Assays of TSH-receptor antibodies in 576 patients with various thyroid disorders: their incidence, significance and clinical usefulness

The incidence and the significance of TSH-receptor antibodies in Graves' disease and in various thyroid disorders have been evaluated. TSH-binding inhibiting antibodies (TBIAb) and thyroid stimulating antibodies (TSAb) were detected in a large proportion of Graves' disease patients (TBIAb in 68.8% and TSAb in 77.8%), in a small number of patients with idiopathic myxoedema or Hashimoto's thyroiditis, and were not detected in patients with endemic euthyroid goitre, differentiated thyroid carcinoma and toxic adenoma. Furthermore, TSH-receptor antibodies were present in some patients with toxic multinodular goitre (TBIAb in 12.7% and TSAb in 15.9%). When TSH-receptor and other thyroid autoantibodies were compared, it was found that 13 of the 15 Graves' patients with negative tests for thyroglobulin and thyroid microsomal antibodies were positive for TSH-receptor antibodies. On the other hand, 9 of the 11 patients with toxic multinodular goitre who had positive TSH-receptor antibody tests, also had serum thyroglobulin and/or thyroid microsomal antibodies. No significant differences in the prevalence of TSH-receptor antibodies were found in Graves' patients irrespective of the presence of ophthalmopathy or pretibial myxoedema. Elevated TBIAb activity at the end of anti-thyroid drug treatment was found in 52.9% of Graves' patients who subsequently relapsed, while in Graves' patients in remission TBIAb was always negative. TSH-receptor antibody results were not predictive of the outcome of radioiodine treatment in Graves' disease. Finally no correlation could be found between TBIAb and TSAb in Graves' disease and Hashimoto's thyroiditis. In conclusion: the high incidence of TSH-receptor antibodies in Graves' disease confirms their pathogenetic role in the development of hyperthyroidism; TSH-receptor antibodies in Graves' disease are not significantly associated with the presence of ophthalmopathy or pretibial myxoedema; TSH-receptor antibody assays may be useful for the diagnosis of Graves' disease in the absence of other signs of autoimmunity. TBIAb seems to be a good predictor of relapse in Graves' patients treated with anti-thyroid drugs; a fraction of toxic multinodular goitre could be a nodular variant of Graves' disease.     

Clinical value of a bispecific antibody binding to thyroglobulin and thyroperoxidase (TGPO-aAb) in various thyroid diseases.

TGPO-aAb is a bispecific antibody which binds to thyroglobulin as well as thyroid peroxidase. It is supposed to be raised in some patients with autoimmune thyroid disease. We investigated 205 patients suffering from Graves' disease (n = 81), Hashimoto's thyroiditis (n = 36), toxic nodular goitre (n = 50), differentiated carcinoma of the thyroid (n = 10), and autoimmune thyropathy of unknown origin (n = 28). An immunoradiometric assay was used to measure serum TGPO-aAb. Eighty-nine of 205 patients had elevated titres of TGPO-aAb. If TGPO-aAb were raised then autoantibodies against thyroglobulin and thyroid peroxidase were always raised, too. This was, however, not true vice versa. We found TGPO-aAb in 61% of patients with Hashimoto's, 49% of patients with Graves', 64% of patients with autoimmune thyropathy, but only in 12% of patients with toxic nodular goitre. In patients with thyroid carcinoma TGPO-aAb was found only if there was evidence of paraneoplastic autoimmune thyroiditis. We re-examined 16 of 36 patients with Hashimoto's thyroiditis after 1 year: 8 patients had retained their raised TGPO-aAb, 4 patients showed no TGPO-aAb on both occasions, and 4 patients had 'lost' their previously raised TGPO-aAb on follow-up. We conclude that TGPO-aAb may provide additional information in Hashimoto's thyroiditis. Determination of TGPO-aAb does not allow to distinguish between various forms of autoimmune thyroid disease. Nevertheless, the presence of TGPO-aAb and its variation during the natural course of autoimmune thyroid disease remains to be understood which would give a better insight into its clinical significance.     

Circulating antibodies to DNA-related antigens in patients with autoimmune thyroid disorders.

