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.