Expression of Th2-associated Surface Markers on T cells in Allergic Disorders

RATIONALE: Chemokine receptors such as CCR3, CCR4, CCR7, and CCR8 and the PGD2 receptor, CRTH2, are associated with Th2 cells. Except for CRTH2⁺T cells, these Th2-associated receptor-positive T cells might not be good markers for cytoplasmic Th2 cytokines under physiological conditions in our previous study (presented in AAAAI 2017). Based on these findings, this study examined whether these Th2-related receptors can be disease markers in allergic disorders.

METHODS: With institutional review board approval, 20 patients with allergic disorders, including food allergy, bronchial asthma (BA), atopic dermatitis, and chronic urticaria, and six control patients with non-allergic disease were enrolled. Surface expression of CCR5 for Th1 and CRTH2, CCR3, CCR4, CCR7, and CCR8 for Th2 CD4⁺ lymphocytes was analyzed by flow cytometry.

RESULTS: The percentages of CCR5⁺, CRTH2⁺, CCR3⁺, CCR4⁺, CCR7⁺, and CCR8⁺ T cells showed no significant difference among allergic disorders. A significantly higher frequency of CRTH2⁺ T cells was observed in patients with BA compared that in the diseased control group in the absence of active allergic and non-allergic inflammations (n = 5 and 12, respectively; p = 0.012). Conversely, there were no significant differences in chemokine receptor expression between the two groups. Unexpectedly, the percentages of CRTH2⁺ T cells and CCR5⁺ T cells significantly correlated with age (r = 0.720, p = 00003; r = 0.483, p = 0.012, respectively).

CONCLUSIONS: Consistent with our previous findings in physiological conditions, T cell expression of CRTH2, but not these chemokine receptors could be a suitable marker for Th2-diseases such as BA.