The Expression of ST2+mDC in Allergic Rhinitis after Inhaled Allergen Challenge

RATIONALE: Myeloid dendritic cells (mDCs) are professional antigen-presenting cells. Allergen inhalation increases the number of peripheral blood mDCs and the release of epithelial derived cytokines, such as IL-33 in allergic rhinitis patients. The effects of IL-33 have been implicated in the pathogenesis of allergic disease, which are IL-33 receptor (ST2) depended. However, the effects of inhaled allergens on the levels of ST2⁺mDCs, and the effects of ST2⁺mDCs in the pathogenesis of allergic rhinitis are unknown.

METHODS: Allergic rhinitis patients which were postive to house dust mite (n = 8) were challenged with inhaled Der p1. Peripheral blood were collected and ST2+mDCs were determined using flow cytometry at 0 h, 0.5 h, 2 h and 4 h after the allergen challenge. Moreover, mDCs were induced from CD14+ monocyte cells, and the levels of ST2+mDCs were investigated under the stimulation of IL-33 and IL-2 by flow cytometry.

RESULTS: Inhaled Der p1 significantly increased ST2⁺mDC levels in the PBMCs of AR patients at 0.5 h and 2 h after challenge, and the ST2⁺mDC reached the peak at the time point of 0.5 h. Moreover, the percentage of ST2⁺mDC was up-regulated after the stimulation of IL-33 and IL-2 in vitro

CONCLUSIONS: ST2 expression is up-regulated on blood mDCs after allergen inhalation in AR patients. IL-33 stimulation upregulated ST2 expression on mDCs. It suggests that the ST2⁺mDCs may play important roles in the pathologies of allergic diseases.