Influence of antigen exposure on the loss of long-term memory to childhood vaccines in HIV-infected patients.

The role of antigen exposure and of CD4 cell deficiency in the long-term persistence of immune memory to childhood vaccines remains uncertain, particularly during HIV infection. We analyzed in vaccinated ART-treated HIV+ patients with undetectable plasma HIV and CD4 cells >250/mm(3) the persistence of two memory cell pools: effector IFNgamma-producing and proliferative central memory T cells against two vaccines: (i) vaccinia against the eradicated smallpox virus, and (ii) BCG against Mtb, a persistent pathogen. None of the HIV+ patients had IFNgamma-effector cells against VV while the one patient with BCG-specific effector T cells had a recent history of tuberculosis.

Greater viral rebound and reduced time to resume antiretroviral therapy after therapeutic immunization with the ALVAC-HIV vaccine (vCP1452).

Objective: Evaluate immunogenicity and clinical efficacy of two immunization strategies with the ALVAC-HIV-recombinant canarypox vaccine (vCP1452) in treated HIV-infected patients.

Design: Randomized, double-blind, placebo-controlled, phase II study of vCP1452 immunization in chronically HIV-infected patients on therapy with CD4 T-cell count more than 350 cells/microl, CD4 nadir less than 400 cells/microl and pHIV-RNA less than 400 copies/ml. Patients were equally randomized to four injections at weeks 0, 4, 8, 20; three injections at weeks 4, 8, 20; and placebo.