Antigen-presenting Cells in Pregnant and Non-pregnant Human Myometrium

Problem Inflammatory cells play a crucial role in human parturition. Different populations of leucocytes invade the reproductive tract. Numerous studies have described the decidual immune cell population in pregnant and non-pregnant endometrium. However, little is known about the presence of immune cells in human myometrium. Method of study We herein analysed a spectrum of immune cells in human myometrium comparing tissue samples from non-pregnant (n = 8) and pregnant (n = 10) uteri. Applying immunohistochemistry with a panel of antibodies specific for T cells, monocytes, natural killer cells, B cells and antigen-presenting cells (CD4, CD8, CD14, CD15, CD16, CD19, CD56, CD68, CD83, HLA-DR, DC-Sign, mast cell tryptase), we characterized the immune cell population of human myometrium. Results A significantly higher number of CD14, CD15, CD16, DC-SIGN as well as CD4-positive cells were found in myometrium of pregnant compared to non-pregnant uteri, while mast cells were significantly reduced in pregnant myometrium. Conclusion All markers found increased in pregnant myometrium indicate monocyte/macrophage lineage cells and thus suggest a possible involvement of these cells in healthy pregnancy maintenance. Monocytes/macrophages might produce a microenvironment that permits a controlled invasion of trophoblast cells into the myometrium while preventing a rejection of the semiallogenic conceptus and providing an important barrier against invading pathogenes.