How Do Uterine Natural Killer and Innate Lymphoid Cells Contribute to Successful Pregnancy?

Innate lymphoid cells (ILCs) are the most abundant immune cells in the uterine mucosa both before and during pregnancy. Circumstantial evidence suggests they play important roles in regulating placental development but exactly how they contribute to the successful outcome of pregnancy is still unclear. Uterine ILCs (uILCs) include subsets of tissue-resident natural killer (NK) cells and ILCs, and until recently the phenotype and functions of uILCs were poorly defined. Determining the specific roles of each subset is intrinsically challenging because of the rapidly changing nature of the tissue both during the menstrual cycle and pregnancy. Single-cell RNA sequencing (scRNAseq) and high dimensional flow and mass cytometry approaches have recently been used to analyse uILC populations in the uterus in both humans and mice. This detailed characterisation has significantly changed our understanding of the heterogeneity within the uILC compartment. It will also enable key clinical questions to be addressed including whether specific uILC subsets are altered in infertility, miscarriage and pregnancy disorders such as foetal growth restriction and pre-eclampsia. Here, we summarise recent advances in our understanding of the phenotypic and functional diversity of uILCs in non-pregnant endometrium and first trimester decidua, and review how these cells may contribute to successful placental development

How Do Uterine Natural Killer and Innate Lymphoid Cells Contribute to Successful Pregnancy?

Innate lymphoid cells (ILCs) are the most abundant immune cells in the uterine mucosa both before and during pregnancy. Circumstantial evidence suggests they play important roles in regulating placental development but exactly how they contribute to the successful outcome of pregnancy is still unclear. Uterine ILCs (uILCs) include subsets of tissue-resident natural killer (NK) cells and ILCs, and until recently the phenotype and functions of uILCs were poorly defined. Determining the specific roles of each subset is intrinsically challenging because of the rapidly changing nature of the tissue both during the menstrual cycle and pregnancy. Single-cell RNA sequencing (scRNAseq) and high dimensional flow and mass cytometry approaches have recently been used to analyse uILC populations in the uterus in both humans and mice. This detailed characterisation has significantly changed our understanding of the heterogeneity within the uILC compartment. It will also enable key clinical questions to be addressed including whether specific uILC subsets are altered in infertility, miscarriage and pregnancy disorders such as foetal growth restriction and pre-eclampsia. Here, we summarise recent advances in our understanding of the phenotypic and functional diversity of uILCs in non-pregnant endometrium and first trimester decidua, and review how these cells may contribute to successful placental development

Tissue-Specific Education of Decidual NK Cells.

During human pregnancy, fetal trophoblast cells invade the decidua and remodel maternal spiral arteries to establish adequate nutrition during gestation. Tissue NK cells in the decidua (dNK) express inhibitory NK receptors (iNKR) that recognize allogeneic HLA-C molecules on trophoblast. Where this results in excessive dNK inhibition, the risk of pre-eclampsia or growth restriction is increased. However, the role of maternal, self-HLA-C in regulating dNK responsiveness is unknown. We investigated how the expression and function of five iNKR in dNK is influenced by maternal HLA-C. In dNK isolated from women who have HLA-C alleles that carry a C2 epitope, there is decreased expression frequency of the cognate receptor, KIR2DL1. In contrast, women with HLA-C alleles bearing a C1 epitope have increased frequency of the corresponding receptor, KIR2DL3. Maternal HLA-C had no significant effect on KIR2DL1 or KIR2DL3 in peripheral blood NK cells (pbNK). This resulted in a very different KIR repertoire for dNK capable of binding C1 or C2 epitopes compared with pbNK. We also show that, although maternal KIR2DL1 binding to C2 epitope educates dNK cells to acquire functional competence, the effects of other iNKR on dNK responsiveness are quite different from those in pbNK. This provides a basis for understanding how dNK responses to allogeneic trophoblast affect the outcome of pregnancy. Our findings suggest that the mechanisms that determine the repertoire of iNKR and the effect of self-MHC on NK education may differ in tissue NK cells compared with pbNK.This work was supported by Wellcome Trust Grants 090108/Z/09/Z and 085992/Z/08/Z, as well as by British Heart Foundation Grant PG/09/077/27964. P.R.K. was the recipient of a Wellcome Trust Ph.D. studentship.This is the final version of the article. It first appeared from the American Association of Immunologists via http://dx.doi.org/10.4049/​jimmunol.150122

RNA-Seq reveals changes in human placental metabolism, transport and endocrinology across the first-second trimester transition.

The human placenta is exposed to major environmental changes towards the end of the first trimester associated with full onset of the maternal arterial placental circulation. Changes include a switch from histotrophic to hemotrophic nutrition, and a threefold rise in the intraplacental oxygen concentration. We evaluated their impact on trophoblast development and function using RNA-sequencing (RNA-Seq) and DNA-methylation analyses performed on the same chorionic villous samples at 7-8 (n=8) and 13-14 (n=6) weeks of gestation. Reads were adjusted for fetal sex. Most DEGs were associated with protein processing in the endoplasmic reticulum (ER), hormone secretion, transport, extracellular matrix, vasculogenesis, and reactive oxygen species metabolism. Transcripts higher in the first trimester were associated with synthesis and ER processing of peptide hormones, and glycolytic pathways. Transcripts encoding proteins mediating transport of oxygen, lipids, protein, glucose, and ions were significantly increased in the second trimester. The motifs of CBX3 and BCL6 were significantly overrepresented, indicating the involvement of these transcription factor networks in the regulation of trophoblast migration, proliferation and fusion. These findings are consistent with a high level of cell proliferation and hormone secretion by the early placenta to secure implantation in a physiological low-oxygen environment

RNA-Seq reveals changes in human placental metabolism, transport and endocrinology across the first-second trimester transition.

