Abstract: To investigate the relationship between hepatitis C virus(HCV)hypervariable region 1(HVR1) quasispecies complexity and the response to interferon (IFN) therapy． MethodsThe types of HCV were determined by the gene chip technique and the HVR1 quasispecies complexity was determined by the polymerase chain reactionmediated single strand conformation polymorphism (SSCP) method． ResultsAfter IFN treatment，the HCV RNA negative transformation rates in SSCP bands of HCV HVR1≤3 and ＞3(detected prior to the IFN treatment) were 77.78％ and 21.43％， and there were significant differences between them(P＜0.01)． The number of SSCP bands was 2.44±0.73 in the effective group while it was 4.50±0.65 in the ineffective group， also there were significant differences between them(P＜0.01). ConclusionThe high complexity of HCV HVR1 quasispecies indicates nonresponse to IFN therapy in patients with HCV 1 b infection, and it is an important predictive factor for the effectiveness of IFN therapy．

Key words: Chronic hepatitis C, Interferon, Quasispecies, Hypervariable region 1