Study of the Th1/Th2 balance, including IL-10 production, in cultures of peripheral blood mononuclear cells from birch-pollen-allergic patients.

Abstract

Excessive production of interleukin (IL)-4, IL-5, IL-10, and IL-13 is thought to be important in the development of allergy and asthma. The objective of this investigation was to study Th1/Th2-like cytokine profiles in vitro in seven patients allergic to birch pollen and six nonallergic controls during the birch-pollen season. Peripheral blood mononuclear cells (PBMC) were isolated and cultured with birch-pollen extract (BPE) or tetanus toxoid (TT) for 7 days, harvested, and restimulated with the mitogens phytohemagglutinin (PHA) and phorbol 12-myristate 13-acetate (PMA) for 24 h. Cytokine production was determined by ELISA, and logarithmic cytokine ratios were compared between the two groups and between the antigens. In the allergic group, the cultures prestimulated with BPE had a more Th2-like cytokine response than the TT-prestimulated cultures; i.e., lower IFN-gamma and higher IL-10 production (P<0.05), as well as higher IL-5/IFN-gamma and IL-13/ IFN-gamma ratios (P<0.05). There were also significantly higher IL-4/IFN-gamma (P<0.005) and IL-5/IFN-gamma (P<0.05) ratios in BPE-stimulated cultures in the allergic group than in the control group. The IL-4 and IL-13 production in vitro correlated with the specific serum IgE levels. BPE stimulation induces a Th2-like cytokine response by PBMC isolated during the pollen season from birch-pollen-allergic patients, indicating a Th2-type immune response to birch pollen in vivo.