HIV remodels germinal centers through T follicular helper cell loss

T follicular helper cells (Tfh) play a pivotal role within germinal centers as they serve as a crucial component of the HIV viral reservoir. Due to their significant involvement in affinity maturation, plasma cell production, and memory B cell generation, comprehending this vital reservoir is essential for both cure strategies and understanding immunodeficiency in individuals living with HIV (PLWH).

Through analysis of clinical samples from PLWH, researchers have observed alterations in both the cellular makeup and structure of germinal centers that align with the immunodeficiency observed in PLWH, irrespective of their CD4 count. It has been noted that there is a notable reduction in germinal center Tfh cells and an increase in follicular CD8 T cells in the lymphoid tissues of PLWH.

Furthermore, it has been determined that HIV causes a decrease in germinal center size, both in the context of HIV infection and increased age. Single-cell RNA sequencing data indicates that HIV rapidly reduces the expression of Tfh B-cell support pathways and disrupts the expression of cell trafficking receptors in Tfh cells. Additional research using a lymphoid organoid model of acute infection that mimics germinal center-like structures has corroborated these findings, indicating that innovative methodologies could be instrumental in understanding the impact of HIV on the reservoir and immunodeficiency.

This study sheds light on the previously unknown remodeling of the germinal center niche in PLWH, offering valuable insights into the immune microenvironment of a critical HIV reservoir that may aid in informing future cure strategies.