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Background: Immunoassays used to measure total and free thyroxine (T4 and FT4) and total and free triiodothyronine (T3 and FT3) can provide inaccurate results due to interference from endogenous autoantibodies., Case Report: A 74-year-old female treated for hypothyroidism with levothyroxine replacement had elevated thyroid stimulating hormone (TSH), FT4, and FT3. Due to concern for hyperthyroidism, levothyroxine was discontinued and further workup was initiated. A pituitary MRI revealed a microadenoma but the alpha-subunit was normal. She was given octreotide for suspected TSH secreting pituitary adenoma without improvement in her TSH, FT4, or FT3 levels. She was referred to our clinic, where inaccurate lab values for FT4 and FT3 were suspected., Results: Testing via equilibrium dialysis liquid chromatography tandem mass spectrometry (LC-MS/MS) method revealed lower levels of FT4 and FT3. Subsequent testing included heterophile blocking tube treatment, polyethylene glycol (PEG) precipitation, and anti-T3/T4 autoantibody levels. The tests revealed thyroid hormone autoantibodies (THAAs) as the cause of immunoassay interference., Conclusions: When thyroid hormones are elevated and TSH is not suppressed, confirmatory testing with another method such as equilibrium dialysis LC-MS/MS, which is not susceptible to interference from autoantibodies, should be considered., (Copyright © 2021. Published by Elsevier Inc.)

In some instances, when chemicals bind to proteins, they have the potential to induce a conformational change in the macromolecule that may misfold in such a way that makes it similar to the various target sites or act as a neoantigen without conformational change. Cross-reactivity then can occur if epitopes of the protein share surface topology to similar binding sites. Alteration of peptides that share topological equivalence with alternating side chains can lead to the formation of binding surfaces that may mimic the antigenic structure of a variant peptide or protein. We investigated how antibodies made against thyroid target sites may bind to various chemical-albumin compounds where binding of the chemical has induced human serum albumin (HSA) misfolding. We found that specific monoclonal or polyclonal antibodies developed against thyroid-stimulating hormone (TSH) receptor, 5'-deiodinase, thyroid peroxidase, thyroglobulin, thyroxine-binding globulin (TBG), thyroxine (T4), and triiodothyronine (T3) bound to various chemical HSA compounds. Our study identified a new mechanism through which chemicals bound to circulating serum proteins lead to structural protein misfolding that creates neoantigens, resulting in the development of antibodies that bind to key target proteins of the thyroid axis through protein misfolding. For demonstration of specificity of thyroid antibody binding to various haptenic chemicals bound to HSA, both serial dilution and inhibition studies were performed and proportioned to the dilution. A significant decline in these reactions was observed. This laboratory analysis of immune reactivity between thyroid target sites and chemicals bound to HSA antibodies identifies a new mechanism by which chemicals can disrupt thyroid function., Competing Interests: The authors declare no conflicts of interest.

Objective Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disorder that is frequently seen in the eastern Mediterranean region. The thyroid gland can be affected in FMF patients through autoimmunity or amyloidosis. Here, we aimed to evaluate the structure and functions of the thyroid gland in addition to possible autoimmunity in FMF patients. Subjects and methods The study was conducted by the Endocrinology and Metabolism and Internal Medicine Departments. Thirty FMF patients and 30 age and gender-matched healthy controls were enrolled in the study. Free thyroxin (fT4), free triiodothyronine (fT3), thyroid-stimulating hormone (TSH), and anti-thyroid peroxidase (anti-TPO) autoantibodies were investigated. Detailed thyroid grayscale and Doppler Ultrasonography examinations and shear-wave elastosonography (SWE) were performed in the patient and control groups. Results Anti-TPO was detected in 24% (n = 7) of the patients. On the grayscale US, mean thyroid volumes were similar between the FMF and the control groups (p > 0.05). By Doppler US, thyroid vascularity observed was detected in 10.3% (n = 3) of the patients. SWE revealed that the mean velocity value of right vs. left lobe in the patient group was 1.77 ± 0.45 m/s and 1.95 ± 0.51 m/s, respectively. Compared to the control group, the mean velocity values were significantly higher in the right (p = 0.004) and left (p = 0.01) lobes of the patient group. The mean stiffness value in the patient group was also significantly higher in the right and left lobes [10.13 ± 5.65 kPa (p = 0.005) and 12.24 ± 6.17 kPa (p = 0.02), respectively]. Conclusion Recognizing the complications of FMF early in the course of the disease is as important as the early diagnosis of the disorder. Based on this, thyroid functions and changes in its structure should be evaluated carefully for early diagnosis of a possible coexisting thyroid disorder. Arch Endocrinol Metab. 2020;64(1):66-70.

Background: Conclusions regarding the association between antithyroid antibodies or thyroid dysfunction and rapid cycling bipolar disorder (RCBD) have been conflicting. Previous studies suggest that the impact of antithyroid antibodies on mental wellbeing seems to be independent of thyroid function. Here, we investigated their independent association with RCBD in a large, well-defined population of bipolar disorder (BD)., Methods: Fast serum levels of free thyroxine (FT4), free triiodothyronine (FT3), thyroid Stimulating Hormone (TSH), TPO-abs and Tg-abs were simultaneously measured in 352 patients with BD. Clinical features of BD were collected through semi-structural interview conducted by trained interviewers with background of psychiatric education., Results: Neither hypothyroidism nor hyperthyroidism was significantly associated with RCBD. Both TPO-abs and Tg-abs were significantly related to RCBD, even after controlling for gender, age, marriage status, education, antidepressants treatment, comorbidity of thyroid diseases, and thyroid function (serum levels of FT3, FT4 and TSH). Although TPO-abs and Tg-abs were highly correlated with each other, binary logistic regression with forward LR selected TPO-abs, instead of Tg-abs, to be associated with RCBD. TPO-abs was significantly, independently of Tg-abs, associated with hyperthyroidism, while Tg-abs was marginally significantly related to hypothyroidism at the presence of TPO-abs., Conclusion: TPO-abs might be treated as a biomarker of RCBD. Further exploring the underlying mechanism might help understand the nature of RCBD and find out new treatment target for it.

Autoimmune thyroid diseases (AITDs), including Hashimoto's disease (HD) and Graves' disease (GD), are archetypes of organ-specific autoimmune diseases, but the prognosis of patients with AITD varies. Autoimmune diseases, including AITDs, are believed to develop in response to both genetic and environmental factors. Interleukin (IL)-6 plays a major role in B cell differentiation and T cell proliferation, and methylation of the IL6 gene is associated with IL-6 production. To clarify the role of IL6 gene methylation in the pathogenesis and prognosis of AITDs, we measured the methylation levels of -666, -664, -610, -491 and -426 CpG sites in the IL6 gene. We measured the methylation levels of 5 CpG sites in 29 patients with HD, 31 patients with GD and 16 healthy volunteers using pyrosequencing. The methylation level at each of the -664, -491 and -426 CpG sites was negatively correlated with the age at the time of sampling. Multiple regression analysis indicated that patients with HD, including severe or mild HD, showed higher methylation levels at the -426 CpG site than control subjects. Patients with intractable GD showed lower methylation levels at the -664 and -666 CpG sites than patients with GD in remission. In conclusion, IL6 gene methylation levels were related to the susceptibility to HD and the intractability of GD.

