Virological and immunological studies in patients with acute viral hepatitis.

One hundred and seven patients with acute viral hepatitis (AVH) were studied prospectively regarding the viral aetiological agent HAV, HBV and NANB (by exclusion) using radioimmunoassay. Acute HAV infection occurred in 43 patients, and acute HBV infection in 34 patients, while HDS occurred in two patients only. Acute, presumably NANB, infection occurred in 28 patients. Ten out of 28 sera of patients with AHBV infection were positive for smooth muscle antibody by immunofluorescence. Important findings include: (1) presence of delta superinfection in the absence of HBsAg; (2) HBsAg as the only marker in two patients with AHBV infection; (3) concurrent presence of HBsAg and anti-HBsAg in three patients with AHBV infection.