Longitudinal analysis of CD8 T-cell responses to HIV and hepatitis C virus in a cohort of co-infected haemophiliacs.
Harcourt, Gillian C a; Donfield, Sharyne b; Gomperts, Edward c; Daar, Eric S d; Goulder, Philip JR a; Phillips, Rodney E a; Klenerman, Paul a; Hemophilia Growth and Development Study (HGDS)
[Miscellaneous Article] AIDS. 19(11):1135-1143, July 22, 2005.

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Objective: To investigate CD8 T-cell responses to HIV and hepatitis C virus (HCV) over time in a group of co-infected children with haemophilia to assess the influence of the virus infections on each other and on clinical outcome.

Design: The HIV and HCV CD8 T-cell response of HLA-A2 co-infected individuals in the cohort were analysed at two time points, looking at the frequency and phenotype of HIV-specific T cells and assessing overall responses to the two viruses.

Methods: Peripheral blood mononuclear cells (PBMC) from 72 HLA-A2 co-infected individuals were analysed using an HIV HLA-A2 tetramer and by IFN-[gamma] ELISpot using a panel of HIV and HCV antigens. PBMC from a group of 26 HLA-A2 HIV mono-infected adults were also analysed as a comparison.

Results: We identified two distinct patterns of response: some patients had a limited response to either virus whilst others made responses to a range of HIV epitopes. HCV responses were detected only in those who made multiple responses to HIV epitopes (P<0.0001). HCV infection had an influence on the phenotype of HIV-specific CD8 T cells, with a reduction in relative perforin and CD57 expression. Lack of functional or tetramer-positive HIV-specific T cells was associated with a decline in absolute CD4 T-cell counts between the time points (up to 7 years; P = 0.005).

Conclusion: HCV infection has an impact on the phenotype of HIV-specific CD8 T cells. In this well-defined cohort, failure to maintain effective CD8 T-cell responses against HIV may contribute to disease progression.

(C) 2005 Lippincott Williams & Wilkins, Inc.