Hepatitis C virus superinfection of liver grafts: a detailed analysis of early exclusion of non-dominant virus strains

Liver transplantation (LT) of hepatitis C virus (HCV)-infected grafts into HCV-infected recipients leads to superinfection with two different virus strains. To characterize the virological outcomes of HCV superinfection immediately after LT, we performed phylogenetic analysis of a fragment of the NS5B gene in donor and recipient serum samples prospectively collected before and after LT, starting on day 1. In four of six cases, the donor strain finally prevailed, while in the remaining two cases, the native recipient strain overtook the donor quasispecies. Clonal sequence analysis showed that, in three cases, the expelled strain was undetectable 1 day after LT. Our study shows that superinfection with a different HCV strain can lead to the exclusion of one strain by the other as soon as the first day after LT. This would suggest that competition might not be limited to the replication level, but could also take place during virus entry.