Influence of Human T Cell Lymphotropic Virus Type 2 Coinfection on Virological and Immunological Parameters in HIV Type 1–Infected Patients
1Service of Infectious Diseases, Hospital Carlos III, Madrid, and 2Biotechnology Department, University of Alicante, Alicante, Spain
Background.
Human T cell lymphotropic virus type 2 (HTLV‐2) infection is not rare among injection drug users with human immunodeficiency virus (HIV) infection and may exert a protective role in the progression of HIV disease.
Methods.Immunological and virological parameters were compared in HIV–HTLV‐2–coinfected patients and a control group of HIV‐monoinfected subjects. All individuals were antiretroviral therapy naive. HIV‐specific CD8+ T cell levels were measured using an interferon‐γ assay in response to 125 optimally defined HIV peptides divided into 5 pools. Immune activation was evaluated by measuring levels of CD38 in different CD4+ and CD8+ T cell subsets. In a subgroup of patients, the production of CCL4 in parallel with interferon‐γ was assessed in response to Gag peptides.
Results.Lower plasma HIV‐RNA levels were found in HIV–HTLV‐2–coinfected patients than in HIV‐monoinfected patients, despite the 2 groups having similar CD4+ T cell counts. Coinfected patients also had significantly lower levels of CD38 expression in total CD8+ T cells and in its naive subset. CD8+ T cell levels specific for each pool of peptides were similar in both groups, but cells mainly contributing to HIV Gag–specific responses in coinfected patients were CCL4 positive and interferon‐γ negative, whereas for HIV‐monoinfected subjects, the response was dominated by CCL4‐positive and interferon‐γ–positive cells.
Conclusions.HTLV‐2 coinfection may exert a protective role on HIV disease progression by lowering HIV replication and immune activation. A predominance of CCL4 single positive HIV‐specific CD8+ T cells in HIV–HTLV‐2–coinfected patients could explain this effect.
Received 12 July 2006; accepted 29 August 2006; electronically published 21 November 2006.