RECOMBINANT IMMUNOBLOT ASSAY REACTION PATTERNS AND HEPATITIS-C VIRUS-RNA IN BLOOD-DONORS AND NON-A, NON-B-HEPATITIS PATIENTS

To establish the value of the second-generation recombinant immunoblot assay (RIBA-2) and cDNA polymerase chain reaction (cDNA PCR) for conf irmation of hepatitis C virus (HCV) infection, anti-HCV reaction patte rns and the presence of HCV RNA were examined in 610 blood donors and 255 non-A,non-B hepatitis patients who were positive or indeterminate in RIBA-2. Of RIBA-2-positive donors (n = 191) and patients (n = 224), 75.4 and 89.7 percent, respectively, were HCV RNA positive. The most frequently observed anti-HCV recognition patterns in HCV RNA-positive donors and patients were c22, c33c, and c100 and/or 5-1-1 (67.3%, 57.7 %) and c22, c33c (24.8%, 29.3%). Among subjects with a RIBA-2-indeterm inate result, HCV RNA was detected more often in patients (n = 31) tha n in donors (n = 419): 67.7 and 2.1 percent, respectively. In viremic persons with single-band reactivity in RIBA-2, this reactivity was alw ays directed against either c22 or c33c. HCV RNA was detected by cDNA PCR in none of 162 persons with only anti-c100 and/or anti-5-1-1 react ivity. Therefore, RIBA-2 reactivity against c100 in combination with 5 -1-1 should not be considered positive but indeterminate. In RIBA-2-in determinate persons, HCV RNA detection is necessary for reliable confi rmation of HCV infection.