Thyroid dysfunction during interferon alpha therapy for chronic hepatitis C

Interferon-alpha therapy is well known to induce a wide range of thyroid dysfunction. A 22-year-old woman with chronic hepatitis C developed overt hyperthyroidism while on interferon-alpha and ribavirin therapy. Tc-99m thyroid scintigraphy demonstrated virtually absent tracer uptake consistent with subacute thyroiditis. Ten months after starting antiviral therapy, overt hyperthyroidism recurred. Repeat thyroid scintigraphy revealed diffusely increased tracer uptake throughout the thyroid gland consistent with Graves disease. This is an unusual case of 2 forms of hyperthyroidism-confirmed scintigraphically and occurring in the same patient over time while on interferon-alpha therapy.

Usefulness of the 2nd generation assay for anti-TSH receptor antibodies to differentiate relapse of Graves' thyrotoxicosis from development of painless thyroiditis after antithyroid drug treatment for Graves' disease

After antithyroid drug (ATD) treatment for Graves' disease, either a relapse of Graves' thyrotoxicosis or painless thyroiditis can develop. It is important to differentiate these two types of thyrotoxicosis because of the difference in required therapy. However, differentiation of thyrotoxicosis is usually difficult without radioactive iodine uptake (RAIU) which is not available in general practice. We investigated the clinical usefulness of the 2nd generation assay for anti-TSH receptor antibodies (TRAb) to differentiate these two types of thyrotoxicosis after ATD treatment for Graves' disease. We recruited 26 patients who developed thyrotoxicosis after ATD treatment for Graves' disease. These patients once became negative for TRAb and seemed to be in remission after ATD treatment. Upon development of thyrotoxicosis after ATD treatment, TSH, free T4, free T3 and TRAb were measured. TRAb were measured by the 2nd generation assay using recombinant human TSH receptors instead of porcine TSH receptors. Fourteen patients relapsed into Graves' thyrotoxicosis and 12 patients developed painless thyroiditis. Twelve (85.7%) of 14 patients with relapse of Graves' thyrotoxicosis were positive for TRAb. Eleven (91.7%) of 12 patients with development of painless thyroiditis after ATD treatment for Graves' disease were negative for TRAb. Levels of TRAb were significantly different between patients with relapse of Graves' thyrotoxicosis (4.86 +/- 6.45 IU/L) and those with painless thyroiditis (0.62 +/- 0.61 IU/L) (P<0.001). The 2nd generation assay for TRAb was useful to differentiate relapse of Graves' thyrotoxicosis from development of painless thyroiditis in patients who seemed to be in remission after ATD treatment for Graves' disease.

Dissociation between iodide-induced thyroiditis and antibody-mediated hyperthyroidism in NOD.H-2h4 mice

NOD.H-2h4 mice are genetically predisposed to thyroid autoimmunity and spontaneously develop thyroglobulin autoantibodies (TgAb) and thyroiditis. Iodide administration enhances TgAb levels and the incidence and severity of thyroiditis. Using these mice, we investigated the interactions between TSH receptor (TSHR) antibodies induced by vaccination and spontaneous or iodide-enhanced thyroid autoimmunity (thyroiditis and TgAb). Mice were immunized with adenovirus expressing the TSHR A-subunit (or control adenovirus). Thyroid antibodies, histology, and serum thyroxine levels were compared in animals on a regular diet or on a high-iodide diet (0.05% NaI-supplemented water). Thyroiditis severity and TgAb levels were enhanced by iodide administration and were independent of the type of adenovirus used for immunization. In contrast, TSHR antibodies, measured by TSH-binding inhibition, thyroid-stimulating activity, and TSH-blocking activity, were induced in the majority of animals immunized with TSHR (but not control) adenovirus and were unaffected by dietary iodide. The NOD.2h4 strain of mice was less susceptible than BALB/c or BALB/k mice to TSHR adenovirus-induced hyperthyroidism. Nevertheless, hyperthyroidism developed in approximately one third of TSHR adenovirus-injected NOD.2h4 mice. This hyperthyroidism was suppressed by a high-iodide diet, probably by a nonimmune mechanism. The fact that inducing an immune response to the TSHR had no effect on thyroiditis raises the possibility that the TSHR may not be the target involved in the variable thyroiditis component in some humans with Graves' disease.

