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Thyroid function after bone marrow transplantation: possible association between immune-mediated thyrotoxicosis and hypothyroidism.

BACKGROUND: Thyroid dysfunction after bone marrow transplantation (BMT) has been investigated in many studies, and most posttransplant thyroid disorders are now recognized as a late complication of transplantation. However, these studies mainly focused on late thyroid function after BMT, and we have little information on early changes of thyroid function after BMT. METHODS: We prospectively investigated thyroid function in 57 patients receiving BMT. Serum thyroid-stimulating hormone, free triiodothyronine, and free thyroxine levels were determined at least monthly in the first 3 months, once between 3 and 12 months and once in the second year after BMT. RESULTS: During the first 6 months after BMT, 24 and 7 patients were diagnosed as having euthyroid sick syndrome (ETS) and thyrotoxicosis, respectively. Of the 52 patients alive 1 year after transplantation, 9 patients were still diagnosed as having ETS, and 8 patients developed hypothyroidism. Patients with thyrotoxicosis showed similar characteristics, and the high incidence of thyrotoxicosis after BMT is a novel finding. The median for the onset of thyrotoxicosis was day 111 after transplantation. Thyrotoxicosis was transient in all of the patients, but in seven patients hypothyroidism followed, the median onset at 12 months after BMT. Serum thyroglobulin levels were elevated in five patients, and antibodies autoreactive to the thyroid gland were detected in seven patients. CONCLUSIONS: Thyrotoxicosis may be a distinct clinical entity of thyroid dysfunction after BMT and may serve to predict the development of hypothyroidism. Immune-mediated thyroid injury may contribute to the development of posttransplant hypothyroidism.

Adolescent↗

T lymphocyte subsets in autoimmune thyroid diseases and subacute thyroiditis detected with monoclonal antibodies.

Peripheral T lymphocyte subsets were analysed with monoclonal antibodies, by highly standardized fluorescence-activated cell sorter analysis instead of manual counting by the indirect immunofluorescence method, in autoimmune thyroid diseases and subacute thyroiditis. Total lymphocyte counts were increased in patients with thyrotoxic Graves' disease and subacute thyroiditis. The percentage of total T (Leu 1) cells was significantly lower in patients with thyrotoxic Graves' disease and Hashimoto's disease with destructive thyrotoxicosis than in normal subjects. No significant changes were observed in the percentages of suppressor-cytotoxic T (Leu 2a) cells or helper-inducer T (Leu 3a) cells or in the Leu 3a-Leu 2a ratio in different groups of patients. There were no correlations between the percentages of E rosette-forming cells and Leu 1 cells and between the percentages of T gamma cells and Leu 2a cells in normal subjects and patients. The peak position of fluorescence intensity of Leu 2a cells showed a significant sex difference even in normal controls. The most important finding was a significant decrease in the peak position of Leu 2a cells in patients with thyrotoxic Graves' disease and with hypothyroid or thyrotoxic Hashimoto's disease. These findings indicate the significant association of qualitative, but not quantitative, abnormality of suppressor-cytotoxic T (Leu 2a) cells with thyroid dysfunction in autoimmune thyroid diseases.

Adult↗

Heterogeneity of autoantibodies against thyroid peroxidase in autoimmune thyroid disease: evidence against antibodies directly inhibiting peroxidase activity as regulatory factors in thyroid hormone metabolism.

