9TH EUROPEAN AIDS CONFERENCE (EACS) 1st EACS RESISTANCE & PHARMACOLOGY WORKSHOP October 25 - 29, 2003 Warsaw, Poland

Background: Impairments in CD4+ O-cell proliferative responses and absence of strong HIV-1-specific Th responses are among the first functional defects described in chronically HIV-1-infected subjects.

Objectives: Our aim was to study the recovery of Th - function and to correlate it with the frequency of HIV-1-specific IFN-γ-producing CD4+ T cells in HIV-1+ patients receiving HAART.

Materials and Methods: 20 chronically HIV-1-infected pts under HAART for 24 months were enrolled. Lymphoproliferative and IFN-γ responses to PHA and specific HIV-1 p24 Ag were measured radiometrically and by ELISPOT.

Results and Conclusions: At baseline T - cell responses were impaired in all patients. A recovery of responses to PHA and recall antigens but not to specific HIV-1 p24 antigen was observed six months later in 8 patients with baseline SI to PHA > 3.0 (p<0.05). On month 12 the strongest T-cell responses were measured when the number of HIV-1-specific, IFN-γ-secreting CD4+ T cells correlated with specific lymphoproliferative responses (p<0.001). In all other patients a partial recovery of IFN-γ but not of lymphoproliferative responses was found.

A recovery of T-cell responses during HAART was registered only in patients with preserved Th function before therapy. The discordance between HIV-1-specific IFN-γ-producing T cells and HIV-1 specific lymphoproliferation could be due to active HIV-1 replication in vivo causing proliferative defects in these cells. The fact that in the course of HAART strong HIV-1-specific T-cell responses were found in some of the patients indicated that HIV-1-induced proliferative defects could be reversible.

Presenting Author: Professor Roumiana Markova, National Center of Infectious and Parasitic Diseases, Dept. Immunology and Allergy, 26 Yanko Sakazov Blvd, 1504, Sofia, Bulgaria, Phone: ++359 2 944 6999/257

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