Lynn Morrison

Placental malaria. I: Pathological classification

Pregnant women are more likely to contract malaria than their non‐pregnant counterparts. The aim of this study was to develop a simple classification system for the histopathological diagnosis of placental malaria infection applicable to placentas collected in field conditions. The placentas were classified into four groups depending on the presence and disribution of parasites and malaria pigment: active infection, active‐chronic infection, past‐chronic infection, not infected. The frequency of parasitized placentas (26.4%) was in keeping with the prevalence of placental parasitaemia documented in epidemiological studies. An additional 29.8% placentas showed pigment in fibrin only, indicating pastchronic infection. Chronic placental malaria infection was most common in primigravidae, possibly reflecting ineffective clearance of parasites from the placenta. Seasonal fluctuations between infection categories support progression of placental infection with delayed clearance of pigment from fibrin. The proposed classification system has allowed diagnosis of different categories of placental malaria infection by two independent observers. A stadardized method of diagnosis may enhance understanding of placental pathology and reduced birth weight in malaria infection during pregnancy.

Expression of the proliferation markers Ki67 and transferrin receptor by human trophoblast populations

Immunohistochemical techniques were used to investigate the expression of proliferation markers (Ki67 and transferrin receptor) by fetal trophoblast in normal human pregnancy. In placental villous tissue, transferrin receptor was detected not only on the apical syncytiotrophoblastic membrane but also on the proximal portion of cytotrophoblast columns, an area of high cellular proliferative activity. The majority of cells in cytotrophoblast columns and shell showed nuclear reactivity with Ki67. Villous syncytiotrophoblast was uniformly unreactive with Ki67 but a proportion of the underlying cytotrophoblast was Ki67-positive throughout pregnancy. Occasional Ki67-positive trophoblast cells were identified within chorion laeve at term. In contrast, interstitial and endovascular extravillous trophoblast in maternal uterine decidual tissue failed to label with either proliferation marker. Thus, chorionic villous cytotrophoblast and extravillous trophoblast in the chorion laeve appear to retain their proliferative capacity into late pregnancy. Cytotrophoblast columns represent a zone of cellular proliferation which may be dependent on transferrin.

Immunohistochemical Localization of Interferons in Human Placental Tissues in Normal, Ectopic, and Molar Pregnancy

ABSTRACT: Interferon (IFN)α, β, and γ have been localized in normal and pathological human pregnancy using both polyclonal and monoclonal antibodies in immunohistochemical techniques. IFNα was localized to fetal chorionic villous syncytiotrophoblast throughout normal pregnancy, as well as to extravillous trophoblast in the placental bed and chorion lave. Maternal decidual leukocytes, as well as fetal Hofbauer cells in the villous mesenchyme, also contained IFNα. IFNγ was detected in villous syncytiotrophoblast, while anti‐IFNβ showed only patchy weak reactivity with syncytiotrophoblast. Reaction patterns on ectopic pregnancy tissues were similar to those in early intrauterine pregnancy. In molar pregnancy, reactivity for IFNα, β, and γ was observed in syncytiotrophoblast. Along with their potential anti‐viral effects, placental interferons could play a role in local immunomodulation or in regulation of embryonic cell proliferation and differentiation.

Placental malaria. II. A semi‐quantitative investigation of the pathological features

Malaria in pregnancy is associated with reduced birth weight. Most pathological studies of placental malaria infection have focused on severe Plasmodium falciparum infection. In the present study of 121 placentas delivered in a rural area of The Gambia, malaria infection was diagnosed in tissue sections using a simple classification system and severity of pathology was ranked semiquantitively. Deposition of malaria pigment in circulating cells was associated with active infections whereas pigment in fibrin was a feature of active‐chronic infections. Primigravidae had higher levels of pigment at all sites, although these observations were not always significant. Thickening of the trophoblast basement membrane occurred in all infection categories but fibrinoid necrosis of chorionic villi was a feature of active and active‐chronic infection. Both birth weight and placental weight were increased in infected placentas but widespread trophoblast basement membrane thickening was associated with decreased birth weight. Both birth weight and placental weight decreased with increased fibrinoid necrosis and cytotrophoblast prominence but the results were not sigaificant. By this approach it has been possible to correlate placental pathology with different infection categories and to analyse the pathological features associated with decreased birth weight.

Endometrial lymphoid tissue in the timed endometrial biopsy: Morphometric and immunohistochemical aspects

OBJECTIVES The purpose of this study was to provide a morphometric profile of endometrial granulated lymphocytes and to investigate qualitative and quantitative differences in leukocyte subsets in precisely timed luteal phase endometrial biopsies. STUDY DESIGN Endometrial biopsies were obtained from 24 normal fertile women at 4, 7, 10, and 13 days after the luteinizing hormone surge. Endometrial granulated lymphocytes were assessed morphometrically in 2 microns resin sections. Eleven monoclonal antibodies were used to characterize leukocytes in frozen sections. Semiquantitation was performed with a Quantimet 970 image analyzer. Data were analyzed with one-way analysis of variance. RESULTS CD8+ (T suppressor-cytotoxic) cells increased significantly from 4 to 7 days after the luteinizing hormone surge, whereas CD68+ macrophages increased from days 10 to 13. Lymphocytes with an unusual phenotype (CD56+, CD38+, CD2+) increased dramatically after 7 days. The volume fraction of endometrium occupied by the nuclei of endometrial granulated lymphocytes did not alter, but their mean nuclear diameter and axial ratio decreased from days 7 to 13. CONCLUSION The morphometric findings indicate in situ proliferation of endometrial granulated lymphocytes rather than migration from the peripheral circulation. T lymphocytes, macrophages, and endometrial granulated lymphocytes increase significantly between certain stages of the luteal phase.

