Abstract: There were more kinds of cells in the early human pregnancy decidual tissue.It may be difficult to distingush these cells into classes with HE stain.Two kinds of cells,big and small,were identified.Big cells contained rich glycogen and lipid,while small cells did not contain them.With immunohistochemical stain,We have found a lot of macrophages and HLA-DR positive cells.However,Tlymphocytes were scarce.This study supported the view that small cells were suppressor cells.They suppressed the proliferation and immunocom-peteace of Tlymphocytes.Because of the suppression of Tlymphocytes, blastocytes could be immplanted and embryos could not be rejected from maternal decidua.

Key words: decidua, lymphocyte, macrophage, HLA-DR positive cell, immunohistochemistry