Evaluation of a tanned red cell technique for thyroid microsomal antibodies

Laboratory Thyroid Tests: A Historical Perspective

Background: This review presents a timeline showing how technical advances made over the last seven decades have impacted the development of laboratory thyroid tests. Summary: Thyroid tests have evolved from time-consuming manual procedures using isotopically labeled iodine as signals (¹³¹I and later ¹²⁵I) performed in nuclear medicine laboratories, to automated nonisotopic tests performed on multianalyte instruments in routine clinical chemistry laboratories. The development of isotopic radioimmunoassay techniques around 1960, followed by the advent of monoclonal antibody technology in the mid-1970s, led to the development of a nonisotopic immunometric assay methodology that forms the backbone of present-day thyroid testing. This review discusses the development of methods for measuring total thyroxine and triiodothyronine, direct and indirect free thyroid hormone measurements and estimates (free thyroxine and free triiodothyronine), thyrotropin (TSH), thyroid autoantibodies (thyroperoxidase, thyroglobulin [Tg] and TSH receptor autoantibodies), and Tg protein. Despite progressive improvements made in sensitivity and specificity, current thyroid tests remain limited by between-method differences in the numeric values they report, as well as nonspecific interferences with test reagents and interferences from analyte autoantibodies. Conclusions: Thyroid disease affects ∼10% of the U.S. population and is mostly managed on an outpatient basis, generating 60% of endocrine laboratory tests. In future, it is hoped that interferences will be eliminated, and the standardization/harmonization of tests will facilitate the establishment of universal test reference ranges.

The immunofluorescence techniques in the diagnosis of endocrine autoimmune diseases

In the study of autoimmune diseases, the laboratory plays a very important role. We describe the immunofluorescence techniques (direct, indirect, complement-fixing, double) for determining the presence of autoantibodies and their role in the autoimmune endocrine diseases.

Point-of-care assays for autoantibodies to thyroid peroxidase and to thyroglobulin

Point-of-care (POC) assays for autoantibodies to thyroid peroxidase (TPOAb) and to thyroglobulin (TgAb) are described. Both assays are based on the ability of autoantibodies in test samples (whole blood, plasma, or sera) to inhibit the binding of monoclonal antibodies to TPO or to Tg. The assays require no special equipment and give results in 10 minutes. Analysis of samples from healthy blood donors (n = 80), patients with autoimmune thyroid disease (n = 97) and nonthyroid autoimmune diseases (n = 20) showed that results with the POC tests compared well to those obtained by agglutination assay and enzyme-linked immunosorbent assay (ELISA). The reference immunoprecipitation assays (IPA) based on 125I-labeled TPO or Tg were more sensitive than the POC tests particularly in the case of TgAb measurements. However, no samples were found positive by POC test and negative by IPA emphasizing the high specificity of the POC assays. Our results suggest that POC testing for TPOAb and TgAb with assays such as those we describe could be useful in certain situations. These include prediction of postpartum thyroiditis and the development of interferon-alpha-related thyroid disease.

Thyroid autoimmunity in chronic urticaria

BACKGROUND

Chronic urticaria (CU) is an autoimmune process in some patients. An association between CU and autoimmune thyroid disease has also previously been proposed. Our group has identified functionally significant histamine-releasing autoantibodies in one subset of CU patients (subset 1), predicted by positive autologous intradermal serum tests and positive histamine release from donor basophil leucocytes in vitro. Sera from a second subset of patients (subset 2), all of whom had positive autologous intradermal serum tests, failed to release histamine from donor basophils. A final disease subset (subset 3) has no identifiable skin reactivity (negative autologous serum skin test) or in vitro histamine releasing activity.

OBJECTIVES

In order to examine further the possible relationships between thyroid autoimmunity, thyroid dysfunction and CU, we have examined thyroid autoantibodies and thyroid-stimulating hormone (TSH) levels (an indirect measure of thyroid dysfunction) in the three CU subsets.

PATIENTS/METHODS

We studied 182 patients (69% female), of whom 90 had a positive autologous intradermal serum test.

RESULTS

Eighteen skin test-positive and four skin test-negative patients had thyroid microsomal antibodies (TMA). TSH outside the normal range was found in 13 skin test-positive and one skin test-negative patient. These findings represent clustering of TMA positivity [risk ratio (RR) 4.06, 95% confidence interval (CI) 1.56-10.6] and of abnormal thyroid function (RR 15.5, CI 2.07-11.6) among the skin test-positive patients. However, in the overall study group an elevated TSH was present in seven patients (3.8%, CI 1.6-7.8) comparable to the 5% expected prevalence in the community. Thyroglobulin antibodies (TGA) were present in two of 182 patients.

