Natural History of Post-transfusion Non-A, Non-B Hepatitis

BACKGROUND:

Hepatitis following the transfusion of blood and blood products continues to be an important problem, despite routine hepatitis surface antigen (HBsAg) screening of donor blood. In the mid 1980s, seven to ten percent of transfused individuals developed post-transfusion hepatitis (PTH). The majority of the cases were ascribed to the virus(es) of NANB hepatitis. Because the viral agent or agents responsible for this disease had not been identified in 1988, it was not possible to prevent the illness. There was evidence that the incidence of NANB PTH could be reduced by the use of volunteer donor blood instead of commercial blood. Other measures, in the absence of a specific test, related to efforts to develop a surrogate test to screen donor blood. The most promising approach in 1988 was to measure ALT activity and to exclude donors with increased levels of the enzyme. The measurement of antihepatitis-B core antigen (anti-HBc) was another surrogate test that appeared to be useful. Acute hepatitis caused by this agent(s) is mild and often asymptomatic, although in rare instances fulminant hepatitis may result and indeed may be associated with a higher mortality than that occurring in the course of acute hepatitis A or B.

Of greater concern was the finding that chronic hepatitis appeared to be a common outcome of acute NANB PTH. Chronic NANB hepatitis was defined as the presence of chronic liver disease in a patient who was negative for the serologic markers of hepatitis B virus, hepatitis A virus, cytomegalovirus, and Epstein-Barr virus, and who did not have a history of drug toxicity, alcoholism, or heart failure.

It appeared likely that chronic liver disease occurred at least as commonly, and perhaps more commonly, following infection with the NANB virus(es) than with the hepatitis B virus. Furthermore, evidence suggested that the presumed serious histopathologic abnormalities of chronic active hepatitis and cirrhosis were also more common.

The chronic sequelae of NANB hepatitis infection may therefore be more important than the acute illness. That information was of profound importance to blood bankers. Because the most disturbing data had been derived primarily from isolated studies, suggesting possible regional overtones or an effect of large volume transfusion, it seemed appropriate to study the problem of chronic NANB hepatitis on a wider scale.