289   Outcome after 1 Year of HAART, 3 Cycles of STI and 12 Months Off Therapy vs Natural Evolution Without ART in Early Chronic HIV-1 Infection (CHI). A Case-Control Study.

F. García*¹, M. Plana¹, G. M. Ortiz², A. Soriano¹, C. Vidal¹, A. Cruceta¹, M. Arnedo¹, C. Gil¹, G. Pantaleo³, T. Pumarola¹, T. Gallart¹, D. F. Nixon², J. M. Miró¹, and J. M. Gatell¹.
¹Barcelona, Spain;²New York, NY; and³Lausanne, Switzerland.

Background:Our objective was to compare the viral load (VL) set-point, immunological evolution and specific anti-HIV-1 CTL and helper responses in 10 CHI patients (CASES = CA) with a BVL >5,000 c/ml and CD4⁺T cells >500 randomized (EARTH-1 study) to perform 1 year of HAART, then followed by 3 cycles of STI and 1 year off ART, with 20 matched patients of the control group (CONTROLS = CO) of the same EARTH-1 study who were followed during 1 year without ART.

Methods:Plasma VL, lymphocyte immunophenotyping, CD4⁺lymphocyte proliferative responses to HIV-1 antigens and HIV-1-specific CTL responses were assessed both in CA and in CO groups.

Results:At baseline, there were no differences in the plasma VL [4.4 (SE 0.1) vs 4.5 (SE 0.2), p = 0.45, CO group vs CA group, respectively] or CD4⁺T cells [582 (SE 25) vs 620 (SE 47), p = 0.34, CO group vs CA group, respectively]. After 1 year of follow-up off ART, VL changed a mean log₁₀of +0.24 (SE 0.1) in the CO group vs -0.54 (SE 0.2) in the CA group (p = 0.004). The mean viral load was 50118 c/ml in the CO group and 10,000 c/ ml in the CA group. CD4⁺T cells changed a mean of -91 (SE 35) in the CO group vs +145 (SE 45) in the CA group (p = 0.0007). The CO group had a significantly lower proportion of CD8⁺CD28⁺T cells and higher proportion of CD8⁺CD38⁺T cells than CA group (p = 0.001 and p = 0.05, respectively). With regard to the HIV- 1-specific helper responses against p24 Ag, none of the CO group patients (n = 7) showed positive responses vs 5 out of 9 patients in the CA group [mean of stimulation index 1.2 (SE 0.25) in the CO group vs 3.7 (SE 0.8) in the CA group, p = 0.02]. Only 1 out of 7 patients showed CTL response at week 48 of follow-up in the CO group vs 7 out of 9 patients in the CA group.

Conclusions:After 1 year off therapy, patients who performed 1 year of HAART and 3 cycles of STI had significantly lower viral load, higher CD4⁺T cell counts, lower values of immune activation markers and higher specific helper and CTL responses against HIV-1 than a control group of naive patients followed up during one year without ART.