Epitope binding of human thyroglobulin autoantibodies of different IgG subclasses.

Autoantibodies against thyroglobulin in patients with Hashimoto's thyroiditis are believed to recognize only three main epitopes. The possibility that antibodies of different IgG subclass recognize these separate epitopes has been suggested by preliminary studies with monoclonal antibodies against thyroglobulin. To assess whether this is a more general phenomenon, sera from 9 Hashimoto patients were fractionated into subclasses IgG1, IgG2 and IgG4 by negative selection on affinity columns. Binding of each subclass to thyroglobulin both in a competition ELISA and an assay of radiolabelled thyroglobulin immunoprecipitation was significantly inhibited by the other subclasses. These results indicate that there is no restriction of thyroglobulin epitope recognition by different IgG subclasses in unselected patients with autoimmune thyroiditis.     

Demonstration of circulating autoantibodies against the plasma membrane of isolated thyroid cells in Graves' disease

Antibodies against the plasma membrane of isolated human and porcine thyroid cells were demonstrable by a linear fluorescence pattern in sera from 29 out of 37 patients with Graves' disease. In 3 cases the antibodies reacted only with human thyroid cells. In a group of patients with Hashimoto's thyroiditis, 6 of 8 sera reacted with human thyroid cells in a granular fluorescence pattern. With one exception, sera from patients with non-toxic goiter showed no binding of IgG to thyroid cells. Sera from healthy controls were negative in this test system. There was no correlation between the presence of antibodies against thyroid cells and antibodies against thyroglobulin. Antibodies against thyroid microsomal antigens were found in 80% of patients with circulating thyroid cell membrane antibodies; 5 sera with membrane antibodies were negative for microsomal antibodies. Twenty sera of patients with Graves' disease were tested by passive haemagglutination test against peak I and peak II of the human thyroid fractionation with Sephadex G100. Antibodies against peak I were found in 14 sera and against peak II in all 20 sera. The data indicate that the antibodies in sera from patients with Graves' disease are directed mainly against a species-unspecific antigen of the plasma membrane from thyroid cells with a probable molecular weight between 4-7 S and are unrelated to thyroglobulin.     

Concordance of eight kits for antithyroid peroxidase autoantibodies determination.

Numerous methods are proposed to quantify antithyroid peroxidase autoantibodies. No standardization exists but most assays use the standard MRC 66/387 with a calibration factor. Costs of the tests vary between the different kits. We evaluated the concordance of eight peroxidase autoantibodies assay kits in two centres, using a panel of sera from 269 subjects: controls (n=100), patients with autoimmune thyroid disease (n=77; Graves' disease, Hashimoto's thyroiditis), patients with non-autoimmune thyroid disease (n=69; nodular goiter, differentiated thyroid carcinoma) and individual sera with thyroglobulin antibodies only (n=23). The concordance between the eight methods was high, ranging from 88.3% to 98.8% with the total panel of sera. The majority of assays demonstrated high diagnostic performance. We encountered some false-positive results at borderline positive levels, and the nonrecognition of some sera by competitive assays.     

Patterns of cellular immune responses to thyrocyte membrane antigens and specific immunoregulatory defects in autoimmune thyroid disease

Although Graves' disease (GD), Hashimoto's thyroiditis (HT) and idiopathic myxoedema (Myx) are clinically distinct autoimmune thyroid diseases, previous studies using crude thyroid preparations as a source of antigens have failed to identify differences in cellular immune responses. In this study, we have assessed cellular immunity in patients with these disorders to two antigen preparations (derived from thyroid gland and cervical fat) enriched in cell membranes and known to share a functional TSH receptor. Using an indirect T-lymphocyte migration inhibitory factor (T-LIF) assay, T-cell immunity to thyroid membranes was demonstrated in 11/11 patients with GD, 4/5 with HT and 4/5 with Myx, but in none of 18 patients with chronic active hepatitis (another organ-specific autoimmune disease) or sixteen healthy controls. In contrast, T lymphocytes responsive to adipocyte membranes were detected only in patients with GD. TSH binding inhibiting antibodies were found exclusively in six patients with GD, and thyroid stimulating antibodies in five of these patients. In co-culture experiments designed to study the activity of antigen-specific suppressor T cells, low numbers of T cells from 6/6 normal controls, 4/4 patients with HT and 5/5 patients with myxoedema suppressed the response to adipocyte membranes of T lymphocytes from patients with Graves' disease. The results of this study demonstrate different patterns of T-cell reactivity to thyroid antigens in patients with Graves' disease, Hashimoto's thyroiditis and myxoedema and suggest that cellular immunity to the TSH receptor is restricted to patients with Graves' disease and associated with a defect in the specific immunoregulatory control of this response.     

