Snezana Djurisic

Controlling the Immunological Crosstalk during Conception and Pregnancy: HLA-G in Reproduction

In several years after its discovery in the placenta, the human leukocyte antigen (HLA) class Ib protein, HLA-G, was not given much attention, nor was it assigned great importance. As time has unraveled, HLA-G has proven to have distinctive functions and an unforeseen and possibly important role in reproduction. HLA-G is characterized mainly by its low polymorphism and restricted tissue distribution in non-pathological conditions. In fact, its expression pattern is primarily limited to extravillous cytotrophoblast cells at the maternal-fetal interface during pregnancy. Due to low polymorphism, almost the same protein is expressed by virtually all individuals. It is these unique features that make HLA-G differ from its highly polymorphic HLA class Ia counterparts, the HLA-A, -B, and -C molecules. Its function, seemingly diverse, is typically receptor-mediated, and involves interactions with a wide range of immune cells. As the expression of HLA-G primarily is limited to gestation, this has given rise to the hypothesis that HLA-G plays an important role in the immunological tolerance of the fetus by the mother. In keeping with this, it might not be surprising that polymorphisms in the HLA-G gene, and levels of HLA-G expression, have been linked to reproductive failure and pre-eclampsia. Based on recent studies, we speculate that HLA-G might be involved in mechanisms in reproductive immunology even before conception because HLA-G can be detected in the genital tract and in the blood of non-pregnant women, and is present in seminal fluid from men. In addition, HLA-G expression has been found in the pre-implanted embryo. Therefore, we propose that a combined contribution from the mother, the father, and the embryo/fetus is likely to be important. Furthermore, this review presents important aspects of HLA-G in relation to reproduction: from genetics to physiological effects, from pregnancy and pregnancy complications to a short discussion on future possible means of preventative measures and therapy.

Soluble Human Leukocyte Antigen-G in Seminal Plasma is Associated with HLA-G Genotype: Possible Implications for Fertility Success

We have previously shown that human seminal plasma contains immunomodulatory soluble HLA‐G (sHLA‐G). We investigated whether sHLA‐G levels in seminal plasma are associated with a specific 14 base pair (bp) insertion/deletion (ins/del) polymorphism in the 3′‐untranslated region of the HLA‐G gene and/or with the outcome of assisted reproduction treatments (ART) in couples attending a fertility clinic.

The many faces of human leukocyte antigen-G: relevance to the fate of pregnancy.

Pregnancy is an immunological paradox, where fetal antigens encoded by polymorphic genes inherited from the father do not provoke a maternal immune response. The fetus is not rejected as it would be theorized according to principles of tissue transplantation. A major contribution to fetal tolerance is the human leukocyte antigen (HLA)-G, a nonclassical HLA protein displaying limited polymorphism, restricted tissue distribution, and a unique alternative splice pattern. HLA-G is primarily expressed in placenta and plays multifaceted roles during pregnancy, both as a soluble and a membrane-bound molecule. Its immunomodulatory functions involve interactions with different immune cells and possibly regulation of cell migration during placental development. Recent findings include HLA-G contributions from the father and the fetus itself. Much effort has been put into clarifying the role of HLA-G during pregnancy and pregnancy complications, such as preeclampsia, recurrent spontaneous abortions, and subfertility or infertility. This review aims to clarify the multifunctional role of HLA-G in pregnancy-related disorders by focusing on genetic variation, differences in mRNA stability between HLA-G alleles, differences in HLA-G isoform expression, and possible differences in functional activity. Furthermore, we highlight important observations regarding HLA-G genetics and expression in preeclampsia that future research should address.

