Hum. Reprod. Advance Access published online on July 10, 2008
Human Reproduction, doi:10.1093/humrep/den261
Fetal cells in the maternal appendix: a marker of inflammation or fetal tissue repair?
1 Division of Surgery, Oncology, Reproduction and Anaesthesia, Faculty of Medicine, Institute of Reproductive and Developmental Biology, Imperial College London, UK 2 Centre for Fetal Care, Queen Charlotte's and Chelsea Hospital, London, UK 3 Department of Obstetrics and Gynaecology, University College Cork and Cork University Maternity Hospital, Cork, Ireland 4 Department of Pathology, Hammersmith Hospitals Trust, Du Cane Road W12 0NN, London, UK 5 University of Queensland Centre for Clinical Research, Brisbane, Australia
6 Correspondence address: Department of Reproductive Medicine and Gynaecology, University Medical Centre Utrecht, PO Box 85500, 3508 GA, Utrecht, The Netherlands. E-mail: m.daavoribeirodossantos{at}umcutrecht.nl
BACKGROUND: Fetal microchimeric cells that have trafficked into the maternal circulation persist in maternal tissues for years after pregnancy, but their biological role is unclear. We investigated whether fetal cells participate in maternal tissue repair during human pregnancy.
METHODS: Appendix specimens were acquired from women undergoing appendicectomy during (n = 8) or after (n = 1) pregnancy. Fluorescence in situ hybridization (FISH) determined the presence of male presumed-fetal cells, and immunostaining indicated the fetal cell phenotype.
RESULTS: Male cells were identified in appendiceal tissues from all women with known present or past male pregnancies (n = 7) and from a woman with a previous spontaneous abortion of undetermined gender (n = 1), but not in one woman with three daughters. One woman was only 6 weeks pregnant at appendicectomy. Male cells were evenly distributed through appendix tissues, in larger numbers where there was a greater degree of inflammation and when the current pregnancy was male. Combined immunostaining and Y-FISH demonstrated male desmin+ muscle cells and CD3+ lymphocytes, suggesting fetal cells had differentiated.
CONCLUSIONS: Male-presumed fetal cells of haematopoietic and mesenchymal origin were identified in the appendix of all pregnant women who had sons. We suggest that fetal cells are present at sites of maternal tissue injury during pregnancy, and may participate in tissue repair.
Key words: fetal cell microchimerism/pregnancy/appendix/fetal cells/tissue repair
Submitted on March 31, 2008; resubmitted on May 19, 2008; accepted on May 22, 2008.