Correlation of antithyroglobulin and antithyroid-peroxidase antibody profiles with clinical and ultrasound characteristics of chronic thyroiditis

AI-Assisted Ultrasound for the Early Diagnosis of Antibody-Negative Autoimmune Thyroiditis

The prevalence of antibody-negative chronic autoimmune thyroiditis (SN-CAT) is increasing. The early diagnosis of SN-CAT can effectively prevent its further development. Thyroid ultrasound can diagnose autoimmune thyroiditis and predict hypothyroidism. Primary hypothyroidism with a hypoechoic pattern suggested by thyroid ultrasound and negative thyroid serum antibodies is the main basis for the diagnosis of SN-CAT. However, for early SN-CAT, only hypoechoic thyroid changes and serological antibodies are currently available. This study explored how to achieve an accurate and early diagnosis of SN-CAT and prevent the development of SN-CAT combined with hypothyroidism. The diagnosis of a hypoechoic thyroid by artificial intelligence is expected to be a breakthrough in the accurate diagnosis of SN-CAT.

The prevalence of thyroid dysfunction and autoimmune thyroid disease in patients with rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is one of the most common chronic non-organ-specific autoimmune diseases; meanwhile, autoimmune thyroid disease (AITD) is the most common organ-specific autoimmune disease that can lead to hypo or hyperthyroidism. Although the etiology of both diseases is complex with a combination of genetic and environmental factors, there are overlaps in genes contributing to the pathogenesis of both diseases. Numerous studies found a correlation between thyroid abnormality and RA in different populations, yet some didn’t. This study is aimed to evaluate the prevalence of thyroid dysfunction, AITD, and anti-thyroid peroxidase (anti-TPO) positively in Iranian patients with RA.

Methods

A total of 250 RA patients and 248 patients with non-inflammatory rheumatologic disease were included in this case–control study. All participants underwent complete clinical and laboratory assessments. Participants were also assessed for thyroid function testing, including anti-TPO antibodies.

Results

Thyroid dysfunction was twice as common in RA patients as in controls (OR = 2.16; P-value > 0.001). Overt hypothyroidism was the most common thyroid dysfunction among RA patients (58 out of 84). Anti-TPO positivity was also significantly more common in RA compared with controls (OR = 2.65; P-value > 0.001). The proportion of controls and RA patients with AITD were 9 and 21.5%, respectively. AITD was found 2.8 times more common in RA group than controls (OR = 2.77; P-value > 0.001).

Conclusion

It was demonstrated that RA was an independent factor associated with thyroid dysfunction and AITD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41927-022-00293-9.

68Ga-FAPI Uptake of Thyroiditis in a Patient With Breast Cancer

ABSTRACT

68Ga-fibroblast activation protein-specific inhibitor (FAPI)-04 PET/CT was performed in a 49-year-old woman diagnosed with breast cancer. In PET/CT imaging, intense 68Ga-FAPI uptake was observed in the primary tumor, axillary lymph nodes, and also in the thyroid gland, whereas pathological 18F-FDG uptake was not observed in the thyroid gland. On thyroid ultrasonography, parenchyma was heterogeneous, and an area of focal thyroiditis was observed in the superior part of the right lobe. Biochemical parameters were found to be consistent with thyroiditis. This case shows that FAPI uptake in the thyroid gland may be associated with thyroiditis and should be evaluated clinically.

Compared with classic Hashimoto's thyroiditis, chronic autoimmune serum-negative thyroiditis requires a lower substitution dose of L-thyroxine to correct hypothyroidism

PURPOSE

Serum-negative-chronic-autoimmune-thyroiditis (SN-CAT) is considered a milder variant of classic Hashimoto's thyroiditis (CHT). However, its prevalence remains unknown and it is still unclear whether SN-CAT behaves differently in terms of L-thyroxine (LT4) substitution treatment of hypothyroidism. Aims of this study were to estimate the prevalence of SN-CAT in a large series of hypothyroid patients and to compare LT4 requirements in hypothyroid patients with SN-CAT and CHT.

