560. Immune Recovery of Acute HIV-Treated Patients Is Characterized by an Increase in Immune Senescence

BACKGROUND: ARV treatment (ART) administered during acute HIV-infection presents several immunological benefits leading to a better CD4+ T-cell recovery and a diminished HIV reservoir. METHODS: Patients with acute HIV-infection, enrolled in the VIHIA cohort, had blood samples taken at diagnosis and at 2, 6 and 12 months after ART initiation. Flow-cytometry analysis was performed in fresh whole blood. Naïve-(Nv), central memory (CM), effector memory (EM) and terminally differentiated T-cells (TMRA), as well as activation markers were defined using CD3, CD4, CD8, CD45RA, CCR7, CD38, CD31 and HLA-DR markers. CD28 and CD57 were used to identify immunosenescent cells. Fox-P3, CD 25, CD127 and CD45RA were used to identify Regulatory T cells (Treg) and their subsets. To assess changes over time, Wilcoxon-matched-pairs signed rank test was used for each value between baseline and months 2 and 12 independently. RESULTS: Four patients were diagnosed at Fiebig stage II; 5 patients at Fiebig stage III, 24 patients at stage IV and 5 patients in stage V. All patients received treatment within the first 24 hours of HIV diagnosis. Only 13 patients had flow-cytometry data at baseline and 1 year of follow-up. All subjects were MSM with a mean age of 32 y.o. Mean CD4+ T-cell count was 439 cells/μL and mean viral load was 1.2 million copies/mL (23,379–10 × 10(6) copies/mL) at baseline. The change in T-cell differentiation patterns at 0 and 12 months is shown in Figure 1. Activation markers decreased in all studied subsets at 2 months and furthermore at 12 months. Total T-regs increased from 5.1% to 7.8% at 1 year of follow-up (Figure 2). Immunosenescence markers increased steadily throughout the study in all T-cell subsets, being statistically significant in the total T-cell CD8 population at 12 months of follow-up (Figure 3) unrelated to Fiebig stage. CONCLUSION: It has been hypothesized that early ART decreases T-cell immunosenescence; however, in our cohort despite treatment during acute HIV, we observed that at 1 year follow-up immunosenescence markers increased despite a decrease in immune activation and a recovery of T-cell subsets. [Image: see text] [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.