Dermatitis herpetiformis is associated with atrophic but not with goitrous variant of Hashimoto's thyroiditis

BACKGROUND: Dermatitis herpetiformis (DH) is a gluten-sensitive skin disease that is associated with a variety of autoimmune disorders. Several investigations demonstrated an association between DH and autoimmune thyroid disease. However, it has not been shown if DH is associated with atrophic or goitrous variant of Hashimoto's thyroiditis. MATERIALS AND METHODS: We investigated a cohort of 41 DH patients (18 male, 23 female) and a control group (11 male, 19 female; sex and age matched healthy volunteers) to find out which variant of Hashimoto's thyroiditis is associated with DH. All patients had thyroid hormones and antibodies measured. In addition to that, thyroid sonography as well as detailed history-taking of previous thyroid disease were performed. RESULTS: In the control group no individual with elevated levels of thyroid antibodies nor abnormal thyroid hormones nor thyroid atrophy was found. Median thyroid volume in the control group was 11 mL (range 4.8-24.7 mL). However, in nine DH patients (22%) elevated levels of antithyroid microsomal (TM) antibodies were seen (P < 0.01). Three of them had abnormal thyroid hormones (7%). In the group of DH patients a significantly smaller thyroid volume was found (median 8 mL, range 1. 6-25.2 mL; P < 0001). Thyroid atrophy (volume < 4.4 mL) was found in 10 DH patients (24%) of whom 9 were females. All patients with elevated levels of TM antibodies or abnormal thyroid hormones and all patients with a history of previous hypothyroidism had a thyroid volume < 7 mL. Goitrous variant of Hashimoto's thyroiditis was not seen in any of the DH patients. CONCLUSIONS: Our findings demonstrate that DH is associated with atrophic but not with goitrous variant of Hashimoto's thyroiditis.     

The measurement of complement fixation by autoantibodies directed against thyroid membrane antigens.

This paper describes the use of sensitized sheep red blood cells for the detection and titration of complement fixation by autoantibodies directed against human thyroid membranes in the serum of patients with autoimmune thyroid disease. Patients with elevated circulating levels of TPO antibodies and diagnosed as having autoimmune hypothyroidism (including Hashimoto's disease) or autoimmune hyperthyroidism (Graves' disease) were studied. Complement fixation titres were highest in those patients with autoimmune hypothyroidism compared with the autoimmune hyperthyroid group. Serum samples obtained from a group of patients with thyroid neoplasia and from normal healthy volunteers were negative in this test. The TPO antibody activity when "corrected" for its CF potency suggests that the autoantibodies found in autoimmune hypothyroidism are potentially more destructive than those found in the non-destructive autoimmune thyroid diseases.     

Thyroiditis: differential diagnosis and management

Thyroiditis is a group of inflammatory thyroid disorders. Patients with chronic lymphocytic thyroiditis (also referred to as Hashimoto's thyroiditis) present with hypothyroidism, goiter, or both. Measurement of serum thyroid autoantibodies and thyroglobulin confirms the diagnosis. Subacute granulomatous thyroiditis (sometimes referred to as de Quervain's disease) is a self-limited but painful disorder of the thyroid. Physical examination, elevated erythrocyte sedimentation rate, elevated thyroglobulin level and depressed radioactive iodine uptake (RAIU) confirm the diagnosis. Subacute lymphocytic thyroiditis (silent thyroiditis) is considered autoimmune in origin and commonly occurs in the postpartum period. Symptoms of hyperthyroidism and depressed RAIU predominate. Acute (suppurative) thyroiditis is a rare, infectious thyroid disorder caused by bacteria and other microbes. The rare, invasive fibrous thyroiditis (Riedel's thyroiditis) presents with a slowly enlarging anterior neck mass that is sometimes confused with a malignancy.     

