Seasonal variations of T-cell cytokine pattern in peripheral blood from atopic subjects

Previous studies on the effect of seasonal exposure to the sensitizing anti gen on T-cell cytokine pattern from atopic subjects evaluated T-cell cytoki ne production by titration in the serum or culture supernatants. The purpos e of this study was to determine the seasonal variations of T-cell cytokine pattern from atopic subjects at the single-cell level. We examined the int erleukin-4 (IL-4) and interferon-gamma expression in peripheral blood CD4and CD8+ T cells from 11 subjects with grass-pollen-sensitive allergy befor e and during the 1999 grass pollen season using a flow cytometric method of intracellular cytokine detection. Eight healthy volunteers served as the c ontrol group. Flow cytometric analysis of peripheral blood lymphocytes show ed no seasonal variations of IL-4- and interferon-gamma -producing T cells in atopic subjects. However, there was a decreased percentage of IL-4-produ cing cells among peripheral blood CD4+ and CD8+ T cells from the atopic sub jects both during and outside the pollen season in comparison to the contro ls. We did not find seasonal variations of T-cell cytokine pattern in perip heral blood from atopic subjects. However, ive observed a decreased percent age of IL-4-producing T cells in peripheral blood from these subjects in co mparison to healthy controls. These data add to the view of a continuous mi gration of T helper 2 (TH2) cells from the blood to the tissues of primary allergen exposure.