Objective To investigate the relationship between inflammatory factors, oxidative stress and type 1 deiodinase (DIO-1) concentration in patients with chronic renal failure (CRF) with or without euthyroid sick syndrome (ESS). Methods This study recruited patients with CRF and divided them into two groups: group 1 had low free triiodothyronine (FT3) levels; and group 2 had normal FT3 levels. Group 3 consisted of healthy volunteers. Serum levels of interleukin (IL)-6, IL-1β, tumour necrosis factor (TNF)-α, 8-isoprostane and DIO-1 were measured using enzyme-linked immunosorbent assays. Multiple regression analysis was used to analyse correlations between parameters. Results Sixty patients were enrolled into each group and the groups were comparable in terms of vital signs, white blood cell count, free thyroxine and thyroid stimulating hormone concentrations. The serum DIO-1 concentration was significantly higher in group 2 than in groups 1 and 3. Multivariate regression analysis revealed that the DIO-1 concentration was inversely correlated with the TNF-α concentration. Conclusions Patients with CRF without ESS showed higher concentrations of DIO-1 than patients with ESS. The DIO-1 concentration was inversely correlated with the TNF-α concentration, which might indicate that the inflammatory response was milder in the patients with CRF without ESS than in those with ESS.

Innate immune cells, including macrophages, have recently been identified as target cells for thyroid hormone. We hypothesized that optimal intracellular concentrations of the active thyroid hormone triiodothyronine (T3) are essential for proinflammatory macrophage function. T3 is generated intracellularly by type 2 deiodinase (D2) and acts via the nuclear thyroid hormone receptor (TR). In zebrafish embryos, D2 knockdown increased mortality during pneumococcal meningitis. Primary murine D2 knockout macrophages exhibited impaired phagocytosis and partially reduced cytokine response to stimulation with bacterial endotoxin. These effects are presumably due to reduced intracellular T3 availability. Knockdown of the main TR in macrophages, TRα, impaired polarization into proinflammatory macrophages and amplified polarization into immunomodulatory macrophages. Intracellular T3 availability and action appear to play a crucial role in macrophage function. Our data suggest that low intracellular T3 action has an anti-inflammatory effect, possibly due to an effect on macrophage polarization mediated via the TRα. This study provides important insights into the link between the endocrine and innate immune system.

Objectives: Animal studies suggest that exposure to pesticides may alter thyroid function; however, few epidemiologic studies have examined this association. We evaluated the relationship between individual pesticides and thyroid function in 679 men enrolled in a substudy of the Agricultural Health Study, a cohort of licensed pesticide applicators., Methods: Self-reported lifetime pesticide use was obtained at cohort enrolment (1993-1997). Intensity-weighted lifetime days were computed for 33 pesticides, which adjusts cumulative days of pesticide use for factors that modify exposure (eg, use of personal protective equipment). Thyroid-stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3) and antithyroid peroxidase (anti-TPO) autoantibodies were measured in serum collected in 2010-2013. We used multivariate logistic regression to estimate ORs and 95% CIs for subclinical hypothyroidism (TSH >4.5 mIU/L) compared with normal TSH (0.4- < 4.5 mIU/L) and for anti-TPO positivity. We also examined pesticide associations with TSH, T4 and T3 in multivariate linear regression models., Results: Higher exposure to the insecticide aldrin (third and fourth quartiles of intensity-weighted days vs no exposure) was positively associated with subclinical hypothyroidism (OR Q3 =4.15, 95% CI 1.56 to 11.01, OR Q4 =4.76, 95% CI 1.53 to 14.82, p trend <0.01), higher TSH (p trend =0.01) and lower T4 (p trend =0.04). Higher exposure to the herbicide pendimethalin was associated with subclinical hypothyroidism (fourth quartile vs no exposure: OR Q4 =2.78, 95% CI 1.30 to 5.95, p trend =0.02), higher TSH (p trend =0.04) and anti-TPO positivity (p trend =0.01). The fumigant methyl bromide was inversely associated with TSH (p trend =0.02) and positively associated with T4 (p trend =0.01)., Conclusions: Our results suggest that long-term exposure to aldrin, pendimethalin and methyl bromide may alter thyroid function among male pesticide applicators., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objective: Previous studies have shown that functional abnormalities of the thyroid are associated with the pathogenesis of several neurological diseases. However, their relationship in patients with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis remains to be defined., Methods: Forty-three patients with anti-NMDAR encephalitis were examined for thyroid function and autoimmune indications, in comparison with 225 healthy controls (CTL). Patients were further classified into 2 subgroups based on their free tri-iodothyronine (fT3) levels. Moreover, fT3 levels were also investigated after at least three months of follow-up. The clinical characteristics of the patients and CTL were described in detail., Results: Serum levels of fT3 and thyroid-stimulating hormone (TSH) were found to be relatively lower in patients with anti-NMDAR encephalitis than in CTL (both p < 0.001). Low T3 syndrome also occurred more frequently in anti- NMDAR encephalitis (25.6 vs. 0.4%, p < 0.001). However, no statistical differences were detected between patients and CTL in terms of the positive rate of thyroid antibodies and other types of thyroid dysfunction. Patients with low T3 levels tended to have a longer hospital stay (p = 0.006), a higher rate of abnormal brain magnetic resonance imaging (MRI) findings (p = 0.033), a higher frequency of consciousness declination (p = 0.029), and a higher modified Rankin scale (mRS) score during hospitalization. Low fT3 levels were also associated with abnormal MRI findings, a decline in consciousness, and the mRS score on admission. In addition, fT3 seemed to gradually return to normal levels upon improvement of the mRS score (r = -0.649, p = 0.002)., Conclusions: Low T3 syndrome often copresents in anti-NMDAR encephalitis and indicates a longer hospitalization, abnormal MRI findings, consciousness declination, and a higher clinical severity. However, fT3 levels do not seem to influence the prognosis of anti-NMDAR encephalitis., (© 2018 S. Karger AG, Basel.)

