In the absence of a specific marker, the observed prevalence of so called non-A non-B hepatitis depends on the sensitivity of the markers of the other viral infections known to induce hepatitis. We ...have reevaluated this prevalence after using sensitive markers of HBV (HBs monoclonal radioimmunoassay M-RIA and IgM anti-HBc), EBV (IgM anti-VCA), CMV (IgM anti-CMV) and HSV (IgM anti-HSV) in a group of 53 subjects usually considered as having acute or chronic hepatitis. Detection of IgM against HBc, CMV and HSV used immunocapture tests. Among the 37 patients with acute hepatitis, 11 (30 p. 100) were positive for at least one sensitive marker, including 10 markers of HBV (7 M-RIA and 3 IgM anti-HBc) and one IgM anti-CMV. Among the 16 patients with chronic hepatitis, one was positive for HBV by M-RIA; five patients had a false positive reaction to EBV (IgM anti-VCA) disappearing when rheumatoid factor was eliminated. This study shows that many cases of the so-called non-A non-B hepatitis are in fact due to HBV or to a variant of HBV. Definition of non-A non-B hepatitis must include subjects negative for HBV by M-RIA and IgM anti-HBc and negative for CMV by IgM anti-CMV.
