AEGiS-15IAC: Study of interleukin-12 producing dendritic cells in HIV infected patients.

15th International AIDS Conference

Bangkok, Thailand - July 11-16, 2004

Study of interleukin-12 producing dendritic cells in HIV infected patients.

Int Conf AIDS 2004 Jul 11-16; 15:(abstract no. A10280)

Klangsinsirikul P, Dettrairat S, Promchim C
Department of Clinical Immunology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand

BACKGROUND: Dendritic cells (DCs) are potent antigen presenting cells that are critical for the initiation of primary and secondary immune responses. One of the most important cytokines produced by DCs is interleukin-12 (IL-12) which plays a major role in HIV specific cytotoxic T cell (CTL) response. Disruption of normal DC function has been proposed as a major factor in immune dysregulation associated with HIV disease. Therefore, we examined the percentages of IL-12 producing DC in normal individuals compared to those of HIV infected patients with various CD4 counts (CD4<200, 201-500 and >500/mul).

METHODS: IL-12 producing DCs were enumerated using intracellular flow cytometry by activating peripheral blood with gamma interferon (IFN-γ) and lipopolysaccharide (LPS) in the presence of brefeldin A. DCs were enumerated as the cells that positive for HLA-DR and negative for other lineage markers (CD3, CD14, CD16, CD19, CD20, CD56). Intracellular cytokine and cell surface markers were analyzed simultaneously.

RESULTS: Our results showed that the percentages of IL-12 producing DCs in the both groups of CD4 count less than 200/mul and between 201 and 500/mul were 6.84±1.38 (n=27, p<0.05) and 6.73±1.11 (n=36, p<0.05) respectively which were significantly decreased compared to that of normal individuals (11.47±2.28, n=23).

CONCLUSION: The results showed the decrease in IL-12 producing DCs when the CD4 count was less than 500/mul. As DCs are targets for HIV and IL-12 plays an important role in CTL regulation, this may help to explain the loss of HIV specific CTL in later stages of disease when the patient had low CD4 count. The research was supported by the funding form the Ministry of the University Affair, 2002.

Keywords: AEGIS, Acquired Immunodeficiency Syndrome, HIV Seropositivity, Interleukin-12, Dendritic Cells, HIV Infections, CD4 Lymphocyte Count, Interferon Type II, Cytokines, T-Lymphocytes, Cytotoxic, Flow Cytometry, Humans

040711
A10280