AEGiS-15IAC: Cell cycle perturbation of circulating CD4+ T lymphocytes in HIV-1-infected subjects.

15th International AIDS Conference

Bangkok, Thailand - July 11-16, 2004

Cell cycle perturbation of circulating CD4+ T lymphocytes in HIV-1-infected subjects.

Int Conf AIDS 2004 Jul 11-16; 15:(abstract no. A10320)

Kallas EG, Chaves MM
Federal University of Sao Paulo, Sao Paulo, Brazil

BACKGROUND: One of the hallmarks of HIV infection is the progressive peripheral blood CD4+ T lymphocyte loss. One of the possible explanations for this phenomenon is the process of apoptosis, as suggested by several studies, which also may exert an effect on the cell cycle normal distribution. The present study was conducted to evaluate the cell cycle distribution of CD4+ and CD8+ lymphocytes, correlating the findings with absolute cell counts and HIV-1 RNA viral load.

METHODS: Initially, two methods to identify CD4+ and CD8+ lymphocytes for cell cycle analysis were evaluated, using either magnetic beads or concurrent staining with CD4 and CD8 monoclonal antibodies, both followed by DNA staining with propidium iodine. There was no significant difference between the two methods, although higher result variability was observed when the magnetic bead cell separation method was employed.

RESULTS: The optimized method was applied in the study of cell cycle of CD4+ and CD8+ lymphocytes in HIV-1-infected subjects and healthy controls. An increase in the proportion of cells in the S phase was observed in the HIV-1 group (2.69% vs. 1.19%, p=0.016), coupled with a decrease in G1 (96.11% vs. 98.10%, p=0.005) in CD4+ lymphocytes. This phenomenon was not observed in CD8+ lymphocytes. No correlation was detected between the percentage of cells in the different cell cycle phases and absolute counts of CD4+ or CD8+ T lymphocytes or the HIV-RNA viral load. The lack of the latter correlation may be explained by the higher numbers of CD4+ T lymphocyte counts in the enrolled participants.

CONCLUSION: The present work was important in developing a novel approach to evaluate peripheral lymphocyte cell cycle distribution, applied in the setting of HIV-1 infection. These analyses may contribute with the better understanding of the mechanisms involved in the depletion of CD4+ T lymphocytes of these patients.

Keywords: AEGIS, CD4-Positive T-Lymphocytes, HIV-1, CD8-Positive T-Lymphocytes, HIV Infections, Viral Load, Antigens, CD4, Cell Cycle, T-Lymphocytes, Antigens, CD8, Humans, immunology

040711
A10320