessed immunohistochemical staining, scoring intensity as weak (+), moderate (++), or strong (+++). Patients' mean age was 56.9 years, with a male-to-female ratio of 1.18. Pathologically, vasculitis involved small blood vessels in all cases. Immunohistochemical analysis showed granular positive MPO staining in 59.1% of cases. Staining intensity was weak in 46.15%, moderate in 46.15%, and strong in 7.69%. Staining was patchy in 84.62% and diffuse in 15.38% of cases. MPO expression, detected in 59.1% of cutaneous LCV tissues, exhibited a patchy and peri-vascular distribution. It holds potential as a diagnostic marker for patients with early or minor histological changes.

Objective: Autoimmune diseases commonly feature the presence of specific humoral autoantibodies. However, the prevalence of a large panel of systemic autoantibodies has never been assessed in the general population. We, therefore, described the prevalence of about 50 humoral systemic autoantibodies in a sample of the general Bavarian adult population., Methods: Non-fasting venous serum samples from 331 participants were analyzed for 7 autoantibody screening tests (nuclear, cytoplasmic, and mitotic ANA, ANCA, cANCA and pANCA, anti-ENA autoantibodies) and 44 different monospecific humoral non-organ specific/systemic autoantibodies using indirect immunofluorescence tests, ELISAs, and line blots. In order to assess associations between sex, age, BMI, education level, smoking status and the presence of systemic autoantibodies, logistic regression analyses were conducted., Results: At least one screening test was positive in 29.9% of the participants, and 42.3% of the participants were seropositive for at least one monospecific autoantibody. The most frequently found monospecific autoantibodies were rheumatoid factor (35.6%), ß2-glycoprotein 1 IgM (4.8%), and cardiolipin IgG (1.8%). Only few associations between sex, age, BMI, education, smoking status and autoantibody frequencies were observed., Conclusion: Systemic autoantibodies are common in the general Bavarian population, and largely independent of sex, age, BMI, education, or smoking status. The study results may give orientation to clinicians about the occurrence of autoantibodies in the population, not (yet) associated with clinical symptoms., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Rohm, Kling, Hoffmann, Meisinger and Linseisen.)

ANCA-associated vasculitides (AAV) are small-vessel necrotizing vasculitides, with no or few immune deposits. They are usually associated with the presence of ANCA antibodies (AntiNeutrophil Cytoplasmic Antibody), targeted either against proteinase 3 (PR3-ANCA) or myeloperoxidase (MPO-ANCA). ANCA-associated vasculitides include granulomatosis with polyangiitis (formerly Wegener's), microscopic polyangiitis and eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss syndrome). The most commonly afflicted organs involve the lungs and the respiratory tract, ENT area, and the kidneys. Renal involvement typically manifests as pauci-immune necrotizing crescentic rapidly progressive glomerulonpehritis. Pulmo-renal syndrome with lung haemorrhage and deteriorating kidney function may be acutely life-threatening. Diagnostic methods include ANCA measurement, imaging methods and biopsy. Early recognition of the diagnosis and an early start of adequate treatment are necessary for a good outcome. The current treatment typically consists of corticosteroids and either cyclophoshapmide or rituximab (a monoclonal antibody directed against CD20 antigen). The addition of plasma exchange may be considered in severe cases. Rituximab is preferred for the treatment of all relapsing forms of this vasculitis.

Introduction: Small fiber neuropathy [SFN] is a common peripheral neurologic disorder with a vast array of implicated etiologies. It has previously been proposed that some forms of immune-mediated small fiber neuropathy are driven by vasculitis, though antinuclear cytoplasmic antibodies [ANCA] antibodies have not commonly been reported in association with SFN, thus far. We present this case series to discuss the observation of a possible novel association between ANCA and SFN., Methods: This is a retrospective case series of 6 patients with SFN and ANCA positivity, with and without systemic manifestations. Patients included were diagnosed with SFN by skin biopsy or autonomic function testing and were seropositive for ANCA by ELISA., Results: Six patients are outlined, including 4 females and 2 males. Antigen specific antibodies were MPO alone in 4 cases, PR3 alone in 1 case and both MPO and PR3 in 1 case. Systemic vasculitis was noted in 2 patients. Five patients received immunosuppression. Three patients experienced partial improvement, while symptoms stabilized in 3 patients., Discussion: This is the first series of patients with suspected immune-mediated SFN and ANCA antibody positivity, raising the possibility of ANCA mediated isolated SFN. This is in contradistinction to the more typical ANCA-mediated peripheral neuropathy manifestations of mononeuropathy multiplex or axonal sensorimotor neuropathy. We cannot unequivocally prove ANCA-associated vasculitis [AAV] causality in these cases; however, the stabilization in SFN symptomatology and associated improvement in ANCA antibody titer, after AAV treatment, may be indicative of an association., (© 2023. Fondazione Società Italiana di Neurologia.)

