Three groups of individuals were studied as depicted in Table 1 ; HCV mono-infected (n = 6), HCV/HIV co-infected who were not receiving HAART (n = 8) and HCV/HIV co-infected who were receiving HAART for greater than one year at the time of evaluation (n = 12). All individuals never received prior treatment for HCV and underwent liver biopsies for staging and evaluation for pegylated-interferon/ribavirin treatment. HCV/HIV co-infected individuals had higher HCV viral loads. On average, CD4 T-cell counts of HIV infected individuals were .400/ml in both groups. Of note, the mean hepatic fibrosis scores were higher in the HAART treated and mono-infected groups in this cohort, indicating that individuals in these groups had more advanced disease at the time of biopsy in this study.