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Frontiers in Immunology 2020Seventy to ninety percentage of preformed xenoreactive antibodies in human serum bind to the galactose-α(1,3)-galactose Gal epitope, and the creation of Gal knockout... (Review)
Review
Seventy to ninety percentage of preformed xenoreactive antibodies in human serum bind to the galactose-α(1,3)-galactose Gal epitope, and the creation of Gal knockout (KO) pigs has eliminated hyperacute rejection as a barrier to xenotransplantation. Now other glycan antigens are barriers to move ahead with xenotransplantation, and the N-glycolyl neuraminic acid, Neu5Gc (or Hanganutziu-Deicher antigen), is also a major pig xenoantigen. Humans have anti-Neu5Gc antibodies. Several data indicate a strong immunogenicity of Neu5Gc in humans that may contribute to an important part in antibody-dependent injury to pig xenografts. Pig islets express Neu5Gc, which reacted with diet-derived human antibodies and mice deleted for Neu5Gc reject pancreatic islets from wild-type counterpart. However, Neu5Gc positive heart were not rejected in Neu5Gc KO mice indicating that the role of Neu5Gc-specific antibodies has to be nuanced and depend of the graft situation parameters (organ/tissue, recipient, implication of other glycan antigens). Recently generated Gal/Neu5Gc KO pigs eliminate the expression of Gal and Neu5Gc, and improve the crossmatch of humans with the pig. This review summarizes the current and recent experimental and (pre)clinical data on the Neu5Gc immunogenicity and emphasize of the potential impact of anti-Neu5Gc antibodies in limiting xenotransplantation in humans.
Topics: Animals; Antibodies, Heterophile; Disease Models, Animal; Gene Knockout Techniques; Graft Rejection; Heterografts; Humans; Islets of Langerhans; Islets of Langerhans Transplantation; Neuraminic Acids; Swine; Transplantation, Heterologous
PubMed: 32351506
DOI: 10.3389/fimmu.2020.00622 -
Xenotransplantation Jul 2019The role of complement in xenotransplantation is well-known and is a topic that has been reviewed previously. However, our understanding of the immense complexity of its... (Review)
Review
The role of complement in xenotransplantation is well-known and is a topic that has been reviewed previously. However, our understanding of the immense complexity of its interaction with other constituents of the innate immune response and of the coagulation, adaptive immune, and inflammatory responses to a xenograft is steadily increasing. In addition, the complement system plays a function in metabolism and homeostasis. New reviews at intervals are therefore clearly warranted. The pathways of complement activation, the function of the complement system, and the interaction between complement and coagulation, inflammation, and the adaptive immune system in relation to xenotransplantation are reviewed. Through several different mechanisms, complement activation is a major factor in contributing to xenograft failure. In the organ-source pig, the detrimental influence of the complement system is seen during organ harvest and preservation, for example, in ischemia-reperfusion injury. In the recipient, the effect of complement can be seen through its interaction with the immune, coagulation, and inflammatory responses. Genetic-engineering and other therapeutic methods by which the xenograft can be protected from the effects of complement activation are discussed. The review provides an updated source of reference to this increasingly complex subject.
Topics: Adaptive Immunity; Animals; Animals, Genetically Modified; Antibodies, Heterophile; Blood Coagulation; Blood Coagulation Factors; Blood Platelets; Complement Activation; Complement System Proteins; Endothelium, Vascular; Graft Rejection; Heterografts; Humans; Immunosuppressive Agents; Inflammasomes; Inflammation; Primates; Receptors, Complement; Swine; Tissue and Organ Harvesting; Transplantation Immunology; Transplantation, Heterologous
PubMed: 31033064
DOI: 10.1111/xen.12517 -
TouchREVIEWS in Endocrinology Nov 2022For over 50 years, immunoassays have been extensively used to quantitate hormones in blood, other fluids and tissues. Each assay has its own sensitivity, specificity and... (Review)
Review
For over 50 years, immunoassays have been extensively used to quantitate hormones in blood, other fluids and tissues. Each assay has its own sensitivity, specificity and other analytical components. Despite the differences between commercial products, these assays provide important clinical information about hormone levels in patients. However, inaccurate results can occur because of technical issues, as well as patient-specific factors that can interfere with immunoassay hormone measurements. The latter include excessive normal blood or serum components, the presence of cross-reacting substances, extremely high levels of hormones leading to the high-dose hook effect, and interference from a variety of endogenous factors such as human antibodies that interact with the assay components or high levels of biotin in the serum from exogenous ingestion. This article briefly reviews the sources and recognition of endogenous interference, and describes methods to determine the correct serum hormone concentration.