Barriers to the conduct of randomised clinical trials within all disease areas

BackgroundRandomised clinical trials are key to advancing medical knowledge and to enhancing patient care, but major barriers to their conduct exist. The present paper presents some of these barriers.MethodsWe performed systematic literature searches and internal European Clinical Research Infrastructure Network (ECRIN) communications during face-to-face meetings and telephone conferences from 2013 to 2017 within the context of the ECRIN Integrating Activity (ECRIN-IA) project.ResultsThe following barriers to randomised clinical trials were identified: inadequate knowledge of clinical research and trial methodology; lack of funding; excessive monitoring; restrictive privacy law and lack of transparency; complex regulatory requirements; and inadequate infrastructures. There is a need for more pragmatic randomised clinical trials conducted with low risks of systematic and random errors, and multinational cooperation is essential.ConclusionsThe present paper presents major barriers to randomised clinical trials. It also underlines the value of using a pan-European-distributed infrastructure to help investigators overcome barriers for multi-country trials in any disease area.

A Phenotypic Analysis of Regulatory T Cells and Uterine NK Cells from First Trimester Pregnancies and Associations with HLA-G.

The prevalence of regulatory T cells and NK cells expressing activation and HLA‐G receptors, and the influence of in vivo sHLA‐G and mHLAG on HLA‐G receptors expressed by NK cells in the uterine compartment is unclear.

Specific barriers to the conduct of randomised clinical trials on medical devices

BackgroundMedical devices play an important role in the diagnosis, prevention, treatment and care of diseases. However, compared to pharmaceuticals, there is no rigorous formal regulation for demonstration of benefits and exclusion of harms to patients. The medical device industry argues that the classical evidence hierarchy cannot be applied for medical devices, as randomised clinical trials are impossible to perform. This article aims to identify the barriers for randomised clinical trials on medical devices.MethodsSystematic literature searches without meta-analysis and internal European Clinical Research Infrastructure Network (ECRIN) communications taking place during face-to-face meetings and telephone conferences from 2013 to 2017 within the context of the ECRIN Integrating Activity (ECRIN-IA) project.ResultsIn addition to the barriers that exist for all trials, we identified three major barriers for randomised clinical trials on medical devices, namely: (1) randomisation, including timing of assessment, acceptability, blinding, choice of the comparator group and considerations on the learning curve; (2) difficulties in determining appropriate outcomes; and (3) the lack of scientific advice, regulations and transparency.ConclusionsThe present review offers potential solutions to break down the barriers identified, and argues for applying the randomised clinical trial design when assessing the benefits and harms of medical devices.

Evidence-based practice within nutrition : what are the barriers for improving the evidence and how can they be dealt with?

BackgroundEvidence-based clinical research poses special barriers in the field of nutrition. The present review summarises the main barriers to research in the field of nutrition that are not common to all randomised clinical trials or trials on rare diseases and highlights opportunities for improvements.MethodsSystematic academic literature searches and internal European Clinical Research Infrastructure Network (ECRIN) communications during face-to-face meetings and telephone conferences from 2013 to 2017 within the context of the ECRIN Integrating Activity (ECRIN-IA) project.ResultsMany nutrients occur in multiple forms that differ in biological activity, and several factors can alter their bioavailability which raises barriers to their assessment. These include specific difficulties with blinding procedures, with assessments of dietary intake, and with selecting appropriate outcomes as patient-centred outcomes may occur decennia into the future. The methodologies and regulations for drug trials are, however, applicable to nutrition trials.ConclusionsResearch on clinical nutrition should start by collecting clinical data systematically in databases and registries. Measurable patient-centred outcomes and appropriate study designs are needed. International cooperation and multistakeholder engagement are key for success.

Evaluation of OneTouch Verio®, a new blood glucose self-monitoring system for patients with diabetes