METHODS

Five-hundred-eighty-one consecutive patients with primary-autoimmune-hypothyroidism were enrolled in a cross-sectional study. LT4 requirements and thyroid-volume changes were longitudinally evaluated in 49 hypothyroid patients with SN-CAT and in 98 sex and age-matched hypothyroid patients with CHT.

RESULTS

In our series the prevalence of SN-CAT was 20.8%. At diagnosis, patients in the CHT and SN-CAT groups had similar male/female ratio, age and BMI, while serum TSH and thyroid-volume were significantly greater in the CHT group. In the longitudinal study, during a follow-up of 8.9 ± 4.6 years, 8 out of 49 (16.3%) SN-CAT patients developed positive tests for of circulating TPO-Ab and/or Tg-Ab. Thyroid-volume significantly decreased in CHT patients, but not in those with SN-CAT. The maximum daily substitution dose of LT4 was smaller in SN-CAT patients as compared with the CHT ones. Multivariate analysis showed that age, BMI, basal TSH and thyroid antibody status independently and significantly predicted the maximum daily substitution dose of LT4.

CONCLUSIONS

SN-CAT accounts for a significant proportion of patients with autoimmune hypothyroidism. Compared with hypothyroid patients diagnosed with CHT, the SN-CAT ones require smaller doses of LT4 to correct their hypothyroidism.

Basedow's disease with associated features of Hashimoto's thyroiditis based on histopathological findings

BACKGROUND

Basedow's disease and Hashimoto's thyroiditis are autoimmune thyroid disorders and usually diagnosed with elevation of serum autoimmune antibodies. Thyrotropin receptor antibodies (TRAb) and/or thyroid-stimulating antibody (TSAb) are usually used for diagnosis of Basedow's disease, and thyroid peroxidase antibodies (TPOAb) and/or thyroglobulin antibodies (TgAb) are for diagnosis of Hashimoto's thyroiditis. However, it is difficult to diagnose a subject as Basedow's disease with associated features of Hashimoto's thyroiditis only with elevation of such autoimmune antibodies.

CASE PRESENTATION

A 44-year-old woman with 5-year history of Basedow's disease underwent a total thyroidectomy. She did not have a goiter. TRAb, TSAb, TPOAg and TgAb were all positive before a total thyroidectomy. In histopathological macroscopic examination, diffuse hyperplasia of the thyroid gland was observed. Furthermore, in histopathological microscopic examination, both characteristics of Basedow's disease and Hashimoto's thyroiditis were observed. After a total thyroidectomy, titers of all thyroid-associated autoimmune antibodies were markedly reduced.

CONCLUSION

Herein, we report a subject with Basedow's disease without a goiter whose TPOAb and TgAb were relatively high at the onset of Basedow's disease. In addition, interestingly, the histopathological findings of this subject showed direct signs of Basedow's disease and Hashimoto's thyroiditis in the same thyroid gland. Considering from such findings, she seemed to have Basedow's disease with associated features of Hashimoto's thyroiditis. In conclusion, we should bear in mind the possibility of Basedow's disease with associated features of Hashimoto's thyroiditis in subjects with Basedow's disease, particularly when TPOAb and TgAb as well as TRAb and TSAb are positive.

Non-immune-related hypothyroidism and its relationship with excess iodine

PURPOSE

In iodine-sufficient areas, autoimmune hypothyroidism has been regarded as the major subtype of hypothyroidism. Non-immune-related hypothyroidism has received little attention because it is considered to be rare. The aim of this study was to evaluate the prevalence of non-immune-related hypothyroidism in Korea and to identify its associating factors.

METHODS

A total of 6434 participants in the Korea National Health and Nutrition Examination Survey VI (2013-2015) without known thyroid disease who were examined for thyroid stimulating hormone, free thyroxine, TPO Ab, and urine iodine concentration (UIC) were enrolled. The weighted proportions, demographic variables, and severity of immune-related and non-immune-related hypothyroidism were compared. To assess the effect of iodine on hypothyroidism in TPO Ab positive or negative populations, the weighted prevalence of hypothyroidism was assessed in each population according to UIC or estimated iodine intake subgroups.

