The effects of cyclosporin A on apoptosis of IL-5 stimulated eosinophils in patients with atopic dermatitis

Abstract

Background: Apoptosis is the physiological changes to maintain homeostasis. Dysregulation of apoptosis can lead to pathophysiologic changes and, especially, delayed apoptosis of eosinophils has been considered to be an important mechanism to contribute to eosinophilia. In atopic dermatitis, peripheral blood eosinophils increase in severe condition and decrease with therapeutic improvement. Cyclosporin A (CsA), potent immunosupressant, has been reported to be effective in the treatment of severe atopic dermatitis. Objective: We investigated the effect of cyclosporin A on apoptosis of IL-5 stimulated eosinophils by analysing the cell cycle. Method: Peripheral eosinoiphils were isolated from 21 patients with atopic disease using Ficoll-Hypaque gradient and purified by negative selection technique using MACS (Miltenyi Biotec, Auburn, CA) system. The samples were divided into 3 groups: Group A, cultured without IL-5; Group B, cultured in the presence of recombinant human IL-5 (0.1 ng/ml); and group C cultured in the presence of recombinant human IL-5 (0.1 ng/ml) and cyclosporin A (10 U/ml). Eosinophil apoptosis were measured by FACScan (Becton Dickinson Co., Saujose, USA). Results: At 24 hours, 48 hours, and 72 hours without IL-5 (group A), 35.87±4.75%, 52.01±9.73%, and 69.31±5.56%, respectively of eosinophils showed apoptosis, whereas 27.71±3.81%, 43.69±9.72%, and 57.32±3.21% of the cells showed apoptosis in the presence of 0.1 ng/ml human recombinant IL-5 without cyclosporin A (group B). However the addition of cyclosporin A (10 U/ml) significantly enhanced the eosinophil apoptosis to 41.79±5.92%, 59.69±8.91%, and 80.10±5.21%, respectively (group C). Conclusion: These results indicate that apoptotic death of eosinophils stimulated by IL-5, is augmented with cylosporin A, and that apoptosis of eosinophil of peripheral blood in atopic dermatitis may be due to account for the inhibitory effect of cyclosporin A on eosinophilia.