Immunosuppressive Treatment in Children With IgA Nephropathy and the Clinical Value of Podocytopathic Features

Abstract

Introduction: There is a need for treatment guidelines and prognostic factor identification in children with primary IgA nephropathy. We analyzed the causative effect of steroids and the applicability of the Oxford classification. Methods: A total of 82 consecutive children (mean 10.6 years; median follow-up 3.3 years) were reviewed; 21 patients (25.6%) presented with acute kidney injury, and 6 (7.3%) with nephrotic syndrome. Renal biopsies were scored for Oxford classification and podocytopathic features in 2 groups: a group treated with steroid therapy (some in association with cyclophosphamide) and supportive care (renin angiotensin system blockade) and a group treated by supportive care alone. Results: The 2 groups were not comparable because baseline clinical data were different. Estimated glomerular filtration rate (eGFR) in immunosupressive group significantly improved between M0 (at onset) and M6 (6 months after treatment) from 89.9 [61.2–114.5] to 110.5 [93.7–120] ml/min per 1.73 m2, P < 0.001. Proteinuria also significantly decreased from (1.6 [1–4.3] to 0.3 [0.2–0.7] g/g, P < 0.001). In the supportive care group, eGFR and proteinuria remained stable. Podocytopathic features were predictive of renal function decline by univariable (−4.9 ± 14.9 ml/min per 1.73 m2, P = 0.0079) and multivariable analysis and of poor renal prognosis to a combined event (renal function impairment more than 10% of the eGFR baseline or chronic kidney disease stage 3 at 6 months) in univariable analysis. MEST-C score failed to prove its prognostic value. Conclusion: Immunosuppressive treatment, especially steroid therapy, seems beneficial in children with glomerular inflammation and proliferation. The Oxford classification does not appear to be entirely appropriate in predicting long-term renal prognosis for children, whereas the characteristics of podocytopathy are strongly predictive of renal prognosis. Keywords: children, histopathology, IgA nephropathy, renal biopsy, steroid