PubMed: 36694886
DOI: 10.17925/EE.2022.18.2.141 -
Endocrine Jun 2021Hyperprolactinemia can have different causes: physiological, pharmacological, and pathological. When investigating the etiology of hyperprolactinemia, clinicians need to...
Hyperprolactinemia can have different causes: physiological, pharmacological, and pathological. When investigating the etiology of hyperprolactinemia, clinicians need to be aware of several conditions leading to misdiagnosis. The most popular pitfalls are: acute physical and psychological stress, macroprolactin, hook effect, even though antibodies interferences and biotine use have to be considered. A 52-year-old woman was referred to Endocrinology clinic for oligomenorrhoea and headache. She worked as a butcher. Hormonal evaluation showed very high PRL (305 ng/ml, reference interval: <24 ng/ml) measured with the ECLIA immunoassay analyzer Elecsys 170. The patient's pituitary MRI was normal and macroprolactin was normal. Hormonal workup showed LH: 71.5 mU/ml (2-10.9 mU/ml), FSH: 111.4 mU/ml (3.9-8.8 mU/ml), Estradiol: 110.7 pg/mL (27-122 pg/ml). Since an interference was suspected, the sample was sent to another laboratory using a different assay. After antibody blocking tubes treatment (Heterophilic Blocking Tube, Scantibodies) PRL was 28.8 ng/ml (reference interval < 29.2 ng/ml). Analytical interference should be suspected when assay results are not consistent with the clinical picture. Endogenous antibodies (EA) include heterophile, human anti-animal, autoimmune and other nonspecific antibodies, and rheumatoid factors, that have structural similarities and can cross-react with the antibodies employed by the immunoassay, causing hyperprolactinemia misdiagnosis. The patient's job (butcher), led us to suspect the presence of anti-animal antibodies. Clinicians should also carefully investigate the use of supplements. Biotin can falsely increase hormone concentration in competitive assays. Many clinicians are still not informed about these pitfalls that are not mentioned in some recent reviews on PRL measurement.
Topics: Antibodies; Diagnostic Errors; Female; Humans; Hyperprolactinemia; Immunoassay; Middle Aged; Prolactin
PubMed: 32949349
DOI: 10.1007/s12020-020-02497-w -
Expert Opinion on Biological Therapy Oct 2014The advent of cancer immunotherapy is going to profoundly transform the therapy of cancer. In this context, therapeutic cancer vaccines will offer significant... (Review)
Review
INTRODUCTION
The advent of cancer immunotherapy is going to profoundly transform the therapy of cancer. In this context, therapeutic cancer vaccines will offer significant opportunities, provided an efficient and robust technology is developed.
AREAS COVERED
Targeting tumor-associated antigens via immunization with homologous immunogens derived from other species, an approach called xeno vaccination, combined with gene delivery is believed to be a viable strategy. Xenogene vaccination has demonstrated to be more efficient than vaccination with 'self' antigens in rodent models in prophylactic and therapeutic settings against cancer. Depending upon the targeted antigen, the mechanism of action of xeno vaccines has been shown to depend upon the development of antibody and/or cytotoxic T-cell responses. More importantly, xenogene vaccination has been shown to reproducibly affect cancer growth and to improve survival in veterinary cancer patients, mainly in dogs affected by spontaneous disease. One of these vaccines against dog melanoma has been approved by regulatory authorities in USA. Finally, several xenogene vaccines have been advanced to early Phase I/II human clinical trials where they have shown to be safe, well tolerated and capable to induce detectable immune responses against human tumor antigens.
