Immune protection against HCV is thought to be largely dependent upon the CD8 T cell response. Therefore using the latest T cell detection technology the investigators will develop a panel of tetramers specific for all potential HCV epitopes. To produce the tetramers the investigators will utilize HLA ligand exchange technology which allows the production of very large collections of peptide-HLA multimers for T cell staining. The investigators have already performed a large scale identification of HCVg1 and HCVg4 CD8 T cell epitopes using published viral sequences and algorithm prediction databases. Using this information the investigators are currently in the process of developing collections of peptide-HLA multimers for T cell staining. Therefore the investigators require large lymphocyte pools from HCV+ patients to test both the sensitivity and accuracy of each tetramer on the CD3+CD8+ T cells.