PROBLEM:Patients with diarrhea-predominant irritable bowel syndrome have an increased risk of recurrent miscarriage (RM). Loss of chromosomally normal post-implantation embryos is triggered by the proinflammatory cytokines interferon-γ and TNF-α from NK cells and macrophages. Mouse models of RM similar to human unexplained RM have implicated fecal LPS as an important abortifacient. However, subnormal expression of immunosuppressive CD200L at the feto-maternal interface has also been implicated in RM. Human stool contains desquamated epithelium expressing immunosuppressive CD200L and stromal CD56+ NK cells releasing proinflammatory CD200S+ granules. We asked if subnormal epithelial CD200L was associated with increased degranulation of stromal CD200+CD56+NK cells. Systemic effects would include an augmented proinflammatory milieu at the feto-maternal decidual interface. METHODS OF STUDY:Quantitative analysis of biopsies of proximal and distal colon for immunostained for CD200L, CD200S, and CD56-positive cells. CD200 ELISA Assay of stool extracts was done. RESULTS:Epithelium and underlying stroma showed CD200L+ cells, CD200S+ cells, and CD56+ cells releasing CD200S-positive granules. As epithelial CD200L expression decreased, the proportion of the degranulating CD56+ cells significantly increased. Degranulation was significantly greater in irritable bowel syndrome, diarrhea predominant subtype (IBS-D) cases compared to controls. CD200L was detected in stool extracts. CONCLUSIONS:Decreased epithelial CD200L increased both CD66+ CD200S+ stromal cells and their degranulation. This implies potential functional effects. Stool CD200 may reflect the level of CD200 at the feto-maternal decidual interface.

PROBLEM:There is a higher incidence of irritable bowel syndrome with miscarriages, and recurrent miscarriages of otherwise normal embryos have been linked to subnormal expression of the immune checkpoint inhibitor CD200L. We sought to determine if alterations in the expression of the CD200 immune checkpoint inhibitor occur in colonic tissue in IBS-D patients. METHOD OF STUDY:Quantitative immunohistochemical staining of biopsies from proximal and distal colon or rectum for the inhibitory CD200L and CD200S molecules was done. CD56 cells were also enumerated as they play a role in recurrent miscarriages and may express CD200S. RESULTS:CD200L was decreased and CD200S was unchanged in epithelium but not stroma of 3 IBS-D cases. One case had an increase in both CD200L and CD200S. CD56 cells were also stained for CD200S. Degranulation was assessed by the percentage of extracellular CD200S that was increased as epithelial CD200L decreased. CONCLUSIONS:This pilot study was promising and warrants a larger sample to determine if a correlation between uterine implantation site CD200L and CD200S expression in normal and failing implantation sites is needed. Colonic epithelial CD200L may then provide useful information about the pathogenesis of the spontaneous miscarriage in individual cases.

The eutopic secretory phase endometrium in endometriosis overproduces and releases a soluble immunosuppressive CD200 molecule (CD200L) and is populated by stromal cells that contain a truncated CD200 (CD200S) that promotes a proinflammatory environment. The CD200S+ cell population persists when pregnancy occurs and are abundant in the early pregnancy decidua of women with missed abortion. In the present study, CD200S+, CD56+, and CD68+ cells were enumerated in formalin-fixed paraffin-embedded tissue sections from women with endometriosis and non-endometriosis controls. CD200S+ cells were more numerous than CD68+ macrophages and were similar in number and location to CD56bright endometrial NK cells. In some endometria, there was an additional population of CD200S- CD56+ NK cells. In ectopic endometrial peritoneal deposits and in ectopic myometrial deposits (adenomyosis), CD200S+ cells were less frequent, consistent with the known paucity of CD56+ NK cells in sites of ectopic deposits. CD200S+ cell frequency was greater in stroma surrounding the smaller ectopic cystic deposits. Dual immunofluorescent antibody staining confirmed CD200S+ cells were CD56+ NK cells. CD200S+ NK cell frequency may be greater in endometriosis patients' endometrium and may affect embryo survival in early pregnancy. In our opinion, regulation of alternative splicing that results in CD200S rather than CD200L may provide new diagnostic and therapeutic options for women with endometriosis.

