A person’s sexual behaviour could affect their immune system and gut microbiome, which can potentially increase the risk of HIV infection, according to a new study.
Recent studies have found that men who have sex with men (MSM) have very distinct microbiomes compared with men who have sex with women (MSW), regardless of HIV-infection status. Researchers at the University of Colorado Anschutz Medical Cambridge to know whether this altered gut microbiome induces T cell activation associated with HIV transmission risk and the increased severity of the disease.
What is the gut micobiome?
The microbiome is a community of microbes in the gut, which play an important role in the immune system.
The link between microbiome composition and immune activation
The researchers took stool samples of 35 healthy men, both men who had sex with men and men who had sex with women, and transplanted them into mice.
The mice who received the MSM stool samples showed increased evidence of activation of CD4+ T cells. This would put them at a higher risk of HIV if they were human.
The study’s senior author Brent Palmer, PhD, associate professor of medicine in the Division of Allergy and Clinical Immunology at the CU School of Medicine, said: “These results provide evidence for a direct link between microbiome composition and immune activation in HIV-negative and HIV-positive MSM, and a rationale for investigating the gut microbiome as a risk factor for HIV transmission.”
Palmer added: “There is a unique microbiome associated with men who have sex with men that drives immune activation in the gut that may also drive higher levels of HIV infection. But we still don’t know exactly why this is.”
Palmer concluded that gaining further understanding of this microbiome is important, because it could directly affect the immune system of high-risk men and lead to an increased risk of HIV infection.