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

Gut TLRs and IFN pathways mRNA expression and frequencies of CD4+T cell expressing CD38 or HLA-DR go in parallel during HIV immunopathogenesis

While much is known about the expression of interferon (IFN) pathways in the blood of people living with HIV (PLWH), their role in the intesinal tract has only recently been appreciated. The aim of this study was to evaluate gut mRNA expression levels of innate immune genes involved in the HIV-host interaction and their association with CD4+T cell immune activation in long-term HAART-experienced PLWH. PLWH had increased intestinal levels of TLR4, type I IFN (IFN-α2, IFN-α14, IFN-β) and IFNAR1 mRNAs, as well as increased frequencies of CD4+T lymphocytes expressing CD38 or HLA-DR compared to the healthy donors. Moreover, TLR4, TLR9, IRF3, IRF7 and IFN-α14 mRNA expression was positively correlated with the frequency of CD4+T cells expressing CD38 or HLA-DR. These findings suggest a dysregulation of innate immunity, particularly of the TLRs and IFN pathways in the gut of PLWH. Genes in these pathways also appear to correlate with the levels of CD4+T cell immune activation.

Gut Microbiome Alteration in HIV/AIDS and the Role of Antiretroviral Therapy-A Scoping Review

(1) Background: The gut microbiota plays a crucial role in chronic immune activation associated with human immunodeficiency virus (HIV) infection, acquired immune deficiency syndrome (AIDS) pathogenesis, non-AIDS-related comorbidities, and mortality among people living with HIV (PLWH). The effects of antiretroviral therapy on the microbiome remain underexplored. This study aims to map the evidence of the impact of integrase strand transfer inhibitors (INSTI) and non-nucleoside reverse transcriptase inhibitors (NNRTI) on the gut microbiota of PLWH. (2) Methods: A scoping review was conducted using PubMed, Web of Science, and Embase, with reports collected following PRISMA for Scoping Reviews (PRISMA-ScR). (3) Results: Evidence suggests that INSTI-based regimes generally promote the restoration of alpha diversity, bringing it closer to that of seronegative controls, while beta diversity remains largely unchanged. INSTI-based therapies are suggested to be associated with improvements in microbiota composition and a tendency toward reduced inflammatory markers. In contrast, NNRTI-based treatments demonstrate limited recovery of alpha diversity and are linked to an increase in proinflammatory bacteria. (4) Conclusions: Based on the review of the current literature, it is indicated that INSTI-based antiretroviral therapy (ART) therapy facilitates better recovery of the gut microbiome.

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.