68-year-old female patient with no significant medical history presents with a 3-month history of progressive neurological symptoms, which began with left eye ptosis, blurred vision and non-painful jaw discomfort, followed by left spastic weakness and hyper-reflexia with positive Babinski and Hoffman signs. An elevated T3 level, a positive peroxidase and an antigraves antibody level led to an ultrasound, which confirmed a sub acute-chronic autoimmune thyroiditis. A nerve conduction studies/electromyogram showed normal motor and sensory velocity conduction with a small amplitude compound motor action potential, indicative of likely axonal damage. Following treatment with carbimazole, the neurological symptoms greatly improved. The authors concluded that the left pyramidal syndrome was secondary to autoimmune free T3-thyrotoxicosis., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

The serum concentrations of anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-TG) antibodies are directly correlate in the induction and diagnosis of autoimmune thyroid disorders (AITDs). Therefore, the evaluation of serum anti-TPO and anti-TG antibodies in relation to thyroid function test parameters including thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4). This evaluation would be helpful in early diagnosis of abnormal thyroid function and associated autoimmune thyroid diseases. In this cross-sectional study, the serum anti-TPO, anti-TG, T3, T4 and TSH levels of 311 suspected patients of autoimmune thyroid disorders and 40 control subjects were evaluated. The data were presented as mean, ± standard deviations of the mean. Pearson correlation and chi-square tests were used to assess the correlation coefficients and significance in the contingency tables. The thyroid function test parameters in normal and AITDs suspected patients were significantly different in correlation to elevated serum levels of anti-TPO antibody. A significant association was detected between female gender and elevated levels of anti-TPO (P value = 0.047). A higher percentage of women showed elevated levels of anti-TG, but it was not statistically significant (P value= 0.107). The findings of the study reveal a strong correlation between thyroid function test and thyroid antibodies levels, elaborating the clinical importance of thyroid antibodies in clinical examination and follow-up of patients with autoimmune thyroid disorders.

The massive meat production of broiler chickens make them continuously exposed to potential stressors that stimulate releasing of stress-related hormones like corticosterone (CORT) which is responsible for specific pathways in biological mechanisms and physiological activities. Therefore, this research was conducted to evaluate a wide range of responses related to broiler performance, immune function, plasma biochemistry, related gene expressions and cell death morphology during and after a 7-day course of CORT injection. A total number of 200 one-day-old commercial Cobb broiler chicks were used in this study. From 21 to 28 d of age, broilers were randomly assigned to one of 2 groups with 5 replicates of 20 birds each; the first group received a daily intramuscular injection of 5 mg/kg BW corticosterone dissolved in 0.5 ml ethanol:saline solution (CORT group), while the second group received a daily intramuscular injection of 0.5 ml ethanol:saline only (CONT group). Growth performance, including body weight (BW), daily weight gain (DG), feed intake (FI) and feed conversion ratio (FC), were calculated at 0, 3 and 7 d after the start of the CORT injections. At the same times, blood samples were collected in each group for hematological (TWBC's and H/L ratio), T- and B-lymphocytes proliferation and plasma biochemical assays (total protein, TP; free triiodothyronine hormone, fT3; aspartate amino transaminase, AST; and alanine amino transaminase, ALT). The liver, thymus, bursa of Fabricius and spleen were dissected and weighed, and the mRNA expression of insulin-like growth factor 1 gene (IGF-1) in liver and cell-death-program gene (caspase-9) in bursa were analyzed for each group and time; while the apoptotic/necrotic cells were morphologically detected in the spleen. From 28 to 35 d of age, broilers were kept for recovery period without CORT injection and the same sampling and parameters were repeated at the end (at 14 d after initiation of the CORT injection). In general, all parameters of broiler performance were negatively affected by the CORT injection. In addition, CORT treatment decreased the plasma concentration of fT3 and the mRNA expression of hepatic IGF-1. A significant increase in liver weight accompanied by an increase in plasma TP, AST and ALT was observed with CORT treatment, indicating an incidence of liver malfunction by CORT. Moreover, the relative weights of thymus, bursa and spleen decreased by the CORT treatment with low counts of TWBC's and low stimulation of T & B cells while the H/L ratio increased; indicating immunosuppressive effect for CORT treatment. Furthermore, high expression of caspase-9 gene occurred in the bursa of CORT-treated chickens, however, it was associated with a high necrotic vs. low apoptotic cell death pathway in the spleen. Seven days after termination of the CORT treatment in broilers, most of these aspects remained negatively affected by CORT and did not recover to its normal status. The current study provides a comprehensive view of different physiological modulations in broiler chickens by CORT treatment and may set the potential means to mount a successful defense against stress in broilers and other animals as well.

Sepsis is a systemic inflammatory response syndrome with high mortality, which results from severe infection and can lead to secondary organ dysfunction. It is one of the most common cause of death in intensive care unit. Clinical reports have shown that sepsis was often accompanied by thyroid dysfunction, which is called "low triiodothyronine (T3)" syndrome and characterized by decreased blood total T3 and free T3, and by normal or decreased thyroxine (T4) and thyroid stimulating hormone (TSH). This syndrome may greatly affect the prognosis of patients with sepsis. The main purpose of this review is to illustrate the role of thyroid hormone disorder in the development and prognosis of sepsis.

Tri-iodothyronine (T3) is the active form of thyroid hormone at the nuclear cell level. About 80% of tri-iodothyronine is produced by peripheral deiodination of thyroxine. The determination of the free form of this hormone is useful for the diagnosis and the follow-up of hyperthyroidism. In routine clinical laboratories, immunoassays remain the most used technics. After recalling the main points related to the physiological data, the authors point out the possible errors during the analytical steps of the assay.

Background: Macro-hormones are circulating conjugates of hormones with immunoglobulins, which often artefactually elevate biochemical test results. Particularly when causing only moderate elevation no suspicion will be raised. By far the most frequently encountered macro-hormone is macro-prolactin. Here we report a female patient with rheumatoid arthritis who had persistently and grossly elevated thyroid stimulating hormone (TSH) but normal free thyroxine in electrochemiluminescent assays. Although clinically euthyroid, she was put on thyroxine therapy which caused hyperthyroid symptoms., Methods: An analytic interference by macro-TSH was assumed by dilution experiments, polyethylene-glycol-precipitation, the addition of a heterophilic antibody blocking reagent and size exclusion chromatography., Results: Further workup, however, revealed the presence of anti-ruthenium antibodies., Conclusions: To our knowledge this is the first report of anti-ruthenium antibodies selectively interfering with a TSH assay and causing erratic gross elevation of TSH mimicking macro-TSH.

The purpose of modelling the negative-feedback control mechanism of the hypothalamus-pituitary-thyroid (HPT) axis in autoimmune (Hashimoto's) thyroiditis is to describe the clinical course of euthyroidism, subclinical hypothyroidism and overt hypothyroidism for patients. Thyroid hormone thyroxine (T4) and triiodothyronine (T3) levels are controlled by negative-feedback control through thyroid-stimulating hormone (TSH). T4, like other hormones, can be bound or unbound; the unbound T4 (FT4) is used as a marker for hypothyroidism. Autoimmune thyroiditis is a disease in which the thyroid-infiltrating lymphocytes attack autoantigens in follicle cells, destroying them over a long time. To describe the operation of the feedback control, we developed a mathematical model involving four clinical variables: TSH, FT4, anti-thyroid peroxidase antibodies and the thyroid gland's functional size. The first three variables are regularly measured while the last variable is determined through relationships between the other three variables. The problem of two different time scales for circulating hormones and thyroid damage is addressed using singular perturbation theory. Analysis of the mathematical model establishes stability and conditions under which the diseased state can maintain the slow movement toward diseased state equilibrium. Although we have used four variables in modelling the feedback control through the HPT axis, the predicted clinical course given any set of parameters is shown to depend on the steady-state levels of TSH and FT4. This observation makes possible the development of the clinical charts based only on the levels of TSH, time and potential steady-state values. To validate the model predictions, a dataset obtained from a Sicilian adult population has been employed., (© The Authors 2013. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.)

