Fetal cell microchimerism in tissue from multiple sites in women with systemic sclerosis

Objective. The realization that fetal cells pass into the maternal circulat ion and can survive for many years has raised the question of whether fetal microchimerism can cause subsequent disease in the mother. Available data suggest that fetal-maternal transfusion may be related to some autoimmune d iseases, notably systemic sclerosis (SSc). The goal of the current work was to identify and quantify tissue-specific fetal microchimerism in women wit h SSc. Methods. We analyzed multiple tissue specimens obtained at autopsy from wom en with SSc as well as women who had died of causes unrelated to autoimmuni ty, using fluorescence in situ hybridization to detect the presence of male cells in women with sons. Tissues analyzed included adrenal gland, heart, intestine, kidney, liver, lung, lymph node, pancreas, parathyroid, skin, an d spleen. Results. Male cells were observed in tissue from at least 1 site in each wo man with SSc and were found most frequently in spleen sections. After splee n, male cells were observed most frequently in lymph node, lung, adrenal gl and, and skin tissue. The only tissue type in which male cells were not see n in any patient was pancreatic tissue. Male cells were not observed in tis sue from women who had died of causes unrelated to autoimmunity. Conclusion. The results of this study suggest that fetal cells migrate from the peripheral circulation into multiple organs in women with SSc. All of the women studied had previously given birth to sons, so it is likely that these cells are of fetal origin. While the relevance of this finding to the pathogenesis of SSc remains to be elucidated, the presence of fetal cells in internal organs suggests that they could play a role in disease pathogen esis and that they may preferentially sequester in the spleen. The presence of these male cells may also be a result of disease, possibly through the migration of terminally differentiated and/or progenitor cells to areas of tissue damage.