Identification of Maternal Hematopoietic Cells in a 2nd-Trimester Fetus

Objective: To study the subset of maternal cells in fetal tissue in a 2nd-trimester fetus with malformations. Methods: By cell sorting and PCR amplification, we studied the presence of maternal CD3+ (T cells), CD19+ (B cells), CD34+ (hematopoietic progenitor cells), and CD45+ (leukocytes) in different tissues in a 2nd trimester fetus. Results: Maternal cells could be detected in fetal liver, lung, heart, thymus, spleen, adrenal gland, kidney, and placenta, but not in pancreas or gonadal tissue. In thymus, liver, and spleen, cell separation showed CD3+, CD19+, CD34+, and CD45+ positive cells of maternal origin. Conclusions: The present study indicates that maternal cells are widely distributed in a 2nd-trimester fetus. In addition, we found subpopulations of maternal cells belonging to lymphoid and myeloid lineages and hematopoietic progenitors with engraftment capacity in liver, spleen, and thymus. The study warrants further investigations on presence and possible biological function of maternal cells in normal and malformed fetuses.