[Amiodarone and the thyroid gland]

Amiodarone is an iodine-rich drug. Its chronic administration may lead to disturbances in thyroid hormone metabolism and/or overt gland dysfunction. It causes an increased in serum fT4, rT3, and TSH concentrations and a decreased serum level of fT3 without thyroid dysfunction. Amiodarone may induce thyrotoxicosis (AIT--Amiodarone-induced thyrotoxicosis) or hypothyroidism (AIH--Amiodarone-induced hypothyroidism) in some persons. AIT occurs more frequently in areas with low iodine intake. The excess iodine contributes to excessive thyroid hormone synthesis-type I AIT or may lead to thyroiditis and a destructive process of thyroid follicular cells, resulting in excess thyroid hormone release-type II AIT. The mixed form of AIT also occurs. Type I AIT should be treated with antithyroid drugs alone or in association with potassium perchlorate, type II AIT benefits from treatment with glucocorticoids, whereas the mixed form of AIT is most effectively treated with a combination of thionamides, potassium perchlorate, and glucocorticoids. AIT often requires thyroidectomy after restoration of euthyroidism or radioiodine therapy, provided that 24-h thyroid radioactive iodine uptake values permit. AIH prevails in areas with high dietary iodine intake. It requires a discontinuation of amiodarone therapy and thyroid hormone (levothyroxine) replacement. It can remit spontaneously. Amiodarone and L-thyroxine therapy is also possible. Baseline thyroid function tests, thyroid antibodies, and imaging examinations such as thyroid ultrasound on initial evaluation and follow-ups every 6 months must be carefully monitored before starting amiodarone therapy.

FLIP and FasL expression by inflammatory cells vs thyrocytes can be predictive of chronic inflammation or resolution of autoimmune thyroiditis

Spontaneous autoimmune thyroiditis (SAT) in NOD.H-2h4 mice is a model of chronic inflammation of the thyroid, while granulomatous experimental autoimmune thyroiditis (G-EAT) is a model with spontaneous resolution of inflammation. In chronic inflammation (SAT), Fas, FasL, and FLIP were upregulated and predominant in inflammatory cells. There were few apoptotic cells, and low expression of active caspase-8 and -3. In resolving G-EAT in CBA/J and NOD.H-2h4 mice, FasL and FLIP were predominantly expressed by thyrocytes. There were many apoptotic inflammatory cells, and increased expression of active caspase-8 and -3. Depletion of CD8+ T cells inhibited G-EAT resolution and resulted in chronic inflammation. FLIP was expressed predominantly by inflammatory cells, and apoptosis of inflammatory cells and expression of active caspase-3 was reduced as in chronic SAT. Thus, differences in expression of pro- or antiapoptotic molecules in SAT or G-EAT were apparently related to the acute vs chronic nature of the inflammatory response rather than the method of disease induction. Upregulation of FLIP by inflammatory cells may block Fas-mediated apoptosis, contributing to chronic inflammation, whereas increased FLIP expression by thyrocytes in resolving G-EAT may protect thyrocytes from apoptosis, and FasL expression by thyrocytes may induce apoptosis of inflammatory cells, contributing to resolution.

