Reduced CD4+ terminally differentiated effector memory T cells in moderate-severe house dust mites sensitized allergic rhinitis patients

Background: Terminally differentiated effector memory (T-EMRA) T cells exert potent effector function after activation. The proportions of CD4(+) T cell subsets especially memory cells in allergic rhinitis (AR) patients sensitized to house dust mites (HDMs) have not been extensively studied. Objective: This study aimed to compare the mean percentages and absolute counts of CD4(+) memory T cell subsets between: (i) non-allergic controls and AR patients; (ii) mild AR patients and moderate-severe AR patients. Methods: Sensitization to Dermatophagoidesfarinae and Dermatophagoidespteronyssinus were determined in 33 non-allergic controls, 28 mild AR and 29 moderate-severe AR patients. Flow cytometry was used to determine the percentage of CD4(+) nalve (T-N; CD45RA(+)CCR7(+)), central memory (T-CM; CD45RA-CCR7(+)), effector memory (T-EM; CD45RA-CCRT) and T(EMR)A (CD45RA(+)CCR7(-)) T cells from the peripheral blood. The absolute counts of CD4(+) T cell subsets were obtained by dual platform method from flow cytometer and hematology analyzer. Results: There were no significant differences in the mean percentages and absolute counts of CD4(+) T cell subsets between non-allergic controls and AR patients sensitized to HDMs. However, there were significant reduction in the mean percentage (p = 0.0307) and absolute count (p = 0.0309) of CD4(+) T-EMRA cells in moderate-severe AR patients compared to mild AR patients sensitized to HDMs and 13/24 (54.2%) moderate-severe AR patients sensitized to HDMs had persistent symptoms. Conclusion: Reduction in the mean percentage and absolute count of CD4(+)CD45RA(+)CCR7(-) T(EMR)A cells were observed in moderate-severe AR patients compared to mild AR patients in our population of AR patients sensitized to HDMs.