Loss of Preexisting Immunological Memory Among Human Immunodeficiency Virus-Infected Women Despite Immune Reconstitution With Antiretroviral Therapy

Background. It is unclear whether human immunodeficiency virus (HIV) infection results in permanent loss of T-cell memory or if it affects preexisting antibodies to childhood vaccinations or infections. Methods. We conducted a matched cohort study involving 50 pairs of HIV-infected and HIV-uninfected women. Total memory T-cell responses were measured after anti-CD3 or vaccinia virus (VV) stimulation to measure T cells elicited after childhood smallpox vaccination. VV-specific antibodies were measured by means of enzyme-linked immunosorbent assay (ELISA). Results. There was no difference between HIV-infected and HIV-uninfected study participants in terms of CD4(+) T-cell responses after anti-CD3 stimulation (P = .19) although HIV-infected participants had significantly higher CD8(+) T-cell responses (P = .03). In contrast, there was a significant loss in VV-specific CD4(+) T-cell memory among HIV-infected participants (P = .04) whereas antiviral CD8(+) T-cell memory remained intact (P> .99). HIV-specific antibodies were maintained indefinitely among HIV-uninfected participants (half-life, infinity; 95% confidence interval, 309 years to infinity) but declined rapidly among HIV-infected participants (half-life; 39 years; 24-108 years; P = .001). Conclusions. Despite antiretroviral therapy-associated improvement in CD4(+) T-cell counts (nadir, <200/4 mu L; >350/4 mu L after antiretroviral therapy), antigen-specific CD4(+) T-cell memory to vaccinations or infections that occurred before HIV infection did not recover after immune reconstitution, and a previously unrealized decline in preexisting antibody responses was observed.