Objective:

To assess CD4+ T-cell responsiveness to IL-7 and IFN-α in HIV-infected patients who experience poor recovery of CD4+ T-cell counts during therapy (immune failure patients).

Design:

Responses to IL-7 and IFN-α were compared between HIV-infected immune failure (CD4+ cell counts< 379 cells/μl) patients and immune success (CD4+ cell counts> 500 cells/μl) as well as healthy control patients.

Methods:

Flow cytometry was used to assess peripheral blood mononuclear cells for IL-7-induced proliferation, CD25 expression, and signaling (signal transducer and activator of transcription 5 phosphorylation and Akt phosphorylation) in CD4+ T cells. Freshly isolated cells were characterized by expression of IL-7Rα (CD127) among CD4+ T-cell maturation subsets by flow cytometry and sorted CD3+ T cells were assessed for expression of IFN-α and interferon stimulated genes (2′–5′-oligoadenylate synthetase-1 and myxovirus resistance A protein) by quantitative real-time PCR. Responses to IFN-α were assessed by induction of signal transducer and activator of transcription 1 phosphorylation and inhibition of IL-7-induced CD4+ T-cell proliferation.

Results:

IL-7-induced proliferation and CD25 expression were decreased in CD4+ T cells from immune failure patients. CD127 expressing CD4+ T cells were decreased, whereas expression of 2′–5′-oligoadenylate synthetase-1, myxovirus resistance A protein, and IFN-α mRNA were increased in total CD3+ T cells from immune failure patients. CD127 expression correlated with CD25 induction but not proliferation, whereas T-cell IFN-α mRNA was associated with reduced proliferation in CD4+ T cells from immune failure patients. IFN-α-mediated induction of signal transducer and activator of transcription 1 phosphorylation and inhibition of proliferation were not diminished in CD4+ T cells from immune failure patients.

Conclusion:

IL-7 responsiveness is impaired in immune failure patients and may be related to expression of CD127 and IFN-α.