CONCLUSIONS

There were significant differences between skin test-positive and skin test-negative patients with regard to autoimmune thyroid disease. Evidence for autoimmune thyroid disease and abnormal thyroid function was largely found among the skin test-positive patients, supporting the theory of an autoimmune aetiology in this group.

Autoimmune response to the thyroid in humans: thyroid peroxidase--the common autoantigenic denominator

Autoimmunity to thyroid peroxidase (TPO), manifest as high affinity IgG class autoantibodies, is the common denominator of human thyroid autoimmunity, encompassing patients with overt hyper- or hypothyroidism as well as euthyroid individuals with subclinical disease. The identification and cloning of TPO (the "thyroid microsomal antigen") provided the critical tool for analyzing B and T cell reactivity to this major thyroid autoantigen. In particular, the availability of immunoreactive TPO permitted the isolation of essentially the entire repertoire of human monoclonal antibodies, a feat unparalled in an organ-specific autoimmune disease. These recombinant autoantibodies (expressed as Fab) provide insight into the genes encoding their H and L chains as well as the conformational epitopes on TPO with which serum autoantibodies interact. Analyses of TPO autoantibody epitopic "fingerprints" indicate a lack of epitope spreading as well as a genetic basis for their inheritance. Limited data are available for the responses and cytokine profiles of T cells to endogenously processed TPO. Moreover, the role of thyroid cells in initiating the autoimmune response to TPO, and of B cells in expanding and/or modulating the response of sensitized T cells, has yet to be established. Finally, because autoantibody (and likely T cell) responses to TPO parallel those to TSH receptor and thyroglobulin, manipulation of T and B cell responses to TPO may provide the basis for the development of immunospecific therapy for autoimmune thyroid disease in general.

Cytotoxic T lymphocyte antigen-4 (CTLA-4) gene polymorphisms and susceptibility to type 1 autoimmune hepatitis

Genetic susceptibility to type 1 autoimmune hepatitis is indicated by a preponderance of female subjects and strong associations with human leukocyte antigens (HLA) DRB1*0301 and DRB1*0401. The gene encoding cytotoxic T-lymphocyte antigen-4 (CTLA-4) on chromosome 2q33 may also influence autoimmunity. To determine the frequency and significance of the exon 1 adenine (A)-guanine (G) base-exchange polymorphism for CTLA-4 in patients with type 1 autoimmune hepatitis, 155 northern European Caucasoid patients and 102 ethnically-matched control subjects were tested by polymerase chain reaction. The genotype distribution was significantly different in patients compared to controls (AA = 50/155 patients vs. 51/102 controls; AG = 84/155 patients vs. 38/102 controls; GG = 21/155 patients vs. 13/102 controls, chi(2) = 8.94, P =.011). This difference was caused by a significant over-representation of the G allele in patients compared to controls (105/155 patients vs. 51/102 controls, chi(2) = 8.34, P =.004, odds ratio = 2.12). The GG genotype was associated with a significantly higher mean serum aspartate transaminase level (P =. 03), greater frequency of antibodies to thyroid microsomal antigens (P =.004) and was found more commonly in patients with HLA DRB1*0301 (P =.02). Treatment outcomes, however, were not affected by the genotype. The CTLA-4 G allele is more common in patients with type 1 autoimmune hepatitis and may represent a second susceptibility allele. Furthermore, there may be synergy between the HLA-DRB1*0301 and the GG genotype in terms of disease risk.