A high prevalence of antibodies to double-stranded DNA (AbDNAds) has been recently reported in serum of patients with autoimmune thyroid disorders, but the specificity of this finding has been questioned. For this reason, the prevalence of several antibodies to DNA-related nuclear antigens (AbDRENA) has been evaluated in sera of patients with autoimmune and non-autoimmune thyroid disease. The study group included: 46 Graves' disease patients, 28 Hashimoto's thyroiditis patients, 25 patients with toxic nodular goitre and 11 with non-toxic nodular goitre. Twenty-eight Graves' patients were retested during methimazole (MMI) therapy, and 5 after radioiodine administration. Twenty-two patients with systemic lupus erythematosus and 28 normal subjects served as positive and negative controls, respectively. AbDRENA included: AbDNAds by RIA or immunofluorescence (IF); antibodies to single-stranded DNA (AbDNAss) and antibodies to histone (AbHist) by ELISA methods; antibodies to nuclear antigens (ANA) by immunofluorescence. RIA values were considered to be abnormal when 2 SD above the mean of normal controls. In our study 13% of Graves' patients were positive for AbDNAds by RIA: all of them had negative tests by IF; 11% were positive for AbDNAss, 2% for AbHist and 7% for ANA. A comparable prevalence of positive results for AbDNAds by RIA, with negative IF tests, was found in Hashimoto's thyroiditis patients. No significant changes of antibody levels were observed in Graves' patients during MMI treatment or after radioiodine administration. A positivity for AbDNAds or AbDNAss was found in 8% of patients with toxic nodular goitre, but in none of those with non-toxic goitre.(ABSTRACT TRUNCATED AT 250 WORDS)     

Detection of bovine serum albumin in the circulating IgA immune complexes of patients with IgA nephropathy

Alimentary antigenic challenge has been postulated to have a role in the genesis of IgA circulating immune complexes (CIC), resulting in mesangial IgA disease. In this study, we examined the relationship between bovine serum albumin (BSA) and IgA CIC in patients with IgA nephropathy. Of the 47 patients studied, elevated IgA CIC levels were found in 32% by the F(ab')2 anti-C3 and Raji cell enzyme immunoassays (EIA). Elevated IgA anti-BSA antibody levels were found in 9 patients, and there was a positive correlation between these levels and IgA CIC as measured in the Raji cell EIA (R = 0.60, P less than 0.001). In 4 patients with elevation of both IgA CIC and IgA anti-BSA antibody levels, solubilization experiments were done to demonstrate the presence of BSA antigen in the IgA CIC. Using the Raji cell EIA, the IgA CIC levels decreased significantly after preincubating the sera with serial concentrations of excess BSA. No corresponding effect was seen with human serum albumin used as control. Hence, BSA may be the antigenic stimulus in the formation of IgA CIC in selected patients with IgA nephropathy. The pathogenic capacity of these IgA-BSA CIC remains to be determined.     

Circulating immune complexes in old people and in diabetics: correlation with autoantibodies.

Circulating immune complexes (CIC) were detected by a solid-phase radioassay in 34% of fifty-three insulin-dependent diabetics (IDD) as compared to 18% of forty-five non-insulin-dependent diabetics (NIDD) and 14% of 173 control subjects. In control subjects, the prevalence of CIC increased with age and was higher in males than in females. In IDD, immune complexes were found with the highest frequency before the age of 30 and after 50. There was no significant difference between the incidence of CIC in old IDD and their age-matched controls. The same sera were also tested for the presence of the following autoantibodies; nuclear , thyroid, gastric, smooth and striated muscle; mitochondria, sub-maxillary and adrenal gland and liver-kidney microsome. Sera containing at least one antibody were found in 16.4% of controls, 55.3% of IDD and 40% of NIDD. The prevalence of autoantibodies increased with age in controls but not in IDD. Islet cell antibodies were present in 28.5% of IDD and 2.9% of control subjects; they were more frequent in young patients. CIC and autoantibodies were statistically associated both in controls and IDD; in the patients, CIC were associated not only with islet cell antibodies but also with other autoantibodies. The possible relation between autoimmunity, degenerative vascular diseases and CIC is discussed.     

T, B and K cells in autoimmune thyroid disease.

