OBJECTIVEChronic airway inflammation is associated with the polarization of TH2 cells in asthma. Prostaglandin D2 (PGD2) plays an important role in the polarization of TH2 cells. This study aimed to investigate the changes of PGD2 receptors (DP1/CRTH2) on T lymphocytes and their significance in asthma.

METHODSSeventy-two children with asthma were assigned to two groups: acute attack (n=42) and remission (n=30). Thirty-five healthy children were used as the control group. Plasma levels of TH2 cytokines IL-4 and IL-5, and TH1 cytokine INF-gamma were detected using ELISA. Radiological binding assay (RBA) was used to measure the contents of DP1/CRTH2 receptors on T cells in peripheral blood (PPB).

RESULTSThe total combining contents of DP and CRTH2 on T cells in PPB in the acute attack and the remission groups were significantly higher than those in the control group (p<0.01). There was no significant difference in the DP1 content among the three groups. Serum levels of IL-4 and IL-5 significantly increased (p<0.01), in contrast, serum levels of TH1 cytokine IFN-gamma were significantly reduced in the acute attack and the remission groups compared with those in the control group (p<0.01).

CONCLUSIONSThe total combining contents of DP and CRTH2 on T cells increased, serum levels of TH2 cytokines also increased, but serum levels of TH1 cytokine decreased significantly in the acute attack and the remission phases in children with asthma. This showed that a polarization of TH2 cells occurred in children with asthma and suggested that CRTH2 antagonism may be a new target for the treatment of asthma.