Background: Graves' ophthalmopathy (GO) occurs commonly in children with Graves' disease (GD). However, there are limited studies on the clinical manifestations and thyroid autoantibodies in pediatric GO. The aim of this study was to investigate the prevalence and risk factors of GO in childhood GD., Methods: Clinical and biochemical data from children and adolescents with GD were retrospectively reviewed. Eighty patients under 19 years of age were included in the present study. We compared the clinical and biochemical differences between patients with and without GO., Results: Thirty-nine percent of the patients had GO, and 81% of the GO patients were females. Of these, two patients showed unilateral GO. Triiodothyronine (T3) levels were higher in GO patients than in those without GO. Anti-thyroglobulin antibody and thyroid stimulating hormone receptor antibody titers were not significantly different between the two groups. Anti-thyroid peroxidase antibody (TPO Ab) positivity was 68% in the patients with GO and only 47% in the patients without GO. In multivariate regression analysis, high T3 levels and TPO Ab positivity were related to the presence of GO., Conclusion: In children and adolescents with GD, TPO Ab positivity and high T3 levels could act as predictive factors for the presence of GO.

The endocrine system participates in regulating macrophage maturation, although little is known about the modulating role of the thyroid hormones. In vitro results demonstrate a negative role of one such hormone, triiodothyronine (T3), in triggering the differentiation of bone marrow-derived monocytes into unpolarized macrophages. T3-induced macrophages displayed a classically activated (M1) signature. A T3-induced M1-priming effect was also observed on polarized macrophages because T3 reverses alternatively activated (M2) activation, whereas it enhances that of M1 cells. In vivo, circulating T3 increased the content of the resident macrophages in the peritoneal cavity, whereas it reduced the content of the recruited monocyte-derived cells. Of interest, T3 significantly protected mice against endotoxemia induced by lipopolysaccharide i.p. injection; in these damaged animals, decreased T3 levels increased the recruited (potentially damaging) cells, whereas restoring T3 levels decreased recruited and increased resident (potentially beneficial) cells. These data suggest that the anti-inflammatory effect of T3 is coupled to the modulation of peritoneal macrophage content, in a context not fully explained by the M1/M2 framework. Thyroid hormone receptor expression analysis and the use of different thyroid hormone receptor antagonists suggest thyroid hormone receptor β1 as the major player mediating T3 effects on macrophages. The novel homeostatic link between thyroid hormones and the pathophysiological role of macrophages opens new perspectives on the interactions between the endocrine and immune systems., (Copyright © 2014 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

This work described the construction of a reagentless and ultrasensitive electrochemiluminescence (ECL) immunosensor using poly-L-lysine as a co-reactant with Ru(bpy)3(2+) for signal amplification and magnetic Fe3O4 loaded graphene nanosheet as nanoprobes, which can achieve an impressive detection limit of 0.03 pg/mL human total 3,3',5-triiodothyronine (T3), a kind of diagnostic markers of thyroid disease. The bionanoprobes were prepared based on the coimmobilization of Ru(bpy)3(2+) and T3 detection antibody on the Fe3O4 loaded graphene nanosheet and the sensing interface was achieved by assembling T3 capture antibody on the gold nanoparticles (AuNPs) loaded electro-deposited L-lysine film modified bare glass carbon electrode (GCE). ECL responses were generated from the modified electrodes described above by just immersing them in phosphate buffer solutions (PBS) based on the sandwich-type immunoreactions. T3 was measured quantitatively in the range from 0.1 pg/mL to 10 ng/mL, which exhibits sufficiently high sensitivity and stability. The reagentless ECL immunoassay is a promising approach for the detection of a wide range of molecular analytes., (Copyright © 2013 Elsevier B.V. All rights reserved.)

T-helper (Th) 22 and Th17 cells are involved in the pathogenesis of autoimmune diseases. However, their roles in the pathogenesis of Graves'disease (GD) are unclear. This study is aimed at examining the frequency of peripheral blood Th22, Th17, and Th1 cells and the levels of plasma IL-22, IL-17, and IFN-γ in patients with GD. A total of 27 patients with new onset GD and 27 gender- and age-matched healthy controls (HC) were examined for the frequency of peripheral blood Th22, Th17, and IFN-γ cells by flow cytometry. The concentrations of plasma IL-22, IL-17, and IFN-γ were examined by enzyme-linked immunosorbent assay. The levels of serum TSHR antibodies (A-TSHR), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) were examined by radioimmunoassay and chemiluminescent assay, respectively. The levels of serum TSAb were examined by enzyme-linked immunosorbent assay. In comparison with those in the HC, significantly elevated percentages of Th22 and Th17 cells, but not Th1 cells, and increased levels of plasma IL-22 and IL-17, but not IFN-γ, were detected in GD patients (P<0.0001, for both). The percentages of both Th22 and Th17 cells and the levels of plasma IL-22 and IL-17 were correlated positively with the levels of serum TSAb in GD patients (r = 0.7944, P<0.0001; r = 0.8110, P<0.0001; r = 0.7101, p<0.0001; r = 0.7407, p<0.0001, respectively). Th22 and Th17 cells may contribute to the pathogenesis of GD.

Unlabelled: An elevated serum level of neopterin indicates the activation of the cellular immune system., Aim: The objective was to find a correlation in autoimmune thyroid patients between neopterin levels and the clinical stage of the disease and to examine whether neopterin can predict the relapse of the disease., Methods: Serum neopterin, thyroid stimulating hormone, free thyroxine, free triiodothyronine, anti-thyroglobulin and anti-thyroid peroxidase antibody levels were determined in 137 patients with Graves' disease (in different stages), 25 with Hashimoto's thyroiditis and 14 with toxic adenoma., Results: The neopterin levels were significantly higher in patients with Graves' disease (hyper-, eu-, hypothyroidism and relapsed hyperthyroidism) and Hashimoto's thyroiditis. Positive correlation was found between neopterin and anti-thyroglobulin and anti-thyroid peroxidase antibody levels, but no correlation was detected between neopterin levels and thyroid hormones, thyroid stimulating hormone values and antibodies against thyroid stimulating hormone receptors., Conclusions: Higher level of serum neopterin reflects an underlying autoimmune process, and does not correlate with changes in thyroid hormone levels. Determination of neopterin level can be an important indicator in the exacerbation of autoimmune processes.