The K-cell cytotoxic activity of peripheral blood lymphoid cells from 104 patients with autoimmune thyroid disease and from age and sex matched control subjects was measured using chicken erythrocytes as target cells. Patients with Hashimoto thyroiditis,primary hypothyroidism and thyrotoxicosis who were either newly diagnosed and untreated or had received therapy for less than or equal to 1 year showed a significant increase in K-cell cytotoxic activity. Patients who had received treatment for greater than 1 year and less than or equal to 5 years showed no such comparable increase in cytotoxic activity. Within the group of patients with untreated thyrotoxicosis it was found that K-cell cytotoxic activity was related to both goitre size and serum antibody titre. Thus patients with little or no goitre showed a highly significant elevation of cytotoxic activity whereas patients with moderate to large goitres gave values within the normal range. Similarly patients with no detectable serum thyroid autoantibodies showed high K-cell activity while patients with positive antibody titres did not. It was also shown that neither the absolute number nor the proportion of circulating T and B lymphocytes in patients with autoimmune thyroid disease as assessed by the sheep red cell rosette method and by indirect immunofluorescence was significantly different from that observed in the normal control population. No correlation was found between peripheral blood K-cell cytotoxic activity and the percentage of circulating null cells, i.e. 100-(percentage T + percentage B) in either patients or control subjects.     

Cell-Mediated Immunity to Yersinia enterocolitica Serotype 3 in Patients with Thyroid Diseases

The cellular immunity to Yersinia enterocolitica serotype 3 and crude human thyroid extract in 64 patients with thyroid diseases and 25 controls was studied by the leucocyte migration test. In the patient group as a whole and in patients with Graves' disease and nontoxic diffuse goitre a significantly reduced leucocyte migration towards Yersinia was found when compared with the controls. In controls the migration index was not related to the presence or titre of circulating yersinia antibodies, whereas the migration index of patients with yersinia antibodies was lower than the migration index of patients without yersinia antibodies as well as that of the controls. The leucocyte migration inhibition in two patients with recent yersiniosis was normal during the recovery phase.
In the presence of thyroid extract leucocyte migration inhibition differed only significantly in Graves' disease. However, a significantly positive correlation between inhibition of migration by thyroid extract and by Yersinia was found, while no correlation could be demonstrated in the controls.
The cell-mediated immunity towards Yersinia in thyroid diseases thus demonstrated adds further evidence to the association between Yersinia and thyroid disease.     

Serum autoantibodies and thyroid lymphocytic infiltration in endemic goitre.

Patients with thyroid diseases from areas of endemic goitre in Northern Italy were examined for thyroid antibodies by passive haemoagglutination. Of 40 schoolboys with goitre only one had thyroid antibodies (AT) in the blood. Among 182 adults with grade 1-2 goitre, examined within an area of low endemia, the frequency of AT was 7%, not significantly different from that found in the 286 persons with thyroid 'O' living in the same area. Among 181 adults with grade 2-3 goitre, examined within an area of serious endemia, the frequency of AT was 16%; the percentage went up to 24% in 144 patients operated on for goitre. AT frequency was 36% in 87 patients with toxic goitre, more than 70% in 97 patients with Graves' disease and 17% in 60 patients with cancer of the thyroid. AT occurred three times more frequently in women than in men. Microsomal antibodies were more frequently detected than anti-thyroglobulin antibodies: the opposite was true in thyroid cancer. Lymphocytic infiltration (IL) of the gland was observed in 45% of the 464 simple goitres and in 52% of the 60 cancers of the thyroid: it was more frequent and intense in women. Among the 144 patients operated on for goitre the frequency and the titre of AT progressed in parallel with the intensity of the lymphocytic infiltration. Patients with a greater lymphocytic infiltration and higher AT had a higher TSH. Multinodular non-toxic goitre and autoimmune lymphocytic thyroiditis can be present in the same thyroid gland and the clinical expression will depend on which condition predominates.     

