HLA-DR-positive cells in the human amniochorion

Human amniochorion has been studied by indirect immunofluorescence using a monoclonal antibody to a monomorphic determinant of HLA-DR antigens. Positive staining was noted only on significant numbers of large cells with irregular cytoplasmic processes in the mesenchymal connective tissue layer of the membranes. These cells resemble the dendritic-type, strongly HLA-DR-positive cells described by Steinman [3] and may be particularly relevant in immunobiological events at this important materno-foetal interface.