The close relationship between thyroid microsomal antigen and thyroid peroxidase (TPO) is now well established. The present study evaluates the significance of autoantibodies against TPO (anti-TPO-Abs) in the various forms and stages of autoimmune thyroid disease with respect to a possible heterogeneous nature and particularly to their influence on TPO activity. When measured by a RIA using purified human TPO, anti-TPO-Abs were highly correlated with microsomal antibodies determined by enyzme-linked immunosorbant assay (r = 0.96; P less than 0.0001) and with the results of a TPO immunoprecipitation assay using crude microsomal preparations (r = 0.76; P less than 0.001). Relating the results of these assays to the reactivities of patients' sera with thyroid microsomes in immunoblot under nonreducing and reducing conditions, discordant results could be observed in a few cases. Further analysis of these data indicate a heterogeneous nature of anti-TPO-Abs, which react with at least two antigenic domains of the TPO molecule. The comparative analysis of patients with hyperthyroid Graves' disease, patients with Graves' disease in clinical remission, and patients with hypothyroid Hashimoto's thyroiditis revealed no significant differences in the antibody spectrum. When evaluating the direct influence of anti-TPO-Abs on the activity of TPO under a rigorous methodological approach, we found no significant inhibition of the enzymatic activity by any of the sera investigated from patients with autoimmune thyroid disease compared to that in sera from normal controls. In conclusion, the data indicate a heterogeneous nature of anti-TPO-Abs. The spectrum of antigenic epitopes recognized by anti-TPO-Abs seems not to be significantly different in the various forms and stages of autoimmune thyroid disease. The lack of an inhibitory effect of autoantibodies on TPO activity argues against direct binding of autoantibodies to the enzymatic sites of TPO and indicates that they are not important factors in producing thyroid dysfunction in autoimmune thyroid disease.

Adult↗

Autoimmune thyroiditis in infants with Down's syndrome.

Children with Down's syndrome are at high risk of thyroid dysfunction, including autoimmune thyroiditis. We describe two infants with Down's syndrome in whom chronic autoimmune thyroiditis was diagnosed at ages 5 months and 8 months. We suggest that follow-up of thyroid function and thyroid autoantibodies should be started from infancy in Down's syndrome to prevent further deterioration of mental development and growth.

Autoantibodies↗

Relations between thyroid function, hepatic and lipoprotein lipase activities, and plasma lipoprotein concentrations.

Lipoprotein concentrations and activities of lipoprotein lipase (LPL) and hepatic lipase (HL) were measured in 70 subjects with thyroid function ranging from overt hypothyroidism over subclinical hypothyroidism and euthyroidism to hyperthyroidism. In parallel with serum T3 (S-T3) concentrations increasing from low in hypothyroidism to high in hyperthyroidism there were gradually higher HL activities over the full spectrum of thyroid function, accompanied by decreasing levels of total and low density lipoprotein (LDL) cholesterol. High density lipoprotein (HDL) cholesterol was lower (P less than 0.05) in hyperthyroidism than in euthyroidism but not significantly changed in the hypothyroid groups. HL was correlated to S-T3 (r = 0.77, P less than 0.001), LDL cholesterol to log S-T3 (r = -0.76, P less than 0.001), and LDL cholesterol to log HL (r = -0.55, P less than 0.001). The activity of LPL was decreased (P less than 0.001) in overt hypothyroidism compared to euthyroidism but, in contrast to HL, the activity of LPL was not increased in hyperthyroidism. The plasma triglyceride (P-TG) concentration was elevated (P less than 0.01) in overt hypothyroidism but not significantly changed in subclinical hypothyroidism or in hyperthyroidism. The LPL activity was correlated to log S-T3 (r = 0.45, P less than 0.001), P-TG to log S-T3 (r = -0.37, P less than 0.01) and P-TG to log LPL activity (r = -0.71, P less than 0.001). Our results demonstrate that thyroid hormones influence HL and LPL activities in different ways, suggesting different mechanisms of action. Changes in HL activity seem to be an important mechanism for the disturbance of cholesterol metabolism in thyroid dysfunction while the thyroid hormone influence on LPL seems to be of importance mainly for the disturbance in triglyceride metabolism.

Adult↗

HCV infection and extrahepatic manifestations.

Hepatitis C virus infection is associated with various extrahepatic manifestations such as mixed cryoglobulinemia, membranoproliferative glomerulonephritis and porphyria cutanea tarda. The link between mixed cryoglobulinemia and hepatitis C virus infection is actually well known. Interferon alpha therapy decreases hepatitis C viremia and improves the clinical signs and biochemical abnormalities of cryoglobulinemia. The rare combination of hepatitis C and panarteritis nodosa has still not been confirmed. The sicca syndrome also seems to be associated with hepatitis C virus, but this is not the typical Sjogren's syndrome. It is not yet well established if hepatitis C virus plays a pathogenic role in the development of thyroid dysfunction and autoimmune thyroiditis. Probably interferon therapy may be implicated in the development in this and other extrahepatic manifestations of hepatitis C virus infection. Although an epidemiological association of hepatitis C with lichen planus, neuropathies and other diseases has been observed, the etiological role and the pathogenic involvement of the hepatitis C infection remains unclear. Extrahepatic clinical manifestations are frequently observed in hepatitis C virus patients and involve primarily the joints, muscles, and skin. The most frequent immunological abnormalities include mixed cryoglobulins, antinuclear antibodies, and anti-smooth muscle antibodies.

