Long-term follow-up of and infectivity in blood donors with hepatitis C antibodies and persistently normal alanine aminotransferase levels


1Angelo Rossini, MD, Assistant, Department of Internal Medicine, Università di Brescia, Medicina Interna III, Spedali Civili, P. le Spedali Civili 1, 25123 Brescia, Italy.


BACKGROUND: Little is known about the prevalence of serum hepatitis C virus (HCV) RNA in blood donors with HCV antibodies and persistently normal alanine aminotransferase (ALT) levels. STUDY DESIGN AND METHODS: Thirty-nine anti-HCV-positive donors with normal ALT on four determinations at 3-month intervals were further tested monthly for 6 months, and they had normal ALT values. The presence of HCV RNA was determined in these 39 donors. RESULTS: Serum HCV RNA was detected in 16 of 39 donors, 14 of 14 who reacted on second-generation recombinant immunoblot assay (RIBA-2) and 2 of 15 who were indeterminate. None of the 10 RIBA-2-nonreactive donors had evidence of viremia. The 15 RIBA-2- indeterminate samples were tested with third-generation RIBA (RIBA-3); the results showed reactivity in 5 (including the 2 HCV RNA positive), an indeterminate pattern in 7, and nonreactivity in 3 (all RNA negative). Among HCV RNA-positive subjects, mean age (p < 0.05), mean ALT (p < 0.001), signal-to-cutoff (S:CO) ratio on second-generation enzyme-linked immunosorbent assay (p < 0.001), and gamma globulin levels (p < 0.05) were higher than those among HCV RNA-negative subjects. During 6 additional months of ALT monitoring, completed by 36 of 39 donors, increased values were detected in 6 (5 HCV RNA positive). In 4 of those 6, however, ALT levels were less than 1.5-fold the upper normal limit. HCV RNA results were unchanged at the end of 1-year follow-up. CONCLUSION: Forty-one percent of anti-HCV-positive donors with persistently normal ALT had active HCV infection. Long-term ALT monitoring allowed the detection of significantly increased enzyme values in only 2 of 16 viremic donors. Reactivity on RIBA-2 or -3, greater age, mean ALT levels in the upper range of normal, higher S:CO ratio on second-generation enzyme-linked immunosorbent assay, and higher gamma globulin levels were predictive of viremia.