Restoration of CD4 T-cell responses to cytomegalovirus is short-lived in severely immunodeficient HIV-infected patients responding to highly active antiretroviral therapy

Abstract

Objectives. To define the level of pathogen-specific immune reconstitution persisting over 3 to 5 years of highly active antiretroviral therapy (HAART) in HIV-infected patients who began therapy with CD4 T-cell counts below 50 cells/μL. Methods. Cytomegalovirus (CMV)-specific T-cell responses were analysed in adult HIV-1-infected patients with nadir CD4 T-cell counts below 50 cells/μL before HAART. CMV-specific CD4 T-cell responses were measured by interferon-γ enzyme-linked immunospot assay (ELISpot assay), lymphoproliferation and interferon-γ levels in cell culture supernatants. Results. CD4 T-cell responses to CMV were low in untreated patients and remained low during the first year on HAART, but increased progressively to levels similar to those found in HIV-seronegative CMV-seropositive controls at 3 years. Responses then declined markedly and at 5 years were lower than controls. This could not be explained by changes in CD4 or CD8 T-cell counts or plasma HIV RNA levels. Interferon-γ and interleukin-5 responses to a mitogen were maintained or elevated. Conclusions. CMV-specific CD4 T-cell responses were found to decline after 3-5 years on HAART and may provide inadequate long-term protection against CMV disease in patients who are severely immunodeficient prior to treatment. © 2004 British HIV Association.