3.1. Decidual tissue has a distinct

3.1. Decidual tissue has a distinct T cell composition in comparison to peripheral blood T cellsThe T cell composition of decidua basalis and decidua parietalis was compared with that from control PBL (cPBL) and maternal PBL (mPBL). The proportions of CD4+, CD8+ and CD4-CD8- T cells were similar in cPBL and mPBL samples (Fig. 1a). In contrast, decidua basalis and decidua parietalis tissue isolates contained significantly lower percentages of CD4+ T cells and a significantly higher percentage of CD8+ and CD4-CD8- T cells (Fig. 1a). In addition, decidua parietalis CD3+ cells contained a significantly increased proportion of γδTCR+ T cells in comparison to decidua basalis and the cPBL and mPBL samples (Fig. 1b). The γδTCR+ T cells were mainly found within the CD4-CD8- T cells phenotype (Fig. 1b). However in decidua parietalis, a small but not significantly increased percentage of CD8+ γδTCR+ T cells is observed in comparison with decidua basalis and the cPBL and mPBL samples. In order to determine whether the decidual CD4-CD8- T cells are NKT cells, analysis for the NKT cell specific T cell receptor chains Vα24 and Vβ11 was performed. Similar to previously published results (Boyson et al., 2002) approximately 0.5% of all decidual T cells were found to be Vα24+Vβ11+ NKT cells and displayed a CD3+CD4-CD8- phenotype (data not shown). Expression of the NK cell marker CD56+ is observed in low proportions in all T cell fractions (Fig. 1c). A significantly increased percentage of CD4+CD56+ T cells was observed in decidua parietalis comparison with cPBL samples (Fig. 1c).