Abstract
Asthma is an allergic inflammation and house dust mite (HDM) is a major allergen to induce asthma pathogenesis. Regulation of eosinophil apoptosis is an essential immune process and its dysregulation is implicated in asthma. In the present study, we examined the effects of HDM on spontaneous apoptosis of asthmatic eosinophils and on cytokine secretion in eosinophils of normal subjects including non-atopic and atopic normal. Extract of Dermatophagoides pteronissinus (DP) inhibited eosinophil apoptosis in a time-dependent manner. DP increased the secretion of G-CSF, GM-SCF, and IL-4, which is involved in suppression of eosinophil apoptosis, but IL-5 expression was not altered after DP stimulation. DP also elevated the release of IL-6, IL-8, tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and CCL2, which are anti-apoptotic or survival factors. The secretion of G-CSF, GM-CSF, IL-6, IL-8, and TNF-${\alpha}$ due to DP is higher in atopic normal than that in non-atopic normal. In conclusion, DP increases the survival of eosinophils and its mechanism may be associated with cytokine release. These findings may enable elucidation of asthma pathogenesis induced by HDM.
