Objectives To investigate the association between decreased serum IgG levels caused by remission-induction immunosuppressive therapy of antineutrophil cytoplasmic antibody-associated vasculitis (AAV) and the development of severe infections. Methods We conducted a retrospective cohort study of patients with new-onset or severe relapsing AAV enrolled in the J-CANVAS registry, which was established at 24 referral sites in Japan. The minimum serum IgG levels up to 24 weeks and the incidence of severe infection up to 48 weeks after treatment initiation were evaluated. After multiple imputations for all explanatory variables, we performed the multivariate analysis using a Fine-Gray model to assess the association between low IgG (the minimum IgG levels < 500 mg/dl) and severe infections. In addition, the association was expressed as a restricted cubic spline (RCS) and analysed by treatment subgroups. Results Of 657 included patients (microscopic polyangiitis, 392; granulomatosis with polyangiitis, 139; eosinophilic granulomatosis with polyangiitis, 126), 111 (16.9%) developed severe infections. The minimum serum IgG levels were measured in 510 patients, of whom 77 (15.1%) had low IgG. After multiple imputations, the confounder-adjusted hazard ratio of low IgG for the incidence of severe infections was 1.75 (95% confidence interval: 1.03–3.00). The RCS revealed a U-shaped association between serum IgG levels and the incidence of severe infection with serum IgG 946 mg/dl as the lowest point. Subgroup analysis showed no obvious heterogeneity between treatment regimens. Conclusion Regardless of treatment regimens, low IgG after remission-induction treatment was associated with the development of severe infections up to 48 weeks after treatment initiation.

Introduction: Diffuse alveolar hemorrhage (DAH) is associated with high mortality. We examined the efficacy of plasma exchange (PE) therapy for reducing mortality in patients with patients with microscopic polyangiitis (MPA) and DAH. Methods: In this 52-week, nonrandomized, open-label, one-arm, historical control, double-center controlled trial, four patients with MPA and DAH admitted to Juntendo University Hospital or Juntendo Koto Geriatric Medical Center between 2018 and 2021 were enrolled. Sixteen patients with MPA and DAH admitted to the two centers between 1998 and 2018 who did not receive PE were included as the historical control group. The primary outcome was the 52-week survival rate of patients in each treatment arm. Results:The 52-week survival rate of patients in the PE group (n = 4) was higher than that of the historical control group (n = 16) (100% vs. 13%, p = 0.04). Conclusion:We found that PE may be efficacious for reducing mortality in patients with MPA and DAH.

Objectives: This study was conducted to determine autoantibodies associated with lupus nephritis, especially those useful in diagnosing proliferative and membranous nephritis. Methods: 106 patients with lupus nephritis and 63 patients with SLE but no nephritis were enrolled. 55 patients were selected from the lupus nephritis group and were divided into two groups: proliferative nephritis patients (n=36) and membranous nephritis patients (n=19). The autoantibody profiles of patients’ sera were evaluated using the EUROLINE ANA profile 3 (IgG) kit. Results: A higher positivity rate of anti-dsDNA antibody and anti-histone antibody were seen in lupus nephritis patients compared to non-renal SLE patients. In comparing between proliferative and membranous nephritis, positivity of anti-nucleosome antibody was higher in proliferative nephritis compared to membranous nephritis, although it was not statistically significant. However, anti-nucleosome antibody-positive patients with lupus nephritis had higher prevalence of hematuria and pyuria, which are strong indications of proliferative nephritis. Also, a significantly higher positivity rate of anti-RNP70 antibody was seen in membranous nephritis compared to proliferative nephritis. Conclusions: Our results showed anti-nucleosome antibody and anti-RNP70 antibodies may be predictive non-histological factors for discriminating between proliferative and membranous lupus nephritis.

Objectives Lupus cystitis is a rare but serious complication of systemic lupus erythematosus (SLE) that can cause permanent bladder dysfunction, leading to irreversible deterioration of kidney function. We report two cases of SLE with lupus cystitis who showed different images from the same cause of disease. Methods Patient 1, a 67‐year‐old woman diagnosed with SLE presented with persistent dysuria for 3 weeks with sudden headache and vomiting. She was hospitalized because of acute kidney injury; the serum creatinine level was 10.68 mg/dL. Computed tomography (CT) showed significant bilateral ureteral stenosis and bilateral hydronephrosis. Patient 2, a 45‐year‐old woman diagnosed with SLE presented with dysuria requiring self‐catheterization. CT showed significant bilateral ureteral dilatation and bilateral hydronephrosis. Results In patient 1, the right kidney was afunctional. Left nephrostomy was performed on Day 2. Her serum creatinine returned to the normal range. In patient 2, After admission, she changed to an indwelling bladder catheter. Her serum creatinine level improved from 2.04 to 1.31 mg/dL. Conclusion In patients with lupus cystitis, the urinary tract is commonly dilated, but stenosis has been seen in rare case. Physicians should be careful in diagnosing it.

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ObjectiveTo clarify seasonal and other environmental effects on the onset of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).MethodsWe enrolled patients with new-onset eosinophilic granulomatosis with polyangiitis (EGPA), microscopic polyangiitis (MPA), and granulomatosis with polyangiitis (GPA) registered in the database of a Japanese multicenter cohort study. We investigated the relationship between environmental factors and clinical characteristics. Seasons were divided into four (spring, summer, autumn, and winter), and the seasonal differences in AAV onset were analyzed using Pearson's chi-squared test, with an expected probability of 25% for each season.ResultsA total of 454 patients were enrolled, with a mean age of 70.9 years and a female proportion of 55.5%. Overall, 74, 291, and 89 patients were classified as EGPA, MPA, and GPA, respectively. Positivity for myeloperoxidase (MPO)-ANCA and proteinase 3 (PR3)-ANCA was observed in 355 and 46 patients, respectively. Overall, the seasonality of AAV onset significantly deviated from the expected 25% for each season (p=0.001), and its onset was less frequently observed in autumn. In ANCA serotypes, seasonality was significant in patients with MPOANCA (p<0.001), but not in those with PR3-ANCA (p=0.97). Additionally, rural residency of patients with AAV was associated with PR3-ANCA positivity and biopsy-proven pulmonary vasculitis.ConclusionThe onset of AAV was influenced by seasonal variations and was less frequently observed in autumn. In contrast, the occurrence of PR3-ANCA was not triggered by season, but by rural residency.