A new construction of a test-system for free thyroid hormone 3,3',5-triiodothyronine determination (free T3) in human blood serum in ELISA and IRMA variants was described. For this purpose a low-molecular weight bifunctional conjugate containing T3 and vitamin H (biotin, Bt) residues was synthesized. The conjugate (T3-Bt) can be bound via its biotin function to biotin-binding proteins on a solid phase whereas its T3-portion can interact with monoclonal antibody against T3 (anti-T3-MAb) labeled with horseradish peroxidase or iodine-125 in an enzyme immunoassay or an immunoradiometric assay system (ELISA or IRMA), respectively. The immunochemical interaction is hindered if the T3 residue takes part as a component of a preformed solid phase complex between T3-Bt and avidin. Computer modeling shows that in this complex glycan component of avidin shields iodothyronine residue. The binding of T3-Bt both with T3-free sites on anti-T3-MAb and the solid phase avidin achieves with help of a delayed T3-Bt addition into avidin-covered containers with preliminary co-incubated labeled anti-T3-MAb and an assayed T3 sample.

A cross-sectional study was performed in order to examine the association between canine aggression to familiar people and serum concentrations of total thyroxine (TT4), free thyroxine (fT4), thyroxine autoantibodies (T4AA), total triiodothyronine (TT3), free triiodothyronine (fT3), triiodothyronine autoantibodies (T3AA), thyroid stimulating hormone (TSH), and thyroglobulin autoantibodies (TgAA). The subjects were 31 dogs historically aggressive to familiar people and 31 dogs with no history of aggression. Behavioral evaluation and physical examination were completed for each dog in addition to a complete blood count, serum chemistry panel, TT4, fT4 by equilibrium dialysis, TT3, fT3, TgAA, T3AA, and T4AA. Significant differences were found between the two groups with respect to only T4AA, which was increased in the aggressive group, but the concentrations for both groups were within the normal reference range. There were no differences between the two groups in the thyroid analytes most commonly measured by veterinary practitioners evaluating thyroid function in dogs. The results of this study revealed no significant difference between aggressive and non-aggressive dogs in the thyroid concentrations most commonly used to diagnose canine hypothyroidism., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Objectives: Alterations in thyroid function appear to play a central role in adaptation to Arctic environments. Increased thyroid activity in indigenous circumpolar populations is associated with upregulated metabolism, including elevated basal metabolic rate (BMR); however, little is known about the possible health consequences of these climate-induced changes on thyroid function. The focus of the present study is to determine the prevalence of autoimmune thyroid disorders and their lifestyle and metabolic correlates among a sample of indigenous Yakut adults from northeastern Siberia., Methods: Anthropometric dimensions, health data, and plasma samples were collected among 281 adults (143 women, 138 men; ≥18 years old) from the rural community of Berdygestiakh (62°N, 127°E; pop. 4,900), Sakha Republic (Yakutia), Russia. BMR measurements were available for 96 women and 98 men. Free triiodothyronine (T(3) ), free thyroxine (T(4) ), thyroid stimulating hormone (TSH), and anti-thyroid peroxidase antibody (TPOAb) levels were determined using enzyme immunoassay., Results: Twenty-two percent of women and 6% of men had clinically elevated (>30 IU/ml) TPOAb. TPOAb was positively correlated with TSH (P < 0.01), T(3) (P < 0.05), and T(4) (P < 0.05) in women and showed a positive trend with T(4) (P = 0.06) in men. Monthly household income was significantly positively correlated with TPOAb in men (P < 0.01) and showed a trend among women (P = 0.06)., Conclusions: Although preliminary, these findings document higher than expected TPOAb levels among Yakut women and suggest possible consequences of increased thyroid activity associated with circumpolar adaptation and social change., (Copyright © 2011 Wiley-Liss, Inc.)

Histamine, serotonin and triiodothyronine (T3) content of different circulating lymphocyte subsets of leukemic (acute lymphocytic leukemia, ALL) and non-leukemic (control) children were investigated by multicolor flow cytometry. The hormone contents of the cells were followed from the time of diagnosis till the end of treatment. Each hormone could be detected in every time in the investigated cell types, although the amounts of them changed during the treatment.T lymphocytes: Significantly lower amount of serotonin was found in each T cell subsets (Th, Tc and activated T lymphocytes) of leukemic children compared to the healthy control group at the time of diagnosis and it was permanently low during the maintenance therapy. The decreased amount of serotonin could be demonstrated in Tc and Th cells even at one year after the end of treatment. However, there was no alteration in the histamine and T3 content of T cell subsets in the time of diagnosis, but significant decrease was detected during the maintenance therapy and after treatment.NK cells: The serotonin and T3 contents of NK cells (both NK and NKT subsets) were significantly lower at the time of diagnosis and during the maintenance therapy. Similar decrease was detected in the case of serotonin in B cells. Although there was no difference in the T3 content of B cells at the time of diagnosis, significantly lower amounts could be detected during the therapy compared to the healthy control group. The serotonin concentration remained low for years after the end of treatment, both in B and NK cells. These observations might have diagnostic and prognostic importance.

Background and Objectives: Chronic autoimmune thyroiditis (CAT) remains the most common cause of acquired hypothyroidism. There is currently no therapy that is capable of regenerating CAT-damaged thyroid tissue. The objective of this study was to gauge the value of applying low-level laser therapy (LLLT) in CAT patients based on both ultrasound studies (USs) and evaluations of thyroid function and thyroid autoantibodies., Study Design/materials and Methods: Fifteen patients who had hypothyroidism caused by CAT and were undergoing levothyroxine (LT4) treatment were selected to participate in the study. Patients received 10 applications of LLLT (830 nm, output power 50 mW) in continuous mode, twice a week, using either the punctual technique (8 patients) or the sweep technique (7 patients), with fluence in the range of 38-108 J/cm(2). USs were performed prior to and 30 days after LLLT. USs included a quantitative analysis of echogenicity through a gray-scale computerized histogram index (EI). Following the second ultrasound (30 days after LLLT), LT4 was discontinued in all patients and, if required, reintroduced. Triiodothyronine, thyroxine (T4), free T4, thyrotropin, thyroid peroxidase (TPOAb) and thyroglobulin (TgAb) antibodies levels were assessed before LLLT and then 1, 2, 3, 6, and 9 months after LT4 withdrawal., Results: We noted all patients' reduced LT4 dosage needs, including 7 (47%) who did not require any LT4 through the 9-month follow-up. The LT4 dosage used pre-LLLT (96 +/- 22 microg/day) decreased in the 9th month of follow-up (38 +/- 23 microg/day; P < 0.0001). TPOAb levels also decreased (pre-LLLT = 982 +/- 530 U/ml, post-LLLT = 579 +/- 454 U/ml; P = 0.016). TgAb levels were not reduced, though we did observe a post-LLLT increase in the EI (pre-LLLT = 0.99 +/- 0.09, post-LLLT = 1.21 +/- 0.19; P = 0.001)., Conclusion: The preliminary results indicate that LLLT promotes the improvement of thyroid function, as patients experienced a decreased need for LT4, a reduction in TPOAb levels, and an increase in parenchymal echogenicity., ((c) 2010 Wiley-Liss, Inc.)