Objectives: To investigate the reliability of elevated titres of antineutrophil cytoplasmic antibody (ANCA) and to identify a cut-off titre in discriminating between ANCA-associated vasculitides (AAV) and its mimickers., Methods: This retrospective observational single-centre study included patients over 18 years with positive myeloperoxidase (MPO)-ANCA and/or proteinase 3 (PR3)-ANCA immunoassays over an 8-year period (January 2010 to December 2018), via their electronic medical files. Patients were classified according to the 2022 ACR/EULAR criteria and alternative diagnoses categorised either as non-AAV autoimmune disorders (ANCA-AI) or disorders without autoimmune features (ANCA-O). Findings from the AAV group were compared with those of ANCA-AI and ANCA-O groups and followed by a multivariate logistic stepwise regression analysis of features associated with AAV., Results: 288 ANCA-positive patients of which 49 had AAV were altogether included. There was no difference between patients between the ANCA-AI (n=99) and the ANCA-O (n=140) groups. The AUC for titres discriminating AAV from mimickers was 0.83 (95% CI, 0.79 to 0.87). The best threshold titre, irrespective of PR3-ANCA or MPO-ANCA, was 65 U/mL with a negative predictive value of 0.98 (95% CI, 0.95 to 1.00). On multivariate analysis, an ANCA titre ≥65 U/mL was independently associated with AAV with an OR of 34.21 (95% CI 9.08 to 129.81; p<0.001). Other risk factors were: pulmonary fibrosis (OR, 11.55 (95% CI, 3.87 to 34.47, p<0.001)), typical ear nose and throat involvement (OR, 5.67 (95% CI, 1.64 to 19.67); p=0.006) and proteinuria (OR, 6.56 (95% CI, 2.56 to 16.81; p<0.001))., Conclusion: High PR3/MPO-ANCA titres can help to discriminate between AAV and their mimickers in patients presenting with small-calibre vasculitides, with a threshold titre of 65 U/mL and above., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Pauci-immune focal necrotizing glomerulonephritis (piFNGN) involves asynchronous onset and progression of injurious lesions in biopsies. Pathologists can describe this heterogeneity within a biopsy, but translating the information into prognostic or expression analyses is challenging. Understanding the underlying molecular processes could improve treatment; however, bulk or single-cell transcriptomic analyses of dissociated tissue disregard the heterogeneity of glomerular injury. We characterize protein and mRNA expression of individual glomeruli in 20 biopsies from 18 patients with antineutrophil cytoplasmic antibody-associated piFNGN using the NanoString digital spatial profiling (DSP) platform. For this purpose, circular annotations of glomeruli were analyzed using protein, immuno-oncology RNA, and Cancer Transcriptome Atlas panels (n=120, 72, and 48 glomeruli, respectively). Histologic evaluation of glomerular patterns of injury was performed in adjacent serial sections. Expression data were processed by log2 transformation, quantile normalization, and batch adjustment. DSP revealed distinct but overlapping gene expression profiles relating to the morphological evolution of injurious lesions, including dynamic expression of various immune checkpoint regulators. Enrichment analysis indicated deregulated pathways that underline known and highlight novel potential mechanisms of disease. Moreover, by capturing individual glomeruli, DSP describes heterogeneity between and within biopsies. We demonstrate the benefit of spatial profiling for characterization of heterogeneous glomerular injury, indicating novel molecular correlates of glomerular injury in piFNGN., (Copyright © 2022 by the American Society of Nephrology.)

To explore the clinical diagnostic efficacy of antineutrophil cytoplasmic antibody associated vasculitis (AAV) by comparing the consistency and coincidence rate of serum anti-myeloperoxidase (MPO) antibody and anti-protease 3 (PR3) antibody detected by digital liquid chip method (DLCM) and enzyme-linked immunosorbent assay (ELISA). To provide reference for the selection of detection methods of anti-MPO antibody and anti-PR3 antibody in clinical laboratory. This study is a cross-sectional study, a total of 307 cases of antineutrophil cytoplasmic antibodies were detected in the Department of Clinical Immunology, West China Hospital of Sichuan University from January to March 2021. The serum samples and related clinical information were collected. At the same time, the levels of anti-MPO antibody and anti-PR3 antibody in serum samples were detected by ELISA and DLCM, indirect immunofluorescence (IIF) was used to re-test the differential samples between the two methods. SPSS 26.0 was used to analyze the test results, Cohen's kappa coefficient analysis was used to compare the consistency of the two methods, and paired chi-square test was used to compare the sensitivity and specificity of the two methods to AAV. The results showed that the positive cases of anti-MPO antibody detected by ELISA and DLCM were 63 and 44, and the negative cases were 244 and 263; the positive cases of anti-PR3 antibody detected by ELISA and DLCM were 34 and 28, and the negative cases were 273 and 279. The results of anti-MPO antibody and anti-PR3 antibody detected by the two methods had good consistency and coincidence rate, in which the total coincidence rate of anti-MPO antibody was 92.51%, the positive coincidence rate was 66.67%, and the negative coincidence rate was 99.18%. The results of consistency analysis showed that kappa=0.741 had well consistency. The total coincidence rate of anti-PR3 antibody is 96.74%, the positive coincidence rate is 76.47%, and the negative coincidence rate is 99.27%. The consistency analysis results show that kappa=0.821 had strong consistency. The results of IIF re-test of differential samples showed that the coincidence rate between DLCM and IIF was higher. The results of comparative analysis of anti-MPO antibody and anti-PR3 antibody showed that the specificity of DLCM was better than that of ELISA, and its sensitivity was lower than that of ELISA. In conclusion, the results of anti-MPO antibody and anti-PR3 antibody detected by DLCM were consistent with those of ELISA. In the combined detection of anti-MPO antibody and anti-PR3 antibody, the specificity of DLCM is better than that of ELISA.

Background: Lymphopaenia is commonly observed in autoimmune diseases, where it has been associated with disease activity or prognosis. However, in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) only a few small-scale studies have been targeted towards this issue. Research has not yet focused on AAV with renal involvement (AAV-RI). Thus the aim of this study was to analyse the association between lymphocyte counts and outcomes in a large cohort of AAV-RI patients., Methods: We used the Maine-Anjou AAV registry that retrospectively gathers data on consecutive patients affected by AAV in four French nephrology centres, recorded since January 2000. We analysed clinical, biological and histological data at diagnosis of AAV-RI. Risk factors for end-stage kidney disease (ESKD) were analysed. Event-free survival was also assessed., Results: Among the 145 patients included in the study, those with lymphopaenia at diagnosis had a lower renal function at baseline [estimated glomerular filtration rate (eGFR) 13 versus 26 mL/min; P = 0.002] and were more likely to require kidney replacement therapy (51% versus 25%; P = 0.003). Lymphopaenia was correlated with histological lesions and especially with the percentage of sclerotic glomeruli (P = 0.0027). ESKD-free survival was lower in lymphopaenic patients (P < 0.0001). In multivariate Cox analysis, lymphopaenia was an independent risk factor for ESKD [hazard ratio 4.47 (95% confidence interval 2.06-9.72), P < 0.001]., Conclusions: Lymphopaenia correlates with the severity of AAV glomerulonephritis at diagnosis and predicts poor renal outcome. In this view, lymphopaenia could be used as a simple and cost-effective biomarker to assess renal prognosis at AAV-RI diagnosis., (© The Author(s) 2021. Published by Oxford University Press on behalf of ERA-EDTA.)

