Fibrillary glomerulonephritis disease natural history and outcomes: a retrospective two centre cohort study.

backgroundFibrillary glomerulonephritis (FGN) is a rare immune complex-mediated glomerulonephritis characterised by the deposition of anomalous fibrillary structures within the glomeruli. The prognosis for patients with FGN is usually poor with rapid progression to end stage kidney disease (ESKD). There are currently limited data to suggest an optimal therapy strategy to prevent this. Most case series describing FGN come from North America with limited research from the UK.

methodsThis is a retrospective case series of patients who presented with biopsy proven FGN to two renal centres within the West Midlands, between 2006 and 2022.

resultsTwenty-one patients with a histological diagnosis of FGN were identified within the 16-year period. Median eGFR at the time of biopsy was 29 mL/min/1.7 (IQR 18-55), serum albumin 31 g/L (IQR 28-33) and ACR was 368 mg/mmol (IQR 303-596). The median follow-up for the cohort was 50 months (range 12-138). DNAJB9 staining was done for five patients, all were positive. Immunosuppression was used in 8 patients following diagnosis of FGN. Treatment varied between steroid, rituximab and cyclophosphamide. Patients with crescents on the biopsy were more likely to receive a trial of immunosuppression. Progression to ESKD was common, 7 (33%) patients required renal replacement therapy within 12 months of diagnosis of FGN.

conclusionsTo date, there are limited numbers of case series of FGN due to the rare nature of the disease. We describe the natural history of this rare kidney condition, and highlight the challenges faced by clinicians where evidence for successful therapeutic options is lacking.