PROBLEM:Estrogen-dependent extrauterine implantation and growth of menstrual endometrial tissue affects roughly 10% of reproductive age women and depends on suppression of local innate immune defenses to prevent ectopic tissue rejection. Immunohistochemistry has shown the immune check-point inhibitor CD200 which can suppress rejection is expressed in eutopic endometrium and in ectopic deposits. Soluble CD200 accumulated in venules draining eutopic and ectopic endometrium of endometriosis cases in the secretory phase but not proliferative phase of the menstrual cycle, and should be increased in the circulation.METHOD OF STUDY:Sera from endometriosis and non-endometriosis controls were tested by ELISA for CD200. Endometrial CD200, CD200R1 and CD200R2 mRNA in eutopic was quantified by RT-PCR and localized by in situ hybridization. CD200R1 protein was quantified by immunohistochemistry.RESULTS:Secretory phase serum CD200 was elevated in women with endometriosis compared to controls. Serum CD200 correlated with matched endometrial CD200 mRNA levels. Expression of mRNA for CD200R1 which signals immune suppression was decreased whereas mRNA for the CD200R2 activating receptor was increased. In situ staining of CD200R1 and CD200R2 mRNA showed both receptors were expressed and the fraction of CD200R that is CD200R1 was reduced in secretory and menstrual phase endometriosis endometrium consistent with the RT-PCR result. By contrast, CD200R1 protein and CD200R1 fraction of total CD200R protein were increased in endometriosis.CONCLUSIONS:Failure to suppress circulating CD200 levels in the secretory phase had an 87% specificity and 90% sensitivity for endometriosis. CD200 and increased CD200R1 expression may facilitate development of ectopic deposits by suppressing rejection mechanisms.

Human pregnancy, critical for our species survival, is inefficient and prone to complications such as infertility, spontaneous miscarriages and preeclampsia (PE). Immunological factors may be important as the embryo is 50% paternal and foreign to the mother. Mouse pregnancy models, and in particular the murine CBA/J x DBA/2 mating combination, has been widely used to investigate mechanisms causing and preventing partner-specific recurrent miscarriages (RM) and PE. Occult losses can represent T cell-mediated rejection, and antigen-specific regulatory T cells (Tregs) with classical αβ T cell receptors (TcR) activated by semen antigens at the time of mating are protective. If there is no occult loss, an inadequate Treg response can also predispose to RM. In RM, proinflammatory cytokines from natural killer (NK)-type cells and macrophages of the innate immune system are responsible and cells with γδ TcR protect via release of TGF-β-type molecules. Immunization of abortion-prone female CBA/J mice or administration of cell-associated or soluble CD200, an immune check point inhibitor, can prevent abortions by augmenting uterine decidual suppressor cell activity. Human studies suggest that is also true in couples with RM. Environmental activators of the innate immune system, such as bacterial LPS and stress, can cause abortions as well as occult losses. The endogenous level of Tregs and activation of Tregs specific for the male H-Y antigen may determine success rates and alter the male:female birth ratio. Intralipid alters LPS clearance, prevents abortions in the CBAxDBA/2 model, and is effective in increasing live birth rates in couples undergoing IVF treatment.

Oral administration of antigen is a potent route for induction of systemic tolerance. Regulatory T cells and TH3 cellsare generated at intestinal mucosal sites. Oral exposure to antigens in seminal plasma has been suggested to be ableto generate ‘tolerance’ at the materno-fetal interface that may reduce the risk of pre-eclampsia and recurrent miscarriage. Issues relating to assessing the applicability of oral exposure to seminal plasma antigens in recurrentmiscarriage are discussed. Such tolerance could represent an unappreciated confounder in immunotherapy trials.