Glomerulonephritis is a heterogeneous group of disorders that present with a combination of haematuria, proteinuria, hypertension, and reduction in kidney function to a variable degree. Acute presentation with full blown nephritic syndrome or rapidly progressive glomerulonephritis is uncommon and is mainly restricted to patients with post-infectious glomerulonephritis, anti-neutrophil cytoplasmic antibodies-associated vasculitis, and anti-glomerular basement membrane disease. Most frequently, patients present with asymptomatic haematuria and proteinuria with or without reduced kidney function. All glomerulonephritis disorders can show periods of exacerbation, but disease flairs characteristically occur in patients with IgA nephropathy or C3 glomerulopathy. The gold standard for the diagnosis of a glomerulonephritis is a kidney biopsy, with a hallmark glomerular inflammation that translates into various histopathological patterns depending on the location and severity of the glomerular injury. Traditionally, glomerulonephritis was classified on the basis of the different histopathological patterns of injury. In the last few years, substantial progress has been made in unravelling the underlying causes and pathogenetic mechanisms of glomerulonephritis and a causal approach to the classification of glomerulonephritis is now favoured over a pattern-based approach. As such, glomerulonephritis can be broadly classified as immune-complex glomerulonephritis (including infection-related glomerulonephritis, IgA nephropathy, lupus nephritis, and cryoglobulinaemic glomerulonephritis), anti-neutrophil cytoplasmic antibodies-associated (pauci-immune) glomerulonephritis, anti-glomerular basement membrane glomerulonephritis, C3 glomerulopathy, and monoclonal immunoglobulin-associated glomerulonephritis. We provide an overview of the clinical presentation, pathology, and the current therapeutic approach of the main representative disorders in the spectrum of glomerulonephritis., Competing Interests: Declaration of interests FCF received unrestricted research grants from Genentech, Hoffman La Roche, Janssen Pharmaceutical, Morphosys, and Retrophin; and consulting fees from Alexion Pharmaceuticals, Biocryst, Galapagos, GlaxoSmithKline, Novartis, Otsuka, and Takeda. All other authors declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Introduction: The "Renal Risk Score" (RRS) and the histopathological classification have been proposed to predict the risk of end-stage kidney disease (ESKD) in ANCA-associated glomerulonephritis (ANCA-GN). Besides, factors associated with kidney function recovery after ANCA-GN onset remain to be more extensively studied. In the present study, we analyzed the value of the RRS and of the histopathological classification for ESKD prediction. Next, we analyzed factors associated with eGFR change within the first 2 years following ANCA-GN diagnosis., Materials and Methods: We included patients from the Maine-Anjou ANCA-associated vasculitis registry with at least 6 months of follow-up. The values of ANCA-GN, histopathological classification, and RRS, and the factors associated with eGFR variations between ANCA-GN diagnosis and 2 years of follow-up were assessed., Results: The predictive values of the histopathological classification and RRS were analyzed in 123 patients. After a median follow-up of 42 months, 33.3% patients developed ESKD. The predictive value of RRS for ESKD was greater than that of the histopathological classification. Determinants of eGFR variation were assessed in 80/123 patients with complete eGFR measurement. The median eGFR increased from ANCA-GN diagnosis to month 6 and stabilized thereafter. The only factor associated with eGFR variation in our study was eGFR at ANCA-GN diagnosis, with higher eGFR at diagnosis being associated with eGFR loss (p<0.001)., Conclusion: The RRS has a better predictive value for ESKD than the histopathological classification. The main determinant of eGFR variation at 2 years was eGFR at ANCA-GN diagnosis. Thus, this study suggests that eGFR recovery is poorly predicted by histological damage at ANCA-GN diagnosis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Brilland, Boud’hors, Copin, Jourdain, Henry, Wacrenier, Djema, Samoreau, Coindre, Cousin, Riou, Croue, Saint-André, Subra, Piccoli and Augusto.)

We previously showed that the rupture of Bowman's capsule (BC) promotes the progression of crescentic glomerulonephritis by enhancing the entry of CD8 + T cells into the glomeruli. In the present study, we utilized digital spatial profiling to simultaneously profile the altered abundances of the messenger RNA (mRNA) transcripts and proteins in the glomerular and periglomerular areas of four biopsy samples of anti-neutrophil cytoplasmic autoantibody-associated glomerulonephritis (ANCA-GN) and two biopsy specimens of minimal change disease (MCD) controls. The paraffin-embedded biopsy samples were stained with collagen IV, CD45, and SYTO 13 to distinguish the glomeruli with periglomerular infiltration but intact BC, with focal BC rupture, and with extensive rupture of BC and glomeruli without crescent formation and leukocytic infiltration in ANCA-GN. By assessing multiple discrete glomerular areas, we found that the transcript expression levels of the secreted phosphoprotein-1 and its receptor CD44 were upregulated significantly in the glomeruli with more severe ruptures of BC, and their expression levels correlated positively with the fibrotic markers. We also found that both alternative and classic complement pathways were activated in the glomeruli from patients with ANCA-GN. Furthermore, M1 macrophages were involved mostly in the early stage of BC rupture, while M2 macrophages were involved in the late stage and may contribute to the fibrosis process of the crescents. Finally, loss of glomerular cells in ANCA-GN was likely mediated by apoptosis. Our results show that digital spatial profiling allows the comparative analysis of the mRNA and protein profiles in individual glomeruli affected differently by the disease process and the identification of potential novel mechanisms in ANCA-GN., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ye, Liu, Zhu, Duan, Wang, Fu, Song, Yuan, Liu, Sun, Liu, Lee, He and Chen.)

Objectives: 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., Methods: 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., Results: A total of 190 consecutive patients with MPO-ANCA associated vasculitis were included in this study. Baseline PLR was positively correlated with CRP ( r =0.333, P <0.001) and ESR ( r =0.218, P =0.003). PLR had no obvious correlation with Birmingham Vasculitis Activity Score (BVAS). Patients having PLR≥330 exhibited better cumulative renal survival rates than those having PLR<330 ( P =0.017). However, there was no significant difference in the cumulative patient survival rates between patients with PLR≥330 and those with PLR<330 at diagnosis ( P >0.05). In multivariate analysis, PLR is associated with the decreased risk of ESRD ( P =0.038, HR=0.518, 95% CI 0.278 to 0.963). We did not find an association between PLR with all-cause mortality using multivariate analysis (HR=1.081, 95% CI 0.591 to 1.976, P =0.801)., Conclusions: PLR is positively correlated with CRP and ESR. Furthermore, PLR may independently predict the risk of ESRD.

