Evaluation of mite allergen-induced Till and Th2 cytokine secretion of peripheral blood mononuclear cells from atopic dermatitis patients: association between IL-13 and mite-specific IgE levels

There have been several reports about Th1/Th2 imbalances in atopic dermatit is (AD), but there have been few precise investigations about the differenc es between Th1 and Th2 cytokine secretion patterns of peripheral blood mono nuclear cells (PBMCs) in such patients. We cultured PBMCs, taken from AD pa tients and healthy subjects, with dust mite extract (DME) and measured subs equent immunoreactive interferon (IFN)-gamma (Th1 cytokine), interleukin (I L)-4, IL-5, and IL-13 (Th2 cytokines) levels in the supernatants by ELISA a ssays. There is a difference between IL-4 and IL-13 secretion patterns by D ME-stimulated PBMCs in AD subjects, immunoreactive IL-4 levels were detecta ble maximally within 24-h cultures, while IL-13 levels increased time-depen dently within 7-day cultures. IL-13 levels were significantly elevated in A D subjects compared to healthy subjects, while IFN-gamma levels did not sig nificantly differ between the two groups. IL-13 levels were significantly h igher in AD patients who had high levels (>100 U/ml) of Dermatophagoides pt eronyssinus-specific IgE (Dp-IgE) than in those AD patients who had low lev els (<10 U/ml) of Dp-IgE. Tacrolimus (FK-506), at a concentration of 10(-8) M, significantly inhibited DME-induced IL-13 production from PBMCs. These findings suggest that IL-13 produced by Th2 cells are involved in IgE overp roduction in AD subjects. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.