High maternal-fetal HLA eplet compatibility is associated with severe manifestation of preeclampsia

Introduction

Preeclampsia is responsible for more than 70 000 and 500 000 maternal and fetal deaths, respectively each year. Incomplete remodelling of the spiral arteries in placenta is the most accepted theory of preeclampsia pathogenesis. However, the process is complexed with immunological background, as pregnancy resembles allograft transplantation. Fetus expresses human leukocyte antigens (HLA) inherited from both parents, thus is semiallogeneic to the maternal immune system. Therefore, induction of fetal tolerance is crucial for physiological outcome of pregnancy. Noteworthy, the immunogenicity of discordant HLA antigens is determined by functional epitopes called eplets, which are continuous and discontinuous short sequences of amino acids. This way various HLA molecules may express the same eplet and some HLA incompatibilities can be more immunogenic due to different eplet combination. Therefore, we hypothesized that maternal- fetal HLA incompatibility may be involved in the pathogenesis of gestational hypertension and its progression to preeclampsia. We also aimed to test if particular maternal-fetal eplet mismatches are more prone for induction of anti- fetal HLA antibodies in gestational hypertension and preeclampsia.

Methods

High resolution next-generation sequencing of HLA-A, -B, -C, -DQB1 and -DRB1 antigens was performed in mothers and children from physiological pregnancies (12 pairs) and from pregnancies complicated with gestational hypertension (22 pairs) and preeclampsia (27 pairs). In the next step HLA eplet identification and analysis of HLA eplet incompatibilities was performed with in silico approach HLAMatchmaker algorithm. Simultaneously maternal sera were screened for anti-fetal HLA class I, class II and anti-MICA antibodies with Luminex, and data were analyzed with HLA-Fusion software.

Results

We observed that high HLA-C, -B, and DQB1 maternal-fetal eplet compatibility was associated with severe preeclampsia (PE) manifestation. Both quantity and quality of HLA epletmismatches affected the severity of PE. Mismatches in HLA-B eplets: 65QIA+76ESN, 70IAO, 180E, HLA-C eplets: 193PL3, 267QE, and HLA-DRB1 eplet: 16Y were associated with a mild outcome of preeclampsia if the complication occurred.

Conclusions

High HLA-C, HLA-DQB1 and HLA-B eplet compatibility between mother and child is associated with severe manifestation of preeclampsia. Both quantity and quality of maternal-fetal HLA eplet mismatches affects severity of preeclampsia.

Immunobiology of pregnancy: from basic science to translational medicine

Embryo implantation failure and spontaneous abortions represent the main causes of infertility in developed countries. Unfortunately, incomplete knowledge of the multiple factors involved in implantation and fetal development keeps the success rate of medically assisted procreation techniques relatively low. According to recent literature, cellular and molecular mechanisms of 'immunogenic tolerance' towards the embryo are crucial to establish an 'anti-inflammatory' state permissive of a healthy pregnancy. In this review we dissect the role played by the immune system in the endometrial-embryo crosstalk, with a particular emphasis towards the fork-head-box-p3 (Foxp3+) CD4+CD25+ regulatory T (Treg) cells and discuss the most recent therapeutic advances in the context of early immune-mediated pregnancy loss.

Changes in the T-helper 1 and 2 cell populations during pregnancy in tacrolimus-treated women with repeated implantation failure and recurrent pregnancy loss

Tacrolimus has received considerable attention as a treatment approach for infertility associated with maternal-foetal immune abnormalities, such as repeated implantation failure (RIF) and recurrent pregnancy loss (RPL). This study examined the changes in T-helper (Th) 1 and 2 cell populations during pregnancy in peripheral blood of tacrolimus-treated RIF patients who delivered a liveborn infant from August 2012 to February 2020 at the National Centre for Child Health and Development. A total of 58 eligible study subjects were divided into two groups according to the presence of a history of RPL: (i) RIF-alone group (n = 31); and (ii) RIF-plus-RPL group (n = 27). In a flow cytometric analysis, the Th1/Th2 cell ratios were significantly higher before pregnancy than after pregnancy, and during the first trimester than the second trimester in the RIF-alone group (p = 0.0071 and p = 0.0087, respectively). However, no significant differences were present in the RIF-plus-RPL group. Although the Th1 immunity was suppressed under tacrolimus treatment in both groups, a delayed reduction in the Th1 cell percentage after initiation of treatment was observed in the RIF-plus-RPL group. In conclusion, the cellular immune alterations in tacrolimus-treated patients with RIF were different depending on the presence or absence of a history of RPL.

Evolution of Placental Hormones: Implications for Animal Models

Human placenta secretes a variety of hormones, some of them in large amounts. Their effects on maternal physiology, including the immune system, are poorly understood. Not one of the protein hormones specific to human placenta occurs outside primates. Instead, laboratory and domesticated species have their own sets of placental hormones. There are nonetheless several examples of convergent evolution. Thus, horse and human have chorionic gonadotrophins with similar functions whilst pregnancy-specific glycoproteins have evolved in primates, rodents, horses, and some bats, perhaps to support invasive placentation. Placental lactogens occur in rodents and ruminants as well as primates though evolved through duplication of different genes and with functions that only partially overlap. There are also placental hormones, such as the pregnancy-associated glycoproteins of ruminants, that have no equivalent in human gestation. This review focusses on the evolution of placental hormones involved in recognition and maintenance of pregnancy, in maternal adaptations to pregnancy and lactation, and in facilitating immune tolerance of the fetal semiallograft. The contention is that knowledge gained from laboratory and domesticated mammals can translate to a better understanding of human placental endocrinology, but only if viewed in an evolutionary context.

Therapy Aimed to Suppress the Production of the Immunosuppressive Protein Progesterone Induced Blocking Factor (PIBF) May Provide Palliation and/or Increased Longevity for Patients With a Variety of Different Advanced Cancers - A Review

Progesterone induced blocking factor (PIBF) is a unique protein that is not present in normal cells, but is found predominantly in rapidly growing cells of the fetal placental unit or cancer cells. There is a larger "parent" form that is a nuclear protein involved in cell to cell regulation, allowing tumor cells to proliferate and invade tissues. The parent compound is cleaved into smaller intracytoplasmic isoforms that can suppress cellular immune response, especially, but not limited to natural killer cells. The progesterone receptor antagonist mifepristone can suppress messenger RNA for PIBF, but can also suppress the intracytoplasmic protein. Treating cancer cell lines, intact animals with a variety of spontaneous cancers, and people with various cancers with mifepristone, has been found to inhibit cancer growth, and provide both palliation of symptoms and longevity possibly by suppressing this unique immunomodulatory protein.