Peripheral Th17 cells expressing β7 intestinal homing receptor in recent and chronic HIV infections

The objective of this study was to conduct an analysis of peripheral blood Th17 cells with the ability to home to gut mucosa (CD4⁺ Th17⁺ β7⁺ ) during recent or chronic human immunodeficiency virus (HIV) infections. The relationship between HIV load and systemic inflammation markers was studied. Twenty-five patients with recent (n = 10) or chronic (n = 15) untreated HIV infections; 30 treated HIV-infected patients with undetectable HIV load at the time of inclusion and 30 healthy controls were included. Bacterial translocation markers (16S rDNA), soluble CD14 (sCD14) and interleukin (IL)-6 monocyte activation parameters, CD4/CD8 ratio and T helper type 17 (Th17) subpopulations [CD4⁺ Th17⁺ expressing the IL-23 receptor (IL-23R) or β7] were analysed at baseline and after 6 and 12 months of anti-retroviral therapy (ART). 16S rDNA was detected in all patients. Significantly increased serum levels of sCD14 and IL-6 and a decreased CD4/CD8 ratio were observed in patients. Similar percentages of CD4⁺ IL-23R⁺ and CD4⁺ Th17⁺ β7⁺ cells were observed in healthy controls and patients at baseline. After 12 months of therapy, patients with a recent HIV infection showed significant increases of CD4⁺ IL-23R⁺ and CD4⁺ Th17⁺ β7⁺ cell percentages and a decrease in IL-6 levels, although 16S rDNA continued to be detectable in all patients. No significant differences were observed in Th17 subpopulations in patients with chronic HIV infection after therapy. Early initiation of ART helps to increase the number of Th17 cells with the ability to home to the intestinal mucosa and to partially restore gut mucosal homeostasis. These results provide a rationale for initiating ART during the acute phase of HIV infection.