Antiphospholipid Syndrome↗

[The prevalence of thyro-peroxidase antibodies and thyroid function in Turner's syndrome].

INTRODUCTION: Higher frequency of autoimmune diseases in patients with Turner's syndrome (TS) compared with the general population has been described. 5 to 10% of cases occur before adolescence. The goal of the study was to determine the prevalence of thyro-peroxidase antibodies (TPO-Ab) in correlation with karyotype, clinical symptoms and hormonal thyroid function in TS patients. MATERIAL AND METHODS: 96 girls with TS, aged 0.5-19.8 years (mean age 12.3+/-5.0) and 58 girls matched for age and BMI (control group) were analysed. The diagnosis of TS was established basing on clinical features and karyotype analysis. 54 had X monosomy, 7--isochromosome, 1--other X chromosome aberration, 11--mosaicism 45,X/46,XX, 3--45,X/47,XXX, 1--45,X/46,XX/47,XXX, 19--mosaicism with structural aberration: 12--45,X/46,X,i(Xq), 2--others, 5--with Y chromosome. In all children TSH, FT(4), FT(3), TPO-Ab, cholesterol, triglyceride levels, physical and ultrasonographic examination were performed. RESULTS: 25% of TS patients were positive for TPO-Ab. This frequency was significantly higher (p=0.0017) than that seen in the control group (5.2%). Positive titers of TPO-Ab were found: in 42% of girls with isochromosome (46,X,i(Xq) and 45,X/46,X,i(Xq)), 22.2% with X monosomy, and 17.4% with other karyotypes. The percentage of positive TPO-Ab titres increased with cumulative age of TS patients. It was 6.7% at the age of 10 years and almost doubled (12.1%) one year later. The next strong increase was observed at the age of 16 (up to 19.1%) and gradually rose to 20 years of age. Mean age of seronegative patients was significantly lower than that of seropositive patients (p=0.018). Only 2 patients manifested symptoms of hyperthyroidism requiring short period of antithyroid treatment. Others did not reveal any clinical features of thyroid dysfunction, although developed thyroid abnormalities such as elevated TSH (11.4%) or goiter (28%). Lack of correlation between TPO-Ab, thyroid hormones and lipid levels was associated with L-thyroxine supplementation, in patients with mildly elevated TSH, prior to the study. CONCLUSIONS: Patients with TS, especially with isochromosome, have antithyroid antibodies more frequently than their co-evals. Therefore, it is important to monitor TPO-Ab from about the age of 10 years even in asymptomatic patients. However, in routine clinical practice, both the thyroid examination and TSH level (even in asymptomatic patients) should be screened yearly for early detection of subclinical hypothyroidism and risk of more severe growth retardation in girls with TS.

Adolescent↗

Kinetics of drug action in disease states. XXXIV. Effect of experimental thyroid disorders on the pharmacodynamics of phenobarbital, ethanol and pentylenetetrazol.

To determine the effect of thyroid disorders on the concentration-activity relationship of certain drugs acting on the central nervous system, rats were made hyperthyroid by administration of L-thyroxine and hypothyroid by administration of propylthiouracil. They then received a slow i.v. infusion of phenobarbital or ethanol until they lost their righting reflex, or of pentylenetetrazol until the onset of maximal seizures. Drug concentrations in serum, brain and cerebrospinal fluid (CSF) were determined at these pharmacologic endpoints. Hyperthyroidism was associated with a statistically significant increase in the infused hypnotic dose and brain concentration of phenobarbital but had no apparent effect on concentrations of the drug in serum and CSF. The hypnotic dose of ethanol was increased significantly in hyperthyroid rats and decreased in hypothyroid animals; ethanol concentrations in serum, brain and CSF at onset of effect were generally not affected by thyroid dysfunction except for a small but statistically significant increase of serum ethanol concentrations in the hyperthyroid rats. The convulsant dose of pentylenetetrazol was reduced significantly in hypothyroid animals and unaltered in hyperthyroid rats; the concentrations of the convulsant in serum, brain and CSF were not apparently changed by the thyroid dysfunctions. In general, experimental thyroid disorders had no pronounced effect on the pharmacodynamics (concentration-effect relationship) of phenobarbital, ethanol and pentylenetetrazol in rats.

