In an attempt to evaluate the prevalence, kinetics and impact of HCV infection in renal transplantation, we analyzed 140 kidney recipients according to the histopathological status of the liver. Thirty-three HBsAg-negative patients had chronic active hepatitis, 73 HBsAg-negative patients had a normal liver, 21 HBsAg-negative kidney recipients had minimal pathological changes and 13 patients had HBsAg-positive cirrhosis. Serum antibodies to HCV were detected using the ELISA from Ortho Diagnostic and confirmatory tests using the Ortho recombinant-based immunoblot assays. The overall prevalence of antiHCV antibodies was 23.6%. AntiHCV were more frequently present in HBsAg-negative patients with chronic active hepatitis (60.6%) than in HBsAg-negative patients with normal livers (8.2%) (p less than 0.0001) or minimal liver changes (33.3%) (NS) or in HBsAg-positive patients with cirrhosis (0%) (p less than 0.001). The recombinant-based immunoblot assays confirmed antiHCV-positive ELISA results in 86.7% of patients. Among the 27 antiHCV-positive kidney recipients who had serial serological follow-up, 10 (37.0%) were already positive at transplantation and remained antiHCV-positive during follow-up. Eleven patients (40.8%) acquired antiHCV an average of 95 months after renal transplantation, while antiHCV disappeared an average of 111 months after transplantation in six (22.2%), who had antiHCV prior to transplantation. The kinetics of antiHCV antibodies did not differ according to liver histology. Patient and graft survival were not different in antiHCV-positive and antiHCV-negative kidney recipients irrespective of liver histology, and there was no difference in survival between antiHCV-positive and antiHCV-negative patients with chronic hepatitis.(ABSTRACT TRUNCATED AT 250 WORDS)