SEASONAL COMPARISON OF CYTOKINE PROFILES IN ATOPIC ASTHMATICS AND ATOPIC NON-ASTHMATICS

Previous studies have suggested that peripheral blood T cell cytokine release may reflect the situation in the bronchial mucosa in atopic as thmatics. We have therefore examined spontaneous, rye grass pollen-sti mulated, and PHA-stimulated secretion of IL-2, IL-4, IL-5, and IFN-gam ma in cultures of peripheral blood mononuclear cells (PBMC) from atopi c asthmatic, atopic non-asthmatic and normal controls in and out of th e rye grass pollen season. Compared to normal controls, both atopic gr oups showed higher IL-2 and IL-5 production (p < 0.01 and p < 0.05) an d higher percentages of CD4 cells expressing CD25 and HLA-DR (p < 0.05 ) in response to rye grass pollen, elevated IL-4 production in respons e to PHA (p < 0.01), and a non-significant trend towards lower IFN-gam ma production. However, the capacity of PBMC from atopic asthmatics to produce IL-5 was greater than that for atopic non-asthmatics (p < 0.0 5). Furthermore, seasonal changes in symptom score, FEV(1) % predicted , and PD20 methacholine correlated with seasonal elevated production o f IL-5 by PBMC in the asthmatic group (r = 0.862, -0.679, and -0.620; p < 0.01, 0.02, and 0.05, respectively). Our results suggest that elev ated production of IL-2 and IL-4 and higher percentages of activated C D4 T cells are associated with atopy per se, but elevated production o f IL-5 also relates to the clinical expression of atopic asthma.