IgA glomerulonephritis in Japan.

A clinicopathological study was done on 85 Japanese patients with IgA glomerulonephritis. Of patients with glomerulonephritis whose clinical course is of slow progression, the presence of IgA glomerulonephritis was demonstrated immunohistologically. The majority of such patients presented with a mild degree of proteinuria and/or persistent microscopic hematuria. In 15% of the patients, recurrent gross hematuria was noted. These findings suggest that immunohistological study is important in dealing with adult patients with so-called idiopathic renal hematuria. Light-microscopic findings of IgA glomerulonephritis were divided into 4 groups. In 56% of the patients, diffuse stalk thickening of the mesangium was noted and in one third of them, small crescent formations were present. In 22% of the patients, focal segmental proliferation was noted. Diffuse mesangial deposition of IgA noted by immunofluorescence was considered to correspond to the characteristic nodular deposition detected by light microscopy and to the relatively large globular hemispheric deposits detected by electron microscopy.