Expression of gut-homing β7 receptor on T cells: surrogate marker for microbial translocation in suppressed HIV-1-infected patients?

OBJECTIVES: In view of the fact that mucosal damage associated with HIV-1 infection leads to microbial translocation despite successful antiretroviral treatment, we analysed microbial translocation and expression of the gut-homing β7 receptor on peripheral T cells in HIV-1-infected individuals.
METHODS: Fifteen long-term suppressed HIV-1-infected patients, of whom seven had their treatment intensified with maraviroc and eight with raltegravir, were included in the study. Samples at baseline, at week 48 of intensification, and at weeks 12 and 24 after deintensification were analysed for soluble CD14, lipopolysaccharide (LPS), LPS-binding protein, gut-homing β7 receptor and T-cell subsets.
RESULTS: The increases in both microbial translocation and expression of the gut-homing β7 receptor on activated CD8 T cells found during maraviroc intensification were reduced after deintensification. Moreover, the correlations between activated β7(+) T cells and LPS levels found during intensification with maraviroc (P = 0.036 and P = 0.010, respectively) were lost during deintensification. In contrast, microbial translocation was stable during raltegravir intensification, with the exception of decreased LPS levels and activated CD4 β7(+) T cells, which reverted to baseline values after deintensification.
CONCLUSIONS: Microbial translocation is an important factor in gut immune activation and mucosa inflammation, as evidenced by the association between the dynamics of microbial translocation and activated T cells expressing the gut-homing β7 receptor. The recruitment of activated β7(+) T cells to the gut tract when alteration of microbial translocation is maximum may be the major mechanism for recovery of mucosal integrity.