Possible induction of Graves' disease and painless thyroiditis by gonadotropin-releasing hormone analogues

Prolonged administration of gonadotropin-releasing hormone (GnRH) analogues induce a decrease in serum estrogen level, which may aggravate subclinical or mild autoimmune thyroid disease. Two patients developed Graves' thyrotoxicosis in association with an increase in anti-thyrotropin (TSH) receptor antibody activities at 4 months after initiation of buserelin acetate. GnRH analogue therapy was discontinued at the time of diagnosis but it took more than 2 years of methimazole therapy to obtain remission of Graves' disease. Another patient developed painless thyroiditis in association with an increase in antithyroid microsomal antibodies at 4 months after initiation of leuprolide acetate. These results indicate that GnRH analogues possibly induce clinical onset of Graves' thyrotoxicosis or destruction-induced thyrotoxicosis. Clinicians should be aware of this phenomenon. All patients who are to receive GnRH analogue therapy should be examined for antithyroid antibodies and family history of autoimmune thyroid disease, and should be followed accordingly.

[Acute hepatitis C: response to treatment with interferon-alpha plus ribavirin]

INTRODUCTION

Hepatitis C virus (HCV) is one of the most frequent causes of chronic liver disease in our environment. Most patients who present acute HCV infection develop chronic hepatitis, and only between 15 and 30% resolve spontaneously.

PATIENTS AND METHOD

The clinical, biological and viral characteristics, as well as tolerance to treatment and level of response were retrospectively analyzed in nine patients with acute hepatitis C who underwent treatment with interferon-alpha plus ribavirin for 12 to 48 weeks.

RESULTS

The mean alanine-aminotransferase (ALT) and total bilirubin concentrations of patients at diagnosis was 1.469 U/l and 5.5 mg/dl, respectively. All the patients except one were infected with genotype 1b and presented a mean viral load of 634,924 U/ml. At the end of follow-up, in seven patients (77.7%) HCV-RNA levels were undetectable and ALT levels were normal. The therapy was well tolerated except in two patients: one presented a mild depressive syndrome that was controlled with drugs and the other presented thyroiditis, which led to treatment withdrawal at 12 weeks.

CONCLUSIONS

Despite the small number of patients, interferon alpha plus ribavirin seems to achieve a high, sustained response. The treatment was well tolerated and there were few adverse effects.

Lithium-associated thyroiditis

OBJECTIVE

To report an unusual case of thyrotoxicosis caused by "silent thyroiditis" in a lithium-treated patient and to summarize all prior case reports of lithium-associated thyroiditis and compare them with our current case.

METHODS

In addition to reporting our case, we undertook a MEDLINE search of all case reports of lithium-associated thyroiditis from 1978 until the present. All reported cases of lithium-associated thyroiditis must have had documented low thyroid radioiodine uptake to be included.

RESULTS

A 52-year-old man with a history of bipolar disorder, who had been treated with lithium carbonate for 15 years, was admitted because of delusional mania. Although he had discontinued his lithium therapy 3 months before admission, he had noted symptoms of hyperthyroidism at least 1 month before admission. He was diagnosed with thyrotoxicosis due to silent thyroiditis on the basis of a high free thyroxine level, suppressed thyrotropin level, and low thyroid radioiodine uptake. We found only 10 other case reports of lithium-associated thyrotoxicosis due to silent thyroiditis.

CONCLUSION

Thyrotoxicosis caused by silent thyroiditis may be associated with lithium therapy and is likely to be underreported. The pathogenic mechanism for such cases of thyroiditis is still unclear.

Association between lithium use and thyrotoxicosis caused by silent thyroiditis

OBJECTIVE

To determine the incidence of silent thyroiditis in lithium users and characterize lithium-associated thyrotoxicosis.

DESIGN

Retrospective record review.

PATIENTS

400 consecutive patients (300 with Graves' disease and 100 with silent thyroiditis) who underwent radioiodine scanning of the thyroid.

MEASUREMENTS

Odds of lithium exposure.

RESULTS

The odds of lithium exposure were increased 4.7-fold in patients with silent thyroiditis compared with those with Graves' disease (95% CI: 1.3, 17). Lithium-associated silent thyroiditis occurred with an incidence rate of approximately 1.3 cases per 1000 person-years, and lithium-associated thyrotoxicosis occurred with an incidence rate of approximately 2.7 cases per 1000 person-years, higher than the reported incidence rates of silent thyroiditis (< 0.03-0.28 cases per 1000 person-years) and of thyrotoxicosis (0.8-1.2 cases per 1000 person-years) in the general population.

