ad and ay subtypes of hepatitis B antigen in a case of hypogammaglobulinaemia.

We describe the finding of d and y specificities of hepatitis B surface antigen (HBsAg) in a case of hypogammaglobulinaemia of the 'common variable' type treated with fresh frozen plasma infusions. Absorption studies show that the two specificities are on separate particles, suggesting dual infection. It raises important questions regarding the relationship between HBsAg persistence and the immune status of the carrier.