Flow cytometric characterisation of cell populations in human pregnancy decidua and isolation of decidual macrophages.

Methods have been developed for isolating human tissue macrophages from first trimester or term pregnancy decidua. After a two stage enzymic digestion, viable cells were separated from cellular debris by velocity sedimentation at unit gravity or by Percoll centrifugation. Cell populations were analysed by flow cytometry after labelling with monoclonal antibodies. In term decidua, 47% of the cells were of bone marrow origin, comprising 18% macrophages, 3% large granular lymphocytes and 8% T cells. The remaining cells, the proportion of which varied between individuals, were CD16-positive granulocytes. Macrophages were isolated flow cytometrically from both first trimester and term decidual cell dispersions after labelling with an antibody to MHC class II. Yields of up to 4 X 10(6) macrophages, greater than 95% pure, were routinely obtained.