Changes In T Cell Subpopulations After Specific Sublingual Immunotherapy Against Dermatophagoides Farinae

The mechanisms by which allergen-specific immunotherapy induce clinical improvement in allergic asthma remain incompletely understood. Here, the changes in T cell subpopulations, CD4(+) CD25(+) Foxp3(+) Treg cells and Th1/Th2 cells, were determined following sublingual specific immunotherapy against the house dust mite species Dermatophagoides farinae in pediatric asthma patients. The study cohort comprised 25 children with asthma who had received standardized dust mite-specific sublingual immunotherapy for one year (observation group), 27 healthy children (control group), 24 children with medication-uncontrolled asthma (uncontrolled group), and 21 children with medication-controlled asthma (controlled group). Peripheral blood mononuclear cells were isolated from all participants and were stimulated with dust mite extracts for 72 h. The proportions of nTreg and Th1/Th2 cells were measured by flow cytometry. After in vitro dust mite extract stimulation, the percentages of nTreg (nTreg% CD4(+) T) cells were significantly increased (P < 0.05) in each group compared to before stimulation; however, the there were no significant differences between groups. The ratio of Th1/Th2 cells in each group increased after stimulation, significantly so in the controlled group and observation group (P < 0.05), with the ratio of Th1/Th2 cells in the healthy control group higher than that of the other three groups. Thus, a decreased ratio of Th1/Th2 cells exists in children with asthma. Dust mite-specific sublingual immunotherapy may work through reducing the number of Th2 cells and increasing the ratio of Th1/Th2 cells. Further, the ratio of Th1/Th2 cells in peripheral blood could be measured, which may predict the efficacy of dust mite-specific sublingual immunotherapy.