Characterization and antigenic specificity of chlorpromazine-induced antinuclear antibodies

Prolonged treatment with chlorpromazine is often associated with the development of antinuclear antibodies, an immunoglobulin M lupus anticoagulant, and polyclonal serum IgM elevation, but not with clinical features of systemic lupus erythematosus (SLE). Sera from 62 long-term psychiatric patients given treatment daily with 100 mg or more of chlorpromazine for at least 1 year were screened for antinuclear antibodies by indirect immunoperoxidase assay using HEp-2 cells. In 26 samples, antinuclear antibody titers greater than or equal to 1:40 with a homogeneous pattern were seen when anti-human IgM was used as the second antibody, three sera samples reacted with IgG, and four samples reacted with both IgG and IgM antisera. The antinuclear antibody antigenic reactivity was investigated by using histone and nonhistone nuclear antigens by enzyme-linked immunosorbent assay and passive hemagglutination techniques. Forty serum samples reacted with histone. Twenty-five samples reacted with deoxyribonucleoprotein (DNP), 28 with single-stranded DNA, and two with double-stranded DNA. No reaction was obtained with the extractable nuclear antigens RNP or Sm. These results indicate that chlorpromazine-induced antinuclear antibodies, like the antinuclear antibodies induced by hydralazine and procainamide, react mainly with histone nuclear antigens. Unlike the hydralazine and procainamide response, in which both IgG and IgM antibodies are demonstrated, the chlorpromazine-induced autoantibodies are predominantly of the IgM class.     

Natural autoantibodies against Tamm-Horsfall glycoprotein in normal individuals in relation to age and in adult patients with kidney diseases

IgM and IgG natural antibodies to Tamm-Horsfall glycoprotein (THP) were found in serum samples of all healthy individuals tested by the ELISA technique. The IgM anti-THP antibody level was higher in the group 1-20 years old than the IgG anti-THP. The IgG anti-THP rose with increase in age (greater than 21 years old groups) and then the IgG and IgM anti-THP activity over aging remained constant. The natural anti-THP antibodies possess a lower degree of specificity and/or avidity than induced antibodies. The antibody titers against THP determined in 61 adult patients with chronic kidney diseases was significantly lower than that in adult controls. This low level of naturally occurring THP antibodies appears to be a general phenomenon. In these patients, diminished antibody levels appeared against a panel of self (collagen, fibronectin, THP) and non self (bovine gamma globulin (BGG), ovalbumin (OVA)) antigens as compared with normal controls. The low levels of these antibodies are not associated with a concomitant drop of IgG and IgM in their sera.     

Anti-thyroglobulin antibodies]

Measurement of anti-thyroglobulin antibody(TgAb) is used for diagnosis of autoimmune thyroid disease(AITD). Approximately 82-100% of patients with Hashimoto's thyroiditis and 60-70% of patients with Graves' disease are TgAb positive using high sensitive radioimmunoassay. In patients with subacute thyroiditis(SAT), TgAb is usually negative. Therefore, measurement of TgAb is useful to diagnose painless thyroiditis or acute worsening of Hashimoto's thyroiditis from SAT. To predict the post-partum thyroid dysfunction and thyroid dysfunction after interferon treatment, TgAb measurement is important, since patients with positive TgAb are apt to progress thyroid dysfunction.     

