Pregnancy induced TMA in severe preeclampsia results from complement-mediated thromboinflammation

Preeclampsia is a multifactorial vascular disease unique to human pregnancy. While genetic and antiangiogenic factors are important contributors to preeclampsia susceptibility, recent studies have shown that dysregulation and/or over-activation of the complement system has an integral role in dis-ease etiology. Furthermore, the role of the coagulation cascade may be underappreciated in the develop-ment of the disease. Traditionally, for research purposes, the pool of preeclampsia cases has been divided into non-severe and severe disease depending on the onset and severity of the symptoms. However, of particular interest are a small but important minority of cases that present with symptoms likening to those of hemolysis, elevated liver enzymes and low platelets syndrome, atypical hemolytic uremic syn-drome, or thrombotic thrombocytopenic purpura, all thrombotic microangiopathy (TMA) diseases, with the hallmark mechanisms of endothelial dysfunction and aberrant activation of complement and coagu-lation cascades. We therefore propose a third class, severe TMA-like preeclampsia to be included in the categorization of preeclampsia patients. Identifying these patients would target research, diagnostic dif-ferentiation, and novel treatment options to the subclass of patients with life-threatening disease that are most likely to benefit from next-generation drug development. (c) 2021 The Authors. Published by Elsevier Inc. on behalf of American Society for Histocompatibility and Immunogenetics. This is an open access article under the CC BY-NC-ND license (http://creativecommons. org/licenses/by-nc-nd/4.0/).Peer reviewe

Eculizumab Treatment for Postpartum HELLP Syndrome and aHUS—Case Report

Preeclampsia is a pregnancy-specific disorder affecting ca 3% of all pregnant women. Preeclampsia is the source of severe pregnancy complications. Later life consequences for mother and infant include increased risk of cardiovascular disease. Preeclampsia is caused by the dysfunction of the endothelium with subsequent activation of complement and coagulation systems. HELLP syndrome is considered to be an extreme complication of preeclampsia but it can also present independently. Diagnostic symptoms in HELLP syndrome are Hemolysis, Elevated Liver enzymes, and Low Platelets. Similar phenotype is present in thrombotic microangiopathies (TMAs) and HELLP syndrome is considered part of the TMA spectrum. Here, we present a case of severe preeclampsia and HELLP syndrome, which exacerbated rapidly and eventually led to need of intensive care, plasma exchange, and hemodialysis. The patient showed signs of hemolysis, disturbance in the coagulation, and organ damage in liver and kidneys. After comprehensive laboratory testing and supportive care, the symptoms did not subside and treatment with complement C5 inhibitor eculizumab was started. Thereafter, the patient started to recover. The patient had pregnancy-induced aHUS. Earlier initiation of eculizumab treatment may potentially shorten and mitigate the disease and hypothetically decrease future health risks of preeclamptic women.Peer reviewe

The Immunogenetic Conundrum of Preeclampsia

Pregnancy is an immunological challenge to the mother. The fetal tissues including the placenta must be protected from activation of the maternal immune system. On the other hand, the placental tissue sheds into the maternal circulation and must be adequately identified and phagocytized by the maternal immune system. During a healthy pregnancy, numerous immunosuppressive processes take place that allow the allograft fetus to thrive under exposure to humoral and cellular components of the maternal immune system. Breakdown of immune tolerance may result in sterile inflammation and cause adverse pregnancy outcomes such as preeclampsia, a vascular disease of the pregnancy with unpredictable course and symptoms from several organs. Immunological incompatibility between mother and fetus is strongly indicated in preeclampsia. Recently, genetic factors linking immunological pathways to predisposition to preeclampsia have been identified. In this mini-review genetic variation in immunological factors are discussed in the context of preeclampsia. Specifically, we explore immunogenetic and immunomodulary mechanisms contributing to loss of tolerance, inflammation, and autoimmunity in preeclampsia.Peer reviewe

Editorial : Innate Immunity in Normal and Adverse Pregnancy

Non peer reviewe

Regulation of the complement system and immunological tolerance in pregnancy

Preeclampsia is a serious vascular complication of the human pregnancy, whose etiology is still poorly understood. In preeclampsia, exacerbated apoptosis and fragmentation of the placental tissue occurs due to developmental qualities of the placental trophoblast cells and/or mechanical and oxidative distress to the syncytiotrophoblast, which lines the placental villi. Dysregulation of the complement system is recognized as one of the mechanisms of the disease pathology. Complement has the ability to promote inflammation and facilitate phagocytosis of placenta-derived particles and apoptotic cells by macrophages. In preeclampsia, an overload of placental cell damage or dysregulated complement system may lead to insufficient clearance of apoptotic particles and placenta-derived debris. Excess placental damage may lead to sequestration of microparticles, such as placental vesicles, to capillaries in the glomeruli of the kidney and other vulnerable tissues. This phenomenon could contribute to the manifestations of typical diagnostic symptoms of preeclampsia: proteinuria and new-onset hypertension. In this review we propose that the complement system may serve as a regulator of the complex tolerance and clearance processes that are fundamental in healthy pregnancy. It is therefore recommended that further research be conducted to elucidate the interactions between components of the complement system and immune responses in the context of complicated and healthy pregnancy.Peer reviewe

High relative amount of nodular calcification in femoral plaques is associated with milder lower extremity arterial disease.

