Alterations in B Cell Compartment Correlate with Poor Neutralization Response and Disease Progression in HIV-1...

Area of Science:

• Immunology
• Virology
• Pediatrics

Background:

• HIV-1 infection in children leads to B cell defects, including altered subsets and impaired antibody responses.
• B Lymphocyte Stimulator (BLyS) is crucial for B cell homeostasis and its role in pediatric HIV-1 is under investigation.
• Understanding dendritic cell (DC) influence on B cells is vital for developing interventions against HIV-1 in children.

Purpose of the Study:

• To investigate the relationship between DCs, B cell subsets, BLyS expression, and viral neutralization in vertically transmitted HIV-1 infected children.
• To compare these factors in antiretroviral therapy (ART) naïve children with different disease progression rates (progressors vs. long-term non-progressors) and seronegative controls.
• To assess changes in these parameters following ART initiation in progressors.

Main Methods:

• Flow cytometry was used to analyze DC subsets and BLyS expression on DCs.
• B cell subsets and plasma levels of B cell growth factors (IL-4, IL-6, IL-10) and immunoglobulins (IgA, IgG) were quantified.
• Viral neutralization activity was measured using the TZM-bl assay.

Main Results:

• HIV-1 progressors exhibited lower percentages of myeloid and plasmacytoid DCs and higher BLyS expression on myeloid DCs compared to controls.
• Progressors showed reduced naive and resting memory B cells, but increased mature activated and tissue-like memory B cells.
• Higher plasma BLyS levels in progressors correlated with poorer viral neutralization, while ART initiation led to increased resting memory B cells and reduced BLyS, improving neutralization.

Conclusions:

• Elevated plasma BLyS levels are associated with impaired B cell function and poor viral neutralization in HIV-1 infected children.
• ART initiation can restore B cell function, evidenced by increased resting memory B cells and improved viral neutralization, linked to reduced BLyS levels.
• This study highlights BLyS as a potential therapeutic target for restoring B cell immunity in pediatric HIV-1.