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EJIFCC Dec 2022Isolated increase in thyrotropin stimulating hormone (TSH) in a clinically euthyroid patient may be caused by the formation of a macromolecule between TSH and...
Isolated increase in thyrotropin stimulating hormone (TSH) in a clinically euthyroid patient may be caused by the formation of a macromolecule between TSH and autoantibodies causing discordant thyroid function test results. Despite the effort to eliminate interferences in immunoassays, these assays are still vulnerable to different interferences. Immunoassay interferences may cause erroneous results and lead to misdiagnosis which may subject a patient to unnecessary investigations and treatment. Immunoassays are affected by multiple substances; these may be endogenous or exogenous such as heterophile antibodies, autoantibodies, macromolecules, and human anti-mouse antibodies. This case reports a 47-year-old African woman who presented with a persistent elevated TSH with thyroid hormones within normal reference limits. She was found to have a macro-TSH which was associated with IgA paraprotein.
PubMed: 36605299
DOI: No ID Found -
Clinical Medicine (London, England) Jan 2022Cardiac troponin I and T are particularly sensitive and specific markers for cardiomyocyte damage. Myocardial injury can occur due to a discrepancy between oxygen supply...
Cardiac troponin I and T are particularly sensitive and specific markers for cardiomyocyte damage. Myocardial injury can occur due to a discrepancy between oxygen supply and demand (eg coronary artery occlusion and arrhythmias), other cardiac causes (eg pericarditis, myocarditis, cardiac surgery, cardioversion etc) or systemic conditions (eg sepsis, stroke and chronic renal disease). The latest European Society of Cardiology guidelines help to guide clinicians through these different causes. Occasionally troponin concentrations may not fit the clinical presentation and, therefore, other aetiologies should be considered. An under-appreciated basis of a high troponin concentration is a false positive result, which can be attributable to analytical interference from components in the patient's blood. Uncovering this interference can be pivotal to avoid unnecessary and potentially harmful investigations or treatment for patients. We present two cases of false positive troponin results caused by analytical interference. The normal reference range for the assay (Access; Beckman Coulter, High Wycombe, UK) used at our organisation is 0-18 ng/L.
Topics: Biomarkers; Humans; Sepsis; Troponin I
PubMed: 35078800
DOI: 10.7861/clinmed.2021-0633 -
Xenotransplantation May 2017Corneal xenotransplantation is an effective solution for the shortage of human donor corneas, and the porcine cornea may be a suitable candidate for the donor cornea...
BACKGROUND
Corneal xenotransplantation is an effective solution for the shortage of human donor corneas, and the porcine cornea may be a suitable candidate for the donor cornea because of its optical similarity with humans. However, it is necessary to administer additional immunosuppressants to overcome antigenic differences. We aimed to investigate the feasibility of porcine corneas with anti-CD40 antibody-mediated costimulation blockade in a clinically applicable pig-to-non-human primate corneal xenotransplantation model.
METHODS
Five Chinese rhesus macaques underwent deep-lamellar corneal transplantation using clinically acceptable sized (7.5 mm diameter) porcine corneal grafts. The anti-CD40 antibody was intravenously administered on a programmed schedule. Graft survival, central corneal thickness, and intraocular pressure were evaluated. Changes in effector and memory T and B cell subsets and anti-αGal and donor-specific antibodies were investigated in the blood, and the changes in complement levels in the aqueous humor and blood were evaluated. Memory cell profiles in the anti-CD40 antibody-treated group were compared with those from the anti-CD154 antibody-treated group or rejected controls presented in our previous report. The changes in anti-αGal, non-αGal, and donor-specific antibodies after 6 months were compared with baseline values.
RESULTS
Anti-CD40 antibody-mediated costimulation blockade resulted in the successful survival of xenocorneal grafts (>389, >382, >236, >201, and >61 days), with 80% reaching 6 months of survival. Injection of anti-CD40 antibody considerably reduced the infiltration of inflammatory cells into the grafts and significantly blocked the complement response in the aqueous humor (P=.0159, Mann-Whitney U test). Systemic expansion of central or effector memory T cells was abrogated in the anti-CD40 antibody-treated primates compared with those in the rejected controls (P<.05, Mann-Whitney U test) or those in the anti-CD154 antibody-treated primates (P>.05, Mann-Whitney U test). The levels of anti-αGal, non-αGal, and donor-specific antibodies at 6 months were not significantly increased compared with baseline levels (P>.05, Wilcoxon signed rank test).
