Granulated lymphocytes in human endometrium: histochemical and immunohistochemical studies

Abstract

Granulated lymphocytes with an unusual antigenic phenotype (CD56+ CD38+ CD2 +/- CD3- CD16-) form a substantial proportion of leukocytes in human endometrial stroma. The purpose of this study was to examine morphological and antigenic heterogeneity in endometrial granulated lymphocytes (eGL) in imprint preparations, paraffin-embedded sections and frozen sections. eGL in decidual imprints showed variations in cell size, nuclear size, shape and chromatin content and the number and size of cytoplasmic granules. eGL were detected in paraffin-embedded sections using phloxine tartrazine, alcian blue and toluidine blue stains. There was no difference in the number of eGL among the three stains but the granules appeared smaller and more regular when stained with toluidine blue. The proportion of stromal cells which were leukocytes increased from 8.2% in proliferative endometrium to 31.7% in early pregnancy decidua. The number of CD56+ and CD38+ cells increased in late secretory endometrium; CD56+ cells formed greater than 75% of the leukocytes in first trimester decidua. The increased number of CD2+ cells in decidua was not comparable with CD56+ and CD38+ cells suggesting that a lower proportion of CD56+ cells in first trimester decidua coexpress CD2, an observation which was supported by double labelling studies. eGL therefore show morphological and antigenic heterogeneity and the study of granulated lymphocytes in pathological endometrium and decidua will require careful phenotypic and morphological analysis of accurately dated samples.

Immune cells in the placental bed

“…This distribution was confirmed for pregnancy in phloxine tartrazine staining of pregnancy hysterectomies from 8 weeks to term ; granulated leukocytes were rare after 20 weeks gestation. Immunostaining for CD56 has largely confirmed this distribution, although CD56+ cells are present in the proliferative and early secretory phase, albeit in small numbers (Bulmer et al, 1991;King et al, 1989a). Numbers increase in the late secretory phase of the menstrual cycle and even higher numbers are observed in early pregnancy.…”

“…In late secretory phase endometrium and early pregnancy decidua uNK cells are detected predominantly in the stratum functionalis, often forming aggregates around spiral arteries and glands (Bulmer et al, 1991). This perivascular distribution was considered by early workers to reflect diffusion of progesterone from blood into perivascular tissues.…”

“…The large increase in endometrial leukocyte numbers in the mid secretory phase of the menstrual cycle at the expected time of implantation in a fertilized cycle and in early pregnancy (Bulmer et al, 1991;Klentzeris et al, 1992) is one of the major observations implicating endometrial leukocytes as playing a key role in establishment of the fetal-placental unit and the subsequent immunological maintenance of pregnancy. Whether this increase in leukocyte numbers is due to recruitment from other sites or to in situ proliferation in response to direct/indirect hormonal influences and/or locally produced soluble factors is not known.…”

Ly49 receptors activate angiogenic mouse DBA+ uterine natural killer cells

“…[1][2][3] In humans, activation of uterine NK (uNK) cells has been genetically linked with fertility. In contrast, human infertility and gestational complications such as recurrent spontaneous abortion, intrauterine growth restriction and preeclampsia, are seen in specific maternal killer immunoglobulin-like receptors (KIRs) and fetal HLA-C gene combinations that evoke NK cell inhibitory signals.…”

Journal of reproductive immunology

“…It has been widely reported that in early human decidua most lymphocytes are CD%+CD16- (Starkey et al, 1988;King et al, 1989b;Bulmer et al, 1991b). Although some authors observed that most T cells were TCRaP + and few or none expressed TCRyG in this tissue (Chernyshov et al, 1993), others found a large number of TCRyG+ cells, but smaller numbers of TCRccP + cells (Mincheva-Nilsson et al, 1992).…”