Crescents in native kidney biopsies from patients with IgA nephropathy and the risk of recurrence after kidney transplantation: a retrospective cohort study, systematic literature review and meta-analysis of observational studies.

Abstract

Background: IgA nephropathy (IgAN) is associated with a high risk of kidney failure. Whenever this occurs, the best treatment option is kidney transplantation. IgAN recurrence in the kidney allograft may increase the risk of allograft loss. The association of glomerular crescents in native IgAN is a negative prognostic factor for the progression to kidney failure. The aim of our study was to clarify whether the presence of crescents in native kidney biopsies represents a risk factor for IgAN recurrence in renal allografts.

Methods: The association between glomerular crescents in native kidney biopsies and IgAN recurrence was investigated in IgAN patients who underwent kidney transplantation at Lausanne University Hospital from 2003 to 2019. A systematic literature review was performed in MEDLINE, Embase, Cochrane CENTRAL, Web of Science and PMC from inception to November 2025, excluding reviews. Aggregate data were analyzed in a meta-analysis. The overall Risk Ratio (RR) with their corresponding 95% confidence interval (95% CI) was obtained via the Hartung-Knapp-Sidik-Jonkman adjustment method, after verifying heterogeneity (I2). Reporting bias was visualized in a funnel plot using STATA.

Results: The Lausanne cohort included 63 patients with IgAN who underwent kidney transplantation. We found no association between glomerular crescents in native kidney biopsies and IgA recurrence in the renal allograft. Five additional cohorts were included in our meta-analysis, ultimately merging data from 311 patients, of whom 23% with recurrent IgAN. Crescent prevalence ranged from 12 to 62%, confirming the absence of association with an increased risk of IgAN recurrence [RR 1.53 (95% CI: 0.40-5.90), P = .41].

Conclusions: Glomerular crescents, especially when present in more than 25% of viable glomeruli, remain an unfavorable prognostic factor for the progression of IgAN to kidney failure; however, they may not represent a risk factor for disease recurrence in renal allografts.