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

Patients with chronic thyroiditis were selected for study according to specific selection criteria, and comparisons of an enzyme-linked immunosorbent assay (ELISA) method to a hemagglutination method were performed. The ELISA assays contained antithyroglobulin (TG) antibody and antithyroid-peroxidase (PO) antibody, the latter using recombinant human TPO. Four groups were established from 437 patients with chronic thyroiditis; 316 with both antibodies (TG + PO group), 75 with TG antibody alone (TG group), 10 with PO antibody alone (PO group), and 36 with no such antibodies (N group). The hemagglutination assay resulted in much different antibody profiles: PO group based on ELISA occurred in only 2%, whereas a group with microsome antibody alone based on hemagglutination assay occurred in 39%. Subsequently, studies of disease characteristics including age, gender, familial predisposition, thyroid function, and morphology of the gland were performed among the four groups of patients based on ELISA profiles but not on hemagglutination results. The subgroups of TG + PO and TG were derived from randomly selected patients (40 out of a much larger number of patients in each). The results showed that the PO group had smaller thyroid volume (25+/-16 mL, mean +/- SD) with normal echogenicity, and 50% prevalence of hypothyroidism. The TG group had larger thyroid volume (57+/-42 mL) with frequent association of small nodular formation (53%) but less frequent hypothyroidism (23%). In summary, compared to the hemagglutination method, the ELISA was noted to have both a higher sensitivity and specificity for detection of chronic thyroiditis. Correlation of ELISA profiles with ultrasonography of the thyroid gland detected subtle differences in subgroups that may account for differences in thyroid gland morphology and prevalence of hypothyroidism: the PO group has normal echogenicity but high incidence of impaired thyroid function, whereas in the TG group small nodules were associated with a lesser incidence of hypothyroidism.

Immune phenotype of chronic liver disease

Immune disorders in chronic liver disease may reflect common host propensities or disease-specific factors. Our aim was to determine the principal bases for these expressions. Four hundred fifty-one patients with various chronic liver diseases were assessed prospectively for concurrent immune disorders. Individuals with immune diseases were more frequently women (73% vs 60%, P = 0.02) and they had HLA DR4 more often than counterparts with other HLA (46% vs 23%, P = 0.000008). The association between HLA DR4 and immune disease was apparent within individual liver diseases and within different categories of liver disease. Women with HLA DR4 had a higher frequency of immune disease than women without HLA DR4 (52% vs 22%, P < or = 0.000001), and they also had immune diseases more commonly than DR4-positive men (52% vs 31%, P = 0.03). DR4-positive men, however, had higher frequencies of immune disease than DR4-negative men, especially in the nonimmune types of liver disease (26% vs 4%, P = 0.002). We conclude that HLA DR4 and female gender constitute an immune phenotype that is an important basis for autoimmune expression in chronic liver disease.

Genetic predispositions for immunological features in chronic liver diseases other than autoimmune hepatitis

BACKGROUND/AIMS

Human leukocyte antigens DR3 and DR4 influence susceptibility for type 1 autoimmune hepatitis and affect its immunological manifestations. We aimed to determine if autoimmune features in patients with chronic liver diseases other than autoimmune hepatitis are associated with these same antigens.

METHODS

One hundred and seventy-eight patients were evaluated. Class II typing was performed by restriction fragment length polymorphism in all patients and 80 normal subjects.

RESULTS

One or more autoantibodies, including antinuclear antibodies (28%), smooth muscle antibodies (8%), thyroid antibodies (18%) and antimitochondrial antibodies (13%), were found in 92 patients (52%). Concurrent clinical diseases of an immunological nature were recognized in 53 patients (30%). Patients with antinuclear antibodies had a higher frequency of the A1-B8-DR3 haplotype than patients without these antibodies (27% versus 12%, p = 0.04) and patients with concurrent immunological diseases had a higher frequency of HLA DR4 than patients without this antigen (51% versus 26%, p = 0.003). Patients with antinuclear antibodies were more commonly DR3 positive than normals (35% versus 16%, p = 0.03) and patients with concurrent immunological diseases were more commonly HLA DR4 positive than normals (51% versus 30%, p = 0.02).

CONCLUSIONS

We conclude that the clinical expression of antinuclear antibodies is associated with the A1-B8-DR3 haplotype and the presence of concurrent immunological diseases is related to the DR4 antigen. These clinical manifestations have a genetic basis that is not disease-specific.

Thyrotropin response to TRH stimulation in depressed patients with autoimmune thyroiditis

Two thyroid axis findings are often reported in depressed patients: autoimmune thyroiditis and abnormal thyrotropin (thyroid stimulating hormone, TSH) responses to thyrotropin-releasing hormone (TRH). The TSH response to TRH can be exaggerated, suggesting subclinical hypothyroidism; it can alternatively be blunted, for reasons poorly understood. We selected 28 women who had been found to have major depression for TRH testing. Fifteen patients had autoimmune thyroiditis and 13 had diffuse nontoxic goiter. The endocrinological diagnoses were verified by fine-needle aspiration biopsy and cytological assessment. Patients with overt hypothyroidism and hyperthyroidism were excluded from the study. There were no differences between the two groups in total triiodthyronine and thyroxine plasma levels or severity of depression. In the autoimmune group, basal TSH and Dmax TSH tended to be higher (p < 0.1); peak TSH was significantly higher (p < 0.05), suggesting that the prevalence of subclinical hypothyroidism was also higher. Blunted TSH responses were found about as often in one group as the other.