Objectives: Obesity can alter the thyroid hormone status as a result of a dysregulated endocrine loop between the hypothalamo-pituitary unit and adipose tissue. The adipocytokine leptin has been shown to promote autoimmunity; hence, we aimed to clarify whether leptin excess of obesity could increase the susceptibility to develop autoimmune thyroid disease (AITD)., Study Design: This cross-sectional study was performed in a tertiary care center., Methods: Free thyroid hormones, TSH, thyroglobulin, and antithyroid antibodies levels were tested in 165 obese and 118 lean subjects. Results were plotted against variables related to body composition, leptin levels, glucose homeostasis, energy expenditure, and pattern of weight accrual., Results: Compared with controls, obese patients had lower free T3 levels and free T4 levels (P<0.01), greater prevalence of hypothyroidism (P<0.05), and higher commonness of antithyroid antibodies (P<0.05). As a marker of AITD, thyroid peroxidase antibodies were more frequent in the obese group (P<0.01). Correlation analysis showed that leptin levels were associated with AITD (P<0.01) independent of bioanthropometric variables. Multiple logistic regression analysis in pooled groups identified female sex and leptin as significant predictors of AITD., Conclusions: Obesity increases the susceptibility to harbor AITD with an emerging role for leptin as a peripheral determinant, which needs to be confirmed in future investigations.

Background: The development of Graves' disease (GD) from Hashimoto's thyroiditis (HT) has sporadically been reported, but no data are available concerning the prevalence of this sequence of events in GD patients. Our aim was to ascertain HT antecedents in the history of GD children in order to assess for the first time the relative frequency of the event sequence leading from HT to GD in a pediatric population., Study Population and Results: In 105/109 patients, no HT antecedents were documented at GD presentation. The remaining 4 patients had previously exhibited a picture of HT with either hypothyroidism or euthyroidism. The interval between HT diagnosis and GD presentation ranged from 1.5 to 2.8 years. Serum thyrotropin receptor antibodies were higher in the patients with no HT antecedents., Conclusions: In at least 3.7% of the children with GD, hyperthyroidism may be preceded by HT presentation with either hypothyroidism or euthyroidism. The clinical course of GD in these patients is not different from the one observed in those with no HT antecedents. Our report confirms the existence of a continuum between HT and GD within the spectrum of autoimmune thyroid diseases., (Copyright 2010 S. Karger AG, Basel.)

Context: Thyroid dysfunction in early pregnancy is associated with a number of adverse outcomes. Furthermore, the presence of thyroid autoantibodies has been associated with an increased risk of miscarriage., Objective: To determine the prevalence of thyroid autoantibodies and their effect on thyroid function tests in an unselected population of women in early pregnancy., Design and Setting: Cross-sectional study of samples that were collected for aneuploidy screening between 10 and 14 weeks gestation in Northern Sydney Area Health Service. Thyroid function tests (free T3, free T4 and thyroid-stimulating hormone) and thyroid autoantibodies to thyroperoxidase and thyroglobulin were measured., Patients and Methods: Thyroid function tests were performed on a random sample of 257 blood samples., Results: The presence of thyroid autoantibodies was common (18.3%) and was associated with subtle changes in thyroid function consistent with impaired thyroidal reserve., Conclusions: The prevalence of antithyroid Abs in an unselected pregnant population in the late first trimester was about 18%.

Premature, very-low-birth-weight female twins were diagnosed with congenital hypothyroidism (CH). Thyroid hormone antibodies (THAb) directed against triiodothyronine (T3) and thyroxine (T4) of both the IgM and IgG class were detected in both twins. At age 10 months, a rise in thyroid stimulating hormone (TSH) occurred in both infants and measurement of THAb at the same time revealed the appearance of IgM-T4 and IgG-T4 and an increase in IgG-T3 levels in twin 1 (permanent CH), and with a slight increase of IgM-T4 and IgG-T4 levels and appearance of IgM-T3 in twin 2 (transient CH). THAb may contribute to the induction of hypothyroidism in neonates and infants, especially those with underlying autoimmune thyroid disease.

Unlabelled: Selenium as an essential trace element is capable of exerting complex effects on the endocrine and immune system by its antioxidant capacity. The role of selenium is important because the level of free oxygen radicals is elevated in the physiological thyroid hormone synthesis., The Aim of Study: was to determine whether selenium therapy can influence the level of antithyroid peroxidase and antithyroglobulin antibodies or whether there is a correlation between antioxidant capacity and the titer of autoantibodies., Method: 132 patient with autoimmune thyroiditis were investigated in a prospective, blind and placebo-controlled study. L-thyroxine substitution therapy was made in both groups and the level of TSH remained in the normal range. The selenium-treated group (n = 70 patients, 68 female, mean age 41,4 +/- 9,5 year) was compared with the placebo-treated group (n = 62 patients, 61 female, mean age 42,7 +/- 8,3 year). Selenium therapy was continued by L-seleno-methionine (per os 2 x 100 microg/day) for one year. Determination of TSH, fT4, fT3 and autoantibodies was carried out by chemiluminescence method. Total antioxidant capacity was determined by Randox kit, the level of selenium in the sera by atomic absorption technique was measured. In the follow-up study, patients were controlled every third month and at the end of a one-year observation period., Results: The level of selenium in the untreated patients was significantly lower than in treated patients and controls. The fT3/fT4 ration proved to be higher in patients after selenium therapy. The titer of antithyroid antibodies (mostly the antithyroid peroxidase) significantly decreased at the end of the study. An inverse correlation was found between antioxidant capacity and the level of antithyroid peroxidase antibodies. The volume of thyroid gland slightly diminished in treated patients. Side effects were not observed., Conclusions: Selenium completed with L-thyroxine is a suitable therapy for patients with autoimmune thyroiditis.

Background/aim: In several populations, major histocompatibility complex and CTLA-4 (cytotoxic T lymphocyte antigen-4) gene polymorphisms are related to adult subjects with Graves' disease (GD). Our aim was to study the association of +49A>G polymorphism of the CTLA-4 gene in Brazilian children and adults with GD and its correlation with clinical and laboratory markers of disease severity., Methods: CTLA-4 +49A>G polymorphism was established by polymerase chain reaction-restriction fragment length polymorphism analysis in 44 children and 72 adults with GD and compared to a stringent control group consisting of octogenarians with no history of thyroid disease; free T4 and T3 levels and T3/T4 ratio, antithyroid antibodies, and Graves' ophthalmopathy were also evaluated according to genotype., Results: No significant difference was found in the frequency of CTLA-4 +49A>G polymorphism among children and adults with GD compared to controls and within groups. There was no significant correlation between the presence of G allele and Graves' ophthalmopathy, gender, age at diagnosis, and biochemical markers of disease severity., Conclusion: The frequency of CTLA-4 +49A>G polymorphism is not different in children and adults with GD compared to the normal control population and does not seem to contribute independently to the severity of the clinical presentation of GD., (Copyright 2008 S. Karger AG, Basel.)