Anti-neutrophil cytoplasmic antibodies (ANCAs) are autoantibodies that recognize neutrophil cytoplasmic antigens. The major ANCA antigens are myeloperoxidase and proteinase 3. Necrotizing small vessel vasculitis accompanied by ANCA production is called ANCA-associated vasculitis (AAV). In addition to AAV, ANCA is sometimes produced in patients with connective tissue diseases, such as systemic lupus erythematosus, and inflammatory bowel diseases. Indirect immunofluorescence (IIF) and enzyme immunoassay (EIA) have been used to detect ANCAs. Recently, the accuracy of EIA has improved and it has become the gold standard for ANCA detection. However, IIF does not lose its role in ANCA detection because EIA cannot detect ANCAs that recognize antigens other than those coated on the plate. For IIF, neutrophil substrates prepared with two different fixations, namely, ethanol fixation and formalin fixation, are used. There is a recommended protocol for ethanol fixation but not for formalin fixation. This study prepared neutrophil substrates according to the recommended protocol for ethanol fixation and protocols in the literature and original protocols for formalin fixation and then examined ANCA specificity and how storage period would influence the number of cells, antigen distribution, and antigenicity of the substrates. As a result, the number of cells and antigen distribution did not change after storage for up to 2 months regardless of fixation protocols, whereas a time-dependent decline in ANCA antigenicity and a fixation protocol-dependent difference in ANCA specificity were observed. How neutrophils are fixed on the glass slide needs to be checked upon evaluation of ANCAs by IIF., (Copyright © 2021 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a small vessel vasculitis affecting multiple organ systems, including the kidney. Besides investigations focusing on renal outcomes, sex differences associated with distinct clinical and histopathological findings in ANCA glomerulonephritis (GN) have not been systematically investigated. Therefore, we here aimed to systematically analyze sex differences in patients with AAV and biopsy-proven ANCA GN. We provide a comprehensive analysis of 53 kidney biopsies with ANCA GN retrospectively included between 2015 and 2020 and identified specific sex differences in ANCA GN concerning laboratory parameters and systematic scoring of renal histopathology glomerular and tubulointerstitial lesions, and extrarenal manifestations of AAV. We did not observe any correlation between sex and short-term clinical AAV course or disease severity by comparing general AAV parameters. AAV manifestations in females occurred at an older age with more joint involvement. Regarding histopathological findings, we, again, observed no sex difference among ANCA GN classification, but a significant correlation between females and distinct histopathological findings with less tubulointerstitial inflammation and vasculitis of peritubular capillaries. Finally, we here identified fewer associations between clusters of clinical, laboratory parameters, and histopathological findings in females as compared to males. These findings are of great relevance and further improve our understanding of sex differences in the pathogenesis of ANCA GN. While future studies about specific sex differences and conclusions in these clusters are crucial, our observations further support that sex differences are relevant, affect distinct parameters, and influence clinical, laboratory parameters, and histopathological findings in AAV, particularly ANCA GN., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Tampe, Korsten, Ströbel, Hakroush and Tampe.)

A 42-year-old man with undiagnosed Churg-Strauss syndrome (CSS) developed bilateral central retinal artery occlusion (CRAO). His medical history included bronchial asthma and irregular prednisolone usage but no atherosclerotic risk factors. At presentation, visual acuity (VA) was hand motion in the right eye and counting fingers in left eye. On fundoscopy, retinal whitening and a cherry red spot were observed in the right eye, while the fundus was normal in the left eye. After eyeball massage and systemic intraocular pressure lowering agents, his VA improved. On day 5 of treatment, he experienced right limb weakness and purpura on his right foot, and electromyography revealed mononeuritis multiplex. Laboratory tests indicated eosinophilia (52%). Based on the presence of hypereosinophilia, bronchial asthma, mononeuritis multiplex, vasculitis purpura, and sinusitis that was detected during etiological investigations, the patient was diagnosed as having CSS according to the American College of Rheumatology diagnostic criteria. Intravenous methylprednisolone 1 g/day was administrated for 3 consecutive days and 1 g cyclophosphamide was started and continued monthly for 6 months. Foot drop and vasculitic purpura improved after 7 days, but there was no further improvement in visual acuity. In conclusion, in the presence of bilateral CRAO and lack of atherosclerotic risk factors, CSS should be considered as a predisposing factor and investigations should be conducted accordingly.

Background: C3 glomerulopathy (C3G) is a recent disease classification that is characterized by the presence of glomerular deposits (composed of C3) in the absence of significant amounts of immunoglobulin and comprises dense deposit disease and C3 glomerulonephritis (C3GN). Most C3GN manifests as membranoproliferative, mesangial proliferative glomerulonephritis patterns via light microscopy. Pure membranous nephropathy (MN)-like glomerular lesions are rare manifestations of C3GN. Anti-neutrophil cytoplasmic antibodies (ANCAs) are also seldomly reported to be positive in C3GN. Herein, we report the case of a C3GN patient presenting with an MN-like glomerular pattern with ANCA positivity., Case Presentation: A 68-year-old woman was admitted to a local hospital with elevated serum creatinine for two weeks. Laboratory tests showed a hemoglobin level of 85 g/L. Urinalysis was positive for 2 + protein and 360 RBCs/HPF. Blood biochemistry analysis revealed the following concentrations: albumin, 30.3 g/L; globulin, 46.2 g/L; blood urea nitrogen, 19.9 mmol/L; and serum creatinine, 234 µmol/L. The serum C3 level was 0.4950 g/L, and the serum C4 level was 0.1050 g/L. The direct Coombs test was positive. Serologic testing for ANCA revealed the presence of p-ANCA (1:10) by indirect immunofluorescence microscopy assay, as well as the presence of PR3 1.2 (normal range < 1) and MPO 3.5 (normal range < 1) by enzyme immunoassay. Renal biopsy sample pathology showed 2/6 cellular crescents and thickened glomerular basement membranes. Immunofluorescence testing revealed only diffuse, finely granular depositions of C3 along the glomerular capillary walls in frozen and paraffin-embedded tissue sections. Electron microscopy demonstrated the presence of subepithelial electron-dense deposits, similar to those that are observed in membranous nephropathy. Corticosteroid and cyclophosphamide were administered, with a subsequent improvement in renal function., Conclusions: We present the rare case of a patient with MN-like C3GN with ANCA positivity. C3GN with ANCA positivity may be represented by more crescents, severe renal dysfunction and more extrarenal manifestations. More cases are needed to elucidate the clinicopathologic features and optimal treatments of these patients.