RESULTS

The prevalence of undetected hypothyroidism in Korea was 3.8% (n = 233). Of these 233 cases, 171 (71.8%) were non-immune-related. In the TPO Ab negative population, the prevalence of hypothyroidism was increased significantly in the subgroup with UIC between 250 and 749 µg/L (HR 2.12 [1.17, 3.83]) and ≥ 750 µg/L (HR 3.42 [1.93, 6.04]) or the subgroups with estimated iodine intake ≥ 750 µg/day (HR 2.81 [1.64, 4.80]).

CONCLUSIONS

This nationwide study demonstrated that most cases of hypothyroidism in iodine-sufficient areas are non-immune-related and are associated with excess iodine above a certain level. More attention to this unrecognized but widespread potential health risk is needed.

Is only Thyroid Peroxidase Antibody Sufficient for Diagnosing Chronic Lymphocytic Thyroiditis?

Objectives:

Recently, only anti-thyroid peroxidase (anti-TPO) has been suggested as an autoantibody in the diagnosis of chronic lymphocytic thyroiditis (CLT). In contrast, anti-thyroglobulin (anti-Tg) positivity has also been reported to be important. To evaluate this relationship more clearly, we planned to retrospectively investigate the autoantibody levels of the patients who underwent thyroid surgery for various reasons and those with CLT in postoperative pathology.

Methods:

We evaluated 670 patients who underwent thyroid surgery (total/subtotal thyroidectomy) for various reasons at our hospital between January 2015 and March 2017. Patients with indications of Graves’ disease, toxic multinodular goiter, and all malignancies except for thyroid papillary carcinoma (TPC) were excluded. Eighty-nine patients whose pathology findings were compatible with CLT and preoperative thyroid autoantibodies were identified enrolled in to the study. Patients with absence and presence of thyroid antibodies were included in the seronegative CLT group and seropositive CLT group, respectively. In addition, patients were divided into thyroid papillary carcinoma (TPC) and benign groups.

Results:

According to the study criteria, 89 (83 females, six males) (mean age, 46.08±11.19 years) patients who had preoperatively identified autoantibodies were detected. Anti-TPO positivity was found in 47 (52.8%) cases, whereas anti-Tg positivity was found in 49 (55.1%). Only anti-TPO positivity was found in 18 (20.2%) cases, whereas only anti-Tg positivity was detected in 20 (22.5%). Twenty-two (24.7%) of the patients were seronegative. On comparing the seronegative and seropositive groups, seronegativity was more frequent in male patients (p=0.03). Thyroid-stimulating hormone was found to be significantly higher in the seropositive group (p=0.01). TPC was detected in 36 (40.4%) of all cases. No difference regarding age, thyroid function tests, and antibody levels was found between the benign and TPC groups.

Conclusion:

Although all of our cases were histopathologically diagnosed with CLT, serologically, 75.3% of thyroid autoimmunities could be shown when both antibodies were evaluated together. When only anti-TPO was considered, this rate decreased to 52.8%. Therefore, anti-Tg appears to be still important in showing autoimmunity. Prospective studies are needed to evaluate this relationship more clearly.

Linear α-(1 → 6)-d-glucan from Bifidobacterium bifidum BIM В-733D is low molecular mass biopolymer with unique immunochemical properties