As a propaedeutic towards what I want eventually to call "a theory of the corpse," my essay briefly considers images of Romantic remains-in particular, figures of desecrated, diminished, scorned, heaped, abandoned, unburied, forgotten, and otherwise ill-served and instrumentalized bodies of the war dead. Examining the figure of desecrated corpses in Jacques-Louis David, Sir Charles Bell, J. W. Turner, Jane Austen, and Felicia Hemans, I argue that the war dead pose unique challenges to historical knowledge and memory, and to the very concept of representation. The image of the marred corpse, I suggest, captures key features of the social and aesthetic derangements of Romantic war.

Retrograde menstruation is common and in about 10% of women, endometrial tissues implant at ectopic sites and grow as endometriosis (EM) deposits. To date, there has been no marker to identify which patients have an endometrium that will generate deposits. Both endometrial regulatory T cells (Tregs) and increased stromal cell indoleamine 2,3-dioxygenase (IDO) have been implicated, and may suppress rejection by peritoneal NK cells, neutrophils, and cytotoxic macrophages. CD200 is a tolerance signaling molecule which promotes Tregs, [DO producing macrophages, and can directly inhibit cytolytic natural killer (NK) cells and neutrophils. To determine if CD200 might be overexpressed in the endometrium of women with endometriosis, a pilot study using quantitative immunohistochemistry was done using uterine sections and EM deposits from hysterectomy patients. Both CD200 and CD200R proteins were detectable in endometriosis (EM) deposits and in endometrial epithelium and stroma. CD200 increased slightly in secretory phase whole endometrium of EM patients, but strikingly increased soluble CD200 (sCD200) absent sCD200R within venules typified both endometriosis deposits and secretory phase endometrial stromal venules and lymphatics in EM endometria compared to secretory phase NE endometria (P = 0.000006). In our opinion, accumulation of sCD200 in secretory phase endometrial blood vessels may explain development of ectopic deposits and quantifying sCD200 in menstrual blood may cases and identify predisposition to EM. Animal model studies are required to determine if antagonizing CD200 could be therapeutic.

Presence of the CD200 immune check-point inhibitor at the feto-maternal interface is linked to prevention of spontaneous abortion in mice and humans. In human missed abortions (MA), absence of Th17-driven inflammation has been attributed to expression of villus trophoblast CD200 quantified using immunohistochemistry. While rapid aneuploidy (QF-PCR) testing linked low CD200 to pregnancy failure, data showing normal VT CD200 in first trimester normal pregnancy and in abortion of chromosomally abnormal embryos has not been demonstrated. The present report shows normal CD200 in a 7 week gestation termination with normal male QF-PCR and in a 10 week male trisomy 18 MA.

Problem Expression of CD 200 at the feto‐maternal interface is associated with successful murine and human pregnancy. CD 200 binding to CD 200 receptors on lymphomyeloid cells suppresses inflammation and induces Tregs. CD 200 receptors are also expressed on mouse and human placental trophoblast cells. What is the expression of CD 200 and CD 200R in human missed abortions which have preserved Treg levels and in chronic histiocytic intervillositis ( CHI ) where maternal inflammatory cells cause IUGR ? Methods Immunohistiochemistry for CD 200, CD 200R, and Ki67 using human placental sections from missed abortions, term placenta, and CHI . PCR testing was done for trisomy in missed abortion. Results CD 200 and CD 200R were expressed by human villus trophoblasts from 2 weeks post‐implantation to term. Cytotrophoblast proliferation (Ki‐67 + count) decreased at term. In first trimester missed abortion cases, CD 200> CD 200R villus trophoblasts accompanied missed abortion of non‐trisomic male fetuses. CD 200 and Ki67 + trophoblast proliferation was preserved in CHI with maternal inflammatory cell infiltration but CD 200R was greatly decreased. Conclusion Residual CD 200 activity may prevent completion of abortions via induction of Treg cells. In CHI , infiltrating maternal effector T cells may block Treg induction. An autocrine role for CD 200‐ CD 200R interaction versus inhibition of soluble CD 200 by soluble CD 200R is discussed.