Thyroid size and goitre frequency in hyperthyroidism

Thyroid function, the clinical occurrence of goitre and thyroid gland volume, ultrasonically determined, were investigated in 310 consecutive untreated patients with hyperthyroidism. Of 173 patients with Graves' disease (39%), 67 had no goitre, while 53 patients (31%) had a normal thyroid volume. Twenty-three of 91 patients with multinodular glands (25%) had no goitre and ten patients (11%) had a normal thyroid volume. Of 46 patients with solitary autonomous nodules (7%), three had no goitre while six (13%) had a normal thyroid volume. Out of all the hyperthyroid patients (30%), 93 had no clinically detectable goitre, and 69 (22%) had a normal thyroid volume. The lack of a goitre in a large portion of patients with hyperthyroidism could be responsible for delayed diagnosis and subsequent treatment of these patients.     

IgG subclass distribution of thyroglobulin antibodies in patients with thyroid disease

The IgG subclass distribution of thyroglobulin antibodies (TgAb) has been studied in Hashimoto and Graves’ patients by several investigators with conflicting results, in part explainable by methodological problems. We have recently developed a quantitative ELISA to measure in absolute terms the serum concentration of TgAb subclasses. The aim of the present study was to apply this method in a large series of patients with autoimmune as well as, for the first time, non-autoimmune thyroid diseases. We examined 28 patients with Hashimoto's thyroiditis, 30 with Graves’ disease, 21 with thyroid carcinoma and 18 with non-toxic goitre, all selected for the presence of TgAbs. The results indicated that TgAbs in thyroid diseases were not restricted to any particular isotype, but comprised all four IgG subclasses. IgG1 was represented similarly in the four groups. The same was true for IgG3, even though its contribution to the total antibody content was very small. IgG4 was the dominant subclass in patients with Graves’ disease, thyroid carcinoma and non-toxic goitre, probably reflecting a prolonged antigenic challenge. In Hashimoto's thyroiditis IgG2 was dominant, possibly because T helper lymphocytes infiltrating the thyroid are typically Th1 type.     

Autoantibodies against complement C1q correlate with the thyroid function in patients with autoimmune thyroid disease

Autoantibodies against complement C1q (anti-C1q) have been well described in patients with systemic lupus erythematosus, where they correlate with the occurrence of severe lupus nephritis. However, data on anti-C1q in organ-specific autoimmune diseases are scarce. In order to determine the prevalence of anti-C1q in patients with autoimmune thyroid disorders (AITD) and a possible association with thyroid function, we measured prospectively anti-C1q in 23 patients with Graves' disease (GD) and 52 patients with Hashimoto's thyroiditis (HT). Anti-C1q levels were correlated with parameters of thyroid function and autoantibodies against thyroperoxidase, thyroglobulin and thyroid stimulating hormone (TSH) receptor. Twenty-one patients with multi-nodular goitre and 72 normal blood donors served as controls. We found elevated concentrations of anti-C1q more frequently in patients with AITD than in controls: seven of 23 (30%) patients with GD and 11 of 52 (21%) patients with HT, compared with one of 21 (5%) patients with multi-nodular goitre and six of 72 (8%) normal controls. Anti-C1q levels did not correlate with thyroid autoantibodies. However, in GD absolute levels of anti-C1q correlated negatively with TSH and positively with free thyroxine (FT4) and triiodothyronine (FT3). In contrast, in HT, anti-C1q correlated positively with TSH levels. No correlation between TSH and thyroid autoantibodies was found. In conclusion, we found an increased prevalence of anti-C1q in patients with AITD and their levels correlated with the thyroid function in both GD and HT. This correlation seems to be independent of thyroid autoantibodies. Therefore, anti-C1q might point to a pathogenic mechanism involved in the development of AITD that is independent of classical thyroid autoantibodies.     

The effect of hydrocortisone on the incorporation of tritiated thymidine by human blood lymphocytes cultured with phytohaemagglutinin and pokeweed mitogen

Leucocyte migration inhibition tests (LMT) with rat and human liver mitochondria are reported in forty-nine thyroid patients and forty-seven healthy controls. Whereas normal subjects and colloid goitre cases were inactive in this test, patients with autoimmune thyroiditis and thyrotoxicosis gave positive mitochondrial reactions which paralleled the organ-specific thyroid microsomal LMT obtained in the same patients and were not species dependent. The active antigen may be in the inner membranes of the particles.

