Mesangial IgA nephropathy with steroid-responsive nephrotic syndrome: disappearance of mesangial IgA deposits following steroid-induced remission.

This report describes the clinical features and renal biopsy pathology in two patients with immunoglobulin A (IgA) nephropathy and nephrotic syndrome before and after steroid-induced remission. Apart from confirming the frequently relapsing course and mild glomerular changes observed in patients with IgA nephropathy and steroid-responsive nephrotic syndrome (SRNS), we were able to show that mesangial expansion and mesangial IgA deposits disappeared or were greatly reduced in repeat renal biopsies following steroid-induced remission. Because mesangial IgA deposits usually persist in repeat biopsies obtained from patients with typical IgA nephropathy, their resolution in our patients following steroid remission would support the proposal that the association of IgA nephropathy and SRNS may represent a distinct clinical syndrome. It is postulated that the presence of mesangial IgA deposits during nephrotic presentation and their disappearance following steroid-induced remission may result from increased mesangial sequestration of IgA circulating immune complexes (CIC) during the period of enhanced glomerular permeability and that the increased load of IgA CICs may reflect a common defect in mucosal immunity or immunoregulation in these patients.