If You Cannot Grow it, Clone it! Hepatitis C Update

Abstract

In an innovative approach to viral discovery, the successful cloning of an increasing number of antigens from the genome of the hepatitis C virus (HCV) has led to the development of new multiantigen tests for the detection of viral antibody in infected individuals. In the United States, HCV is the most common cause of posttransfusion, parenteral, and sporadic non-A, non-B hepatitis. Sexual, mother-to-child, and intrafamilial are probable but inefficient modes of transmission. In approximately 40% of patients, no specific risk factors have been identified. Typically after infection, HCV viral RNA can be detected within days by polymerase chain reaction, and this is followed by an elevated alanine aminotransferase level within one or two months. Anti-HCV seroconversion takes 6 to 26 weeks to occur. Since HCV testing first began in the early summer of 1990, it is estimated that the number of cases of posttransfusion hepatitis has been reduced by approximately 50%; it is predicted that with the new testing, this figure will improve. However, mounting evidence suggests that as-yet-undiscovered infectious agents are responsible for cases of “non-A, non-B, non-C” hepatitis. Following accidental exposures and needle-stick injuries, prophylactic gamma globulin is indicated. Drug treatment of HCV infection is unsatisfactory, but ongoing prospective trials of new medications, such as thymosin α₁, offer hope.