Renal histology in pauci-immune rapidly progressive glomerulonephritis: 8-year retrospective study

Context: The need to perform reporting of renal biopsies of antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitides in a more uniform manner required relook at our eight-year data. Aims: To document detailed renal histopathology of pauci-immune rapidly progressive glomerulonephritis (RPGN) and also to seek any significant differences in renal histology of C-ANCA-positive, P-ANCA-positive, and ANCA-negative patients. Materials and Methods: A detailed analysis of the histopathologic features of renal biopsies of 48 patients in whom a diagnosis of pauci-immune glomerulonephritis was concluded on renal biopsy and who presented clinically as rapidly progressive renal failure was done. Statistical Analysis Used: One-way ANOVA and Pearson Chi square tests. Results: Compared with ANCA +ve patients, the ANCA -ve patients were much younger (46.85 +/- 16.12 years vs 34.28 +/- 15.94 years). No significant differences were found between renal lesions of C-ANCA, P-ANCA, and ANCA-negative patients, except for diffuse tubular atrophy which was more severe and more frequently present with P-ANCA positivity (P value=0.013). Conclusions: Pauci-immune RPGN (irrespective of ANCA status) is a relatively rare disorder in patients who are undergoing the renal biopsy at our institute, constituting 2% of all renal biopsies submitted. It is mandatory to have ANCA serology status during reporting of a kidney biopsy showing pauci-immune crescentic or necrotizing glomerulonephritis. Also, if a uniform reporting strategy is followed throughout the country, the studies from this vast country will be comparable.