Abstract Introduction. Self-monitoring of blood glucose (SMBG) is important in diabetes management. Reliable and user-friendly instruments are essential. OneTouch Verio® is a new blood glucose concentration-measuring system designed to be used by patients with diabetes and healthcare professionals. The objective of the present study was to evaluate the analytical performance of the OneTouch Verio®. Method. The OneTouch Verio® was evaluated by the Scandinavian evaluation of laboratory equipment for primary healthcare (SKUP) according to a protocol based on ISO 15197 and the American Diabetes Association (ADA) quality goals. Blood samples were collected and measured on the OneTouch Verio® by laboratory personnel and patients with diabetes (n = 91, randomized into groups receiving personal training or mail instructions for the OneTouch Verio® system). Results were compared to a validated routine method, imprecision and bias were calculated. User-friendliness was evaluated with a questionnaire. Results. Quality specifications for blood glucose concentration monitoring systems according to ISO 15197 were fulfilled. The mean coefficients of variation (CV%) of repeatability was 3.4% when tested by laboratory personnel and within the goal of imprecision suggested by ADA. Mean CV% of repeatability for patient self-monitoring was 5.0% and 5.1% in the training- and the mail group, respectively. Total error was 6.4–10.0%. The OneTouch Verio® showed no hematocrit interference or variation between strip lots. Conclusion. The OneTouch Verio® displayed sufficient analytical quality and satisfactory user-friendliness. It is suitable for point-of-care testing of blood glucose concentration when handled by patients and healthcare professionals.

A systematic literature review of evidence-based clinical practice for rare diseases: What are the perceived and real barriers for improving the evidence and how can they be overcome?

BackgroundEvidence-based clinical practice is challenging in all fields, but poses special barriers in the field of rare diseases. The present paper summarises the main barriers faced by clinical research in rare diseases, and highlights opportunities for improvement.MethodsSystematic literature searches without meta-analyses and internal European Clinical Research Infrastructure Network (ECRIN) communications during face-to-face meetings and telephone conferences from 2013 to 2017 within the context of the ECRIN Integrating Activity (ECRIN-IA) project.ResultsBarriers specific to rare diseases comprise the difficulty to recruit participants because of rarity, scattering of patients, limited knowledge on natural history of diseases, difficulties to achieve accurate diagnosis and identify patients in health information systems, and difficulties choosing clinically relevant outcomes.ConclusionsEvidence-based clinical practice for rare diseases should start by collecting clinical data in databases and registries; defining measurable patient-centred outcomes; and selecting appropriate study designs adapted to small study populations. Rare diseases constitute one of the most paradigmatic fields in which multi-stakeholder engagement, especially from patients, is needed for success. Clinical research infrastructures and expertise networks offer opportunities for establishing evidence-based clinical practice within rare diseases.

Evaluation of a competitive enzyme-linked immunosorbent assay for measurements of soluble HLA-G protein

The human leukocyte antigen (HLA) class Ib molecule, HLA-G, has gained increased attention because of its assumed important role in immune regulation. The HLA-G protein exists in several soluble isoforms. Most important are the actively secreted HLA-G5 full-length isoform generated by alternative splicing retaining intron 4 with a premature stop codon, and the cleavage of full-length membrane-bound HLA-G1 from the cell surface, so-called soluble HLA-G1 (sHLA-G1). A specific and sensitive immunoassay for measurements of soluble HLA-G is mandatory for conceivable routine testing and research projects. We report a novel method, a competitive immunoassay, for measuring HLA-G5/sHLA-G1 in biological fluids. The sHLA-G immunoassay is based upon a competitive enzyme-linked immunosorbent assay (ELISA) principle. It includes a recombinant sHLA-G1 protein in complex with β2-microglobulin and a peptide as a standard, biotinylated recombinant sHLA-G1 as an indicator, and the MEM-G/9 anti-HLA-G monoclonal antibody (mAb) as the capture antibody. The specificity and sensitivity of the assay were evaluated. Testing with different recombinant HLA class I proteins and different anti-HLA class I mAbs showed that the sHLA-G immunoassay was highly specific. Optimal combinations of competitor sHLA-G1 and capture mAb concentrations were determined. Two versions of the assay were tested. One with a relatively wide dynamic range from 3.1 to 100.0 ng/ml, and another more sensitive version ranging from 1.6 to 12.5 ng/ml. An intra-assay coefficient of variation (CV) of 15.5% at 88 ng/ml and an inter-assay CV of 23.1% at 39 ng/ml were determined. An assay based on the competitive sHLA-G ELISA may be important for measurements of sHLA-G proteins in several conditions: assisted reproduction, organ transplantation, cancer, and certain pregnancy complications, both in research studies and possibly in the future also for clinical routine use.