Background: Rapidly 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)., Methods: Clinical 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., Results: In 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, p<0.0001), platelet count (HR 0.996, 95% CI 0.992 to 1.000, p=0.046) and serum globulin (HR 0.905, 95% CI 0.854 to 0.959, p=0.001). Patients with lower sC3 levels showed a worse renal outcome than the patients with normal sC3 at diagnosis (p=0.003). Analysis of the components of the renal deposits found that patients with IgG deposits exhibited a poorer renal outcome compared to patients that were IgG negative (p=0.028). Moreover, Bowman's capsule rupture occurred less frequently in patients with IgM deposition compared with IgM negative counterparts (p=0.028). Vascular lesions and granuloma-like lesions had been seen more frequently in cases with IgA deposition than those without IgA deposition (p=0.03 and 0.015, respectively)., Conclusion: In 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., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer SH declared a shared affiliation with several of the authors, JO and PE, to the handling editor at the time of review., (Copyright © 2021 Lin, Shen, Zhong, Ooi, Eggenhuizen, Zhou, Luo, Huang, Chen, Wu, Meng, Xiao, Ao, Peng, Tang, Yin, Xiao, Zhou and Xiao.)

Granulomatosis with polyangiitis (GPA) is a rare necrotising small vessel vasculitis typically associated with oronasal, pulmonary and renal manifestations. Pancreatic disease is an exceedingly rare initial presentation and is associated with delayed diagnosis and rapid progression. We discuss a 66-year-old woman presenting with epigastric pain, elevated lipase and radiographic evidence of focal pancreatitis. She had no relevant medical history and no lithiasis seen on imaging. Pertinent findings include strawberry gingivitis, positive proteinase-antineutrophil cytoplasm antibody (98% specificity) and focal nodular parenchymal lung lesions on CT chest-all of which are consistent with a diagnosis of GPA. She was promptly started on high-dose steroids which resulted in significant clinical and biochemical improvement. Cyclophosphamide was added once biopsy confirmed the absence of malignancy. In order to optimise the clinical outcomes of GPA, physicians must keep a wide differential and high index of suspicion in the setting of unexplained pancreatitis with systemic features., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: In our study, diagnostic and demographic characteristics of patients diagnosed with RPGN by biopsy, clinical and laboratory findings in our country were investigated., Methods: Data were obtained from the Turkish Society of Nephrology Glomerular Diseases (TSN-GOLD) Working Group database. Demographic characteristics, indications for biopsy, diagnosis of the glomerular diseases, comorbidities, laboratory and biopsy findings of all patients were recorded. According to their types, RPGN patients were classified as type 1 (anti-GBM related), type 2 (immuncomplex related) and type 3 (pauci-immune)., Results: Of 3875 patients, 200 patients with RPGN (mean age 47.9 ± 16.7 years) were included in the study which constitutes 5.2% of the total glomerulonephritis database. Renal biopsy was performed in 147 (73.5%) patients due to nephritic syndrome. ANCA positivity was found in 121 (60.5%) patients. Type 1 RPGN was detected in 11 (5.5%), type 2 RPGN in 42 (21%) and type 3 RPGN in 147 (73.5%) patients. Median serum creatinine was 3.4 (1.9-5.7) mg/dl, glomerular filtration rate was 18 (10-37) ml/min/1.73m 2 and proteinuria 2100 (1229-3526) mg/day. The number of crescentic glomeruli ratio was ratio 52.7%. It was observed that urea and creatinine increased and calcium and hemoglobin decreased with increasing crescentic glomerular ratio., Conclusions: Our data are generally compatible with the literature. Advanced chronic histopathological findings were prominent in the biopsy of 21 patients. Early biopsy should be performed to confirm the diagnosis of RPGN and to avoid unnecessary intensive immunosuppressive therapy. In addition to the treatments applied, detailed data, including patient and renal survival, are needed.

There is a recognized association between silica exposure and Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV); however, no clear association between silica exposure and Immunoglobulin A (IgA) nephropathy. We describe the case of a 26-year-old male stonemason who presents with hilar lymphadenopathy, haematuria and acute kidney injury related to silica exposure, AAV and IgA nephropathy. He was asymptomatic on presentation; urinalysis revealed glomerular haematuria (>1000 red blood cells/L) and proteinuria (protein-to-creatinine ratio 84 mg/mmol). ANCA anti-myeloperoxidase serology was strongly positive. Mediastinal lymph node biopsy revealed multiple necrotizing granulomas with silica inclusions, and renal biopsy demonstrated crescentic glomerulonephritis and mesangial IgA staining. The patient was treated with cyclophosphamide and high-dose prednisolone with subsequent improvement in renal function. To our knowledge, this is the first report of both ANCA vasculitis and IgA nephropathy in the setting of silica exposure. This case highlights the relevance of occupational exposures in renal disease, and the immune-stimulatory effect of silica., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

This document follows up on a 2017 revised international consensus on anti-neutrophil cytoplasm antibodies (ANCA) testing in granulomatosis with polyangiitis and microscopic polyangiitis and focuses on the clinical and diagnostic value of ANCA detection in patients with connective tissue diseases, idiopathic interstitial pneumonia, autoimmune liver diseases, inflammatory bowel diseases, anti-glomerular basement membrane (GBM) disease, infections, malignancy, and during drug treatment. Current evidence suggests that in certain settings beyond systemic vasculitis, ANCA may have clinical, pathogenic and/or diagnostic relevance. Antigen-specific ANCA targeting proteinase-3 and myeloperoxidase should be tested by solid phase immunoassays in any patient with clinical features suggesting ANCA-associated vasculitis and in all patients with anti-GBM disease, idiopathic interstitial pneumonia, and infective endocarditis associated with nephritis, whereas in patients with other aforementioned disorders routine ANCA testing is not recommended. Among patients with autoimmune liver diseases or inflammatory bowel diseases, ANCA testing may be justified in patients with suspected autoimmune hepatitis type 1 who do not have conventional autoantibodies or in case of diagnostic uncertainty to discriminate ulcerative colitis from Crohn's disease. In these cases, ANCA should be tested by indirect immunofluorescence as the target antigens are not yet well characterized. Many questions concerning the optimal use of ANCA testing in patients without ANCA-associated vasculitis remain to be answered., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Vasculitides associated with anti-neutrophil cytoplasmic antibodies are heterogeneous, systemic, low prevalence and high morbidity and mortality entities. They include granulomatosis with polyangiitis, microscopic polyangiitis and eosinophilic granulomatosis with polyangiitis. In Latin America, there are few descriptive registries of these patients. The objective of the study was to describe the demographic and clinical characteristics and in-hospital morbidity and mortality of patients with vasculitis associated with anti-neutrophil cytoplasmic antibodies in a university hospital in Colombia. This was a cross-sectional descriptive study. We performed computer searches with terms related to patients with anti-neutrophil cytoplasmic antibody-associated vasculitis, between 2005 and 2017 who met the American College of Rheumatology classification criteria for vasculitis associated with anti-neutrophil cytoplasmic antibodies, and their clinical and laboratory characteristics. One hundred and six patients with anti-neutrophil cytoplasmic antibody-associated vasculitis were included in the study. The average age was 55 years, and 57.5% were women. In 68.8% of the cases, the diagnosis was made during hospitalization, with an average hospital stay of 16.6 days (± 12.22). The distribution by type of vasculitis was: granulomatosis with polyangiitis 52%, microscopic polyangiitis 45.2% and eosinophilic granulomatosis with polyangiitis 1.8%. Alveolar hemorrhage occurred in 35% of patients; 20.7% had variable renal involvement, of which 53.8% progressed to advanced kidney disease. Treatment included glucocorticoids 91.5%, cyclophosphamide 62.2%, plasmapheresis 14.1%, and 41.5% required renal replacement therapy. In-hospital mortality was 16.5%, Sepsis was the most common cause of death. We present clinical information on a group of patients with anti-neutrophil cytoplasmic antibody-associated vasculitis; renal involvement was the the most common type of affectation. Both the clinical and serological characteristics of our registry were similar to those described in other Latin American and European cohorts, and a lower in-hospital mortality rate was evidenced.

