Th1 and Th17 pro-inflammatory profile characterizes iNKT cells in virologically suppressed HIV+ patients with low CD4/CD8 ratio

INTRODUCTION:: Scanty data exist on the phenotype and functionality of invariant natural killer T (iNKT) cells in HIV+ patients (pts). METHODS:: By flow cytometry, we studied iNKT cells from 54 HIV+ pts who started combined antiretroviral therapy (cART) and had undetectable viral load for >1 year. Twenty-five maintained a CD4/CD8 ratio <0.4, while 29 reached a ratio >1.1; 32 age- and sex-matched subjects were healthy controls (CTR). RESULTS:: Pts with low ratio had lower percentage of CD4+ iNKT cells compared to pts with high ratio, and higher CD8+ iNKT cell percentage; double negative (DN) iNKT cells were lower in HIV+ pts compared to CTR. Pts with low ratio had higher percentage of CD4+ and DN iNKT cells expressing CD38 and HLA-DR compared to pts with high ratio. CD4+ iNKT cells expressing PD-1 were higher in pts with CD4/CD8 ratio <0.4, while DN iNKT cells expressing PD-1 were lower compared to pts with ratio >1.1. Pts with low ratio had higher CD4+ iNKT cells producing IL-17, CD8+ iNKT cells producing IFN-γ, TNF-α or IFN-γ plus TNF-α, and DN iNKT cells producing IL-17 or IL-17 plus IFN-γ compared to CTR. Activated CD4+ (or CD8+) T cells correlated with activated CD4+ (or CD8+) iNKT cells, as well as the percentages of CD4+ (or CD8+) T cells expressing PD-1 was correlated to that of CD4+ (or CD8+) iNKT cells expressing PD-1. CONCLUSIONS:: Low CD4/CD8 ratio despite effective cART is associated with altered iNKT cell subsets, enhanced activation and prominent Th1/Th17 pro-inflammatory profile.