The human placenta is exposed to major environmental changes towards the end of the first trimester associated with full onset of the maternal arterial placental circulation. Changes include a switch from histotrophic to hemotrophic nutrition, and a threefold rise in the intraplacental oxygen concentration. We evaluated their impact on trophoblast development and function using RNA-sequencing (RNA-Seq) and DNA-methylation analyses performed on the same chorionic villous samples at 7-8 (n=8) and 13-14 (n=6) weeks of gestation. Reads were adjusted for fetal sex. Most DEGs were associated with protein processing in the endoplasmic reticulum (ER), hormone secretion, transport, extracellular matrix, vasculogenesis, and reactive oxygen species metabolism. Transcripts higher in the first trimester were associated with synthesis and ER processing of peptide hormones, and glycolytic pathways. Transcripts encoding proteins mediating transport of oxygen, lipids, protein, glucose, and ions were significantly increased in the second trimester. The motifs of CBX3 and BCL6 were significantly overrepresented, indicating the involvement of these transcription factor networks in the regulation of trophoblast migration, proliferation and fusion. These findings are consistent with a high level of cell proliferation and hormone secretion by the early placenta to secure implantation in a physiological low-oxygen environment

Composition, Development, and Function of Uterine Innate Lymphoid Cells.

Innate lymphoid cells (ILCs), including NK cells, contribute to barrier immunity and tissue homeostasis. In addition to the role of uterine NK cells in placentation and fetal growth, other uterine ILCs (uILCs) are likely to play roles in uterine physiology and pathology. In this article, we report on the composition of uILCs in the endometrium during the luteal phase and in the decidua during early pregnancy. Whereas nonkiller uILC1s and uILC2s are barely detectable in mouse and not detected in humans, a sizeable population of uILC3s is found in human endometrium and decidua, which are mostly NCR(+) and partially overlap with previously described IL-22-producing uterine NK cells. Development of mouse uILC3 is Nfil3 independent, suggesting unique features of uILCs. Indeed, although the cytokine production profile of mouse uILCs recapitulates that described in other tissues, IL-5, IL-17, and IL-22 are constitutively produced by uILC2s and uILC3s. This study lays the foundation to understand how ILCs function in the specialized uterine mucosa, both in tissue homeostasis and barrier immunity and during pregnancy.Work supported by grants from the Wellcome Trust, the Medical Research Council, the British Heart Foundation and the Leukaemia & Lymphoma Research to FC. EB is the recipient of a Centre for Trophoblast Research Graduate Studentship. SB is the recipient of a Marie Curie FP7 Fellowship.This is the final version of the article. It first appeared from the American Association of Immunologists via http://dx.doi.org/10.4049/​jimmunol.150068

Fatal breakthrough mucormycosis in a multivisceral transplant patient receiving micafungin: Case report and literature review.

INTRODUCTION: Antifungal agents are routinely used in the post-transplant setting for both prophylaxis and treatment of presumed and proven fungal infections. Micafungin is an echinocandin-class antifungal with broad antifungal cover and favorable side effect profile but, notably, it has no activity against molds of the order Mucorales. PRESENTATION OF CASE: A 47-year-old woman underwent multivisceral transplantation for intestinal failure-associated liver disease. She had a prolonged post-operative recovery complicated by invasive candidiasis and developed an intolerance to liposomal amphotericin B. In view of her immunosuppression, she was commenced on micafungin as prophylaxis to prevent invasive fungal infection. However, she developed acute graft versus host disease with bone marrow failure complicated by disseminated mucormycosis which was only diagnosed post mortem. DISCUSSION: Non-Aspergillus breakthrough mold infections with micafungin therapy are rare with only eight other cases having been described in the literature. Breakthrough infections have occurred within one week of starting micafungin. Diagnosis is problematic and requires a high degree of clinical suspicion and microscopic/histological examination of an involved site. The management of these aggressive infections involves extensive debridement and appropriate antifungal cover. CONCLUSION: A high level of suspicion of invasive fungal infection is required at all times in immunosuppressed patients, even those receiving antifungal prophylaxis. Early biopsy is required. Even with early recognition and aggressive treatment of these infections, prognosis is poor

Foot kinematics in patients with two patterns of pathological plantar hyperkeratosis

Background: The Root paradigm of foot function continues to underpin the majority of clinical foot biomechanics practice and foot orthotic therapy. There are great number of assumptions in this popular paradigm, most of which have not been thoroughly tested. One component supposes that patterns of plantar pressure and associated hyperkeratosis lesions should be associated with distinct rearfoot, mid foot, first metatarsal and hallux kinematic patterns. Our aim was to investigate the extent to which this was true. Methods: Twenty-seven subjects with planter pathological hyperkeratosis were recruited into one of two groups. Group 1 displayed pathological plantar hyperkeratosis only under metatarsal heads 2, 3 and 4 (n = 14). Group 2 displayed pathological plantar hyperkeratosis only under the 1st and 5th metatarsal heads (n = 13). Foot kinematics were measured using reflective markers on the leg, heel, midfoot, first metatarsal and hallux. Results: The kinematic data failed to identify distinct differences between these two groups of subjects, however there were several subtle (generally <3°) differences in kinematic data between these groups. Group 1 displayed a less everted heel, a less abducted heel and a more plantarflexed heel compared to group 2, which is contrary to the Root paradigm. Conclusions: There was some evidence of small differences between planter pathological hyperkeratosis groups. Nevertheless, there was too much similarity between the kinematic data displayed in each group to classify them as distinct foot types as the current clinical paradigm proposes