Evidence against hepatitis viruses as important causes of severe autoimmune hepatitis in the United States

To determine if the hepatitis viruses are important etiologic factors in autoimmune hepatitis, the clinical, immunoserologic, virologic and HLA phenotypes of 105 of the latter patients were assessed prospectively and compared to 45 patients with chronic viral hepatitis. Patients with autoimmune hepatitis were more often women with higher serum aspartate aminotransferase and immunoglobulin levels than patients with viral disease. Only eight patients (8%) were seropositive for anti-HBc and anti-HBs (four patients) or anti-HCV (four patients) and none with anti-HCV were reactive by second generation immunoassay or recombinant immunoblot assay. Smooth muscle (90 vs. 22%, P < 0.001) and antinuclear (70 vs. 22%, P < 0.001) antibodies were more common in patients with autoimmune hepatitis and the titers more frequently exceeded 1:80 (84 vs. 11%, P < 0.0001). Patients with autoimmune hepatitis were more often positive for HLA B8 (48 vs. 20%, P < 0.01) and DR3 (49 vs. 20%, P < 0.003) and they more frequently had the HLA A1-B8-DR3 phenotype (38 vs. 10%, P < 0.003). Only one of the 120 patients tested for anti-LKM1 was seropositive. We conclude that in an American referral population autoimmune hepatitis usually lacks virologic markers and has a distinctive clinical, immunoserologic and HLA phenotype. Hepatitis viruses are not important immunogenic stimuli for non-organ specific antibodies and they are unlikely to be important causes of this form of autoimmune hepatitis.

The nature and prognosis of severe cryptogenic chronic active hepatitis

BACKGROUND

Cryptogenic chronic active hepatitis may be an autoimmune or viral disease. Our aims were to determine the clinical features, human leukocyte antigen phenotype, and response to corticosteroid therapy of severe cryptogenic chronic active hepatitis and to compare it with these other diseases.

METHODS

Twelve patients with cryptogenic hepatitis were compared with 94 patients with autoimmune hepatitis and 30 patients with chronic viral hepatitis.

RESULTS

Patients with cryptogenic hepatitis were indistinguishable from those with autoimmune hepatitis by age, gender, and individual laboratory and histological findings. HLA B8 (75% vs. 49%, P = 0.2), DR3 (71% vs. 51%, P = 0.5), and A1-B8-DR3 (57% vs. 38%, P = 0.6) occurred as commonly in each group. Patients with cryptogenic hepatitis entered remission (83% vs. 78%, P > 0.9) and failed treatment (9% vs. 11%, P > 0.8) as frequently as those with autoimmune hepatitis during corticosteroid therapy. In contrast, patients with chronic viral hepatitis had lower biochemical abnormalities, less frequent multilobular necrosis at presentation, and different human leukocyte phenotypes than those with cryptogenic or autoimmune disease.

CONCLUSIONS

Severe cryptogenic hepatitis has a clinical expression, genetic phenotype, and corticosteroid responsiveness that is similar to autoimmune hepatitis. It may be an autoimmune disorder that has escaped detection by conventional immunoserological markers.

The presence of antithyroid antibodies in patients with affective and nonaffective psychiatric disorders

We determined the frequency of antithyroglobulin and antimicrosomal antibodies in 173 consecutively admitted psychiatric inpatients. (We found antithyroid antibodies in 8% (5/65) of patients with DSM-III major depression, 13% (4/31) with biploar disorder, and in 0% (0/4) of those with schizoaffective disorder.) The rate of antibody occurrence was unrelated to lithium exposure either within individual diagnostic categories or for the sample as a whole. The overall frequency of positive antithyroid antibody titers in patients with DSM-III affective disorder, 9% (9/99), did not differ from that in patients with nonaffective disorders, 10% (7/68). However, patients with bipolar affective disorder-mixed or bipolar affective disorder-depressed had a higher rate of positive antithyroid antibody titers than other patients. Our findings confirm earlier reports that thyroid disorders may be particularly common in patients with bipolar affective disorder, even in the absence of lithium exposure. However, as antithyroid antibodies also occurred at a relatively high rate in nonaffective disorders, the possible psychiatric effects of autoimmune thyroiditis do not appear to be limited to affective dysregulation.