Animals↗

Cyclical combination chemotherapy and thyroid function in patients with advanced Hodgkin's disease.

Clinical and biochemical assessment of thyroid function was undertaken in patients with Hodgkin's disease at designated points following diagnosis. At diagnosis, two of 20 patients had either abnormally low routine thyroid indices, or elevated thyroid stimulating hormone (TSH) levels that were not due to iodine-based investigations. Following lymphography, 76.5% of patients had TSH levels that remained elevated for a median period of 3 months. No detectable thyroid dysfunction was induced during chemotherapy. Fifty-four patients were studied at a median time of 35 months after chemotherapy. One euthyroid patient had a nodular goitre, and one had abnormal thyroid indices. Tsh levels were elevated in 44% of patients, although the median TSH level for the group was normal. Half the patients had abnormal TRH stimulation tests. Sixty patients were studied after irradiation and chemotherapy. Four patients had clinical thyroid dysfunction, and 10% of routine thyroid indices were abnormal. TSH levels were abnormal in 80%, with a markedly elevated median level. All thyroid releasing hormone stimulation tests were abnormal.

Antineoplastic Agents↗

Clinical significance of autoimmune thyroid disease in myasthenia gravis.

We investigated thyroid function and autoimmunity in 74 (61% females) consecutive patients with MG. 30 of these patients were tested twice: the time between the investigations ranging from 1 to 4 years. MG was diagnosed on the basis of typical clinical symptoms, a positive tensilone-test, and/or detectable acetylcholine antibodies and/or repetetive stimulation tests. Eye involvement was present in 86%, concurrent thymomas in 56%. The following parameters were measured in the serum of these patients by commercially available kits: free and total T4, TSH, TSH-Receptor-Antibodies ("TRAB"), antibodies against thyroglobulin (Tg-Ab), against thyroid microsomes (M-Ab) and against acetyl-choline-receptors . An age matched group of 50 patients (54% females) with no known thyroid disease from a cardiological ward and from the neurological outpatient department served as control. There was only 1 MG patient with overt thyroid dysfunction (iodine induced thyrotoxicosis in a patient with autonomous adenoma and no circulating thyroid autoantibodies detected at the second investigation). There were, moreover, 1 euthyroid MG-patient on L-thyroxine therapy with a history of Hashimoto's disease and positive thyroid autoantibodies and 1 other MG-patient with mildly elevated TSH without elevated thyroid antibodies, who has had subtotal thyroidectomy without substitution therapy years before for unknown reasons. Tg-Ab were positive (>360 IU/ml) in 5%, M-Ab were positive (>154 IU/ml) in 15% of the MG patients. The control group had 4% Tg-Ab and 6% M-Ab. TRAB levels were normal in all patients and controls. The relative increase in M-Ab frequency was not statistically significant (x-square test). We conclude from our results, that autoimmune thyroid disease may be associated with MG but that the occurrence of thyroid dysfunction induced by autoimmunity is a very rare phenomenon in MG.

Adolescent↗

Management of thyroid disorders.

Autoimmune thyroid disease is the predominant form of thyroid dysfunction in the developed world. Although its precise cause is currently unclear, principles of management have been established. There is a vigorous debate about the management of the increasingly commonly recognised subclinical forms of thyroid dysfunction despite recent recommendations. Nodular thyroid disease and thyroid carcinoma have received wide attention. The effects of drugs and pregnancy on thyroid function have also been investigated widely. This short review attempts to give an overview and clarify the current management of common thyroid disorders.