Role of microorganisms in induction of/protection from autoimmune diseases is proven though molecular mechanisms and bacterial/viral/yeast biopolymers responsible for these effects are in the research stage. Autoantobodies (AAbs) to thyroid peroxidase (anti-TPO) and thyroglobulin (anti-Tg) as well as AAbs to transglutaminase 2 (anti-TG2) and antibodies to gliadins (anti-gliadins) are serological markers of autoimmune thyroid disease and celiac disease, respectively, and players in pathogenesis of these autoimmune diseases. In current study, biopolymer of Bifidobacterium bifidum BIM В-733D that interacts selectively with anti-gliadins (Bb-G_{anti-gliadins}) was isolated by affinity chromatography with anti-gliadins, purified by size exclusion chromatography on TSK 40 gel and identified by NMR as linear α-(1 → 6)-d-glucan with molecular mass about 5000 Da. It was proven that compounds Bb-G_{anti-gliadins} and Bb-G_anti-TPO/Bb-G_anti-Tg isolated early from the same strain [Kiseleva, E. P. et al., Benef Microbes.2013, 4, 375 -391] are the same substance designated G_Bb. Its unique immunochemical property is the ability to interact selectively with anti-TPO, anti-Tg, anti-TG2 and anti-gliadins in presence of no less than 10-fold excess of total immunoglobulins of class G (tIgG), as it was proven by ELISA. Synthesis of G_Bb-bovine serum albumin (G_Bb-BSA) conjugate is an example of increasing the reliability and reproducibility of ELISA results by mediated immobilization of a polysaccharide covalently attached to a well-adsorbed protein. Taking into account that there are population of bispecific anti-gliadins (anti-gliadins and anti-TG2 simultaneously) we regard our data as first argument in favor of hypothesis that G_Bb differentiates between human AAbs per se and other human Ig (e.g. antibodies to antigens of infectious agents) due to its binding with a yet unidentified site which is present in the molecules of all AAbs (independently on their specificity) and absent in other human Igs.

Impact of nutritional iodine optimization on rates of thyroid hypoechogenicity and autoimmune thyroiditis: a cross-sectional, comparative study

BACKGROUND

Since several countries have established mandatory food iodine fortification, there has been a decrease in rates of iodine deficiency disorders in parallel with an increase in prevalence of autoimmune thyroid diseases. This study compared the nutritional iodine status and the prevalence of autoimmune thyroiditis and thyroid hypoechogenicity on ultrasound in schoolchildren in São Paulo (Brazil) in two distinct periods of time in which fortified salt had different concentrations of iodine.

METHODS

We conducted a cross-sectional study evaluating 206 children aged 7-14 years and without a history of thyroid disease. Assessments included measurements of thyrotropin (TSH), free thyroxine, antithyroperoxidase (anti-TPO), and antithyroglobulin (anti-TG) antibodies, urinary iodine concentration, and thyroid ultrasound.

RESULTS

Mean urinary iodine concentration was 165.1 μg/L. Eleven children (5.3%) were diagnosed with autoimmune thyroiditis based on at least two of four criteria adopted in our study: positive anti-TPO or anti-TG antibody, hypoechogenicity of the thyroid parenchyma on ultrasound, and a TSH >4.0 μU/mL. Comparing our results with those from a similar study conducted during a period in which concentrations of iodine in the salt were higher (median urinary iodine concentration >300 μg/L), we observed a trend toward a lower prevalence of autoimmune thyroiditis, although no definitive conclusion could be established.

CONCLUSION

The current nutritional iodine status in our cohort was within optimal levels and lower than levels found in 2003. The prevalence of autoimmune thyroiditis seems to be decreasing in parallel with a decrease in iodine intake, although we could not reach a definitive conclusion.

Serum negative autoimmune thyroiditis displays a milder clinical picture compared with classic Hashimoto's thyroiditis

BACKGROUND

Despite high sensitivity of current assays for autoantibodies to thyroperoxidase (TPO) and to thyroglobulin (Tg), some hypothyroid patients still present with negative tests for circulating anti-thyroid Abs. These patients usually referred to as having seronegative autoimmune thyroiditis (seronegative CAT) have not been characterized, and definite proof that their clinical phenotype is similar to that of patients with classic chronic autoimmune thyroiditis (CAT) is lacking.

OBJECTIVE

To compare the clinical phenotype of seronegative CAT (SN-CAT) and CAT as diagnosed according to a raised serum level of TSH with negative and positive tests for anti-thyroid Abs respectively.

METHODS

A case-control retrospective study enrolling 55 patients with SN-CAT and 110 patients with CAT was performed. Serum free triiodothyronine (FT3), free thyroxine (FT4), TSH, Tg Abs, and TPO Abs were measured in all patients.