A micro reverse haemolytic plaque technique for the detection of antithyroglobulin antibody producing-lymphocytes in Hashimoto's thyroiditis

Employing a micro reverse haemolytic plaque (RHP) technique, antithyroglobulin antibody producing B-lymphocytes have been detected in thyroglobulin challenged peripheral blood lymphocyte cultures from patients with Hashimoto's thyroiditis. The method employs a monolayer of sheep red blood cells instead of a semi-solid matrix as a medium for the development of plaques. This technique which requires very small amounts of immunoreagents, is therefore much less expensive than the macro methods. In our studies of patients with Hashimoto's thyroiditis, peripheral lymphocytes of patients produced a significantly greater number of plaques than lymphocytes from normal subjects on challenging with thyroglobulin. There was a good correlation between the thyroid antibodies detected by the haemagglutination tests in the sera of the patients and the production of plaques by their lymphocytes. The RHP assay also appeared to be more sensitive than the haemagglutination test. The technique should lend itself for the study of the effect of various lymphokines on cultured lymphocytes.     

Cerebellar subacute syndrome due to corticosteroid-responsive encephalopathy associated with autoimmune thyroiditis (also called "Hashimoto's encephalopathy")

The corticosteroid-responsive encephalopathy associated with autoimmune thyroiditis (the so-called "Hashimoto's Encephalopathy") is a rare disorder with multiple symptomatology, breaking out with an acute or subacute onset and having a relapsing course, not correlated to thyroid hormone levels, with autoimmune pathogenesis, and usually associated with Hashimoto's thyroiditis. In this paper, we report on a case study regarding a 46 year-old woman showing a subacute course cerebellar syndrome, associated with Hashimoto's thyroiditis, diagnosed as "Hashimoto's encephalopathy". The possible pathogenesis and the major aspects of the differential diagnostic sector are discussed with particular reference to an ataxic syndrome caused by a progressive non-familial adult onset cerebellar degeneration (PNACD), associated with the thyroid disease itself.     

Demystifying autoimmune thyroid disease. Which disorders require treatment?

The term "autoimmune thyroid disease" encompasses all of the autoimmune thyroid conditions, including Hashimoto's thyroiditis, Graves' disease, most cases of silent thyroiditis, and postpartum thyroiditis. Extrathyroidal manifestations (e.g., ophthalmopathy, dermopathy) can occur in Graves' disease and, less commonly, Hashimoto's thyroiditis. Spontaneous hypothyroidism is common in patients with Hashimoto's thyroiditis, and when it develops, life-long therapy with levothyroxine is needed. In the United States, most adult patients with Graves' disease are initially or eventually treated with radioiodine thyroid ablation. For transient thyroiditis involving hypothyroidism or hyperthyroidism, short-term or symptomatic therapy is adequate.     

Autoimmune thyroid disease: immunological, pathological, and clinical aspects

Autoimmune thyroiditis, most notably Hashimoto's thyroiditis, appears to be increasing in prevalence and is now more easily detected by sensitive laboratory tests and more invasive procedures such as fine needle aspiration. During the last decade, marked progress has been made in the understanding of these diseases. There is a greater awareness of the interaction between the humoral and cell-mediated arms of the immune system in autoimmune thyroiditis. Recent studies implicate a subpopulation of suppressor T lymphocytes which have an antigen-specific defect, resulting in their suboptimal interaction with the helper T lymphocytes and subsequent autoimmune manifestations. There is some evidence that thyroid epithelial cells which inappropriately express HLA-DR may enhance presentation of thyroid antigens to the immune system, possibly significant in the initiation or enhancement of the autoimmune response. The presence of various antithyroid autoantibodies allows the use of laboratory assays to confirm the clinical diagnosis and predict the results of treatment. There appears to be predisposing genetic factors in the development of autoimmune thyroiditis, with some geographical and racial differences. Environmental factors, most notably dietary intake of iodine, have also been implicated in the pathogenesis of Hashimoto's thyroiditis. Several animal models have been developed addressing such issues. Ongoing studies in the areas of postpartum thyroiditis and childhood thyroiditis are helpful in clarifying their relationship with Hashimoto's thyroiditis. Graves' disease and postpartum thyroiditis are being investigated as possible causes of postpartum depression. The association of Hashimoto's thyroiditis and carcinoma of the thyroid gland is still controversial, but its relationship with malignant lymphoma is now well accepted. Thus, although the pathogenesis of autoimmune thyroiditis remains elusive, there has been significant refinement of the clinical diagnosis, and immunological abnormalities of specific intrathyroidal lymphocytes have been identified. Hopefully, these new areas of knowledge will assist in the treatment of these diseases and in the prevention of the development of malignant lymphomas of the thyroid gland.     