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Background and Objectives: Social deprivation is a recognized risk factor for undifferentiated CKD; however, its association with glomerular disease is less well understood. We sought to investigate the relationship between socioeconomic position and the population-level incidence of biopsy-proven glomerular diseases., Design, Setting, Participants, & Measurements: In this retrospective cohort study, a provincial kidney pathology database (2000-2012) was used to capture all incident cases of membranous nephropathy ( n =392), IgA nephropathy ( n =818), FSGS ( n =375), ANCA-related GN (ANCA-GN, n =387), and lupus nephritis ( n =389) in British Columbia, Canada. Quintiles of area-level household income were used as a proxy for socioeconomic position, accounting for regional differences in living costs. Incidence rates were direct standardized to the provincial population using census data for age and sex and were used to generate standardized rate ratios. For lupus nephritis, age standardization was performed separately in men and women., Results: A graded increase in standardized incidence with lower income was observed for lupus nephritis ( P <0.001 for trend in both sexes) and ANCA-GN ( P =0.04 for trend). For example, compared with the highest quintile, the lowest income quintile had a standardized rate ratio of 1.7 (95% confidence interval, 1.19 to 2.42) in women with lupus nephritis and a standardized rate ratio of 1.5 (95% confidence interval, 1.09 to 2.06) in ANCA-GN. The association between income and FSGS was less consistent, in that only the lowest income quintile was associated with a higher incidence of disease (standardized rate ratio, 1.55; 95% confidence interval, 1.13 to 2.13). No significant associations were demonstrated for IgA nephropathy or membranous nephropathy., Conclusions: Using population-level data and a centralized pathology database, we observed an inverse association between socioeconomic position and the standardized incidence of lupus nephritis and ANCA-GN., (Copyright © 2020 by the American Society of Nephrology.)

Background: We investigated the characteristics of antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (ANCA-GN) and immunoglobulin G4 (IgG4)-related kidney disease (IgG4-RKD) overlap syndrome., Methods: This is a 2-center study with 19 patients., Results: Fifteen patients were classified as microscopic polyangiitis (MPA). The initial serum creatinine levels were 320.9 ± 191.4 μmol/l and the BVAS was 19.7 ± 7.4 at diagnosis. Hematuria was absent or slight in 13 (68.4%) cases. Renal histology of these patients revealed concurrent ANCA-GN and IgG4-RKD. Regarding the histological classification of ANCA-GN, 9 (47.4%), 8 (42.1%), 1 (5.3%) and 1 (5.3%) patients were classified as focal, crescentic, mixed and sclerotic ANCA-GN, respectively. MPO-ANCA could be detected in 17/19 (89.5%) patients. IgG subclasses of MPO-ANCA were tested in 10 patients, and all were positive for IgG4-MPO-ANCA. In patients with combined ANCA-GN and IgG4-RKD, the percentage of positive IgG1-MPO-ANCA was significantly lower than the control group of 20 AAV patients without IgG4-RKD (P = 0.002), and the percentage of positive IgG4-MPO-ANCA was higher than the control group, but this difference was not statistically significant (P = 0.14)., Conclusions: ANCA-GN and IgG4-RKD overlap syndrome concerned mainly MPO-ANCA positive patients. The IgG subclass analysis of MPO-ANCA showed lower percentage of IgG1 subclass. The association between ANCA-GN and IgG4-RKD is possible and represents a special entity., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Antimyeloperoxidase (anti-MPO) is regarded as one of the most important circulating autoantibodies for anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAVs). Hence, it is crucial for highly sensitive detection of anti-MPO to monitor efficacy of AAVs in clinical diagnosis. Herein, a highly sensitive electrochemiluminescence (ECL) immunosensor for anti-MPO detection was constructed by combining reduced graphene oxide-supported PtCo nanocubes hybrids (PtCo@rGO) with hybridization chain reaction (HCR) as signal amplification. Multiple ECL luminophores (Dox-ABEI) prepared by cross-linking of N-(aminobutyl)-N-(ethylisoluminol) (ABEI) and doxorubicin (Dox) were intercalated into dsDNA products of HCR, achieving the effective immobilization of ECL luminophores to obtain strong ECL emission. Benefiting from the efficient catalytic activity of PtCo@rGO toward H 2 O 2 , the massive the superoxide radical (O 2 ● -) were generated to further react with ABEI for ECL emission. Thus, the designed ECL immunoassay for anti-MPO detection exhibited excellent sensitivity of a concentration variation from 50 fg/mL to 1 ng/mL and a detection limit of 15.68 fg/mL. Importantly, this work proposed an enzyme-free ECL immunoassay with high sensitivity, excellent specificity for protein detection in clinical diagnosis., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Primary membranous nephropathy (PMN) is a common cause of adult nephrotic syndrome, most commonly associated with autoantibodies against M-type phospholipase A2 receptor (PLA2R). Eosinophilic granulomatosis with polyangiitis (EGPA), previously known as Churg-Strauss syndrome, is a rare disorder characterized by asthma, eosinophilia, and multiorgan vasculitis. Here, we report the case of an adult who presented with typical nephrotic syndrome. Renal biopsy revealed PLA2R-positive PMN without crescents. He had a history of asthma, eczema, and eosinophilia, and testing revealed positive serological proteinase 3 (PR3) and antineutrophil cytoplasmic antibody (ANCA). Further skin and bone marrow biopsy revealed histologic eosinophilic infiltration, and a diagnosis of EGPA was made. The renal biopsy revealed a few eosinophils in glomerular capillary lumen and tubulointerstitial. Treatment with a glucocorticoid and cyclophosphamide was initiated. At 32 months after completing therapy, the patient was in complete clinical remission, and the PR3-ANCA result was negative.