Assessment of antithyroglobulin and antimicrosomal autoantibodies in patients with autoimmune thyroid disease: comparison of haemagglutination assay, enzyme-linked immunoassay and radioligand assay

Four different assay systems for detection of antithyroglobulin (T-Ab) and thyroid antimicrosomal autoantibodies (M-Ab) were evaluated: two passive haemagglutination assays (PHA), an enzyme-linked immunoassay (ELISA) and a radioligand assay (RLA). Antibody levels measured with these methods correlated well (T-Ab: r = 0.72 to 0.88; M-Ab: r = 0.63 to 0.84; p less than 0.0001). However, when the results of the measured samples were classified as normal, slightly elevated and pathological, only 40-50% of the samples showed congruous results in all tests; 60-70% agreed in PHA and ELISA, whereas 80 to 90% corresponded in the two PHAs. RLA and ELISA gave more frequently positive results for T-Ab and negative results for M-Ab than the PHAs. Despite the lower sensitivity of the quantitative methods for M-Ab detection, they depicted more readily small changes after thyroxine treatment than the PHAs. We suggest that differences in autoantibody levels found with different methods may be due to autoantibody heterogeneity.

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.

Measurement of spontaneous and stimulated anti-microsomal antibody synthesis in vitro by avidin-biotin enzyme immunoassay

The spontaneous and stimulated anti-microsomal (anti-Mic) antibody synthesis in vitro by peripheral blood lymphocytes (PBL) from patients with Hashimoto's thyroiditis (HT) was studied by a highly sensitive and thyroid microsome-specific enzyme immunoassay using an avidin-biotin system (A-B EIA). Since the amount of the synthesized anti-Mic antibody by PBL in vitro is very small, it is difficult to study its kinetics and response to mitogens or the specific antigen by conventional assay systems. We applied the avidin-biotin system to conventional indirect EIA and established an assay system which was about four times as sensitive as indirect EIA. PBL from patients with HT synthesized significant amount of IgG anti-Mic antibody spontaneously but those from normal individuals and patients with rheumatoid arthritis did not. IgG anti-Mic antibody synthesis with pokeweed mitogen stimulation was increased in all HT patients and that with thyroid microsome stimulation was increased in three out of five patients. These results indicate that A-B EIA is a useful system to study the mechanism of anti-Mic antibody synthesis in vitro.

The aging thyroid. Relationship between elevated serum thyrotropin level and thyroid antibodies in elderly patients

The relationship of thyroid antibodies and the serum level of thyrotropin in older adults (over age 60) was studied to determine whether thyroid antibodies were a good clue to thyroid failure in elderly persons. Of those with thyroid failure, evidenced by clearly elevated serum thyrotropin values (more than 10 microU/ml), 67 percent had positive antimicrosomal antibody levels, a prevalence much greater (p less than 0.001) than that among those of comparable age with normal thyroid function (18 percent). Nevertheless, one third (33 percent) had thyroid failure without positive antimicrosomal antibody levels; this was true whether or not a low serum thyroxine value was present. Furthermore, of those with positive antimicrosomal antibody levels, most (68 percent) did not have thyroid failure. Thus, although positive antimicrosomal antibody levels occurred more often in elderly patients with thyroid failure than in those with normal thyroid function, a sizable fraction of those with thyroid failure did not have positive antimicrosomal antibody levels. Hence, measurement of thyroid antimicrosomal antibodies is not a good test of early thyroid failure in older patients; direct demonstration of a clearly elevated serum thyrotropin value is a better approach.

