METHODS: The cytokine production and frequency of house dust mite (HDM)-specific T cell subsets in peripheral blood mononuclear cells (PBMCs) were evaluated using flow cytometry in 89 HDM-AR patients (HDM allergen 300 IR dose: n=46, placebo: n=43) who participated in a placebo-controlled study of SLIT with HDM tablets. All patients provided samples both before treatment as a baseline and at the end of the 52-week study. The PBMCs were stained with CellTrace™ Violet (CTV) before culture with HDM extract, and HDM-specific T cells were detected as the proliferated cells with diminished CTV.
RESULTS: HDM-specific IL-5- and IL-13-producing CD27-CD161+CD4+ cells and HDM-specific ST2+CD45RO+CD4+ cells were observed in the peripheral blood from each patient with HDM-AR; these cells significantly decreased after SLIT in the group treated with active tablets, and they associated with the clinical efficacy of SLIT.
CONCLUSIONS: The results suggest that allergen-specific IL-5+IL-13+CD27−CD161+CD4+ cells and ST2+CD45RO+CD4+ cells may be useful as SLIT biomarkers; the results also support a potentially critical role for these cells in the pathogenesis of AR.