CONCLUSIONS
An anti-CD40 antibody-mediated blockade appears to be effective immunosuppressive approach for porcine corneal deep-lamellar xenotransplantation in primates.
Topics: Animals; Antibodies, Blocking; Antibodies, Heterophile; Antibodies, Monoclonal; CD40 Antigens; Complement C3a; Corneal Transplantation; Disaccharides; Epitopes; Graft Survival; Heterografts; Humans; Immunologic Memory; Macaca mulatta; Swine; Swine, Miniature; T-Lymphocyte Subsets; Tissue Donors; Transplantation, Heterologous
PubMed: 28393447
DOI: 10.1111/xen.12298 -
Transplant Immunology Jun 2009The use of porcine organs for clinical transplantation is a promising potential solution to the shortage of human organs. Preformed anti-pig antibody is the primary... (Review)
Review
The use of porcine organs for clinical transplantation is a promising potential solution to the shortage of human organs. Preformed anti-pig antibody is the primary cause of hyperacute rejection, while elicited antibody can contribute to subsequent "delayed" xenograft rejection. This article will review recent progress to overcome antibody mediated xenograft rejection, through modification of the host immunity and use of genetically engineered pig organs.
Topics: Animals; Animals, Genetically Modified; Antibodies, Heterophile; Antibodies, Monoclonal; Antibody-Dependent Cell Cytotoxicity; CD40 Ligand; Complement Activation; Complement System Proteins; Cytotoxicity, Immunologic; Galactosyltransferases; Graft Rejection; Humans; Organ Transplantation; Primates; Swine; Thrombosis; Transplantation, Heterologous
PubMed: 19376229
DOI: 10.1016/j.trim.2009.03.008 -
Toxins Sep 2022Ustilaginoidins are a class of bis-naphtho-γ-pyrone mycotoxins produced by the pathogen of rice false smut, which has recently become one of the most devastating...
Ustilaginoidins are a class of bis-naphtho-γ-pyrone mycotoxins produced by the pathogen of rice false smut, which has recently become one of the most devastating diseases in rice-growing regions worldwide. In this research, the nanobody phage display library was established after an alpaca was immunized with the hemiustilaginoidin F-hapten coupled with bovine serum albumin (BSA). Heterologous antigen selection and combing trypsin with competition alternant elution methods were performed for nanobody screening. Two nanobodies, namely, Nb-B15 and Nb-C21, were selected for the establishment of indirect competitive enzyme-linked immunosorbent assays (ic-ELISAs). For Nb-B15 and Nb-C21, their IC values were 11.86 μg/mL and 11.22 μg/mL, and the detection ranges were at 3.41-19.98 μg/mL and 1.17-32.13 μg/mL, respectively. Two nanobodies had a broad spectrum to quantify the contents of total ustilaginoidins in rice samples according to cross-reactivity. The recognition mechanisms of Nb-B15 and Nb-C21 against ustilaginoidin A were elucidated by molecular modeling and docking. The key amino acid sites for the binding of Nb-B15 or Nb-C21 to ustilaginoidin A were mainly located in the FR1 and CDR1 regions. As Nb-B15 was superior to Nb-C21 in the aspects of protein expression, ELISA titer, and tolerance to organic solvents, it was selected for application in the detection of actual contaminated rice samples. The total ustilaginoidin contents of rice samples were analyzed by Nb-B15-based ic-ELISA and HPLC-DAD, between which the results were found to be consistent. The developed immunoassay based on the nanobody from the alpaca can be employed as a rapid and effective method for detection of total utilaginoidins in contaminated rice samples.
