Assessment of CD69 expression on CD8+ T cells in HIV-infected patients
Krasnoyarsk AIDS Center, Krasnoyarsk, Russian Federation
Background: CD69 is one of the earliest activation antigens that is expressed on the surface of activated peripheral blood T lymphocytes upon in vitro stimulation with provocative stimuli. Several investigators have demonstrated the efficacy of measuring CD69 surface expression on T lymphocytes as a method to assess T-lymphocyte activation and function. We examined expression of CD69 activation marker on CD8-cells in response to phytohemagglutinin (PHA) stimulation in HIV-1-infected patients.
Methods: Whole-blood samples were obtained from HIV-infected (n=202) naive to antiretroviral medications and healthy (n=30) individuals. Samples were incubated at 37°C, 5% CO2 for 4 h with PHA used 10 µg per ml concentration. CD69 expression evaluated by three-color flow cytometry using CD8-FITC/CD69-PE/CD3-PerCP monoclonal antibodies.
Results: HIV-infected patients had significantly increased CD8+CD69+ levels (median 12.26%) in comparison with the HIV-negative controls (median 7.92, p< 0.001). The expression of CD69-antigen on CD8-cells correlated inversely with percent (r= -0.38, p< 0.001) and absolute count (r= -0.27, p< 0.001) of CD4-lymphocyte. The initial group of HIV-infected patients was divided depending on CD4-cells count into 3 subgroup according to CDC classification: 1) 112 patients with CD4-cells more than 500, 2) 78 patients with CD4-cells count from 200 up to 499 and 3)12 person with CD4 levels less than 200 cells. HIV-infected individuals with low CD4 levels had significantly increased CD8+CD69+ measurements in comparison with the HIV-patients with high CD4 levels: 1) 12.1%, 2) 14.2% and 3)19.8% of CD8+CD69+-cells. Also CD8+CD69+ levels correlated positively with concentration of IgG (r=0,13; p < 0,05).
Conclusions: Thus, these results indicated that HIV-infected patients with phenotypic changes of circulating lymphocyte pool have functional changes in response to phytohemagglutinin (PHA) stimulation resulting increased CD8+CD69+-levels. The interrelation between immunological markers of disease progression was revealed: HIV-infected patients with low CD4 count tended to have higher CD8+CD69+-levels than the group of patients with increased CD4-cells.
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