RESULTS

Patients with SN-CAT displayed significantly lower mean levels of TSH (6.6±3.4 vs 10.2±9.8 μU/ml; P=0.009), higher mean FT4 levels (1.1±0.2 vs 0.9±0.2 ng/dl; P=0.0002), and similar FT3 levels when compared with CAT patients. Mean thyroid volume was significantly greater in patients with CAT when compared with SN-CAT patients (11.2±6.5 vs 8.1±3.7 ml; P=0.001). Logistic regression demonstrated that FT4 (0.123 (0.019-0.775); (P=0.026)) and thyroid volume (1.243 (1.108-1.394); (P=0.0002)) were significantly and independently related to the diagnosis (CAT/SN-CAT). Patients with SN-CAT had a similar prevalence of thyroid nodules and female gender but a lower prevalence of overt hypothyroidism (5.4 vs 20.9%; P=0.012) as opposed to patients with CAT.

CONCLUSIONS

These results suggest an autoimmune etiology of SN-CAT, which, however, seems to have a milder clinical course when compared with CAT.

Pegylated interferon de novo-induce autoimmune haemolytic anaemia in chronic hepatitis C patient

A 55-year-old Egyptian woman with chronic hepatitis C undergoing treatment with pegylated interferon (Peg-IFN) alfa-2a plus ribavirin was referred to our hospital on November 2010 with prolonged easy fatigability and an attack of syncope; she had no prior history of autoimmune disorders or allergy. Laboratory investigations documented the presence of Peg-IFN induced autoimmune haemolytic anaemia and autoimmune thyroiditis. Intravenous γ globulin (IVGG) failed to correct the autoimmune process; on the other hand steroid therapy dramatically corrected both haematological and thyroid values, and step down the immune process. Our report indicated that Peg-IFN de novo-induce autoimmune haemolysis, documenting a previous report. IVGG failed to step down the immune process in our case.

Tumor regression following DNA vaccination and regulatory T cell depletion in neu transgenic mice leads to an increased risk for autoimmunity

Modulation of the immune system to amplify anti-tumor immunity carries the risk of developing autoimmune diseases, including hypothyroidism, as seen with cancer patients undergoing clinical trials for immunotherapeutic regimens. Although there is a tendency to view autoimmunity as a positive indicator for cancer immunotherapy, some autoimmune manifestations can be life-threatening and necessitate prolonged medical intervention or removal from trial. We have established murine test models to assess such risks by monitoring, simultaneously, the immune reactivity to tumor-associated rat erbB-2 (neu) and another self Ag, mouse thyroglobulin (mTg). We previously reported that in wild-type, thyroiditis-resistant BALB/c mice that underwent regression of neu(+) TUBO tumors following regulatory T cell (Treg) depletion, immune responses to rat neu and mTg with resultant autoimmune thyroiditis (EAT) were both enhanced. In this study, we tested the balance between tumor immunity and autoimmunity in neu-transgenic BALB NeuT female mice. First, growth and progression of neu(+) tumor were compared in neu tolerant mice treated with either CD25 mAb to deplete Tregs and/or DNA vaccination. Only Treg depletion followed by neu DNA vaccination abrogated tolerance to neu, resulting in complete regression of neu(+) tumors, as well as long-term protection from spontaneous tumorigenesis in 58% of mice. The risk of developing EAT was then assessed by incorporated mTg immunization with or without LPS as adjuvant. In mice with induced tumor regression, mTg response was enhanced with modest increases in EAT development. Therefore, tumor regression induced by Treg depletion and DNA vaccination can exacerbate autoimmunity, which warrants close monitoring during immunotherapy.

Control of Her-2 tumor immunity and thyroid autoimmunity by MHC and regulatory T cells