Background: Multiplex bead assays, also known as addressable laser bead immunoassays (ALBIA) or Luminex® technology, have provided an alternative to enzyme-linked immunoassay, which is still the most widely utilized routine immunoassay for detection of specific autoantibodies. Our laboratory adopted the ALBIA technology early into its routine service., Methods: We report the performance and utility of measurement of three different autoantibody types tested using the FIDIS (BMD, Marne La Vallee, France) ALBIA system. The analytes discussed are thyroid antibodies (thyroglobulin [TG], thyroid peroxidase [TPO]), anti-neutrophil cytoplasmic antibodies (ANCA), and ribonucleo-protein (RNP) antibodies., Results: In single antibody analysis, TPO antibody testing was superior to TG antibody in identifying patients with Graves' disease and Hashimoto's thyroiditis. However, testing only TPO antibody would result in missing 8.6% of Graves' and 11.9% of Hashimoto's thyroiditis patients, hence demonstrating an advantage for the multiplex TG plus TPO assay. With respect to ANCA, the FIDIS ALBIA produced an overall similar level of performance to our comparator method, the Phadia fluorescent enzyme linked immunoassay. Sensitivity of the ALBIA for RNP antibodies was low in comparison to countercurrent immunoelectrophoresis, but performance was improved by altering the cutoff value for the assay., Conclusions: ALBIA technology has many potential advantages in the routine laboratory, but as with any new assay, evaluation must be thorough and ongoing to ensure satisfactory clinical performance is obtained. Both false positive and false negative results have been reported in ALBIA studies. It may be necessary to re-evaluate assay performance and cutoff and consider further clinical correlation.

Scleroderma renal crisis (SRC) remains a high-risk clinical presentation, and many patients require emergency department (ED) management for complications and stabilization. This narrative review provides an evidence-based summary of the current data for the emergency medicine evaluation and management of SRC. While SRC remains a rare clinical presentation, surveillance data suggest an overall incidence between 4 and 6% of patients with scleroderma. The diagnostic criteria for SRC include a new onset blood pressure > 150/85 mm Hg OR increase ≥ 20 mm Hg from baseline systolic blood pressure, along with a decline in renal function, defined as an increase serum creatinine of ≥ 10% and supportive features. There are many risk factors for SRC, including diffuse and rapidly progressive skin thickening, palpable tendon friction rubs, and new anemia or cardiac events. Critical patients should be evaluated in the resuscitation bay, and consultation with the nephrology team for appropriate patients improves patient outcomes.

Objective: The aim of this study was to assess disease characteristics, autoantibodies, and disease activity in granulomatosis with polyangiitis (GPA) patients with ocular manifestations., Methods: The cohort included 46 GPA patients visiting the ophthalmology clinic. Ocular manifestations were recorded, clinical and slit lamp examinations were performed. The Birmingham Vasculitis Activity Score (BVAS) was recorded. Laboratory investigations and the antineutrophil cytoplasmic antibody (ANCA) assay were performed., Results: Median age of the 22 male and 24 female patients was 44.5 (32-63) years, median disease duration 6.5 (1-16) years. Ocular manifestations were present in all patients: 12 (26.1%) had proptosis; 40 (87%) had scleritis/episcleritis, with perforation in 3 (6.5%); 33 (71.7%) had keratoconjunctivitis (KC), with acute infiltrative stromal keratitis in 11, peripheral ulcerative keratitis in 15, and sclerosing keratitis in 11 patients. Uveitis was present in 11 (23.9%) and retinal changes including vasculitis, exudates, and hemorrhage were present in 7 (15.2%). Blurred vision was present in 43 (93.5%) patients and 2 (4.3%) had vision loss. Glaucoma was present in 4 (8.7%) and hypotony in 2 (4.3%) patients. Involvement was bilateral in 32 (69.6%) patients. Rheumatoid factor (RF) was positive in 56.5% and significantly associated with uveitis (p = 0.04), while antinuclear antibody (ANA) was positive in 45.7% and significantly associated with KC (p = 0.04). BVAS tended to be higher in patients with uveitis (p = 0.49)., Conclusion: Ocular involvement must be considered in all GPA patients and referral to an experienced ophthalmologist is mandatory for proper management and improved outcome of such a rare systemic disease. ANA and RF positivity may raise suspicion for KC or uveitis, respectively. There was a remarkable association between uveitis and disease activity.

Objectives: We aimed to elucidate the frequency and associations of MPO-ANCA positivity in patients without ANCA-associated vasculitis (AAV), in a large urban, multi-ethnic teaching hospital., Methods: Retrospective review of 200 patients identified as MPO-ANCA positive over a five-year period at Royal Free Hospital, London, UK., Results: The incidence of anti-MPO positivity in patients without AAV was 39.5%. Gastrointestinal tract disorders, infections and other connective tissue disorders made up the majority of diagnoses, and there was a higher incidence of other concomitant autoantibodies compared to the group with known AAV. Renal disease was common in non-vasculitic patients with anti-MPO antibody positivity (occurring in 48%), the majority of whom went on to renal biopsy to exclude vasculitic involvement., Conclusions: The high incidence of MPO-ANCA positivity in patients with non-vasculitic conditions highlights the need for careful clinical correlation and confirmatory tissue diagnosis.

