急速進行性糸球体腎炎

Direct-acting antiviral (DAA) therapy has dramatically transformed the management of hepatitis C virus (HCV) infection in chronic kidney disease (CKD). Severe renal impairment and dialysis dependence are no longer considered major barriers to virologic cure. The main difficulties have shifted toward efficient diagnosis, choosing the regimen in the presence of cirrhosis and drug interactions, coordinating treatment with kidney transplantation, managing HCV-associated immune-complex kidney disease, and providing treatment in dialysis and resource-limited settings. This narrative review aims to discuss these issues in a decision-oriented manner, using verified guidelines, systematic reviews, important clinical trials, transplant cohorts, and studies of cryoglobulinemic disease, while explicitly comparing the strength and consistency of the underlying evidence and highlighting areas of genuine clinical uncertainty. Present evidence supports using the recommended DAA regimens without renal dose adjustment, while ribavirin needs dose modification when kidney function is reduced and can result in hemolytic anemia. Kidneys from HCV-viremic donors can be transplanted to recipients without HCV infection when proper informed consent, rapid access to DAA treatment, and organized post-transplant monitoring are available, although the minimum effective duration of peri-transplant antiviral prophylaxis remains unresolved. Antiviral therapy is the first-line treatment for HCV-associated glomerular disease, while rituximab-based immunosuppression is largely reserved for severe, rapidly progressive, or persistent cryoglobulinemic vasculitis. Future progress will depend less on proving antiviral efficacy and more on closing the gaps between screening, confirmatory testing, starting treatment, transplantation pathways, and long-term follow-up, gaps that stem from inequities in diagnostic infrastructure, drug reimbursement, and healthcare-system organization as much as from any remaining biomedical uncertainty.

This review describes vasculitis syndromes that can be diagnosed by kidney biopsy. Microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) typically follow a rapidly progressive course, often leading to end-stage renal failure within a few months, with crescentic glomerulonephritis being the predominant finding on a kidney biopsy. However, some types primarily present with fever and elevated C-reactive protein levels, while the kidney function is preserved; in such cases, a kidney biopsy shows arteriolitis. Eosinophilic granulomatosis with polyangiitis (EGPA) is characterized by eosinophil infiltration and small-artery arteritis, and the renal prognosis is often favorable. Anti-glomerular basement membrane (GBM) glomerulonephritis is a hyperacute form of progressive glomerulonephritis that leads to end-stage renal failure within a few weeks, with most glomeruli exhibiting synchronous necrotizing glomerulitis. Among immune complex-mediated small-vessel vasculitides, many cases of IgA vasculitis correspond to IgA nephropathy; however, cases accompanied by endocapillary hypercellularity have also been observed.

BACKGROUND: The study aimed to evaluate the efficacy and safety of eculizumab in addition to conventional therapy for anti-glomerular basement membrane (anti-GBM) disease presenting rapidly progressive glomerulonephritis (RPGN). METHODS: 42 patients with anti-GBM disease presenting with RPGN were included in this multicenter retrospective cohort study. All patients received intensive immunosuppressive therapy including intravenous methylprednisolone pulses followed by maintenance prednisone, in combination with at least two of the following: intravenous cyclophosphamide, therapeutic plasma apheresis, rituximab, or eculizumab. The cohort was stratified into two groups: the eculizumab group (n = 13) which received eculizumab (900 mg once weekly for 1-5 doses) in combination with other therapies, and the control group (n = 29) which did not receive eculizumab. Kidney survival at 12 weeks and 24 weeks, and adverse events (infections, metabolic alterations, laboratory abnormalities), ascertained via clinical and laboratory data. RESULTS: At 12 weeks, the eculizumab group showed significantly higher kidney survival compared with the control group (69.2% vs. 31.0%, p = 0.021). At 24 weeks, kidney survival remained numerically higher in the eculizumab group (66.7% vs. 40.7%, p = 0.081). Kaplan-Meier curves for renal survival by the Gehan-Breslow-Wilcoxon test, which places greater emphasis on early events, revealed a statistically significant difference between the groups (χ² = 4.137; p = 0.042); however, the difference assessed by the log-rank test did not reach statistical significance (χ² = 3.491; p = 0.062). There were no significant differences in the overall incidence of infections or other adverse events. CONCLUSION: Combined therapy with eculizumab showed improved early kidney survival for anti-GBM nephritis at 12 weeks, and did not increase the risk of adverse events. Prospective, large-sample studies with long-term follow-up are needed to validate its efficacy and safety.

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is a multisystem autoimmune disease that may present diagnostic challenges, particularly in patients with coexisting autoimmune conditions. Although the coexistence of rheumatoid arthritis and ANCA-associated vasculitis is recognised, vasculitis more commonly develops several years after rheumatoid arthritis onset. We describe a 68-year-old man who developed rapidly progressive glomerulonephritis due to myeloperoxidase (MPO)-ANCA-associated microscopic polyangiitis within 6 months of a diagnosis of seropositive rheumatoid arthritis. The diagnosis was established following an acute deterioration in renal function, positive MPO-ANCA serology and renal biopsy demonstrating pauci-immune necrotising crescentic glomerulonephritis. This case emphasises the importance of considering ANCA-associated vasculitis in patients with rheumatoid arthritis who develop acute kidney injury, even early in the disease course.

Variants in the inverted formin-2 (INF2) gene are a known cause of hereditary focal segmental glomerulosclerosis (FSGS) and Charcot-Marie-Tooth disease. We report a case of rapidly progressive FSGS associated with a rare INF2 variant. A 12-year-old boy developed proteinuria and was diagnosed with FSGS at age 14 following a renal biopsy. Steroid therapy and subsequent immunosuppressive treatments, including plasma exchange, were ineffective. At age 15, a heterozygous missense variant in exon 6 of the INF2 gene (c.763G>A, p.Asp255Asn) was identified. Despite conservative management, the patient progressed to end-stage kidney disease at age 17. Although exon 6 variants are rarely reported, the present case showed a relatively aggressive renal course.