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. In contrast, an important numerical difference was shown in the expression of CD34 positive cells in liver parenchyma from fetuses with DS, in comparison with those found in liver parenchyma from fetuses after spontaneous abortion (p < 0.02). Furthermore, a modest but significant difference was demonstrated at the level of granulopoiesis between the 20th and 24th week (p < 0.01). Given that, the living newborns with Down's syndrome manifest diverse haematological abnormalities, including a transient leukemoid reaction that usually disappears after some weeks or months, a significantly increased number of CD34 positive and a less significantly increased number of neutrophilic elastase positive cells between the 20th and 24th gestational week could explain this phenomenon in combination with the respective results, if any, in the bone marrow. Regarding our finding of increased stromal CD34 positive cells in the hepatic portal triads, it raises the possibility that a process similar to fibrosis of the bone marrow may contribute to the hepatic fibrosis in DS.

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. All the pregnant patients had been given hormonal medication to support gestation. In addition, a panel of monoclonal antibodies for the identification of leukocytes (CD45/LCA), B-lymphocytes (CD20/L-26), and T-lymphocytes (CD45RO/UCHLI) was performed. Our findings were correlated with those found in 15 placentas obtained from 15 fetuses at the same time, after therapeutic or voluntary abortions. This study demonstrates that, 1) decidual endometrial stromal cells are able to express the CD30 (Ki-1) antigen, 2) the expression of CD30 in decidual cells is higher in cases of hormonal administration (to support gestation), than that found in normal gestation. In the former cases (hormonal support of gestation), a mild mononuclear infiltration of the decidua by UCHLI (T marker) positive cells, accompanies the CD30 positive cells.