Peer reviewe

Smoking during pregnancy reduces vitamin D levels in a Finnish birth register cohort

Objective Maternal vitamin D level in pregnancy may have implications for both the mother and fetus. Deficiency of vitamin D has been linked to several pregnancy complications and fetal skeletal health. Smoking has been associated with reduced serum level of the vitamin D metabolite, 25-hydroxyvitamin D (25(OH)D). Design A nested case-control study within the Finnish Maternity Cohort, a population-based cohort which includes first-trimester sera from 98 % of pregnancies in Finland since 1987. The selection consisted of women with uncomplicated pregnancies. We studied serum concentration of 25(OH)D in 313 non-smoking and forty-six self-reported smoking pregnant women. Setting We hypothesize that pregnant smokers may have an increased risk of low 25(OH)D levels especially during winter months. Participants A control group from an unpublished pregnancy complication study consisting of 359 uncomplicated pregnancies. Individuals who reported that they do not smoke were considered 'non-smokers' (n 313) and those who reported continued smoking after the first trimester of pregnancy were considered 'smokers' (n 46). Results Smokers had significantly lower levels of 25(OH)D irrespective of sampling time (PPeer reviewe

ECCO - A new initiative to support early-career researchers in the complement field

Research on the complement system, like most areas of immunology, has seen tremendous progress over the last decades. Further advances in the complement field will rely on the next generation of scientific leaders, which are today's early-career researchers (ECRs). ECRs are emerging scientists who obtained their PhD degree within the past five years. They represent a distinct population within the scientific community, and accordingly have unique needs. Unfortunately, ECRs are faced with significant challenges that require customized solutions. The current paper provides a snapshot of the major obstacles ECRs face, such as an unhealthy work-life balance, lack of mentor and peer support, and uncertain career prospects. Efforts must consequently be taken to ensure stability and success of ECRs, not only to benefit these researchers in the early stages of their career, but the entire field of complement research. The Early-Career Complementologists (ECCO) was, therefore, launched as a new Task Force to support ECRs in the complement field. This new initiative aims to support and connect ECRs in the complement field worldwide. Furthermore, ECCO is supported by both the International Complement Society (ICS) and the European Complement Network (ECN); two professional societies led by scientists investigating the complement system

Cervicovaginal Complement Activation and Microbiota During Pregnancy and in Parturition

BackgroundVaginal microbiome and the local innate immune defense, including the complement system, contribute to anti- and proinflammatory homeostasis during pregnancy and parturition. The relationship between commensal vaginal bacteria and complement activation during pregnancy and delivery is not known. ObjectiveTo study the association of the cervicovaginal microbiota composition to activation and regulation of the complement system during pregnancy and labor. Study designWe recruited women during late pregnancy (weeks 41 + 5 to 42 + 0, n=48) and women in active labor (weeks 38 + 4 to 42 + 2, n=25). Mucosal swabs were taken from the external cervix and lateral fornix of the vagina. From the same sampling site, microbiota was analyzed with 16S RNA gene amplicon sequencing. A Western blot technique was used to detect complement C3, C4 and factor B activation and presence of complement inhibitors. For semiquantitative analysis, the bands of the electrophoresed proteins in gels were digitized on a flatbed photo scanner and staining intensities were analyzed using ImageJ/Fiji win-64 software. Patient data was collected from medical records and questionnaires. ResultsThe vaginal microbiota was Lactobacillus-dominant in most of the samples (n=60), L. iners and L. crispatus being the dominant species. L. gasseri and L. jensenii were found to be more abundant during pregnancy than active labor. L. jensenii abundance correlated with C4 activation during pregnancy but not in labor. Gardnerella vaginalis was associated with C4 activation both during pregnancy and labor. The amount of L. gasseri correlated with factor B activation during pregnancy but not during labor. Atopobium vaginae was more abundant during pregnancy than labor and correlated with C4 activation during labor and with factor B activation during pregnancy. Activation of the alternative pathway factor B was significantly stronger during pregnancy compared to labor. During labor complement activation may be inhibited by the abundant presence of factor H and FHL1. ConclusionsThese results indicate that bacterial composition of the vaginal microbiota could have a role in the local activation and regulation of complement-mediated inflammation during pregnancy. At the time of parturition complement activation appears to be more strictly regulated than during pregnancy.Peer reviewe