Due to a recently discovered pregnancy dating error in the Pathology Department, the placental tissues in our manuscript (Clark t al., 2015) were from 6 weeks after implantation (Carnegie stage 19), and not – as described in the legend of Fig. 1 in the original anuscript – from 2 weeks after implantation. We now located a true 5 weeks gestation (2 week post-implantation) placenta from an lectively terminated missed abortion (embryo 3.95–4.0 mm, Carnegie stage 11) and obtained similar staining for CD200, CD200R1, and i-67 corresponding to the findings provided in the original figure (Fig. 1).

In an outbred mating typical of human reproduction, the embryo and feto-placental unit express paternal antigens to which the mother's immune system can react. However, the embryo and feto-placental unit can engineer the maternal immune defense system towards helpful rather than harmful reactions. Indeed, this begins with the prospective mother's exposure to paternal seminal plasma. In this review, the pregnancy complications of implantation failure (infertility), recurrent spontaneous abortion, pre-eclampsia and intrauterine growth restriction, and premature labor are examined to determine the degree of similarity between events in women and events in lab mouse models. The artificially induced model of endometriosis (which contributes to infertility) is also compared to what occurs in women. One may conclude that the female mouse provides a good analog of the human female. Nevertheless, it is always important to validate mouse data with human studies. The discussion focuses on the intrauterine interface between embryonic and placental tissues and maternal uterine tissues and the dialogue that is referred to as cross-talk. Issues relating to bidirectional transplacental traffic of immune system cells are not discussed as there is very little relevant data.

Natural Foxp3+ regulatory T cells (nTregs) defined by expression of the Foxp3 marker generated in the thymus against self autoantigens prevent systemic autoimmune and inflammatory disease. A second population of Tregs induced by exogenous antigens in the periphery (iTregs) are currently thought to play a key role in preventing infertility, recurrent pregnancy loss (occult and clinically-evident), pre-eclampsia, fetal growth restriction, and premature birth in outbred matings where the father is histoincompatible with the mother. Curiously, when iTregs are ablated in mice, fertility is usually not impaired and resorption rates in matings with allogeneic males can range from 0% to 100% in individual females. Analysis of possible explanations suggest iTregs prevent abortions by countering effects of environmental stressors. Depletion of iTregs at mid-pregnancy in mice only causes abortions in an artificial transgenic model. Effects of iTreg depletion on pre-eclampsia, fetal growth restriction, and premature birth remain to be tested. Tregs induced during pregnancy may also affect the health of offspring in post natal life as well as the health of the mother.

•CD200 was detected by IHC in human villus trophoblasts at gestational week 5.•CD200R1 was detected by IHC in human villus trophoblasts at 5 weeks’ gestation.•Both CD200 and CD200R1 immunostained in peri-implant decidual cells.

PROBLEM:The CD200 tolerance-signaling molecule that is expressed by a wide variety of tissues, including placental trophoblast and epithelial tumor cells, lacks an intracytoplasmic tail and must act by binding to CD200 receptors that have a limited expression on lymphomyeloid cells. This binding can inhibit inflammation and NK cells, promote macrophage secretion of indoleamine-2,3 dioxygenase (IDO), and promote generation of Treg cells. Recently, CD200R1 was reported on human first trimester placental villous trophoblast cells. CD200R1 has not been described on malignant tumor cells. As malignant tumor cells exhibit a number of characteristics of trophoblast, is CD200R1 expressed?METHOD OF STUDY:Affinity-purified rabbit polyclonal antibodies to CD200 and CD200R1 were used to immunostain tissue blocks available from cases in a previous cross-sectional study of Stage 1-IIIA human breast cancer cases and term placental trophoblast.RESULTS:Affinity-purified anti-CD200R1 stained primary breast cancer cells and term placental villous trophoblasts. Tumor cells were also stained by anti-CD200 as in a previous study (correlation P = 0.0042), but CD200R1 and CD200 were not correlated. Presence or absence of strong CD200 expression in the tumor did not correlate with metastasis, and a similar result was obtained with CD200R1.CONCLUSIONS:This is the first report of CD200R1 expression by human epithelial tumor cells, and specifically, early-stage human breast cancer cells. It is also the first report of CD200R1 expression by term placental villous trophoblasts. The potential biological significance of CD200R1 expression in non-hematopoietic cells is discussed.