Characterization of lymphoid cells in the thyroid of patients with Graves' disease

The distribution and function of lymphoid cells has been investigated in thyroid glands obtained at operation from 16 patients with Graves' disease (GD) using a peroxidase technique to enumerate total T and B lymphocytes as well as helper and suppressor T cell subsets in tissue sections. A spectrum of lymphocytic infiltration was observed and the increase from minimal numbers of immune cells in some GD thyroids to focal thyroiditis in others appeared to be due to a rise in all the lymphoid cell types analysed and was not the result of major change in any one lymphoid compartment. T cells were diffusely distributed whereas B cells tended to occur in aggregates. Small numbers of OKT6+ cells (possibly antigen presenting cells) were observed although these were less numerous than in lymphoid organs such as tonsil. Lymphoid cell suspensions prepared from the thyroid tissue of five of seven GD individuals treated pre-operatively with propranolol synthesized thyroid autoantibodies spontaneously in culture and this synthesis was decreased in the presence of pokeweed mitogen. Since the OKT8+ T cell subset has been shown to suppress immunoglobulin production by lymphocyte cultures containing mitogen, it appears that the suppressor T cells, which are readily demonstrable in GD thyroid sections, are functional. It seems unlikely, therefore, that a defect in this type of suppression is responsible for the initiation or perpetuation of the autoimmune response to thyroid antigens in GD.

Thyroid autoantibody synthesis by cultures of thyroid and peripheral blood lymphocytes. II. Effect of thyroglobulin on thyroglobulin antibody synthesis

The influence of antigen (thyroglobulin, Tg) on Tg antibody synthesis has been investigated using cultures of Hashimoto thyroid and peripheral blood lymphocytes. In cultures of thyroid lymphocytes, Tg antibody synthesis was stimulated by a 24h pulse of Tg (10-100 micrograms/ml) and similar results were obtained using spleen lymphocytes from BALB/c mice immunized with human Tg. In contrast, Tg antibody synthesis by Hashimoto peripheral blood lymphocytes was not affected by similar concentrations of Tg (1-240 micrograms/ml) in the presence or absence of pokeweed mitogen (PWM). However, peripheral blood lymphocytes from two out of nine patients produced increased levels of Tg antibody in the presence of very low concentrations of Tg (50 ng/ml). This increase in Tg antibody production was accompanied by a rise in total IgG synthesis indicating that the response to Tg was polyclonal. On the basis of other unusual features of the lymphocyte cultures from these two patients including a relatively small response to PWM and evidence of circulating plasma cells, it is suggested that sufficient numbers of lymphocytes responsive to Tg are only released into the circulation during active phases of the disease process.

Correlation of thyroid antibodies and cytologic features in suspected autoimmune thyroid disease

Six hundred forty-three patients with antithyroid antibody results were studied. Antithyroglobulin antibodies were found in 101, and antimicrosomal antibodies were found in 338 patients. Fine-needle aspiration biopsy, performed in 122 patients, yielded a satisfactory aspirate in 108 subjects. Significant antithyroglobulin and antimicrosomal antibody titers were found in 28 of 57 and 149 of 267 patients, respectively. In 65 patients with cytologically proved Hashimoto's thyroiditis, only 15 had positive antithyroglobulin antibody results (11 titers were 1:1,600 or higher), whereas 61 had positive antimicrosomal antibody results (50 titers were 1:1,600 or higher). Thus, cytologic diagnosis of Hashimoto's thyroiditis correlated better with antimicrosomal antibodies than with antithyroglobulin antibody titers. These data suggest that antithyroglobulin antibody determination offers no particular advantage over antimicrosomal antibody titers. In subjects with a clinical diagnosis of Hashimoto's thyroiditis and negative antibody results, fine-needle aspiration biopsy remains useful in establishing the diagnosis.

Thyroid autoantibody synthesis by cultures of thyroid and peripheral blood lymphocytes. I. Lymphocyte markers and response to pokeweed mitogen

Thyroid lymphocytes from Graves' and Hashimoto patients have been investigated and compared with lymphocytes from the peripheral blood. Considerably more lymphocytes (20-30 X 10(6)/g) could be isolated from Hashimoto thyroids than from Graves' tissue (1-5 X 10(6)/g) but the cell suspensions extracted from Hashimoto and Graves' glands were similar in terms of cell surface markers and the ability to synthesize immunoglobulin. Thyroid lymphocytes contained a lower proportion of T cells (OKT3+ cells) and in some cases more B cells than the peripheral blood but the ratio of helper to suppressor T cells (OKT4+:OKT8+ cells) was similar to the values obtained for blood lymphocytes. Further, thyroid lymphocytes (unlike blood lymphocytes) synthesized relatively large amounts of microsomal and/or thyroglobulin antibody when cultured in medium only and these levels were significantly decreased by the addition of pokeweed mitogen. The results of this study provide further evidence for the role of the thyroid as a major site of thyroid autoantibody synthesis and emphasize the importance of characterizing the cells infiltrating the gland in autoimmune thyroid disease.

