Frequency of CD4+ and CD8+ IL17-secreting T cells during Acute/Early HIV Infection and in Chronic Aviremic HIV Controllers.

GABRIELA TURK; YANINA GHIGLIONE; MARÍA EUGENIA SOCIAS; ANA MARÍA RODRIGUEZ; JULIANA FAVILENE; MARÍA JULIA RUIZ; OMAR SUED; DANIEL PRYLUKA; NATALIA LAUFER; PEDRO CAHN; MARÍA MAGDALENA GHERARDI; HORACIO SALOMON

Bangkok

Conferencia; AIDS Vaccine Conference 2011; 2011

Background: Understanding how immune homeostasis is perturbed during HIV infection is highly relevant. IL-17 is a protective cytokine against extracellular pathogens and helps maintain mucosal barrier. Objective: To evaluate IL-17-secreting T cell frequency during the first year following HIV infection. Methods:  Frozen PBMCs from 20 HIV+ subjects enrolled during seroconversion (by the Argentinean Group of Seroconverters), 12 HIV+ elite controllers (EC) and 9 healthy donors (HD) were used. Samples from seroconverters were obtained at enrollment (baseline), 3, 6, 9 and 12 months post-infection. Seroconverters were classified as “progressors” if CD4 count dropped below 350 cells/ml or experienced AIDS-related B/C events within 12 months post-infection. IFN-g- and IL-17-secreting T cells were evaluated by flow cytometry upon stimulation with anti-CD3/anti-CD28 antibodies or PMA/Ionomycin. Results: CD3+CD4+: HIV+ subjects showed lower Th17 cell frequency compared to HD but higher Th17/Th1 ratio, indicating that IL-17-producing cells were enriched in the CD4+ subset. No difference between “Progressor” and “Non-Progressor” seroconverters was observed at baseline samples. However, “Progressors” showed higher Th17 cell frequency and higher Th17/Th1 ratio than “Non-Progressors” (p=0.0049 and p=0.00485, respectively) at set-point. Neither Th17 cell frequency nor Th17/Th1 ratio changed significantly over time in both group of seroconverters. No significant difference was observed between seroconverters and EC. CD3+CD8+: Upon strong PBMC stimulation (PMA/Iono), EC showed higher frequencies of Tc17 cells, double-positive IL-17+IFN-g+ cells and higher Tc17/Tc1 ratio than seroconverters (even at set-point samples) and HD (p<0.05 in all cases). Among seroconverters, no differences were observed between “Non-Progressor” and “Progressors”, independently of stimulation and time-point. However, Tc17 cell frequency significantly diminished between baseline and set-point samples, regardless of progression status and stimulation.  Conclusions: Results indicate that IL-17 produced by both CD4+ and CD8+ T cells might be an important mediator involved in host defense