Maternal and fetal cellular relationships in the human placental basal plate

Maternal and fetal cellular relationships in the normal human term placental basal plate were investigated by single and double immunohistochemical labelling techniques. Extravillous fetal trophoblast in the basal plate was uniformly reactive with markers of low-molecular-weight cytokeratins. The predominant maternal leucocyte population in the basal plate consisted of leucocyte-common-antigen-positive, class II MHC-positive macrophages, which exhibited acid phosphatase activity. Double-labelling methods highlighted the close association of these macrophages with extravillous trophoblast: they often extended processes around the fetal cells and were also observed within islands of cytotrophoblast. Other leucocytes were uncommon, although aggregates of T cells were apparent in some tissues.

Subinvolution of the uteroplacental arteries in the human placental bed

Subinvolution of the uteroplacental arteries of the placental bed is a recognized cause of post partum haemorrhage causing significant morbidity. Whilst the physiological changes in these arteries during pregnancy and the part played by endovascular trophoblast migration are well documented, the sequence of events during involution and the pathophysiology of subinvolution are unknown. Using immunohistochemical techniques we have studied uteroplacental arteries in the placental bed in 25 cases of post partum haemorrhage and compared the subinvoluted vessels with normally involuted vessels. Non‐involuted vessels were present in 22 test cases; these abnormal vessels were filled with thrombus and no endothelial lining was detected. Extravillous perivascular trophoblast was usually present in the walls of these abnormal vessels and in some cases was seen in an endovascular position. Subinvolution of placental site vessels may represent an abnormal interaction between maternal uterine cells and fetal trophoblast.

Endometrial leukocyte subpopulations in women with endometriosis

The aim of this study was to investigate whether the endometrium of women with endometriosis differs immunologically from the endometrium of normal fertile women. Endometrial biopsies were obtained from 18 normal fertile women who were requesting sterilisation or reversal of sterilisation and 21 infertile women who had laparoscopically diagnosed pelvic endometriosis. The endometrial biopsies were obtained from both groups during the either early, mid or late luteal phase of the menstrual cycle. A panel of 11 monoclonal antibodies and immuno-histochemical techniques were employed to characterise the endometrial stromal leukocytes in frozen sections. Image analysis was used for semi quantitation of leukocytes. In both groups, the number of endometrial granulated lymphocytes (CD56+ CD38+ cells) and macrophages (CD68+ cells) increased significantly between the early and late luteal phase of the menstrual cycle. Compared with fertile controls, women with endometriosis had fewer T-suppressor/cytotoxic (CD8+) cells and endometrial granulated lymphocytes but more T-helper/inducer (CD4+) cells, CD68+ cells and CD16+ cells. None of these differences reached a statistically significant level. This study has shown that the endometrial lymphoid tissue of women with endometriosis does not differ qualitatively or quantitively from that of normal fertile controls. However, functional differences of endometrial leukocytes between the two groups cannot be excluded.

Lectin binding of endometrium in women with unexplained infertility**Presented at the 5th Meeting of European Association of Gynecologists and Obstetricians, Athens, Greece, October 3 to 6, 1990.

OBJECTIVE To investigate whether peri-implantation phase endometrium in women with unexplained infertility differs from the endometrium of normal fertile women. DESIGN Assessment of the function of the endometrium by using endometrial biopsy specimens and lectin histochemistry. SETTING Infertility Clinic, Jessop Hospital for Women, Sheffield, United Kingdom. PATIENTS Eighteen normal fertile women (group I) and 18 women with unexplained infertility (group II). INTERVENTIONS Endometrial biopsies were obtained from both groups at 5, 7, and 9 days after the luteinizing hormone (LH) surge. MAIN OUTCOME MEASURES Five biotinylated lectins, concanavalin A (ConA), wheat germ agglutinin (WGA), soybean agglutinin, Peanut, and Ulex europaeus I were used as analytical probes to study endometrial glycoconjugates. Histochemical staining was performed using the avidin-biotin peroxidase method. The lectin binding by endometrial glands, surface epithelium, stromal cells, and vessels was assessed. RESULTS In group I, ConA stained the subnuclear glandular cytoplasm, glandular lumen, stroma cells, and surface epithelium. In group II, ConA binding to glandular or surface epithelium was none or equivocal. In group I, WGA bound to glandular cytoplasm and stroma cells on days LH + 5 and LH + 7. In group II, WGA binding was absent in glands but present in stroma. CONCLUSIONS Reproductive failure of women with unexplained infertility may be associated with defective biosynthesis and distribution of glycoconjugates that subsequently results in an unfavorable endometrial environment during the peri-implantation phase.