Expression of activation antigens CD69, HLA-DR, interleukin-2 receptor-alpha (IL-2R alpha) and IL-2R beta on T cells of human decidua at an early stage of pregnancy.

T cells of human decidua at an early stage of pregnancy were examined by flow cytometry for the expression of the T-cell-activation antigens CD69, HLA-DR, interleukin-2 receptor-alpha (IL-2R alpha) and IL-2R beta. The decidua contained a small number of T cells and both CD4+ and CD8+ subsets expressed CD69, HLA-DR, IL-2R alpha and IL-2R beta antigens significantly whereas, in peripheral blood, only a small number of T cells expressed these activation antigens. These findings indicate that T cells in the decidua in the first trimester of pregnancy are regionally activated.