As with thyroid microsomes, intense inhibition with mitochondria was seen in the hypercellular variant of Hashimoto goitre characterized serologically by low or absent thyroglobulin antibodies, and the lowest LMT values occurred in the rare cases showing poor response to thyroxine therapy. An inverse correlation was found between mitochondrial LMT and thyroglobulin antibody titres. Surprisingly, weak LMT was also found in four thyroid patients who happened to have mitochondrial antibodies in the serum in addition to the usual thyroidspecific reactivities. The mitochondrial LMT appears to be of widespread occurrence in autoimmune diseases and also develops following tissue injury. Its possible significance in relation to cellular immunity, cell destruction and the inflammatory response is discussed.

     

Relationship between circulating immune complexes and angiotensin-converting enzyme in pulmonary sarcoidosis

The relationship between circulating immune complexes (CIC), serum angiotensin-converting enzyme (SACE) and clinical features was investigated in 119 patients with sarcoidosis. CIC, measured by the C1q-binding test and a polyethylene glycol precipitation test, were detected in 42% of the patients. A significantly higher level of CIC was found in patients with duration of the disease of more than 2 years and in patients in stage II or III on chest X-ray. SACE was increased in 45% of the patients, most frequently in those with active disease and in those in stage II or III on chest X-ray. No positive correlation was found between CIC and elevated levels of SACE.     

Detection of IgA class circulating immune complexes bound to anti-C3d antibody in patients with IgA nephropathy

IgA class circulating immune complexes (CIC) were detected by solid-phase fluorescent enzyme immunoassay of F(ab')2 anti-C3d antibody in the serum of 52 patients with IgA nephropathy. Conglutinin (Kg) binding IgA class CIC were also measured, and results by these assays were compared. Kg binding IgA class CIC and anti-C3d binding IgA class CIC were detected in 27% and 44%, respectively, of the patients with IgA nephropathy. Either or both of the two were found in 65% of the patients. There was no significant correlation between IgA class CIC detected by these methods and serum IgA. Although all samples with a very high level of anti-C3d binding IgA class CIC did not also have a very high level of Kg binding IgA class CIC, there was a slight quantitative correlation between the 2 assays. Ultracentrifugation analysis showed that anti-C3d binding IgA class CIC were of various sizes between polymeric (21 S) and monomeric IgA (7 S), whereas Kg binding IgA class CIC were mostly monomeric IgA (8 S) with a minor component of heavy fractions (14 S). Both IgA class CIC fixed iC3b and IgA class CIC fixed C3d are present in IgA nephropathy. These observations suggest that the different types of complement bound to IgA class CIC have different roles in IgA nephropathy.     

Thyroid size determined by ultrasound. Influence of physiological factors and non-thyroidal disease

Grading of goitre size according to WHO or the palpatory estimation of thyroid volume does not allow a quantitative estimation of thyroid size or an objective follow-up during treatment with e.g. radioiodine. The present and other studies have demonstrated that the ultrasonic evaluation of thyroid volume is both accurate and precise. In addition, it is non-invasive, rapid, inexpensive and without discomfort to the patient. Using this technique it was demonstrated that thyroid volume increases with increasing age and body weight in both sexes, with weight having the most pronounced influence. The relationship between thyroid volume, body weight and age in non-goitrous healthy subjects can be described using a formula that allows the calculation of normal thyroid size for a population: Thyroid volume (ml) = 1.97 + 0.21 x bodyweight (kg) + 0.06 x age (years). Cigarette smoking is associated with an approximately 10-fold increase in goitre frequency probably due to a combination of an increased sympathetic stimulation of the thyroid and an iodine deficiency state caused by inhalation of thiocyanate. Although no seasonal alteration in serum TSH level could be demonstrated thyroid volume is 23% higher in the winter than in the summer. Cyclic alterations of thyroid volume possibly related to TSH alterations have been found with a 50% difference between minimum values in the first half and maximum values in the second half of the menstrual cycle. Nonthyroidal illnesses are associated with marked alterations in thyroid volume. Thus, chronic renal disease and acute hepatic disease demonstrate significant increases in thyroid volume although the precise mechanisms have not been clarified. Chronic hepatic disease per se and chronic nonrenal nonhepatic disease does not seem to influence thyroid volume. Chronic alcoholism, however, with or without liver cirrhosis is associated with a marked decrease in thyroid volume and an increase in the amount of fibrosis probably related to a direct toxic effect of alcohol on the thyroid. All these factors should be kept in mind when goitre frequency, goitrogenic action of drugs and goitre treatment effects are evaluated.     

