558:
CRTH2 expression on T cell subsets in asthma
Sunday, March 4, 2018
South Hall A2 (Convention Center)
Teerapol Chantveerawong, MD, Panitan Pradubpongsa, MD, Sarawut Jindarat, MD, Wat Mitthamsiri, MD, Rattanaporn Fuengthong, MD, Atik Sangasapaviliya, MD, Tadech Boonpiyathad, MD
RATIONALE: CRTH2(CD294) is the target in allergies treatment due to its expression in various cell types. The rational of CRTH2 expression on T helper cells (Th,CD3+CD4+), regulatory T cells (Treg, CD3+CD4+CD25+CD127-) and cytotoxic T cells(Tc,CD3+CD8+) in asthma patients remains unclear. We assessed CRTH2 expression level in T cell subsets in correlation with clinical data.

METHODS: The CRTH2 expression on T cells in whole blood were analyzed using flow cytometry. %predicted PEFR, asthma control test(ACT), asthma quality of life questionnaire and absolute eosinophil counts were investigated to find the correlation with CRTH2 expression level.

RESULTS: 46 asthma patients(11 eosinophilic asthma patients, 30 non-eosinophilic allergic asthma patients, and 5 non-eosinophilic non-allergic asthma patients) and 11 healthy subjects were enrolled. Asthma patients had higher level of CRTH2+ Treg cells of total CD3+ cells(0.12%±0.09 and 0.04%±0.03, p=0.001) and higher frequency of CRTH2 expression on Tc than healthy(1.04%±0.51 and 0.60%±0.50, p=0.006). No significant difference of CRTH2 expression on Th cells was observed. In subgroup analysis, we found the frequency of CRTH2 expression on Treg cells in eosinophilic asthma patients (0.19%±0.14) was significantly higher than non-eosinophilic allergic asthma patients(0.10%±0.06) and non-eosinophilic non-allergic asthma patients(0.06%±0.03). The frequency of CRTH2 expression on Treg cells among asthma patients had negative correlation with ACT scores(r=-0.29, p=0.04) whereas positive correlation with absolute eosinophil counts(r=0.39, p=0.007).

CONCLUSIONS: Elevated levels of peripheral CRTH2 expression on Treg and Tc cells are key features in asthma. The different correlation of CRTH2+ Treg cells with asthma control and eosinophil counts elucidated as potential targeted therapy for future asthmatic treatment.