Immunological studies in children with acute viral hepatitis.

Sera from 116 consecutive unselected cases of sporadic acute viral hepatitis in children were examined for hepatitis B antigen (HBAg), smooth-muscle autoantibodies (SMA), other autoantibodies and immunoglobulins, and skin tests were performed with dinitrochlorobenzene (DNCB). HBAg was detected in twenty-one and SMA in ninety-eight out of 116 sera that had been obtained during the 1st or 2nd week from the onset of jaundice. Hepatitis B antigen was present in seventeen out of the eighteen SMA negative patients (94-4%) and in only four out of the ninety-eight SMA-positive patients (4-1%).