Gd-IgA1 deposits were localized in a pattern similar to that of IgA in mesangial areas in patients with lupus nephritis class I–IV and in capillary areas in patients with lupus nephritis class V. Gd-IgA1 deposition was also observed in three of four patients with membranoproliferative glomerulonephritis (MPGN) and one patient with primary membranous nephropathy accompanied by IgA deposition. Here, CD79A is linked to primary membranoproliferative glomerulonephritis.