Antithyroid Agents↗

[Preliminary results of thyroid function assessment in children and adolescents with Hodgkin's disease (HD) treated according to PGP-HD-97 protocol].

The intensive treatment of HD (multidrug chemotherapy combined with radiotherapy) carries the risk of early and late complications. One of the late effects is thyroid dysfunction which may occur after radiotherapy of the cervical region. In this report preliminary results of thyroid function assessment in children with HD in correlation with time after cessation of therapy are presented. Between January 1, 1997 and December 31, 2002, 58 children with HD (age: 2.6-18.3 years, median, 14.9 years) were treated in Department of Pediatric Oncology and Hematology PAIP CMUJ in Kraków, according to PGP-HD-97 protocol and these patients were included in the study. Multidrug chemotherapy combined with low-dose involved-field radiotherapy (15-25 Gy) was used in treatment of these children. Therapy was completed in all of analysed patients and in 38 of them (65.5%) at least 24 months before the end of observation. Physical and ultrasound examination of thyroid gland, and plasma levels of T3, T4, fT3, fT4, and TSH were measured before treatment of HD, before the treatment cessation, and every 6-12 months after the completion of therapy. The observation was completed on December 31, 2003. Six hundred and twelve measurements were performed in all of patients. At least one abnormal result of thyroid hormones or TSH levels was found in 50% of children. The most frequent abnormality was the increased level of TSH which occurred in 27.6% of patients. The rates of abnormal results of TSH concentration before HD treatment, and 1 year, 2 years, and later than 2 years after the cessation of therapy were: 8.3%, 8.8%, 21,4%, and 10.2%, respectively. These differences were not statistically significant. Seven patients (12%) require endocrinological treatment due to thyroid dysfunction. These patients as well as other analysed children are clinically euthyreotic. Initial results of thyroid function assessment presented in this report indicate that longer follow up and further thyroid function tests, physical and ultrasound examination of thyroid gland in patients after HD therapy cessation are needed. These studies are essential to early detection and adequate treatment of early and late complications of HD therapy.

Adolescent↗

Free thyroxine or free thyroxine index?

Free thyroxine (FT4) values determined by direct radio-immunoassay and the free thyroxine index (FTI) determined by indirect calculation were compared in 431 consecutive sera from patients with suspected thyroid dysfunction . Sensitivity and specificity were similar for both tests in the thyrotoxic, hypothyroid and euthyroid ranges with appropriate thyroid-binding globulin (TBG) concentrations. However, FT4 was superior to FTI in the euthyroid group with high concentrations of TBG, FT4 is therefore a useful alternative to FTI as a screening test for thyroid dysfunction, and is likely to be a better discriminator of thyroid status in patients with high TBG levels.

Evaluation Studies as Topic↗

[Effects of the combined deficiency of selenium and iodine on thyroid function].

Recent studies reported the role of several trace elements in health and disease. The role of iodine deficiency in thyroid dysfunction is well known. Also the selenium deficiency has been reported to be correlated to thyroid dysfunctions. In fact, although the major role of selenium is related to the glutathione peroxidase system, which protects cellular structures from oxidative damages, selenium plays also an important role in thyroid hormone metabolism as an essential component of the three deiodinase. These regulate inter-conversion of active and inactive forms of iodothyronines. Several studies have been carried out to establish the role of combined selenium and iodine deficiency. This review aims to provide information on the relationship between selenium and iodine intake and thyroid function. Furthermore, the state of art on the effects of the combined deficiency of selenium and iodine is also provided.

Cysteine↗

Thyroid status, disability and cognitive function, and survival in old age.

