Antiretroviral Therapy Dampens Mucosal CD4+ T Lamina Propria Lymphocytes Immune Activation in Long-Term Treated People Living with HIV-1

Deciphering HIV-associated inflammation: microbiome's influence and experimental insights

PURPOSE OF REVIEW

To review novel experimental approaches for studying host:microbe interactions and their role in intestinal and systemic inflammation in people living with HIV (PLWH).

RECENT FINDINGS

Inflammation in PLWH is impacted by interactions between the microbiome, the intestinal epithelium, and immune cells. This complex interplay is not fully understood and requires a variety of analytical techniques to study. Using a multiomic systems biology approach provides hypothesis generating data on host:microbe interactions that can be used to guide further investigation. The direct interactions between host cells and microbes can be elucidated using peripheral blood mononuclear cells (PBMCs), lamina propria mononuclear cells (LPMC's) or human intestinal organoids (HIO). Additionally, the broader relationship between the host and the microbiome can be explored using animal models such as nonhuman primates and germ-free and double humanized mice.

SUMMARY

To explore complex host:microbe relationships, hypotheses are generated and investigations are guided by multiomic data, while causal components are identified using in-vitro and in-vivo assays.

HIV-associated dysbiosis and immune recovery during antiretroviral therapy

The microbiomes of people living with HIV (PLWH) are significantly dysregulated with a loss of bacteria diversity and shifts in composition, including increases in pathogenic and decreases in beneficial species. Because of the microbiome's role in modulating health, the effect of this dysbiosis on immune response in PLWH has been a significant concern, mainly because these shifts can persist even after viral suppression during combination antiretroviral therapy (cART). However, due to limitations on sample availability, few studies have been able to provide insights into these microbiome-immune interactions. Recently, Olivas-Martínez, et al. characterized ileum and caecum mucosa-associated microbiomes of PLWH based on their level of peripheral CD4+ T-cell reconstitution following long-term cART. Their analysis revealed distinct microbiome signatures predictive of recovery. Additionally, differences in markers of gut inflammation and damage between response groups were described, further implicating mucosal disruptions with immune reconstitution. These new data demonstrate an interdependence of microbiome and therapy response, and additional studies were urgently required to fully elucidate this crosstalk and microbiome dynamics from before/after infection and finally, long-term viral suppression with cART.