Alterations in memory B cell subsets upon immunization against Streptococcus pneumoniae in HIV-1 infected adults

AimAim of our study was to assess diversities in memory B cell populations over time post vaccination with the 23-valent polysaccharide pneumococcal vaccine (PPV-23).BackgroundAlterations of B cell subpopulations have been confirmed during HIV infection. HIV seems to disrupt several B cell subsets, impairs memory and leads to hyporesponsiveness to vaccines regardless antiretroviral intake.Materials and methodsA cohort of treated and naive HIV-1 patients was immunized with PPV-23. B cell subpopulations were evaluated pre, 4 and 48 weeks post vaccination by flow cytometry.ResultsThe frequency of total B, memory B cells (CD19+CD27+, BMC), resting memory B cells (CD19+CD27+CD21high, RM) and exhausted memory B cells (CD19+CD21lowCD27−, EM) was higher in treated patients with similar progression over time compared to naïve. Vaccination leads to significant depletion of EM B cells. Vaccine administration also marginally raised the circulating fractions of BMCs, though gradual depletion was observed in both groups. Mean fraction of IgM memory B (CD19+CD27+IgMhigh) cells and isotype-switched memory B cells (CD19+CD27+IgM−, ITS) was higher in the naive group. The percentage change of pre vaccination levels and week 4 and week 48 differed significantly between the two groups. Naïve patients also preserved higher fractions of activated memory B cells (CD19+CD21low+CD27+, AM) pre and post vaccination. Treated patients had higher proportions of RM cells, which differed significantly post vaccination.ConclusionVaccination with the 23-PPV has an immunological effect on certain B cell subsets like RM and ITS memory B cells, triggering alterations of their counts on peripheral blood of HIV-infected patients. Moreover, HAART intake has controversial implication in few of these memory B cell populations.