CONCLUSION

Thyrotoxicosis caused by silent thyroiditis might be associated with lithium use.

Thyroiditis induced by interferon in dialysis

We describe a dialysis patient who acquired acute Hepatitis C infection. Her primary renal disease was systemic lupus erythromatosis. She was having goitre but clinically euthyroid and her thyroid function test was normal. To avoid long term complications of Hepatitis C we elected to treat her with Interferon 3 million units subcutaneously 3 times a week. During treatment she developed some transient side effects initially which subsided but later she felt pressure symptoms around her neck. When we checked her TSH and thyroid antibodies these were elevated. Though this could be related to HCV, rarely, but we think the thyroid change is mostly related to Interferon. Some possible explanation of the effect of Interferon on thyroid have been reviewed and we think patients getting such drugs should be under close monitoring to avoid permanent thyroid dysfunction.

Autoimmune thyroiditis and myelosuppression following treatment with interferon-alpha for hepatitis C

CASE

We describe the case of a 48-year-old woman from Thailand diagnosed with chronic hepatitis C, who experienced a suppression of all blood cell counts accompanied by a newly developed clinically manifested autoimmune thyroid disorder after treatment with interferon alpha-2b (INF-alpha) 46 days after beginning of therapy a decrease of platelet, red and white blood cell counts became obvious. Concomitantly we observed an increase of FT4 and FT3 with a totally depressed TSH level 80 days after starting INF-alpha administration. Antibody assessment resulted in detection of high numbers of antithyroid-microsomal antibodies and antithyroglobulin antibodies. Thyroid hormone levels normalized under treatment with methimazole/propylthiouracil within 4.5 months. However, two months after cessation of antithyroid therapy increasing TSH levels and decreasing FT4 levels indicated a new tendency towards a hypothyroid state.

CONCLUSION

We classify this case as an interferon-alpha-induced disorder of thyroid function accompanied by myelosuppression. A close monitoring for thyroid dysfunction, e.g. evaluation of TSH-levels before and after administration of INF-alpha is mandatory.

Interleukin-1 beta inhibits rat thyroid cell function in vivo and in vitro by an NO-independent mechanism and induces hypothyroidism and accelerated thyroiditis in diabetes-prone BB rats

Interleukin-1 beta has been implicated as a pathogenic factor in the development of autoimmune thyroiditis. When given for 5 days to normal non-diabetes-prone Wistar Kyoto rats, it decreased plasma concentrations of total tri-iodothyronine and thyroxine and increased plasma TSH. These effects were not prevented by co-injection of nitroarginine methyl ester or aminoguanidine, inhibitors of NO synthases. Exposure to interleukin-1 beta dose-dependently reduced iodine uptake in FRTL-5 cells, but had no effect on thyroglobulin secretion. Nitrite was not detected in the FRTL-5 cell culture media after exposure to interleukin-1 beta. However, reverse transcription PCR analysis of mRNA isolated from interleukin-1 beta-exposed FRTL-5 cells revealed a transitory expression of the inducible NO synthase, which was markedly lower than inducible NO synthase induction in interleukin-1 beta-exposed isolated rat islets of Langerhans. Co-incubation with the NO synthase inhibitor NG-monomethylarginine did not ameliorate the effect of interleukin-1 beta on FRTL-5 cell iodine uptake. Furthermore, we demonstrate that daily injections of interleukin-1 beta for 13 weeks aggravated spontaneous thyroiditis and induced severe hypothyroidism in non-diabetic diabetes-prone BB rats. The data suggest that NO does not mediate interleukin-1 beta-induced inhibition of rat thyroid function in vivo or in vitro in FRTL-5 cells, and the induction of hypothyroidism by interleukin-1 beta in diabetes-prone BB rats is speculated to be due to exacerbation of recruitment and activation of intrathyroidal mononuclear cells.

