The Decidua of Early Human Pregnancy: Immunohistochemistry and Function of Immunocompetent Cells

Abstract

Like the endometrial stroma, the decidua contains lymphoreticular cells, and these are probably involved in immunological interactions between the conceptus and the mother. Lymphoreticular cells in decidual tissue obtained from 12 patients undergoing therapeutic abortion of an intact pregnancy at 6–10 weeks’ gestation were investigated in this study. Immunophenotyping with a broad panel of monoclonal antibodies revealed various subpopulations of lymphoreticular cells. Macrophages (Ki-M6+, Ki-M7+, Ki-M8+, KP1+, MAC 387+ and Ki-M1P+) represented the largest fraction of intradecidual lymphoreticular cells. CD3+ and CD8+ lymphocytes were found in moderate numbers and CD4+ cells in small numbers. The majority of the intradecidual lymphoid cells exhibited an unusual phenotype [CD7+, CD2+, CD56+, triple negative (CD3––, CD4––, CD8––)]. The distribution of these unusual lymphocytes mirrored that of the so-called endometrial stromal granulocytes. A few of these stromal granulocytes reacted with the macrophage-associated antibody KP1, but not with Ki-M1P, another macrophage marker. This was confirmed by immuno-electron microscopy. The finding that intradecidual CD3+ lymphocytes express neither the Α/Β nor the Γ/Δ heterodimer of the T cell antigen receptor was unexpected. However, these cells did express the Α/Β heterodimer after in vitro culture with PHA-P and recombinant exogenous interleukin-2. No stimulated T lymphocytes expressing activation antigens could be detected. B lymphocytes, T and B immune accessory cells and CD 15+ granulocytes were found only in small numbers or were absent. Amongst cells expressing NK cell markers, CD 5 7+ and CD 16+ cells were found in small to moderate numbers, while CD 5 6+ cells were detected in large numbers. The potential role of decidual stromal granulocytes in regulating the development of early human pregnancy is discussed.

The production of prostanoids and the identification of macrophages in human decidua vera tissue

“…Macrophages are the predominant intradecidual cell type in early and late pregnancy (Bulmer et al, 1984;Dietl et al, 1992). We found macrophages in abundance within intradecidual lymphoreticular cells, i.e., Ki-M8 mononuclear cells are present in large numbers, and it appears that they intermingle with the decidual stromal cells (Fig.…”

Activation of CD8+ Regulatory T Cells by Human Placental Trophoblasts

“…The lupus anticoagulant and anticardiolipin Abs are present in 1-3% of normal pregnancies but are markedly elevated in patients with recurrent fetal loss (32,33). CD8 ϩ T cells are present at the maternal/fetal interface, albeit at low numbers (34,35). Furthermore, Yeaman et al (36,37) recently described uterine lymphoid aggregates consisting of predominantly CD8 ϩ T cells and B cells in close association during the proliferative phase of the estrous cycle.…”

Marker molecules of human endometrial differentiation can be hormonally regulated under in-vitro conditions as in-vivo

“…In addition to epithelial cells (glandular epithelial cells and surface epithelium) and fibroblasts-the latter being transformed to pre-decidual cells in the late secretory phase of the cycle-there are immunocompetent cells including macrophages, T lymphocytes and large granular lymphocytes (LGL). In particular, LGL increase during the luteal phase (Bulmer et al, 1988;King et al, 1989;King and Loke, 1991;Dietl et al, 1992) and abound in this phase of the cycle. Hence, uterine mucosa consists of different cell types, which are regulated distinctly by steroid hormones and paracrine factors.…”