Non-A, non-B post-transfusion hepatitis.

To clarify the role of hepatitis-A virus (H.A.V.) in the aetiology of post-transfusion hepatitis unrelated to hepatitis-B virus, we have tested and titred pre-transfusion and convalescent serum samples from 32 patients for antibody to hepatitis-A antigen (anti-HA) by quantitative immune adherence haemagglutination. 12 patients had no detectable anti-HA in either pre-transfusion or late convalescent serum; the other 20 had anti-HA in pretransfusion serum and no significant chance in titre during convalescence. This study excludes H.A.V. as the agent responsible for these cases of post-transfusion hepatitis and supports the existence of "non-A, non-B" hepatitis virus(es).