Distinct Defects in Marginal Zone B Cells and Filtration Function Characterize Hyposplenism in Persons With HIV-1 on...

Area of Science:

• Immunology
• Virology
• Hematology

Background:

• Individuals with HIV (PWH) face a higher risk of pneumococcal disease.
• This study investigates spleen filtration and immune function in PWH on long-term antiretroviral therapy (ART).
• Predictors of hyposplenism in this population are explored.

Purpose of the Study:

• To develop and validate a flow cytometry protocol for assessing spleen function.
• To investigate spleen impairment, specifically Howell-Jolly bodies (HJBs) and marginal zone B cells (MZBs), in PWH on prolonged ART.
• To identify potential predictors of hyposplenism in PWH.

Main Methods:

• A flow cytometry protocol was established to quantify HJBs and MZBs.
• The protocol was validated by comparing results from splenectomized patients and healthy donors.
• A cross-sectional study analyzed HJBs and MZBs in 96 PWH on prolonged ART.

Main Results:

• Optimal cutoff values for HJBs (0.05%) and MZBs (10%) were determined for differentiating spleen function.
• Results correlated well with established methods for assessing spleen filtration.
• 9.4% of PWH on ART showed impaired splenic filtration (elevated HJBs), linked to a history of AIDS. 59.4% had decreased MZBs, with no correlation to HJBs.

Conclusions:

• PWH on prolonged ART exhibit reduced splenic marginal zone B cells and some show impaired splenic filtration.
• These findings indicate persistent splenic impairment despite viral suppression.
• Further research is needed to understand long-term HIV impact on spleen function and improve outcomes in aging PWH.