Strong association between membranous nephropathy and hepatitis-B surface antigenaemia in Japanese children.

Renal histology in 163 Japanese children, aged 3 to 15, with proteinuria and/or haematuria showed that 11 had membranous nephropathy (M.N) and the rest had various other renal diseases. Hepatitis-B-virus surface antigen (HBsAg) was identified, by a reversed passive haemagglutination method, in the serum of all the patients with M.N. but in only 4.6% of the patients with other renal diseases. 6 of the 11 mothers of the children with M.N. were positive for HBsAg, and 1 was positive for antibody to HBsAg (anti-HBs). These findings suggest that M.N. in Japanese children is mainly, if not exclusively, caused by hepatitis-B virus and that in most instances the virus is transmitted from mother to child.