Immune reactivity to self-antigens in both cancer and autoimmune diseases can be enhanced by systemic immune modulation, posing a challenge in cancer immunotherapy. To distinguish the genetic and immune regulation of tumor immunity versus autoimmunity, immune responses to human ErbB-2 (Her-2) and mouse thyroglobulin (mTg) were tested in transgenic mice expressing Her-2 that is overexpressed in several cancers, and HLA-DRB1*0301 (DR3) that is associated with susceptibility to several human autoimmune diseases, as well as experimental autoimmune thyroiditis (EAT). To induce Her-2 response, mice were electrovaccinated with pE2TM and pGM-CSF encoding the extracellular and transmembrane domains of Her-2 and the murine granulocyte macrophage colony-stimulating factor, respectively. To induce EAT, mice received mTg i.v. with or without lipopolysaccharide. Depletion of regulatory T cells (Treg) with anti-CD25 monoclonal antibody enhanced immune reactivity to Her-2 as well as mTg, showing control of both Her-2 and mTg responses by Treg. When immunized with, Her-2xDR3 and B6xDR3 mice expressing H2(b)xDR3 haplotype developed more profound mTg response and thyroid pathology than Her-2 or B6 mice that expressed the EAT-resistant H2(b) haplotype. In Her-2xDR3 mice, the response to mTg was further amplified when mice were also immunized with pE2TM and pGM-CSF. On the contrary, Her-2 reactivity was comparable whether mice expressed DR3 or not. Therefore, induction of Her-2 immunity was independent of DR3 but development of EAT was dictated by this allele, whereas Tregs control the responses to both self-antigens. These results warrant close monitoring of autoimmunity during cancer immunotherapy, particularly in patients with susceptible MHC class II alleles.

High prevalence of thyroid dysfunction and autoimmune thyroiditis in adolescents after elimination of iodine deficiency in the Eastern Black Sea Region of Turkey

In the present study we evaluated the effects of iodine intake on the prevalence of thyroid dysfunction, autoimmunity, and goiter in two regions with different iodine status after two years of iodization in Turkey. In total 1733 adolescent subjects were enrolled into the study (993 from an iodine-sufficient area--the Eastern Black Sea Region (group 1) and 740 from an iodine-deficient area--Middle Anatolia (group 2)). We measured free thyroxine (FT(4)), thyrotropin (TSH), antithyroid peroxidase antibodies (Anti-TPO), antithyroglobulin antibodies (Anti-Tg), and urinary iodine (UI), and examined the thyroid gland by ultrasound. Median urinary iodine excretion was found to be significantly different in group 1 and group 2 (139 micro/l vs 61micro/l, p < 0.001). Hyperthyroidism was more frequent in group 1 (3.6% vs 0.7%; p < 0.001), but the hypothyroidism rate was similar between groups (1.8% vs 1.4 %; p>0.05). The percentage of anti-Tg positive subjects was found to be 17.6% in group 1 and 6.4% in group 2; that of anti-TPO positive subjects was 4.3% in group 1 and 1.5% in group 2. The prevalence of antithyroid antibody (anti-Tg and/or anti-TPO) positivity was significantly higher in group 1 than in group 2 (18.52% vs 6.62%; p < 0.001). Thyroid volumes of the hyperthyroid subjects in both groups were significantly higher than hypo- and euthyroid subjects. In conclusion, iodine supplementation in Turkey has resulted in the elimination of iodine deficiency in the Eastern Black Sea Region, and this has been accompanied by an increase in the prevalence of autoimmune thyroiditis and thyroid dysfunction.

Comparison of ultrasonographic characteristics of the thyroid gland in healthy small-, medium-, and large-breed dogs

OBJECTIVE

To determine ultrasonographic characteristics of the thyroid gland in healthy small-, medium-, and large-breed dogs and evaluate the relationships of thyroid gland size and volume with body weight and body surface area (BSA).

ANIMALS

72 dogs of small (6 Toy and 6 Miniature Poodles), medium (12 Beagles), and large breeds (12 Akitas and 36 Golden Retrievers).

PROCEDURE

Each dog's thyroid gland was examined ultrasonographically with a 10- to 5-MHz multifrequency linear-array transducer. Size, shape, echogenicity, and homogeneity of thyroid lobes were evaluated on longitudinal and transverse images. Thyroid lobe volume was estimated by use of the equation for an ellipsoid (pi/6 [length x height x width]).

RESULTS

Thyroid lobes appeared fusiform or elliptical on longitudinal images and triangular or round to oval on transverse images. In most dogs, thyroid lobes were hyperechoic or isoechoic, compared with surrounding musculature, and had a homogeneous echogenic pattern. Mean length, width, height, and volume of thyroid lobes were significantly greater in Akitas and Golden Retrievers, compared with findings in Beagles or Poodles; mean length, width, and height were significantly greater in Beagles, compared with findings in Poodles. Total thyroid gland volume correlated with body weight (r = 0.73) and BSA (r = 0.74).

