Non-A, non-B hepatitis and antibody to hepatitis C virus

Several forms of hepatitis have been found to be caused by specific viruses. The current terminology speaks of hepatitis-A which is caused by Hepatitis-A virus (HAV), and hepatitis-B which is caused by Hepatitis-B virus (HBV). Those individuals who have hepatitis which can not be identified on immunologic grounds as being A or B are classified as having non-A non-B (NANB) hepatitis. This disease is credited with being responsible for a large percentage of all hepatitis within the United States. NANB remains the major complication of blood transfusion with some 5 to 10 percent of all transfusions leading to infection. Recently an immunologic test reagent has been made against another newly-discovered virus, designated Hepatitis-C virus (HCV). Using recombinant gene systems, an artificial viral protein or antigen has been prepared that reacts with antibodies in the blood of HCV-infected individuals. This antigen has been used to test for evidence of HCV infection in the blood of individuals who have demonstrated NANB hepatitis. In a small group of 14 NANB hepatitis patients, five showed the presence of HCV infection. A group of four individuals who did not receive transfusions, but who developed hepatitis after hospitalization were also examined. Three of the four did not show the presence of HCV. These data strongly suggest that approximately 50 percent of all cases of NANB hepatitis that occur within the United States are due to infection with HCV. Of those cases of NANB hepatitis that are not linked to HCV, some may be caused by yet another hepatitis virus. These findings pave the way for new blood screening procedures to protect the integrity of the blood supply.