Hepatitis C virus infection in Italian kidney graft recipients. Changing risk factors and hepatitis C virus genotypes.

BACKGROUND/AIMS: The risk for hepatitis C virus infection in kidney transplant recipients has been reduced by the introduction of accurate diagnostic tests. Little is known, however, of the current risk factors and the molecular genetics of hepatitis C virus infection in Italy. METHODS: We studied 101 Italian kidney allograft recipients, transplanted between 1975 and 1995, in Italy or abroad. Sera were assayed for biochemistry, presence of HBsAg, anti-hepatitis C virus antibodies, hepatitis C virus-RNA (by reverse transcription nested PCR) and hepatitis C virus genotyping. RESULTS: HBsAg was found in 4 sera and anti-Hepatitis C Virus antibodies in 33 (33%). The duration of pre-transplant dialysis was longer in anti-hepatitis C virus positive than in anti-hepatitis C virus negative patients (5.9 +/- 4.3 vs 2.8 +/- 1.9 years, p = 0.0004). Anti-hepatitis C virus seropositivity was more frequent among patients grafted before than after 1990 (50% vs 27%, p = 0.04) and varied depending on the country of transplantation (25% in Italy; 56% in other European countries; and 40% in non-European developing countries). Twenty-seven sera were hepatitis C virus-RNA positive, including 5 without anti-hepatitis C virus antibodies. Hepatitis C virus genotype 1b was found in 13 (48%) patients, the remainder being infected with genotypes 1a (6 cases), 2a, 2c, 3a and 4. Genotype 1b was largely predominant among patients grafted in Europe but never found in those transplanted in developing countries. All but one patient without a sustained antibody response were infected by non-1b genotypes. Hepatitis C virus-RNA seropositivity was associated (p = 0.03) with a higher dose of prednisone (p = 0.03) and a lower dose of cyclosporine (p = 0.05) used as immunosuppressants. CONCLUSIONS: Current risk factors for hepatitis C virus infection in Italian kidney graft recipients include the duration of haemodialysis, transplantation in developing countries and the level of post-transplant immunosuppression. The pattern of hepatitis C virus genotypes is changing from predominantly 1b to non-1b genotypes and the latter infection often occurs without a sustained antibody response. Few patients develop clinical liver disease.