The strong association of HLA-DR4 with spherical mesangial dense deposits in IgA nephropathy.

41 Japanese patients with primary IgA nephropathy (IgA GN) were determined for HLA-A, -B, -C and -DR antigens. The frequency of HLA-DR4 increased slightly in total patients compared with 63 normal control persons, but this increase was not statistically significant. However, 24 patients with spherical mesangial dense deposits (SMDD) in electron micrograph out of 41 patients with IgA GN were found to have markedly increased incidence of HLA-DR4 (chi 2 = 11.52, Relative risk = 6.45, Corrected p less than 0.03). In contrast to this finding, 17 patients without SMDD had no association with any particular HLA antigens. These results suggest that IgA GN might be subdivided by the association of HLA and electron microscopic findings into at least 2 types.