γδ T Cells Are Involved in Acute HIV Infection and Associated with AIDS Progression

Background: Early diagnosis is vital to HIV control. gamma delta T cells play critical roles in viral infections, but their activation in acute HIV infected patients and follow up to 18 months has not been described. Methods: Changes in gamma delta T cells, including subsets, function and activation, in treated and untreated acutely HIV-infected patients (n = 79) were compared by cytotoxicity assay and flow cytometry with healthy controls (n = 21) at month 0, 6, 12 and 18. Results: In acutely HIV-infected patients, V delta 1 cell proportion was elevated (P = 0.027) with V delta 2 population reduced (P = 0.002). Effector and central memory gamma delta T cell factions were decreased (P = 0.006 and P = 0.001, respectively), while proportion of terminal gamma delta T cells increased (P = 0.002). gamma delta T cell cytotoxicity was compromised over time. Fraction of IL-17-producing cells increased (P = 0.008), and IFN-gamma-producing cells were unaffected (P = 0.115). Elevation of a microbial translocation marker, sCD14, was associated with gamma delta T cell activation (P = 0.001), which increased in a time-dependent manner, correlating with CD4/CD8 T cell activation set-points and CD4 counts. Antiretroviral therapy did not affect these changes. Conclusions: gamma delta T cell subpopulation and functions change significantly in acute HIV infection and over time. Early gamma delta T cell activation was associated with CD4/CD8 T cell activation set-points, which predict AIDS progression. Therefore, gamma delta T cell activation represents a potential surrogate marker of AIDS progression.