Immunological studies on acute rheumatic fever and rheumatic heart disease

A controlled prospective study of autoantibody profile on black Kenyan patients with non-toxic goitre (116), thyrotoxicosis (131) and age, sex matched hospital controls is reported. The prevalence of thyroid microsomal and thyroglobulin antibodies is 3.5% in smooth non-toxic goitre and is 5.2% in the nodular non-toxic goitre compared to 1% of the control. The results reflect that autoimmune thyroiditis is less common in Kenyan hospital controls and smooth simple goitre which is even more pronounced in case of multinodular simple goitre as compared to the Caucasians. The prevalence of microsomal antibody of 54% and the occurrence of high titres in 19% of the toxic group is relatively similar in Caucasians and black Kenyans. However, thyroglobulin antibody and parietal cell antibody are far less frequent in the Kenyan toxic group as compared to Caucasians. In conclusion, the black Kenyan toxic cases are reluctant to produce thyroglobulin and parietal cell antibodies while microsomal antibody production is unaffected. The latter is thought to be more significant in the development and progression of autoimmune thyroiditis. The dissociated behaviour of the two thyroid specific antibodies and thyrogastric axis in black Kenyans strongly suggest that the immunogenetic control of these and the related diseases is different in them as compared to the Caucasians.     

Thyroiditis: a clinical update

Thyroiditis may be categorized as acute (suppurative), subacute (granulomatous or lymphocytic), or chronic (invasive fibrous or lymphocytic). Acute suppurative thyroiditis is typically caused by a bacterial infection and resolves with appropriate antibiotic treatment. The subacute thyroiditides are characterized by spontaneously resolving hyperthyroidism associated with low radioiodine uptake, often followed by transient hypothyroidism. Neck pain is the initial symptom in subacute granulomatous thyroiditis, and the disorder recurs only in a minority of patients. Subacute lymphocytic thyroiditis is typically painless, often occurs in the postpartum period, and is being increasingly recognized in the Great Lakes area of the United States. Invasive fibrous thyroiditis (Riedel's struma) is exceedingly rare, often mimics carcinoma, and is associated with extracervical foci of fibrosclerosis. Chronic lymphocytic (Hashimoto's) thyroiditis, an organ-specific autoimmune disease, occurs in at least 2% of women. Although the disorder often produces hypothyroidism, the type of thyroid dysfunction present in patients with Hashimoto's disease reflects the character of the dominant thyroid autoantibody--that is, destructive, blocking, or stimulatory.     

Persistent thyroid autoimmunity after subacute thyroiditis

Subacute (de Quervain's) thyroiditis (SAT) is accompanied by temporary abnormalities in thyroid function and, in a minority of patients, by transient thyroglobulin and thyroid microsome autoantibody formation. In this report we have examined the sera of patients with SAT for the presence of multiple thyroid autoantibodies using qualitative immunoblotting (Western blotting). For this purpose we used a crude thyroid extract (2,000 g supernatant) as a source of antigen, in order to identify antibodies reacting with a wide range of potential autoantibodies. Eight of the 9 patients tested had autoantibodies which reacted with between 2-18 antigenic determinants (molecular weights 177-10 kd) present in the thyroid antigen preparation. None of the sera reacted with thyroglobulin or thyroid microsomes. The majority of these autoantibodies were directed against antigens which were absent from liver membrane preparations. Furthermore there was no diminution in the levels of these autoantibodies over a period of up to 39 months after the onset of SAT. The prolonged presence of these novel thyroid autoantibodies may explain the recent findings of subtle thyroid defects, such as altered gland iodine content, long after apparent clinical resolution of SAT. The accumulated evidence for a viral aetiology in this condition suggests that these sequelae may be due to a virally-induced autoimmune response.     