EXPERT OPINION
Based on this compendium of results we believe that xenogene vaccination may soon become a well-established weapon in the fight against cancer.
Topics: Animals; Antigens, Heterophile; Antigens, Neoplasm; Cancer Vaccines; Humans; Immunotherapy; Neoplasms; Vaccination
PubMed: 25023219
DOI: 10.1517/14712598.2014.927433 -
Journal of Clinical Laboratory Analysis Feb 2019Heterophilic antibodies are still an important source of interference in immunoassays, but reports of interference with D-dimers are rare. Are D-dimer level...
BACKGROUND
Heterophilic antibodies are still an important source of interference in immunoassays, but reports of interference with D-dimers are rare. Are D-dimer level abnormalities, found in the clinic, caused by heterophilic antibodies as well, or are other mechanisms involved? We will elaborate on this issue through two different examples in this article.
METHODS
Serum from two patients with significantly elevated levels of D-dimers were measured and compared by different methods, diluted, and dealt with heterophilic antibody blockers. At the same time, to retrieve the interference, we focused on the cause of D-dimer false positives and made a systematic review of the literature.
RESULTS
The D-dimer values were normal (0.49 and 0.15 μg/mL) detected with different testing method and decreased after addition of heterophilic antibody blocking reagent. According to literature data, there were 66.7% (4/6) references showed the interference were heterophilic antibody.
CONCLUSIONS
The influence of heterophilic antibodies on the measurement of D-dimers remains a big challenge. Different measuring instruments and methods may have significant differences in the measurement of D-dimers. By using a combination of instrumental methods for measuring, incorporating heterophilic antibody blockers, and combining with clinical performance and imaging data, most of the interference can be eliminated.
Topics: Aged; Aged, 80 and over; Antibodies, Heterophile; Female; Fibrin Fibrinogen Degradation Products; Humans; Immunoassay; Reproducibility of Results
PubMed: 30320416
DOI: 10.1002/jcla.22687 -
Journal of the American Heart... Jun 2024Cardiac troponin is extensively used as a biomarker in modern medicine due to its diagnostic capability for myocardial injury, as well as its predictive and prognostic... (Review)
Review
Cardiac troponin is extensively used as a biomarker in modern medicine due to its diagnostic capability for myocardial injury, as well as its predictive and prognostic value for cardiac diseases. However, heterophile antibodies, antitroponin antibodies, and macrotroponin complexes can be observed both in seemingly healthy individuals and patients with cardiac diseases, potentially leading to false positive or disproportionate elevation of cTn (cardiac troponin) assay results and introducing discrepancies in clinical interpretations with impact on medical management. In this review article, we describe the possible mechanisms of cTn release and the sources of variations in the assessment of circulating cTn levels. We also explore the pathophysiological mechanisms underlying antitroponin antibody development and discuss the influence exerted by macrotroponin complexes on the results of immunoassays. Additionally, we explore approaches to detect these complexes by presenting various clinical scenarios encountered in routine clinical practice. Finally, unsolved questions about the development, prevalence, and clinical significance of cardiac autoantibodies are discussed.