Failure of plasmapheresis, corticosteroids and thionamides to ameliorate a case of protracted amiodarone-induced thyroiditis

We report a case of amiodarone-induced thyrotoxicosis of protracted duration, unresponsive to conventional thionamide therapy, with therapy limited by severe adverse drug reactions. Other treatment modalities included high dose corticosteroids, plasmapheresis, lithium and perchlorate. Temporary amelioration was achieved following plasmapheresis; however, this and other measures were unsuccessful in controlling the thyrotoxicosis, which deteriorated to thyroid storm. Histopathologically, a degenerative, inflammatory thyroiditis was evident. We discuss the limitations of conventional drug therapy and the lack of a sustained response to plasmapheresis. The failure of high doses steroids to alter the course of illness and to completely suppress the thyroidal inflammatory process is highlighted. A potential role for renal and hepatic impairment in the observed protracted course of amiodarone-induced thyrotoxicosis is suggested.

Involvement of T cell immunity in the transient thyroid inflammation induced by iodide in goitrous BALB/C and nude mice

To evaluate the involvement of T cell immunity in the thyroiditis induced in goitrous mice by iodide administration, we analyzed the immunological changes happening in the thyroid glands and lymph nodes during goiter involution in balb/c and athymic nude mice of similar background. In both balb/c and nude mice, goiter involution was characterized by thyroid cell necrosis and inflammation. In balb/c mice, the inflammatory infiltrate was made of numerous Ia+ cells. Their number was unchanged during goiter development, but was significantly increased after 2 days of involution and remained high after 8 days. CD4+ and CD8+ T cells were also observed, some of which were clearly activated since they expressed the receptor for Interleukin-2 (IL-2R). The numbers of CD4+, CD8+ and IL-2R+ T cells were increased during goiter as compared to control mice, and they reached a maximum at day 1 of involution. In nude mice, unexpectedly, CD4+ and CD8+ T cells were also found in the thyroid. Their numbers, as well as the number of Ia+ cells, were significantly increased at the onset of involution, but they remained systematically lower than in the corresponding groups of balb/c mice. Iodide treatment of goitrous mice also induced modifications of the lymph nodes draining the thyroid: enlargement of the paracortical T zone, presence of germinal centers in cortical follicles, and increase of the density of IL-2R+ cells. Mesenteric lymph nodes taken as controls were unchanged. Thus, three observations suggest the involvement of T cell immunity in iodine-induced thyroid inflammation: 1. Infiltration of Ia+, CD4+, CD8+ and IL-2R+ cells. 2. Signs of stimulation in thyroid lymph nodes, 3. Significant differences between balb/c and nude mice, in which the inflammatory reaction is weaker.

HgCl2-induced glandular pathosis in the brown Norway rat

Low doses of HgCl2 induce a genetically restricted autoimmune syndrome in Brown Norway (BN) rats (BN(Hg)). Part of the syndrome includes spontaneously developing mononuclear cell foci in salivary and lacrimal glands, morphologically similar to focal sialoadenitis in Sjögren's syndrome in man. In this study, we have shown that Hg-induced focal adenitis in BN rat is not female predominant and not solely dependent on Hg uptake in the glands. In BN(Hg), focal adenitis was found to develop in several different glands (parotid, submandibular, lacrimal, thyroid) as a specific manifestation of immunopathosis induced by Hg in the RT1n-haplotype-carrying BN. Such manifestations were absent in another strain, the Hg-resistant Lewis (RT1l). Also a potent contact sensitizer, DNFB, induced focal adenitis in isolated glands, provided that strong sensitization had occurred. Immunohistochemical characterization of focal adenitis in BN(Hg) with monoclonal antibodies showed that T cells and dendritic cells dominate the early infiltrates, whereas B cells were absent.