Topics: Animals; Oryza; Pyrones; Single-Domain Antibodies; Camelids, New World; Serum Albumin, Bovine; Trypsin; Mycotoxins; Immunoassay; Enzyme-Linked Immunosorbent Assay; Solvents; Haptens; Amino Acids; Antigens, Heterophile
PubMed: 36287930
DOI: 10.3390/toxins14100659 -
Therapeutic Advances in Reproductive... 2021The scenario in which a patient tests positive for human chorionic gonadotropin (hCG) in the absence of pregnancy can pose a diagnostic dilemma for clinicians. The term... (Review)
Review
The scenario in which a patient tests positive for human chorionic gonadotropin (hCG) in the absence of pregnancy can pose a diagnostic dilemma for clinicians. The term "phantom hCG" refers to persistently positive hCG levels on diagnostic testing in a nonpregnant patient and such results often lead to a false diagnosis of malignancy and subsequent inappropriate treatment with chemotherapy or hysterectomy. There remains a need for a consistent and rational diagnostic approach to the "phantom hCG." This article aims to review the different etiologies of positive serum hCG testing in nonpregnant subjects and concludes with a practical, stepwise diagnostic approach to assist clinicians encountering this clinical dilemma.
PubMed: 34179786
DOI: 10.1177/26334941211016412 -
Frontiers in Immunology 2020In pemphigus vulgaris (PV), autoantibodies directed against the desmosomal cadherin desmoglein (Dsg) 3 cause loss of intercellular adhesion. It is known that Dsg3...
In pemphigus vulgaris (PV), autoantibodies directed against the desmosomal cadherin desmoglein (Dsg) 3 cause loss of intercellular adhesion. It is known that Dsg3 interactions are directly inhibited by autoantibody binding and that Dsg2 is upregulated in epidermis of PV patients. Here, we investigated whether heterophilic Dsg2-Dsg3 interactions occur and would modulate PV pathogenesis. Dsg2 was upregulated in PV patients' biopsies and in a human pemphigus skin model. Immunoprecipitation and cell-free atomic force microscopy (AFM) experiments demonstrated heterophilic Dsg2-Dsg3 interactions. Similarly, in Dsg3-deficient keratinocytes with severely disturbed intercellular adhesion Dsg2 was upregulated in the desmosome containing fraction. AFM revealed that Dsg2-Dsg3 heterophilic interactions showed binding frequency, strength, Ca-dependency and catch-bond behavior comparable to homophilic Dsg3-Dsg3 or homophilic Dsg2-Dsg2 interactions. However, heterophilic Dsg2-Dsg3 interactions had a longer lifetime compared to homophilic Dsg2-Dsg2 interactions and PV autoantibody-induced direct inhibition was significantly less pronounced for heterophilic Dsg2-Dsg3 interactions compared to homophilic Dsg3 interactions. In contrast, a monoclonal anti-Dsg2 inhibitory antibody reduced heterophilic Dsg2-Dsg3 and homophilic Dsg2-Dsg2 binding to the same degree and further impaired intercellular adhesion in Dsg3-deficient keratinocytes. Taken together, the data demonstrate that Dsg2 undergoes heterophilic interactions with Dsg3, which may attenuate autoantibody-induced loss of keratinocyte adhesion in pemphigus.
Topics: Animals; Antibodies, Heterophile; Autoantibodies; Cell Adhesion; Cell Line; Desmoglein 2; Desmoglein 3; Gene Knockout Techniques; Humans; In Vitro Techniques; Keratinocytes; Mice; Models, Biological; Pemphigus; Skin; Up-Regulation
PubMed: 33193387
DOI: 10.3389/fimmu.2020.581370 -
BMC Women's Health Jun 2022The optimal management of patients in reproductive endocrinology relies on the accuracy and validity of sex hormone assays. Endogenous or exogenous substances can... (Review)
Review
BACKGROUND
The optimal management of patients in reproductive endocrinology relies on the accuracy and validity of sex hormone assays. Endogenous or exogenous substances can compete with the analyte. This competition can result in interfering errors and falsely indicate elevated serum levels. Obvious interference in estradiol assays appears to occur rarely. Consequently, clinicians who are not familiar with the potential of interference could be misled. In addition to unnecessary investigations and interventions and severe mental stress, falsely elevated estradiol results can result in missed or delayed fertility opportunities.
