Clinicopathological Spectrum and Oxford Mest-C Correlates of Iga Nephropathy: A Retrospective Kidney Biopsy Study

Background: IgA nephropathy (IgAN) varies considerably in clinical presentation and renal biopsy morphology. Indian center-specific data remain important because biopsy practices and disease severity differ across settings. The study is designed to describe the biopsy proportion, clinical profile, immunofluorescence findings, Oxford MEST-C distribution, and selected clinicopathological associations in IgAN. Materials and Methods: This retrospective study reviewed native kidney biopsies diagnosed as IgAN at CPath Labs, Hyderabad, from May 2016 to September 2025. Seventy-two IgAN cases were identified among 1,608 native kidney biopsies. Demographic, laboratory, immunofluorescence, and histopathological data were extracted from existing records. Complete MEST-C scores were available in 59 cases. Mann-Whitney U or Kruskal-Wallis tests were used for serum creatinine comparisons, and chi-square or Fisher exact tests for categorical associations. A two-sided p<0.05 was considered significant. Results: IgAN accounted for 4.5% of native kidney biopsies. Mean age was 34.65 ± 14.29 years; 59.7% were male and 47.2% had hypertension. Mean serum creatinine was 2.66 ± 2.03 mg/dL, and C3c co-deposition occurred in 65.3%. Among 59 MEST-C-scored cases, M1, E1, S1, T1/T2, and C1/C2 were present in 27.1%, 50.8%, 66.1%, 45.8%, and 35.6%, respectively. Mean creatinine increased from 2.21 mg/dL in T0 to 2.94 in T1 and 3.38 in T2 (p=0.053). Positive urine sediment was associated with E1 (p<0.001) and crescentic lesions (p=0.001). No MEST-C component was significantly associated with dipstick albumin grade. Conclusion: The cohort showed frequent segmental sclerosis, endocapillary activity, crescents, and C3c co-deposition. Increasing creatinine across T scores suggested a clinically relevant burden of chronic tubulointerstitial injury. Longitudinal studies are needed to relate these lesions to kidney outcomes.