Our objectives were to investigate thyroid abnormalities and autoimmunity in 120 patients affected by fibromyalgia (FM) and to study their relationships with clinical data and symptoms. Thyroid assessment by means of antithyroglobulin antibodies, antithyroid peroxidase antibodies, free triiodo-thyronine, free thyroxine, and thyroid stimulating hormone analyses was carried out. The clinical parameters "Fibromyalgia Impact Questionnaire", pain, tender points, fatigue, and other symptoms, and the presence of depression or anxiety disorders were evaluated. The basal thyroid hormone levels of FM patients were in the normal range, while 41% of the patients had at least one thyroid antibody. Patients with thyroid autoimmunity showed a higher percentage of dry eyes, burning, or pain with urination, allodynia, blurred vision, and sore throat. Correlations found between thyroid autoimmunity and age or with the presence of depression or anxiety disorders were not significant. However, in the cohort of post-menopausal patients, the frequency of thyroid autoimmunity was higher with respect to pre-menopausal patients. In conclusion, autoimmune thyroiditis is present in an elevated percentage of FM patients, and it has been associated with the presence of typical symptoms of the disease.

Objective: Anti-thyroglobulin, anti-thyroid-peroxidase and anti-TSH receptor antibodies have been observed with high frequency in autoimmune thyroid diseases. Thyroid hormone auto-antibodies (THAA): anti-thyroxine (T4) and anti-triiodothyronine (T3), conversely, have been reported rarely. In both hyperthyroidism and hypothyroidism, patients suffer from muscle weakness and function disorders. The aim of our study was the evaluation of the occurrence rate of autoantibodies targeting muscle proteins in a group of 24 patients with circulating anti-T3 and/or anti-T4 autoantibodies. The control group consisted of 41 healthy blood donors., Methods: In polyethylene tubes coated with muscle antigens: actin, myosin, myoglobin, troponin and tropomyosin solid-phase radioimmunoassay was performed to detect autoantibodies. A reaction with 125I-labelled staphylococcus protein A was used for the detection of antibodies bound to the antigens on the tubes., Results: We found a high occurrence of antibodies to muscle proteins in patients with THAA. Anti-myoglobin autoantibodies were most frequent (54.2% of subjects), the binding index values was very high and exceeded normal values two to four fold. Anti-myosin autoantibodies were detected in 50% of subjects; anti-troponin autoantibodies in 33.3%, and anti-tropomyosin autoantibody in 3 patients (12.5%). Differences between the patients and the controls were statistically significant. The antibody binding index to actin was low and statistically insignificant., Conclusions: Our study indicates that muscle protein antibodies, especially to myoglobin, myosin and troponin, are very frequently present in patients with autoimmune thyroid disease and circulating anti-T3 and anti-T4 autoantibodies, as well as in most cases of chronic thyroiditis with clinical symptoms of hypothyroidisms.

This work deals with the application of stereoselective antibodies against L-T3 as a tailor-made chiral selector in micro-HPLC. The separations were performed in microbore columns using commercially available anti-L-T3 antibodies chemically bonded to 5 microm silica gel. The enantiomers of T3 were baseline separated under mild continuous isocratic elution conditions using 10 mM phosphate buffer, pH 7.4. The D-enantiomer eluted with the void volume, while the L-enantiomer was retained by the antibody phase and eluted second. An indirect competitive and non-competitive enzyme linked immunosorbent assay (ELISA) was used for testing the stereoselectivity of anti-L-T3 antibodies.

Thyroid dysfunction is a common complication after allogeneic hematopoietic stem cell transplantation (SCT). However, thyrotoxicosis as defined by elevated serum-free thyroxine (FT4) or free triiodothyronine (FT3) levels together with low thyroid-stimulating hormone (TSH) levels is rare after SCT. Here we describe 2 patients who developed thyrotoxicosis within the first 50 days after unrelated cord blood transplantation (CBT). Patient 1 is a 32-year-old woman with acute myelogenous leukemia (AML)-M5a who underwent CBT. On day +41, she developed tachycardia. On day +48, FT4 increased to 2.2 ng/dL and TSH was suppressed to less than 0.1 microU/mL. Antithyroid peroxidase antibody was positive. On day +83, FT4 spontaneously decreased to 1.4 ng/dL. Patient 2 is a 42-year-old man with AML-M4 who underwent CBT. On day +42, he developed tachycardia. On day +48, FT3 increased to 4.75 pg/mL and TSH was suppressed to 0.02 microU/mL. Antithyroid peroxidase antibody was positive. Eight months after CBT, his thyroid function spontaneously returned to normal. The presence of antithyroid peroxidase antibody suggested that immune-mediated reactions might be associated with the development of thyrotoxicosis after CBT in our patients. The present study shows that thyrotoxicosis can occur during very early periods after CBT.

A coating procedure that could provide immobilization of antibodies, with increased binding capacity, that is cost effective, simple, robust, and appropriate for production scale application, is described. This coating approach of T3 antibodies to the polystyrene tubes has been systematically investigated to determine its utility for the development of coated tube Radioimmunoassay (RIA) for T3 in human serum. Further, the results obtained by the developed coating procedure are found to be comparable with those obtained by the "gold standard," the liquid phase RIA for T3. The coating procedure is completed in three major steps, each step involving an overnight incubation. The normal rabbit gamma-globulins are physically adsorbed onto the polystyrene tubes and incubated. After washing, a second antibody (goat anti-rabbit antiserum) is added and incubated. To this antigen specific antibody is added (T3 antibody produced in rabbit) and further incubated. Finally, the non-specific sites on the tubes are saturated by the blocking solution. The concentration of normal rabbit globulin, titers of second antibody and T3 antibody, and time required for coating are optimized to arrive at a suitable coating protocol. The coated tubes were evaluated for precision, reproducibility, and stability. Various parameters such as total reaction volume, incubation time and temperature, total number and volume of washings, concentration of 8-anilino-1-naphthalene sulfonic acid (ANS), and quantity of tracer per tube are optimized to arrive at a suitable standard curve. The optimized assay is validated for the quality control parameters such as intra- and inter-assay variations, recovery, and parallelism. The developed coated tubes assay had an assay range of 0.3-4.8 ng/mL with a sensitivity of 0.3 ng/mL at 90% B/B0. Batch to batch variation in coating was < 10%. The coated tubes were stable up to 1 year, which is adequate for production scale.

