Deteriorating pneumococcal-specific B-cell memory in minimally symptomatic African children with HIV infection

Area of Science:

• Immunology
• Pediatrics
• Infectious Diseases

Background:

• Invasive pneumococcal disease (IPD) is a major cause of mortality in children with human immunodeficiency virus (HIV) in sub-Saharan Africa.
• While T-cell defects are known, increased IPD risk persists even with preserved CD4 cell counts, suggesting other immune deficiencies.
• B-cell immunity impairment is hypothesized to amplify the immune defect in HIV-associated IPD.

Purpose of the Study:

• To investigate the role of B-cell immunity in the increased susceptibility to IPD in children with HIV.
• To identify specific alterations in the B-cell compartment during HIV disease progression.
• To assess pneumococcal antigen-specific B-cell responses in HIV-infected versus HIV-uninfected children.

Main Methods:

• Analysis of B-cell compartment shifts towards an apoptosis-prone phenotype in early HIV disease.
• Quantification of isotype-switched memory B cells in HIV-uninfected and HIV-infected children.
• Measurement of pneumococcal protein antigen-specific memory B cells in both groups.

Main Results:

• A shift in the B-cell compartment toward apoptosis-proneness was observed early in HIV disease progression.
• HIV-infected children had lower numbers of pneumococcal protein antigen-specific memory B cells compared to HIV-uninfected children.
• Numbers of isotype-switched memory B cells were similar between healthy HIV-uninfected and minimally symptomatic HIV-infected children.

Conclusions:

• Defective naturally acquired B-cell immunity to pneumococcus contributes to IPD in HIV-infected children.
• These findings underscore the need to evaluate B-cell function and the durability of immune memory for pneumococcal vaccines in this population.
• Optimizing pneumococcal vaccine effectiveness requires understanding B-cell responses in HIV-infected children.