Antiretroviral treatment for HIV has allowed patients to have undetectable viral load indefinitely. Despite that, HIV infection has become a chronic inflammatory disease, with increased mortality. This pro-inflammatory state is in part explained by the dysbiosis of intestinal bacterial populations. However, little is known on the impact of the antiretroviral treatment on this population and very few studies have evaluated these alterations.

The aim of this study is to study microbiome on healthy patients and HIV-infected patients exposed to antiretroviral treatment with integrase strand transfer inhibitors.

Inclusion criteria:

• Willing to sign consent form

• Men with an age >18 years

• Engagement in insertive or receptive anal intercourse with another men

  *Exclusion criteria:

• Previous history of ART exposure

• Use of antibiotics in the past 3 months

• Previous history of inflammatory bowel disease, autoimmune disease or cirrhosis.

We will compare 20 MSM HIV negative patients starting PEP with INSTI with:

• 20 MSM HIV-uninfected and ART naïve (A)
• 20 MSM HIV-infected starting ART (B)
• 20 MSM HIV-infected on ART with >500 CD4 Tcells ( C )
• 20 MSM HIV-infected on ART with <350 CD4 Tcells (D) (the study population has been restricted to MSM given the strong influence of sexual orientation on the microbiota composition