Reclassification of IgA Vasculitis and Nephritis Using Updated Oxford Classification of IgA Nephropathy in Pediatric and Adult Patients

Background The ISKDC classification for IgA vasculitis and nephritis (IgAVN) does not include markers of chronicity, and crescents—a key feature—do not reliably predict renal outcomes. Recent evidence suggests the updated Oxford classification for IgA nephropathy may offer improved prognostic value. This study aimed to compare clinical, laboratory, and histological features between adult and pediatric patients with IgAVN, categorize IgAVN renal biopsies using the updated Oxford classification and correlate clinical/laboratory data with both ISKDC and Oxford classification systems. Materials and Methods This retrospective study spanned 11 years and included IgAVN cases with at least 8 glomeruli per biopsy. Clinical and histopathological records were retrieved and analyzed. Cases were scored according to the updated Oxford classification of IgA nephropathy and the ISKDC classification for IgAVN. Results The study included 59 adults and children with IgAVN. ISKDC grade distribution was: I (3%), II (47%), III (38.9%), IV (8.4%), VI (1.6%). Biopsy MEST-C scores were: M1 (44%), E1 (61%), S1 (18.6%), T1 (8.4%), T2 (1.6%), C1 (35.5%), C2 (11.8%). Markers of chronicity (glomerulosclerosis, tubular atrophy, interstitial fibrosis), mean creatinine, and eGFR were significantly more altered in adults. In the Oxford system, creatinine at presentation correlated with the T score, and active sediments with the M score. No clinical or laboratory parameters correlated with ISKDC grade. At final follow-up, 97.3% of patients achieved remission. Conclusion The updated Oxford classification correlates more strongly with laboratory findings at presentation across age groups than the ISKDC classification. Long-term follow-up is necessary to evaluate its clinical utility.