New infection with heterotypic hepatitis C virus in a patient with long-term hepatitis C virus eradication

Background Experimental hepatitis C virus infection in chimpanzees has show n that natural hepatitis C virus infection does not induce protective immun ity and reinfection can occur in seroconverted animals. Aim. To study the clinical, virological and histological outcome of a new i nfection sustained by a different hepatitis C virus strain after a primary infection with eradication of the original virus. Patients and methods. A young Italian man with chronic hepatitis C virus ty pe 4 hepatitis was treated with Interferon therapy and achieved a sustained biochemical and virological response. After long follow-up, an asymptomati c flare-up of alanine transaminase occurred. This alanine transaminase incr ease was associated with serum hepatitis C virus PNA positivity and a low v iral load, and the infecting hepatitis C virus genotype was type 3. The cli nical and virological course of this new infection is described. Results and Conclusions. This report shows that there is no protective immu nity against hepatitis C virus type 3 after infection by hepatitis C virus type 4 strain.