CONCLUSIONS AND CLINICAL RELEVANCE

Among the dog breeds examined ultrasonographically, thyroid lobe size and volume were more variable than shape, echogenicity, and homogeneity. The correlation of thyroid gland volume with BSA suggests that size of the dog, rather than breed, should be considered when assessing thyroid glands ultrasonographically.

Long-term outcome of interferon-alpha-induced autoimmune thyroid disorders in chronic hepatitis C

BACKGROUND

Autoimmune thyroid disorders are among the well-known adverse effects of interferon-alpha (IFN-alpha) therapy in patients with chronic hepatitis C. However, there are few reports regarding the long-term outcome of this complication. We aimed to evaluate the natural history of IFN-alpha-induced autoimmune thyroid disorders with long-term follow-up.

METHODS

Four hundred and thirty-nine patients with chronic hepatitis C were treated with IFN-alpha for 24 weeks between March 1993 and April 1998. Seventeen of 439 (3.9%) patients developed symptomatic autoimmune thyroid disorders including nine cases of hyperthyroidism and eight cases of hypothyroidism. The patients with hypothyroidism were all women. These 17 patients were followed up for 71.1 +/- 17.8 months (48-120 months) and were evaluated for long-term outcome.

RESULTS

Eight patients could discontinue the thyroid medication (2-36 months, median 10 months). Nine patients needed the thyroid medication at the follow-up period. The patients with hyperthyroidism who needed long-term thyroid medication had a significantly high titer of TSH receptor antibody on onset compared with the patients who could discontinue the thyroid medication. There were no significant differences in age, type of IFN, duration from IFN administration to onset, cessation of IFN, genotype of hepatitis C virus and thyroid hormone levels on onset between the patients who needed long-term thyroid medication and the patients who could discontinue the thyroid medication.

CONCLUSION

All patients with IFN-alpha-induced thyroid disorders could be controlled with medication. However, the IFN-alpha-induced thyroid disorders are not always reversible. One must be careful about not only the development of autoimmune thyroid disorders during IFN-alpha therapy but also the outcome of the thyroid disease.

Temporal relationship between the appearance of thyroid autoantibodies and development of destructive thyroiditis in patients undergoing treatment with two different type-1 interferons for HCV-related chronic hepatitis: a prospective study

In this prospective study we performed repeated evaluations of thyroid status in patients undergoing treatment with different preparations of recombinant interferons (IFNs), in order to identify early markers of thyroid dysfunction. Moreover, we aimed to investigate whether the development of thyroid dysfunction was related to the appearance of thyroid autoimmunity. Our study included 51 consecutive patients without pre-existing thyroid disease, admitted to our hospital for Hepatitis C virus (HCV)-related chronic hepatitis. Thirty-six patients (Gr. A) were treated with IFN-alpha 2b plus ribavirin (RIBA), whereas 15 patients (Gr. B) underwent treatment with IFN-alphacon-1 (CIFN) plus RIBA. Thyroid autoimmunity and function were prospectively evaluated before, every month during treatment and for 6 months after IFN withdrawal. At study entry, all patients were euthyroid and negative for thyroid autoantibodies. In Gr. A, 10 patients developed thyroid autoimmunity after a median period of 3 months (range: 1-6) treatment with IFN-alpha+RIBA. At the time of appearance of thyroid autoantibodies, 4 patients developed destructive thyrotoxicosis (overt in one case, subclinical in 3 cases), while other 4 patients showed a high reduction of serum TSH levels (median decrease: -75.7%, range: -61.9- -84.2), which reached the low values of normal range. After a median period of 2 months (range: 1-3) from these biochemical abnormalities, 6 patients continuing antiviral treatment developed hypothyroidism (overt in 3 cases and subclinical in the other 3). In Gr. B, 5 patients developed thyroid autoimmunity after a median period of 3 months (range: 2-10) of treatment with CIFN+RIBA. Soon after the appearance of thyroid autoantibodies, all patients developed an overt thyrotoxicosis (with hyperthyroidism in 2 cases). Antiviral treatment was discontinued in all 5 cases. Thereafter, thyroid function recovered spontaneously without significant modifications of serum TGAb and TPOAb levels until the end of the study. In conclusion our prospective study demonstrated that: 1) the appearance of thyroid autoantibodies during treatment with IFN was accompanied in most cases by the occurrence of a destructive process in the thyroid gland; 2) The clinical expression of destructive thyroiditis was more evident in patients treated with CIFN than that in patients treated with IFN; 3) The thyroid clinical outcome of these patients was strictly correlated to the continuation of cytokine treatment.