Background: Laboratory tests to support the diagnosis and management of thyroid diseases have undergone significant changes with the introduction of highly sensitive assays for thyroid stimulating hormone (TSH) and free T4 and T3 concentrations in plasma. Given the importance of these measurements, quality specifications are needed to ensure accurate results. Goals for precision and accuracy are available based on known intraindividual and interindividual biological variation., Methods: Results of external quality assurance (EQA) schemes are sufficient to document precision goals but survey materials are not commutable for use in determining bias or detect the presence of unusual antibodies on a case-by-case basis. Because TSH concentrations are inversely related to free T4, this physiologic relationship can be exploited for quality assurance purposes., Results: Significant discordance between this relationship can be caused by subclinical and potentially unrecognized disease, dysequilibrium caused by recent therapy, the presence of abnormal binding proteins or protein binding competitor drugs, and antibody interferences such as human antimouse antibody (HAMA) or rheumatoid factor., Conclusion: A mechanism to automatically track discordances for subsequent follow and investigation can be an effective part of a quality assurance program for thyroid hormone measurements.

The presence or absence of four biologically active hormone or hormone-like molecules was studied in rat immune cells using specific antibodies with flow cytometry and confocal microscopy. Epidermal growth factor (EGF) was not demonstrable at all, digoxin was present only in blood lymphocytes, and insulin was found in the monocyte-macrophage-granulocyte group in peritoneal fluid and thymic lymphocytes. Immunologically demonstrable triiodothyronine (T3) was present in all cells studied (lymphocytes, mast cells and monocyte-macrophage-granulocytes in peritoneal fluid and blood, and thymic lymphocytes). While there is no explanation of the presence of digoxin and insulin, it is assumed that T3 is an extrathyroidal source of the hormone that is needed for maintaining cell proliferation and normal status in the immune system, particularly as it is absent in the case of transitional or durable thyroid deficiency.

Enzyme immunoassays (EIAs) for the determination of autoanti-bodies (AA) to thyroid antigens in canine serum were developed. Streptavidin (SA) was immobilized as capture molecule on microtitreplates (MTP). Thyroglobulin (Tg) purified from canine thyroids and the thyroid hormones thyroxine and triiodothyronine (T3 and T4) were conjugated to biotin labelling reagents and attached to the MTP over the SA-biotin bridge. Bound AA were detected with anti-dog-immunoglobulin G (IgG) labelled with horseradish peroxidase. Serum samples from dogs which were allotted to four groups were analysed: A (n = 31), biochemical evidence of hypothyroidism; B (n = 76), clinical signs of hypothyroidism; C (n = 47), euthyroid with non-thyroidal disease; D (n = 186), clinically healthy. The validity of the assays was tested with two different methods. After thiophilic absorption chromatography of positive sera, a positive reaction in the EIA was only detected in those fractions which coeluted with the canine IgG standard. Furthermore, the positive reaction was blocked by the addition of the corresponding antigen. In 55% of the hypothyroid dogs AA to Tg and/or T3 and T4, respectively, were found (up to a titre of 1 : 1600). In group B 34% of the dogs were diagnosed positive, but the titre was lower (up to 1 : 400). In the groups C and D the number of dogs with AA and their titre was significantly lower. Two different methods for distinguishing positive and negative test results were compared in order to increase the specificity of the tests without decreasing the sensitivity. The EIAs are precise and based on high agreement with previous reported assays able to discriminate dogs with thyroiditis from healthy ones. These assays represent a good alternative to the isotope assays generally used for the analysis of AA to T4 and T3.

A unique 16-year old female patient presented after acute Epstein-Barr virus (EBV) infection with severe primary hypothyroidism. Her thyroid test results were thyrotropin level (TSH) of 198 mU/L (normal, 0.4-4 mU/L), free thyroxine [FT(4)], 2.5 pmol/L (normal, 10-25 pmol/L), total triiodothyronine (TT(3)) > 19.5 nmol/L (normal, 1.3-2.7 nmol/L), and free triiodothyronine (FT(3)), 0.77 pmol/L (normal, 3.3-6.3 pmol/L). She had high titers of thyroglobulin and thyroid peroxidase autoantibodies. In vitro triiodothyronine (T(3))-binding measured by radioimmunoprecipitation was 86% (normal, up to 8.5%) and thyroxine (T(4))-binding 8.2% (normal, 6.4%). Serum immunoglobulin G (IgG) absorption, achieved by protein-G Sepharose beads, decreased TT(3) toward normal. Levothyroxine treatment normalized the low baseline FT(4) and FT(3) values, and suppressed TSH to normal. However, TT(3) remained highly elevated and returned to normal after 20 months, while T(3 )binding gradually decreased. Thus, her severe hypothyroidism was masked by this unusual phenomenon. Thirty-four patients with EBV infection (15 with acute disease and 19 with previous infection) were tested for thyroid hormone levels. EBV antibodies (early antigen immunoglobulin M [IgM] and IgG and anti-Epstein-Barr virus nuclear antigen [EBNA] IgG) were measured by enzyme-linked immunosorbent assay (ELISA). In 15 patients with acute EBV the mean TT(3) level was 2.47 +/- 0.39 nmol/L (5 had TT(3) values above normal) compared to a mean TT(3) of 1.70 +/- 0.53 nmol/L in 19 subjects with previous infection (p < 0.0005; only 1 had a TT(3) result above normal), with no differences in FT(4) and TSH concentrations between the two groups. Acute EBV infection may be associated with transient mild to severe TT(3) elevation as a result of assay interference by anti-T(3) autoantibodies.

When we commonly evaluate the thyroid function, we measure TSH, free T3 and free T4. However, there are some cases that are difficult to diagnose because of the existence of thyroid hormone autoantibodies. We experienced a case of a 14-year-old girl with diffuse struma whose TSH, free T3 and free T4 were elevated by detected with Amerlex M free T3 and free T4 kits, although she did not have any symptoms. As the free T4 level was low by the equilibrium dialysis method, we diagnosed this case as hypothyroidism due to chronic thyroiditis. Because we found thyroid hormone antibodies in her serum, we thought that this case presented pseudoelevations of free T3 and free T4 by the analogue method.

Schistosoma mansoni induces, in the vertebrate host, cutaneous production of interleukin-7 (IL-7), which is beneficial for parasite establishment and development. Infection of mice deficient in IL-7 expression leads to parasite dwarfism. Because similar findings were previously described in hypothyroid mice, this study aimed to elucidate the potential link between IL-7 and thyroid hormones (THs), using several models including hypo- and hyperthyroid mice, modified either transiently or constitutively. Mice treated with thyroxine led to increased worm numbers and development of giant worms, whereas an iodine-deficient diet reduced parasite maturation, egg laying, and liver pathology. Conversely, mice genetically deficient for either of the nuclear TH receptors displayed normal worm development despite modifications in hormone levels, suggesting that thyroxine action is mediated through host receptors. In addition, no modification of antibody titers has been evidenced in thyroxine-treated mice, whereas antibody levels were altered in transgenic animals. These observations suggest that the immune system is not likely to be involved in the modifications of parasite development reported in this study. Interestingly, concomitant treatment with IL-7 and thyroxine had a synergistic effect, leading to recovery of very large worms, thus raising questions about the complexity of interactions between IL-7 and metabolic hormones.