Delayed‐type hypersensitivity responses to HIV Gag p24 relate to clinical outcome after peptide‐based therapeutic immunization for chronic HIV infection
Abstract:Kran A‐MB, Sommerfelt MA, Baksaas I, Sørensen B, Kvale D. Delayed‐type hypersensitivity responses to HIV Gag p24 relate to clinical outcome after peptide‐based therapeutic immunization for chronic HIV infection. APMIS 2012; 120: 204–9.
Therapeutic immunization in chronic HIV infection aims to induce durable, HIV‐specific immune responses capable of controlling disease progression, but immunological correlates of clinical efficacy are poorly defined. We have previously immunized 38 patients with a mixture of four short Gag p24‐like conserved peptides (Vacc‐4x) targeting skin dendritic cells. Antiretroviral treatment (ART) was initially stopped after completed immunizations and resumed post‐protocol during regular clinical follow‐up according to current guidelines. Four years after enrolment, Vacc‐4x‐specific cellular responses were evaluated in vivo by delayed‐type hypersensitivity (DTH) skin test, and in vitro by a T‐cell proliferation assay. Kaplan–Meier product‐limit estimates were used to analyse time until ART was resumed. Peptide‐specific cellular immune responses induced by Vacc‐4x had persisted 4 years after the last immunization in terms of unchanged DTH independent of ART and detectable proliferative T‐cell responses which correlated to the native peptides (R = 0.73, p = 0.01). Circulating bifunctional (IFN‐γ and IL‐10) Vacc‐4x‐specific T‐cell clones were detected in 43% of patients. Subjects with the strongest post‐immunization DTH responses appeared to start ART later compared with DTH low responders (p = 0.07). These data suggest that DTH responses should be further evaluated as a new and convenient tool for predicting clinical efficacy in trials testing therapeutic immunizations.
Document Type: Research Article
Publication date: March 1, 2012