Polyspecificity of antimicrosomal thyroid antibodies in hepatitis C virus-related infection

OBJECTIVES

The outcome of dysthyroidism and the presence of antithyroid antibodies in patients with chronic hepatitis C virus (HCV) infection receiving interferon-alpha therapy is clearly established. However, the prevalence and the specificity of antithyroid antibodies in HCV patients before interferon-alpha therapy remain controversial. The aim of the present study is to clarify within a large population of HCV patients the prevalence of antithyroid antibodies before interferon-alpha therapy and to determine whether their immunodominant antigen is the same as described in autoimmune thyroiditis.

METHODS

Sera from 99 patients with chronic hepatitis C before (n = 99) and after (n = 37) interferon-alpha treatment were investigated for the presence of antimicrosomal and antithyroperoxidase antibodies assessed by indirect immunofluorescence and ELISA, respectively. Dot blotting on human thyroid lysate was designed to further characterize these autoantibodies. Data were compared to those obtained with sera of patients with autoimmune thyroiditis (n = 75) and healthy subjects (n = 96).

RESULTS

In HCV patients, antimicrosomal antibodies were found with a higher proportion before interferon-alpha therapy (12.1%) than after therapy (8%). Thyroperoxidase constitutes the main antigen in only 4% before treatment, a prevalence similar to that observed in healthy controls.

CONCLUSIONS

The prevalence of antithyroid antibodies is low in patients with chronic hepatitis C before interferon-alpha therapy. Thyroperoxidase may not be their main target. Further studies are required to determine whether HCV infection leads to a breakdown of tolerance to a thyroid self-protein other than thyroperoxidase.

Differences between changes in serum thyrotropin-binding inhibitory antibodies and thyroid-stimulating antibodies in the course of antithyroid drug therapy for Graves' disease

There has recently been controversy regarding whether the measurement of thyrotropin-binding inhibitory antibodies (TBIAb) is useful in the management of Graves' disease. Another method of assessing Graves' disease by measuring adenylate cyclase activity in thyroid cells, known as thyroid-stimulating antibodies (TSAb), differs from TBIAb not only in terms of assay but also in immunoglobulin type according to recent studies. In this study, the concentrations of TBIAb and TSAb were compared in serial serum samples collected from 29 patients with Graves' hyperthyroidism during 12 months of antithyroid drug therapy. Before therapy, there was a correlation between TBIAb and TSAb (r = 0.59). The radioactive iodine uptake (RAIU) was not significantly correlated with either TBIAb or TSAb (r = 0.20 and r = 0.29, respectively), and the serum free thyroxine (FT4) concentration was also not significantly correlated with either TBIAb or TSAb (r = 0.06 and r = 0.22, respectively). In patients with Graves' ophthalmopathy, TSAb levels were higher than in patients without ophthalmopathy (1015%+/-851% vs. 456%+/-323%, p<0.01), but the TBIAb levels were not significantly different. After antithyroid treatment, TBIAb did not decrease significantly (from 42.1%+/-20.8% to 20.5%+/-19.5%, p = 0.29). On the other hand, TSAb was significantly decreased after 12 months of treatment (from 649%+/-611% to 294%+/-205%, p< 0.05). These findings indicate that TBIAb and TSAb are not identical, and that TSAb has a closer relationship to thyroid function than TBIAb. In the clinical setting, determination of the serum TSAb level may provide a more accurate index of the thyroid status in Graves' disease patients receiving antithyroid therapy.