Circulating lymphocyte subsets linked to intracellular cytokine profiles in normal humans

Abstract

SUMMARY To determine whether there is an association between intracellular cytokine profiles and the expression of surface antigens, we performed a simultaneous flow cytometric analysis of these laboratory parameters in 11 healthy volunteers. Peripheral blood lymphocytes were double-stained for CD4 or CD8, as well as CD11a, CD25, CD26, CD29 and CD45RA or the chemokine receptors CCR3, CCR4, CCR5 or CXCR3. Portions of the cell samples were cultured for 4 h in the presence of 1 µm monensin and 20 µg/ml brefeldin A with or without stimulation by phorbol myristate acetate plus ionomycin for the detection of intracellular interferon-γ (IFN-γ), interleukin-2 (IL-2), tumour necrosis factor (TNF)-α, and IL-4. As a result, CD4+CD29high helper inducer T cells were closely associated with IFN-γ and TNF-α producing CD4+ cells, while CD4+CXCR3+ cells showed a negative correlation with IL-4-producing cells, suggesting that both of these CD4+ subsets consist mainly of Th1 cells. In contrast, CD4+CD45RA+ cells were correlated inversely with IFN-γ and TNF-α-producing cells, and CD8+CD11ahigh killer effector and total CCR5+ cells showed an inverse correlation with IL-2 producing cells, suggesting an immunoregulatory role for these three subsets in non-pathological conditions. Therefore, monitoring of lymphocyte subsets that express functional surface antigens could provide additional information concerning immune deviation, as assessed by the production of Th1/Th2 type cytokines. Further, this type of combined study may provide clues for the pathogenesis of immune-mediated disorders.