The optimal duration of treatment and expected response rate for hepatitis C virus genotype (HCV-6)-infected patients have not been determined. Our aims were to determine the treatment outcome with pegylated interferon (PEG-IFN) plus ribavirin for HCV-6a-infected patients at Southwest Hospital and assess the association of the on-treatment virological response with the sustained virological response (SVR). Medical records were reviewed retrospectively. Twenty-two HCV-6a-infected patients were treated for 24 weeks, and 21 (95.5%) achieved an early virological response (EVR), 20 (90.9%) an end-of-treatment response (ETR) and 18 (81.8%) a SVR. However, only 18 of the 22 HCV-6a-infected patients were tested for serum HCV RNA level at week 4 of treatment and 15 (83.3%) achieved a rapid virological response (RVR). The rates of SVR, RVR, EVR and ETR in these patients were all similar to those in HCV-2/3 treated for 24 weeks and higher than those in HCV-1b-infected patients treated for 48 weeks. A lower relapse rate (10.0%) was seen in HCV-6a compared with HCV-2/3 (12.5%) or HCV-1b-infected patients (23.3%). The positive predictive values of RVR and EVR for HCV-6a were comparable with those for HCV-2/3-infected patients (86.7%vs 90.9%, P = 0.683 and 85.7%vs 86.8%, P = 0.904, respectively). Of the 3 HCV-6a-infected patients who did not achieve a RVR, 2 achieved an EVR and went on to achieve a SVR. The patient who did not achieve an EVR did not achieve a SVR. In summary, our results indicate that 24 weeks of PEG-IFN plus ribavirin can effectively treat patients with HCV-6a chronic infection.

A continuous cell line, LYCK, derived from the head kidney of large yellow croaker Pseudosciaena crocea was established and characterized. The LYCK cell line multiplied well in Leibovitz's-15 (L-15) medium supplemented with 10% foetal bovine serum (FBS) at 28° C. This cell line, with a population doubling time of 29·5 h at passage 35, has been subcultured for >70 passages. Microscopically, LYCK cells were fibroblast-like. Chromosomal analysis revealed that the modal diploid chromosome number of LYCK cells was 48, which was identical to that of the P. crocea kidney. The cellular fluorescence could be observed in LYCK cells at 48 h after being transfected with pEGFP-N1 plasmid DNA, indicating that LYCK cells were competent for target gene expression in vitro. The expression of mRNA transcripts of the antiviral immune-related molecules interferon regulatory factor-3 I(ir3), interferon regulatory factor-7 (irf7), melanoma differentiation-associated protein 5 (mda5) was obviously up-regulated in LYCK cells in response to the stimulation with poly (I:C), whereas the expression of mRNA transcripts of the inflammatory cytokines tumour necrosis factor-α2 (tnfTNF-α2), interleukin-8 (il8), CC chemokine (lycCC) was up-regulated by lipopolysaccharide. These results indicated that the LYCK cell line could serve as a valuable tool for studies on immune-related gene functions in vitro.