CASE
A 28-year-old female with pregnancy demand was diagnosed with polycystic ovary syndrome, Hashimoto's thyroiditis and subclinical hypothyroidism. She was found to have persistently elevated levels of serum estradiol in the early follicular phase (between 527 and 642 pg/mL). Screening workup was performed for nearly 11 months to find the causes. Serum tumor biomarkers were normal. Abdominal and pelvic computed tomography were negative for adrenal or adnexal masses. A left mesosalpinx cyst and benign pathological results were achieved by laparoscopic surgery. Hormonal substances and dietary supplements were absent, as determined by dietary records. Ultrasound confirmed follicles could grow slowly and eventually ovulate. Falsely elevated estradiol levels were suspected due to the discrepancy among high estradiol levels, follicle growth and normal gonadotropin levels. Immunological interference by heterophile antibody was finally verified by two competitive chemiluminescent immunoassay platforms (estradiol levels in the early follicle phase: 619 pg/mL, Siemens ADVIA CENTAUR and 60 pg/mL, Beckman, DxI 800). Successful clinical pregnancy was eventually achieved by combining induced ovulation, ultrasound monitoring and intercourse guidance.
CONCLUSIONS
Analytical interference and laboratory error should be suspicious at first when the clinical characteristics contradict the laboratory results of serum hormones. Measuring serum estradiol with another immunoassay platform is an easy and non-time-consuming method to exclude the heterophile interfering.
Topics: Adult; Antibodies, Heterophile; Estradiol; Female; Fertility; Humans; Hypothyroidism; Immunoassay; Pregnancy
PubMed: 35710471
DOI: 10.1186/s12905-022-01828-5 -
Clinical Diabetes and Endocrinology 2019Pitfalls in hormonal assays are commonly seen in clinical practice and may lead to erroneous clinical impressions and treatments. In this article, we address common... (Review)
Review
Pitfalls in hormonal assays are commonly seen in clinical practice and may lead to erroneous clinical impressions and treatments. In this article, we address common laboratory pitfalls encountered during evaluation of patients with real or presumed endocrine disorders including high dose hook effect and falsely normal prolactin in cases of macroprolactinomas, macroprolactinemia and falsely elevated prolactin, macrothyrotropinemia and falsely elevated TSH, heterophile antibodies leading to false elevation of hormonal concentration, biotin interference with different hormonal assays, cross-reactivity of steroid hormones immunoassays, and others. We describe the mechanisms of such laboratory pitfalls, review clinical scenarios in which they might occur, and discuss the ways to resolve such conundrums. The aim of this article is to present a learning material for the endocrine trainees and practitioners.
PubMed: 31367466
DOI: 10.1186/s40842-019-0086-7 -
Clinical Chemistry and Laboratory... Jul 2023The International Federation of Clinical Chemistry Committee on Clinical Applications of Cardiac Biomarkers (IFCC C-CB) provides educational documents to facilitate the...
The International Federation of Clinical Chemistry Committee on Clinical Applications of Cardiac Biomarkers (IFCC C-CB) provides educational documents to facilitate the interpretation and use of cardiac biomarkers in clinical laboratories and practice. Our aim is to improve the understanding of certain key analytical and clinical aspects of cardiac biomarkers and how these may interplay. Measurements of cardiac troponin (cTn) have a prominent place in the clinical work-up of patients with suspected acute coronary syndrome. It is therefore important that clinical laboratories know how to recognize and assess analytical issues. Two emerging analytical issues resulting in falsely high cTn concentrations, often several fold higher than the upper reference limit (URL), are antibody-mediated assay interference due to long-lived cTn-antibody complexes, called macrotroponin, and crosslinking antibodies that are frequently referred to as heterophilic antibodies. We provide an overview of antibody-mediated cTn assay interference and provide recommendations on how to confirm the interference and interpret the results.
Topics: Humans; Myocardial Infarction; Biomarkers; Chemistry, Clinical; Antibodies; Troponin
PubMed: 36952681
DOI: 10.1515/cclm-2023-0028