Prevalence of chronic lymphocytic thyroiditis in adolescent girls

Chronic lymphocytic thyroiditis (CLT) is the most common cause of thyroid enlargement in children and adolescents in iodine sufficient areas. The prevalence and pattern of CLT in adolescent girls in iodine deficient regions supplemented with iodine is as yet not known. We therefore, carried out clinical examination for the presence of goitre in 330 healthy girls from Delhi in the age group of 16-20 years and those with goitre were further subjected to detailed biochemical (T3, T4, TSH), immunological (ATg ad ATm) and cytomorphological examination. The prevalence of goitre was found to be 40%. Fine needle aspiration cytology (FNAC) carried out in 94 girls with goitre (74%) revealed finding consistent with CLT in 13 (13.8%), colloid goitre with non-specific thyroiditis in 7 (7.4%), colloid goitre in 71 (75.5%) and specimen was inadequate in 3 (3.2%) girls. Thyroid antibodies were estimated in 114 of the goitrous subjects and both ATg and ATm were positive in 11 (9.6%) cases. Overall prevalence of CLT in this population was 4.0% and among those with goitre was 13.8%. When thyroid antibodies were also considered as an indicator of thyroiditis, prevalence rose to 14.4% among goitrous girls. Thyroid function tests were found to be within normal limits in all goitrous girls. This study for the first time reveals a high prevalence of CLT in goitrous adolescent girls from iodine supplemented region and underscores the need to study the prevalence of CLT in different age and sex groups from different regions of the country.     

Circulating immune complexes in primary biliary cirrhosis: interactions with lymphoid cells

To evaluate the interactions between circulating immune complexes (CIC) and lymphoid cells in primary biliary cirrhosis (PBC), we determined (1) whether antibodies to lymphocytes in PBC serum, independent of CIC, could account for binding in the Raji cell assay for CIC and (2) whether CIC or other humoral factors in PBC serum could interact with lymphoid cells to alter their function. We found that three quarters of CIC positive PBC sera bound specifically to Raji cells via complement receptors, while only one quarter had antibodies to lymphoid cells or Raji cells devoid of complement receptors. We also demonstrated factors which inhibited cell-mediated cytotoxicity and suppressor cell activity in PBC sera; however, we found no correlation between the level and presence of CIC or of lymphocyte antibodies and the level or presence of these serum inhibitory factors. Thus, although the detection of CIC in PBC is not artifactual, the contribution of CIC and other serum factors to the other immunological aberrations in PBC remains to be elucidated.     

Association of anti-heart antibodies and circulating immune complexes in the post-pericardiotomy syndrome

The post-pericardiotomy syndrome (PPS) is a common complication of cardiac surgery. In order to better understand the pathogenesis of this complication we undertook a prospective, triple blind study of consecutive long term survivors of cardiac surgery. We followed 82 patients and determined anti-heart antibodies (AHA), circulating immune complexes (CIC) and anti-viral antibodies (AVA) on sera pre-operatively and serially post-operatively. According to the clinical features of pericarditis, fever and leucocytosis, patients were divided into three groups: (1) complete PPS with all three symptoms, (2) incomplete PPS with two symptoms and (3) no PPS with one or no symptoms. Clinical PPS was found in 16 patients (19.6%). All of these patients had positive AHA, 12 patients (75%) had increased CIC and five patients (31%) had a four-fold or greater rise in titre to viruses studied. Twenty-four patients (29.2%) had an incomplete PPS. It was accompanied by positive AHA in 17 patients (70.8%), increased CIC in 14 patients (58.3%) and a four-fold rise or greater in virus titre in seven patients (29.2%). No PPS was found in forty-two patients (51.2%). It was accompanied by positive AHA in eight patients (19%), increased CIC in 10 patients (24%) and a four-fold or greater rise in virus titre in 12 patients (28.6%). There was a good correlation between the presence of PPS, AHA, CIC and the type of operation. Heart valve replacement surgery was more frequently complicated by PPS. Development of post-operative AHA and increased CIC were also more frequently found. We found a good correlation between PPS, positive AHA and increased CIC. No correlation was found between PPS and virus serology.     

