Disappearance of glomerular IgA deposits in childhood IgA nephropathy showing diffuse mesangial proliferation after 2 years of combination/prednisolone therapy.

BACKGROUND: The prognosis of children with severe IgA nephropathy showing diffuse mesangial proliferation is poor. However, the prognosis can be improved by combination therapy (prednisolone + azathioprine or mizoribine + warfarin + dipyridamole) or prednisolone alone over a 2-year period, and disappearance of glomerular IgA deposits is often observed. Details of the incidence and clinicopathological significance of glomerular IgA disappearance remain unclear.
METHODS: To investigate this phenomenon, we retrospectively screened and analysed 124 consecutive children (age ≤ 18 years at first biopsy) with newly diagnosed severe IgA nephropathy showing diffuse mesangial proliferation, who received combination therapy or prednisolone alone for 2 years and underwent repeat biopsies.
RESULTS: Among these patients, 90 received combination therapy, and 34 received prednisolone alone. After 2 years of treatment, 27 of the patients (21.8%) showed disappearance of glomerular IgA. Logistic analysis showed that IgA disappearance was associated with less severe urinary protein excretion at the end of treatment. Kaplan-Meier analysis of the long-term course revealed a significant difference in proteinuria-free survival after the 2-year treatment period between the patients with IgA disappearance and those without (P = 0.008; log-rank test). The Cox proportional hazards model showed that disappearance of glomerular IgA after the treatment was a factor significantly associated with proteinuria-free survival in both univariate and multivariate analyses.
CONCLUSIONS: The present results suggest that disappearance of IgA after 2 years of treatment indicates milder disease severity, even in patients with diffuse mesangial proliferation, and is a prognostic factor related to proteinuria-free survival.