Autoimmune thyroid disease: an integrated concept of Graves' and Hashimoto's diseases

Graves' disease and Hashimoto's thyroiditis have been previously considered separate clinical and pathologic entities. Current knowledge of the autoimmune cause of specific systemic syndromes has been applied to these seemingly dissimilar diseases and now permit evolution of a unified integrated concept for considering them as two subsets of a single pathologic process. Experimental and clinical data now support the thesis that autoimmune thyroid disease is a genetically conditioned immunologic dysfunction, perhaps an abnormality of suppressor lymphocytes that results in production of humoral and tissue antibodies directed against thyroid gland cells and receptors of other somatic tissues. Thyroid autoantibodies possess hormonally stimulatory qualities and cytotoxic (inflammatory or destructive) properties. They may be present singly or together in the same individual with resulting diverse clinical and biochemical patterns depending upon the predominance or concordance of specific antibodies. Further, antibodies in autoimmune thyroid disease may be directed against other somatic structures such as ocular muscle, skin, hair, pigment cells, hematologic organs, or other endocrine glands. The immune etiology appears to predispose to nonendocrine systemic autoimmune disorders that coincide with thyroid disease. It is not clear at this time how genetic factors influence the onset, course, or ultimate outcome of autoimmune thyroid disease or why certain associated immunopathies tend to cluster with one or the other of these syndromes. Our understanding of the immune etiology common to Graves' and Hashimoto's diseases permits a more precise definition of the terms hyperthyroidism and thyrotoxicosis, the former denoting a pathologic goitrous phenomenon and the latter, a peripheral tissue manifestation of cellular receptor site excess of thyroid hormones.(ABSTRACT TRUNCATED AT 250 WORDS)     

Specific T helper cells that activate B cells polyclonally. In vitro enrichment and cooperative function

C3H/HeJ T cells which specifically recognize B cell-surface antigens of the related, major histocompatibility complex-compatible C3H/Tif strain, can be substantially enriched in vitro by long-term exposure (2- -6 wk) of primed lymph node cells to the relevant cellular antigens. These enriched T cells contain functional helper cells as demonstrated by their capacity to induce large numbers of Ig-secreting plaque- forming cells (PFC) in cultures of antigenic B cells. The cooperative interaction results in activation of a large fraction of all splenic B cells, with consequent exponential growth and maturation to high rate secretion of IgM, IgG1, and IgG2, but not IgG3. The IgM PFC response includes antibody specificities to a number of different antigens and can be considered, therefore, as polyclonal. The T helper cell- dependent B-cell response is insensitive to inhibition by anti-delta antibodies, and in contrast with lipopolysaccharide-induced PFC responses, is only partially sensitive to the inhibitory effects of anti-mu antibodies. Finally, B-cell activation to growth and maturation by helper T cells strictly required direct T-cell recognition of antigens on the surface of responding B cells, leading us to the conclusions that if any soluble factors are generated in the collaborative process, they are either antigen specific or incompetent to initiate B-cell growth.     

Apoptosis in the pathogenesis of autoimmune thyroid disease]

Apoptosis is a physiological process of cell death that occurs as part of normal development and in response to a variety of physiological and pathophysiological stimuli. The effector mechanisms, which carry out the death program, are well preserved across species and evolution. This article summarizes the recent studies on apoptosis in view of its molecular mechanism and the relation to autoimmune thyroid diseases. In Hashimoto's thyroiditis, which is a typical organ-specific autoimmune disease, Fas-FasL-mediated apoptosis has been demonstrated as the mechanism of follicular epithelial cell death. In Graves' disease, Anti TSH receptor antibody inhibits Fas antigen-mediated apoptosis of thyrocytes through the inhibitory effect of Fas antigen expression, resulting in the promotion of growth of the thyroid gland.