CONTEXT: Despite the equivocal outcomes of randomized controlled trials, general clinical opinion favors screening and treatment of elderly individuals with subclinical thyroid disorders. OBJECTIVES: To determine whether subclinical thyroid dysfunction should be treated in old age and the long-term impact of thyroid dysfunction on performance and survival in old age. DESIGN, SETTING, AND PARTICIPANTS: A prospective, observational, population-based follow-up study within the Leiden 85-Plus Study of 87% of a 2-year birth cohort (1912-1914) in the municipality of Leiden, the Netherlands. A total of 599 participants were followed up from age 85 years through age 89 years (mean [SD] follow-up, 3.7 [1.4] years). MAIN OUTCOME MEASURES: Complete thyroid status at baseline; disability in daily life, depressive symptoms, cognitive function, and mortality from age 85 years through 89 years. RESULTS: Plasma levels of thyrotropin and free thyroxine were not associated with disability in daily life, depressive symptoms, and cognitive impairment at baseline or during follow-up. Increasing levels of thyrotropin were associated with a lower mortality rate that remained after adjustments were made for baseline disability and health status. The hazard ratio (HR) for mortality per SD increase of 2.71 mIU/L of thyrotropin was 0.77 (95% confidence interval [CI], 0.63-0.94; P = .009). The HR for mortality per SD increase of 0.21 ng/dL (2.67 pmol/L) of free thyroxine increased 1.16-fold (95% CI, 1.04-1.30; P = .009). CONCLUSIONS: In the general population of the oldest old, elderly individuals with abnormally high levels of thyrotropin do not experience adverse effects and may have a prolonged life span. However, evidence for not treating elderly individuals can only come from a well-designed, randomized placebo-controlled clinical trial.

Activities of Daily Living↗

Effect of 1-year treatment with interferon-beta1b on thyroid function and autoimmunity in patients with multiple sclerosis.

OBJECTIVE: Interferon-beta (IFN-beta) is a widely used therapy for multiple sclerosis (MS), a demyelinating disease of the central nervous system. This study has evaluated the effect on thyroid function and autoimmunity of a 1-year treatment with IFN-beta1b in patients with MS. PATIENTS: We studied 31 patients (age 34+/-7 years, 21 women) with relapsing-remitting MS during IFN-beta1b treatment of 1 year duration. Systematic thyroid assessment and measurements of serum interleukin-6 (IL-6) levels were performed at baseline and every 3 months during treatment. RESULTS: Sixteen percent of the patients had autoimmune thyroiditis before IFN-beta1b, all positive for anti-peroxidase antibodies. The overall incidence of thyroid dysfunction was 33% over 1 year (10% hyperthyroidism, 23% hypothyroidism). Thyroid autoimmunity developed in 5/26 patients (19%), in one case without dysfunction. In addition to autoantibody positivity at baseline, female gender and the presence of an ultrasound thyroid pattern suggestive of thyroiditis were identified by multiple logistic regression as additional risk predictors for the development of thyroid dysfunction. During IFN-beta1b treatment, serum IL-6 levels rose in a consistent biphasic pattern; there was, however, no difference between patients with or without incident thyroid abnormalities. CONCLUSIONS: We conclude that IFN-beta1b therapy can induce multiple alterations in thyroid function, some of which are unrelated to thyroid autoimmunity. IL-6 measurement is not useful to identify patients prone to develop thyroid abnormalities. Though thyroid dysfunction is generally subclinical and often transient, systematic thyroid assessment should be performed during IFN-beta1b treatment.

Adjuvants, Immunologic↗

Persistent viral infection of the thyroid gland: alteration of thyroid function in the absence of tissue injury.

The possible role of viruses as the cause of some thyroid disorders was evaluated in three strains of mice neonatally infected with lymphocytic choriomeningitis virus. We report the first definitive evidence that viruses can persist in the thyroid gland, particularly thyroid epithelial cells in which thyroglobulin is synthesized. Concomitant with the infection of these cells was a significant reduction in the level of thyroglobulin mRNA and circulating thyroid hormones. Another virus that causes persistent infection but does not replicate in the thyroid gland failed to alter serum levels of thyroid hormones, indicating the thyroid dysfunction was not a generalized result of stress accompanying a persistent infection. This alteration in thyroid homeostasis during persistent infection with lymphocytic choriomeningitis virus is not caused by autoantibodies to the thyroid. Moreover, despite infection of the thyroid gland, neither necrosis nor inflammation occurs. Thyroid dysfunction was noted both when persistence was initiated at birth and in utero during congenital infection. These observations in an experimental model raise the issue that viruses may play a role in the pathogenesis of some thyroid disorders in man.

Animals↗