Human decidual cells can express the Hodgkin's cell-associated antigen Ki-1 (CD30) in spontaneous abortions during the first trimester of gestation.

CD30 (Ki-1) antigen has been considered to be expressed on hematopoietic cells including the ones of the recently described anaplastic large cell lymphoma (ALCL), the Reed-Sternberg (RS) cells of Hodgkin's disease and the scattered large parafollicular cells in normal lymphoid tissues. Since then, several reports have been published describing CD30 expression in non-hematopoietic and malignant cells, such as cultivated human macrophages, human decidual cells, histiocytic neoplastic cells, mesothelioma cells, embryonal carcinoma, and seminoma cells. In the present study, we investigated the immunohistochemical expression of CD30 antigen in 15 paraffin-embedded placentas from fetuses after spontaneous abortion in the first trimester of gestation (8th, 10th, and 12th week, respectively) using the monoclonal antibody Ber-H2.

Expression of laminin, type IV collagen and fibronectin molecules is related to embryonal skin and epidermal appendage morphogenesis.

Basement membrane zones are specialized sheets--like arrangements of extracellular matrix proteins and glycosaminoglycans, and act as an interface between parenchymal cells and support tissue. They separate epithelium, endothelium, muscle cells and Schwann cells from adjacent connective tissue stroma, and also from a limiting membrane in the central nervous system. They are involved in several cellular and biological processes, including adhesion, migration and cellular differentiation.

Expression of fibrillar proteins and vimentin in developing chorionic villi is related to fetal maturation.

Using an immunocytochemical technique, the extracellular matrix components fibronectin, vimentin, laminin and collagen type IV were investigated in human chorionic villi of various stages of development. Fibronectin and laminin were consistently positive throughout embryonic development. Vimentin and collagen type IV were negative in first and second trimester chorionic villi, but became positive in term placentas.

The immunophenotypic profile of hepatic hemopoiesis in fetuses with Down's syndrome during the second trimester of development.

The yolk sac and aorto-gonad-mesonephros region are well recognized as the principal sites of hematopoiesis in the developing embryo, and the liver is the principal site of hematopoiesis in the fetus. In the present study, we investigated the immunohistochemical expression of Glycophorin C (erythrocytes), Neutrophilic elastase (granulocytes), and CD34 (progenitor hematopoietic stem cells, progenitor stromal cells, and vascular endothelial cells) in hepatic parenchyma from fetuses with Down's syndrome (DS) (16th, 20th, and 24th week of gestational age), and correlated the findings with the equivalent of the hepatic parenchyma from fetuses after spontaneous abortion. Our results did not demonstrate a quantitative difference at the level of erythropoiesis in all three periods examined.