Evaluation of VZV-specific cell-mediated immunity in adults infected with HIV-1 by using a simple IFN-γ release assay

The development of herpes zoster is associated with reduced varicella zoster virus (VZV)-specific cell-mediated immune (CMI) reactions. In this study, VZV-specific CMI reactions in 42 anti-VZV-IgG antibody-positive adults infected with HIV-1 were evaluated by measuring the IFN-γ production levels in whole blood in response to stimulation with ultraviolet light-inactivated live attenuated VZV vaccine. The median VZV-specific IFN-γ production level in all patients was 63 pg/ml. Antiretroviral therapy (ART)-naïve patients with an AIDS-defining illness (HIV classification category C) had significantly lower IFN-γ production than ART-naïve patients in categories A and B and patients receiving ART (P=0.0194 and P=0.0046, respectively). IFN-γ production increased significantly in patients within 1 month of the onset of recurrent VZV disease and at more than 1 year from onset, compared with patients who had never had recurrent VZV disease (P=0.0396 and P=0.0484, respectively). In multivariate analyses, category C and history of recurrent VZV disease were significant factors affecting IFN-γ production. Levels of IFN-γ were measured before and after ART in seven ART-naïve patients with no history of recurrent VZV disease, and no significant changes were observed. The results indicate that VZV-specific CMI reactions were reduced in patients with an AIDS-defining illness and enhanced in patients with a history of recurrent VZV disease, but not enhanced by ART alone. Vaccination may be necessary to inhibit the development of herpes zoster in patients receiving ART; this IFN-γ releasing assay is one useful method for evaluating VZV-specific CMI reactions in clinical settings.