Humoral Autoimmune Manifestation in Subacute Thyroiditis

To study the autoimmune manifestations in subacute thyroiditis (SAT), the patterns of thyroid antibodies, thyroglobulin and circulating immune complexes were investigated in 10 patients during the course of the disease. Eight patients were thyrotoxic at diagnosis, and became euthyroid during recovery with a median observation of 8 months (4-30 months). Thyroid stimulating immunoglobulins were measured as TSH binding inhibiting immunoglobulins (TBII) and as thyroid stimulating antibodies (TSAb). TBII were present in all patients at least once during the observation period and remained detectable in six patients after recovery. TSAb were detected in three patients without relation to the hyperthyroid state. Thyroglobulin antibodies (TgAb) were present in four patients and persisted in three, while microsomal antibodies (MAb) were negative. Thyroglobulin (Tg) in the TgAb negative patients (n = 6) was high at diagnosis (median 229 micrograms/l, range 55-375) and fell rapidly during the course of SAT. Circulating immune complexes (CIC), which were found in all patients, reached maximal levels shortly after the onset of the disease and persisted after recovery. No correlation could be demonstrated between the different thyroid antibodies, and there was no clear relation between the levels of CIC and presence of the autoantibodies. However, the changes in CIC paralleled the changes in TBII, and it is suggested that immune complex formation is a major feature of the regulatory mechanisms controlling the immune responses in SAT.     

Antibodies targeting the calcium binding skeletal muscle protein calsequestrin are specific markers of ophthalmopathy and sensitive indicators of ocular myopathy in patients with Graves' disease

We have identified several eye muscle antigens and studied the significance of the corresponding serum autoantibodies in patients with Graves' disease. Of these antigens, only calsequestrin is expressed more in eye muscle than other skeletal muscles, which could explain at least partly the specific involvement of eye muscle in patients with Graves' disease. Earlier, we found a modest relationship between anti-calsequestrin antibodies and ophthalmopathy, but in that study we used calsequestrin prepared from rabbit heart muscle and measured antibodies by immunoblotting. We have reinvestigated the prevalences of anti-calsequestrin antibodies in larger groups of well-characterized patients with thyroid autoimmunity with and without ophthalmopathy and control patients and healthy subjects, using standard enzyme-linked immunosorbent assay incorporating highly purified rabbit skeletal muscle calsequestrin, which has a 97% homology with human calsequestrin, as antigen. Anti-calsequestrin antibodies were detected in 78% of patients with active congestive ophthalmopathy, in 92% of those with active inflammation and eye muscle involvement, but in only 22% of patients with chronic, 'burnt out' disease. Tests were also positive in 5% of patients with Graves' hyperthyroidism without evident ophthalmopathy (two patients) and one patient with 'watery eyes' but no other clear signs of congestive ophthalmopathy and IgA nephropathy and no known thyroid disease, but in no patient with Hashimoto's thyroiditis, toxic nodular goitre, non-toxic multi-nodular goitre or diabetes, or age- and sex-matched healthy subjects. In serial studies of all 11 patients with Graves' hyperthyroidism who had active ophthalmopathy at the time of the first clinic visit, or developed eye signs during the first 6 months, and positive anti-calsequestrin antibodies in at least one sample, anti-calsequestrin antibodies correlated with the onset of ocular myopathy in six patients. Antibodies targeting calsequestrin appear to be specific markers for ophthalmopathy and sensitive indicators of the ocular myopathy subtype of ophthalmopathy in patients with thyroid autoimmunity. However, these results must be considered preliminary until a large prospective study of patients with newly diagnosed Graves' hyperthyroidism, in which serum levels of calsequestrin antibodies are correlated with clinical changes and orbital eye muscle and connective tissue/fat volumes, has been carried out.