The controversial impact of B cells subsets on immune response to pneumococcal vaccine in HIV-1 patients

• The vast majority of vaccine non-responders were on HAART.
• Most B cell subsets were lower among ART-naïve patients compared to treated patients at baseline.
• Memory B cells and IgM memory B cells demonstrated no correlation with the vaccine IgG response.
• The total B cell count and exhausted memory B cells predicted the antibody response to the vaccine.
• Activated B cells at baseline were associated with the baseline viral load, and resting memory B cells moderately correlated negatively with viral load at baseline.

SummaryBackgroundChronic HIV infection leads to severe perturbations of the B cell populations and hypo-responsiveness to vaccines. The associations between circulating B cell subpopulations and the antibody response to pneumococcal polysaccharide vaccine in antiretroviral-naïve and treated patients were studied.MethodsSixty-six HIV-infected adults were grouped according to antiretroviral therapy (ART) and CD4+ cell count; 31 were ART-naïve and 35 were ART-treated, and they were matched for age, CD4 cell count, and duration of HIV infection. All subjects were immunized with the 23-valent polysaccharide vaccine against Streptococcus pneumoniae. Pre- and post-vaccination B cell subpopulations were assessed by flow cytometry. Serum IgG concentrations for vaccine serotypes were quantified by ELISA at baseline and at 4 and 48 weeks post-vaccination.ResultsPatients under highly active antiretroviral therapy (HAART) had significantly higher antibody levels against pneumococcal vaccine antigens, while an adequate number of patients responded to vaccination. Memory B cells were diminished over time, although treated patients maintained higher levels of all subsets studied, with the exception of activated memory and isotype-switched memory B cells.ConclusionsLow concentrations of total B cells and exhausted memory B cells was the strongest independent predictor of poor pneumococcal vaccine responsiveness, emphasizing that B cell subset disturbances are associated with a poor vaccine response among HIV-infected patients.