Topics: Humans; Biomarkers; Autoantibodies; Heart Diseases; Predictive Value of Tests; Troponin I; Prognosis
PubMed: 38879450
DOI: 10.1161/JAHA.123.035128 -
Frontiers in Veterinary Science 2022The genome contributes to the uniqueness of an individual breed, and enables distinctive characteristics to be passed from one generation to the next. The allelic... (Review)
Review
The genome contributes to the uniqueness of an individual breed, and enables distinctive characteristics to be passed from one generation to the next. The allelic heterogeneity of a certain breed results in a different response to a pathogen with different genomic expression. Disease resistance in chicken is a polygenic trait that involves different genes that confer resistance against pathogens. Such resistance also involves major histocompatibility (MHC) molecules, immunoglobulins, cytokines, interleukins, T and B cells, and CD4+ and CD8+ T lymphocytes, which are involved in host protection. The MHC is associated with antigen presentation, antibody production, and cytokine stimulation, which highlight its role in disease resistance. The natural resistance-associated macrophage protein 1 (Nramp-1), interferon (IFN), myxovirus-resistance gene, myeloid differentiation primary response 88 (MyD88), receptor-interacting serine/threonine kinase 2 (RIP2), and heterophile cells are involved in disease resistance and susceptibility of chicken. Studies related to disease resistance genetics, epigenetics, and quantitative trait loci would enable the identification of resistance markers and the development of disease resistance breeds. Microbial infections are responsible for significant outbreaks and have blighted the poultry industry. Breeding disease-resistant chicken strains may be helpful in tackling pathogens and increasing the current understanding on host genetics in the fight against communicable diseases. Advanced technologies, such as the CRISPR/Cas9 system, whole genome sequencing, RNA sequencing, and high-density single nucleotide polymorphism (SNP) genotyping, aid the development of resistant breeds, which would significantly decrease the use of antibiotics and vaccination in poultry. In this review, we aimed to reveal the recent genetic basis of infection and genomic modification that increase resistance against different pathogens in chickens.
PubMed: 36439341
DOI: 10.3389/fvets.2022.1032983 -
Frontiers in Immunology 2022After producing triple (Gal, H-D and Sd)-KO pigs, hyperacute rejection appeared to no longer be a problem. However, the origin of xeno-rejection continues to be a... (Review)
Review
After producing triple (Gal, H-D and Sd)-KO pigs, hyperacute rejection appeared to no longer be a problem. However, the origin of xeno-rejection continues to be a controversial topic, including small amounts of antibodies and subsequent activation of the graft endothelium, the complement recognition system and the coagulation systems. The complement is activated via the classical pathway by non-Gal/H-D/Sda antigens and by ischemia-reperfusion injury (IRI), via the alternative pathway, especially on islets, and via the lectin pathway. The complement system therefore is still an important recognition and effector mechanism in xeno-rejection. All complement regulatory proteins (CRPs) regulate complement activation in different manners. Therefore, to effectively protect xenografts against xeno-rejection, it would appear reasonable to employ not only one but several CRPs including anti-complement drugs. The further assessment of antigens continues to be an important issue in the area of clinical xenotransplantation. The above conclusions suggest that the expression of sufficient levels of human CRPs on Triple-KO grafts is necessary. Moreover, multilateral inhibition on local complement activation in the graft, together with the control of signals between macrophages and lymphocytes is required.
Topics: Animals; Antigens, Heterophile; Complement Activation; Complement System Proteins; Graft Rejection; Humans; Swine; Transplantation, Heterologous
PubMed: 35493484
DOI: 10.3389/fimmu.2022.860165 -
Journal of Medical Virology Jul 2021Coronavirus disease 2019 (COVID-19) has brought a huge impact on global health and the economy. Early diagnosis of severe acute respiratory syndrome coronavirus 2... (Review)
Review
Coronavirus disease 2019 (COVID-19) has brought a huge impact on global health and the economy. Early diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is essential for epidemic prevention and control. The detection of SARS-CoV-2 antibodies is an important criterion for diagnosing COVID-19. However, SARS-CoV-2 antibody testing also has certain false positives causing confusion in clinical diagnosis. This article summarizes the causes of false-positive detection of SARS-CoV-2 antibodies in clinical practice. The results indicate that the most common endogenous interferences include rheumatoid factor, heterophile antibodies, human anti-animal antibodies, lysozyme, complement, and cross-antigens. The exogenous interference is mainly incomplete coagulation of the specimen, contamination of the specimen, and insufficient optimization of the diagnostic kit's reaction system.
Topics: Antibodies, Viral; COVID-19; COVID-19 Testing; Clinical Laboratory Techniques; False Positive Reactions; Humans; Immunologic Tests; SARS-CoV-2
PubMed: 33710634
DOI: 10.1002/jmv.26937