A kidney biopsy is done to determine the etiology of the glomerulonephritis (GN) and the severity of the lesion, to identify whether other lesions, related to or not related to the GN, are present on the kidney biopsy and finally to ascertain the extent of chronicity of the GN. The etiology of GN is based on the classification of GN into five groups: immune complex-mediated GN, antineutrophil cytoplasmic antibody (ANCA)-associated GN, anti-glomerular basement membrane (GBM) GN, monoclonal immunoglobulin-mediated GN and C3 glomerulopathy. Immune complex GN includes multiple specific diseases such as lupus nephritis, IgA nephropathy, infection-related GN and fibrillary GN. ANCA GN, anti-GBM GN and C3 glomerulopathy are specific diseases in themselves, while monoclonal Ig GN includes proliferative GN with monoclonal Ig deposits and monoclonal Ig deposition disease. Thus identification of the class of GN and within it the specific disease determines the etiology of GN. Ancillary studies may be required to confirm the etiology of GN. The severity of the GN is revealed by the pattern of injury, such as crescentic, necrotizing, diffuse proliferative, exudative, membranoproliferative, mesangial proliferative or a sclerosing GN. Secondary diagnosis either related or unrelated to the GN, such as diabetic glomerulosclerosis, acute tubular necrosis or thrombotic microangiopathy, may also be present. The secondary diagnosis may sometimes be the reason for the kidney biopsy. The chronicity of GN is determined by evaluating the extent of glomerulosclerosis, tubular atrophy and interstitial fibrosis and vascular sclerosis present on the biopsy. This review summarizes the approach to standardizing a kidney biopsy report that includes these components in a logical and sequential manner.

The eventual presence of anti-neutrophil cytoplasmic antibodies (ANCA) can initially be screened with indirect immunofluorescence (IIF). The majority of laboratories that facilitate ANCA testing use commercial kits. Although in-house assays are not encouraged in routine clinical laboratories, knowledge on the methodological aspects of the assay remains of importance. These aspects include choice of substrate, choice of fixative, staining procedure, and interpretation procedure. In this paper details on the methodology are provided and discussed in the context of the clinical application.

Neutrophils have long been considered a homogeneous cell type where all circulating cells of a particular individual express the same proteins. Lately, however, this view is changing and distinct neutrophil subsets, defined by the presence or absence of different proteins, are being increasingly recognized. At least two separate protein markers, CD177 and Olfactomedin-4 (OLFM4) are known to be expressed by some, but not all, circulating neutrophils of a given individual. We recently described the existence of subset-restricted serum autoantibodies targeting OLFM4; these were discovered during clinical testing for anti-neutrophil cytoplasmic antibodies (ANCAs). ANCA testing is part of the clinical examinations routinely carried out to support diagnosis of suspected autoimmune conditions, especially vasculitis. Positive sera typically react with all neutrophils from a single donor, whereas subset-restricted ANCA sera (such as those containing anti-OLFM4 antibodies) only react with a fraction of neutrophils. Described in this chapter is an indirect immunofluorescence (IIF) approach to test human sera for the presence of subset-restricted ANCA as well as instructions for costaining experiments using sera and purified antibodies directed against established subset markers.

Rational: Granulomatous polyangiitis (GPA) is a type of vasculitis involving medium and small arteries, typically affecting the upper and lower respiratory tract with coexisting glomerulonephritis. GPA is also characterized by necrotizing granulomatous inflammation and the presence of antineutrophil cytoplasm antibodies (ANCA). So far, various infections have lead to elevation of titers of serum ANCA, making it difficult to diagnose., Patient Concerns: We report a 50-year-old woman who was diagnosed as tuberculous lymphadenitis. During the treatment by anti-tuberculosis (TB) drugs, rapidly progressive renal failure and pleurisy had appeared with elevated titer of PR3-ANCA. Renal biopsy revealed crescentic glomerulonephritis., Diagnosis: Renal biopsy revealed crescentic glomerulonephritis and diagnosis of GPA was made., Interventions: Steroid therapy had been started with continuation of anti-TB drugs., Outcomes: Renal dysfunction had gradually recovered and pleurisy had disappeared with decreasing titer of PR3-ANCA., Lessons: This is the first report of GPA complicated by TB infection. When we encounter a case with rapidly progressive renal failure during the TB infection, complication of GPA should be suspected as 1 of the different diagnosis.

Objective: To investigate the change of circulating follicular helper T cells (cTfh) in patients with anti-neutrophil cytoplasmic myeloperoxidase antibody-associated vasculitis (MPO-AAV), and to analyze the relationship between cTfh and disease activity. Methods: Thirty-eight untreated MPO-AAV patients (patient group) and thirty-eight healthy volunteers (control group) were enrolled in this study. cTfh and membrane expression of inducible co-stimulator (ICOS) and programmed cell death protein 1 (PD-1) were detected by flow cytometry (FCM). Serum anti-neutrophil cytoplasmic myeloperoxidase antibody (MPO-ANCA) was measured by ELISA. Disease activity was evaluated by Birmingham vasculitis activity score (BVAS). Results: Compared with those in control group, the proportions of cTfh, ICOS(+)Tfh and PD-1(+) Tfh cells in patient group were significantly higher [(25.9±3.8)% vs. (21.0±5.3)%, P <0.001; (1.8±0.8)% vs. (0.8±0.5)%, P <0.001 and (10.2±2.8)% vs. (8.2±2.2)%, P= 0.001, respectively]. Meanwhile, the expression of ICOS and PD-1 on cTfh in patient group was markedly more intensive (59.6±10.0 vs.49.2±6.9, P <0.001 and 532.6±104.2 vs. 485.1±73.4, P= 0.025, respectively). In patient group, the proportion of cTfh was positively correlated with the ratio of ICOS(+)Tfh, the expression of ICOS, the level of MPO-ANCA and BVAS ( r= 0.407, P= 0.011; r= 0.705, P< 0.001; r= 0.737, P< 0.001 and r= 0.663, P< 0.001, respectively). The expression intensity of ICOS on cTfh was positively associated with ICOS(+)Tfh ratio, serum MPO-ANCA and BVAS ( r= 0.388, P= 0.016; r= 0.645, P< 0.001 and r= 0.653, P< 0.001, respectively). Nevertheless, the expression of PD-1 on cTfh was only positively correlated with the ratio of PD-1(+) Tfh ( r= 0.473, P= 0.003). Conclusions: Enhanced cTfh in patients with MPO-AAV might produce MPO-ANCA, which is related to the aggravation of MPO-AAV. Thus, cTfh and its ICOS could be potentially targeted for the treatment of MPO-AAV.