HIV progression is closely associated with chronic immune activation driven by leakage of
bacterial products from a damaged gut, the investigators largest immunological organ.
Notably, the degree of immune activation has been suggested to be a better predictor of
disease progression than plasma viral load, and markers of immune activation and gut damage
have been identified as therapeutic targets per se. The major damage by HIV to the immune
system is an initial massacre of gut mucosal CD4+ Th17 cells. Interestingly, a normal gut
flora has been shown to induce the maturation of Th17 cells in the small intestine mucosa.
Preliminary reports have shown that the gut flora is altered in HIV-1 infection compared to
controls. In this project, the investigators will characterize microbial composition of gut
flora in chronic HIV infection with ultradeep sequencing. Gut flora composition will be
related to clinical data as well as quantitative data of circulating microbial products and
activation markers. Second, in a randomized clinical trial (RCT) the effect of probiotic
lactobacilli on HIV pathogenesis and progression will be tested. This Gram-positive strain is
clinically tested and is able to colonize the gut.