A novel surface molecule of Th2-and Tc2-type cells, CRTH2 expression on human peripheral and decidual CD4(+) and CD8(+) T cells during the early stage of pregnancy

It has been demonstrated that pregnancy induces the immunomodulation of cyt okine responses away from the Th1 paradigm and towards the Th2 paradigm. In this study, we examined the expression of CRTH2 (chemoattractant receptor- homologous molecule expressed on Th2) on decidual CD4(+) and CD8(+) T cells during the early stages of pregnancy. Examination of the cytokine profile revealed that CRTH2 was expressed on CD4(+)-type-2 T helper (Th2-type) and CD8(+)-type 2 T cytotoxic (Tc2-type) cells. The percentages of CRTH2(+) cel ls in CD3(+)/CD4(+) T cells and CD3(+)/CD8(+) T cells were significantly hi gher in the decidua than in the peripheral blood. These results indicate th e significance of Th2- and Tc2-type cells of the decidua in the maternal im mune system, presumably through their production of cytokines which may con tribute to the maintenance of pregnancy.