375   No Substantial Changes either in TRECs or in CD45RA⁺CD62L+ CD4⁺Lymphocytes Following Treatment with Interleukin-2 in Advanced HIV.

G. Marchetti*, L. Meroni, C. Molteni, S. Varchetta, M. Galli, M. Moroni, F. Franzetti, and A. Gori.
Inst. of Infectious Diseases and Tropical Med., Univ. of Milan, Italy.

Background:Our objective was to investigate whether the restoration of the CD4⁺T-cell compartment following interleukin-2 (IL-2) adjuvant therapy correlates with an increase both in phenotypically naïve T cells and in recent thymic emigrants.

Methods:We evaluated ten HIV⁺patients in treatment with HAART (1 PI and 2 NRTI) with a discordant viro- immunological response. All patients had the following characteristics: HIV-1 RNA levels <80 copies/ml for at least six months and CD4⁺T cell count prior to IL-2 treatment persistently <200/mL. Patients received scIL-2 at a dosage of 3 MU qd for 2 consecutive weeks every 4 weeks for 3 cycles. Phenotypically naive cells (CD4⁺CD45RA⁺CD62L⁺) were also measured by flow cytometry. Thymic output was evaluated measuringdRec-yJα;TRECs in CD4⁺cells by a PCR-ELISA assay.

Results and Conclusions:CD4⁺T-cell number increased significantly after each IL-2 cycle in all the patients. At T₇₅the median CD4⁺value was 269/mL as compared to 169/mL at T₀(p = 0.03). CD4⁺T-cell rise was not statistically correlated to an increase in phenotypically naive CD4⁺cells. In all patients TRECs content in CD4⁺T-cells did not show any significant change between T₀and T₇₅. Concordant results were observed after adjusting for the cell division rate measured by the expression of Ki-67 antigen. IL-2 treatment significantly increases CD4⁺T-cells in viro-immunological discordant patients. The CD4⁺rise does not correlate with an increase in CD45RA⁺CD62L⁺cells and in TRECs content and is likely to be due to peripheral extrathymic expansion.