An enzyme-linked immunoassay for thyroid microsomal antibodies

An enzyme-linked immunoassay (ELISA) for microsomal antibody is described. The method was found to be rapid, sensitive and precise and analysis of 115 serum samples showed good correlation between the ELISA and the conventional tanned red cell haemagglutination test. The presence of thyroglobulin antibody, rheumatoid factor, antinuclear factor or gastric parietal cell antibodies did not interfere in the microsomal antibody ELISA but some sera with mitochondrial antibody activity appeared to cause a non-specific effect. The ELISA was particularly useful for analysing microsomal antibody production by Hashimoto lymphocyte cultures and in some cases antibody synthesis could be studied in the absence of mitogen. The high capacity of the ELISA combined with its sensitivity suggest that it will be a valuable technique for studying microsomal autoantibody activity both in serum and in lymphocyte cultures.

Prediction of therapeutic response to radioactive iodine in Graves' disease using TSH-receptor antibodies and HLA-status

We have examined the combined usefulness of TSH-receptor antibody detection and HLA status on the therapeutic response to standard doses of radioactive iodine (RAI) in forty-three hyperthyroid Graves' patients. Twenty-three patients had detectable TSH-receptor antibodies as measured by 125I-TSH binding-inhibition (TBI) prior to administration of 7 mCi RAI. Eighteen (78%) of these patients were rendered euthyroid within 3 months. In contrast, twenty patients were TBI negative prior to RAI and sixteen (80%) of these individuals remained hyperthyroid at 3 months and required two, or more, doses of RAI to control their thyroid function. DR3 status alone was not strongly associated with resistance to RAI. However, of sixteen patients without detectable TBI activity and who required two or more doses of RAI, ten patients were DR3 positive (62%) compared with 25% in a control population. Only one patient who was both TBI and DR3 negative required more than one dose of RAI. These data indicate that TBI may be an accurate predictor of the therapeutic response to RAI in patients with hyperthyroid Graves' disease. Investigation of HLA status alone was of limited value, although it appeared that the combination of TBI and DR3 may be of additional help in developing an overall strategy for the treatment of hyperthyroid Graves' disease.

Natural history of autoimmune thyroiditis

One hundred and sixty-three asymptomatic people with thyroid antibodies or raised serum thyrotrophin (TSH) concentrations, or both, and 209 age-matched and sex-matched controls without either marker of thyroid disorder were followed up for four years to determine the natural history of autoimmune thyroiditis. Mildly raised TSH concentrations alone and the presence of thyroid antibodies alone did not significantly increase the risk of developing overt hypothyroidism during the four years compared with the controls. Overt hypothyroidism developed at the rate of 5% a year in women who initially had both raised TSH concentrations and thyroid antibodies. Prophylactic treatment with thyroxine may be justified in women found to have both markers of impending thyroid failure. The cost effectiveness of screening the adult population remains to be evaluated.

Carbimazole and autoantibody synthesis in Hashimoto's thyroiditis

Serum thyroxine, thyrotrophin, and thyroid microsomal antibody levels were measured in 20 patients with Hashimoto's thyroiditis and hypothyroidism before, during, and after treatment with carbimazole or placebo. Thyroid microsomal antibody levels fell during treatment in the 10 patients who received carbimazole, while serum thyroxine and thyrotrophin levels did not change. There were no changes in the placebo group. The study proves support for the concept that carbimazole may act directly on autoantibody synthesising lymphocytes localised in the thyroid. Such an effect might be valuable in influencing the autoimmune process in autoimmune thyroid disease.

Thyroxine replacement therapy: prescribing patterns and problems in 2710 patients. Scottish Automated Follow-up Register Group

The use of thyroxine replacement therapy was studied in 2710 patients with a previous diagnosis of either thyrotoxicosis or primary hypothyroidism. The patients, who were treated in five centres, were followed-up continuously using an automated register. Seventy per cent of patients had been prescribed daily doses of thyroxine of 200 microgram or more. The estimated 10-year cumulative incidence of detected undertreatment was 13 . 2% (95% confidence limits 10 . 9-15 .6%). The median cumulative incidence of recognised overtreatment was 6 . 2%. Improved patient education and the dissemination of guidelines to doctors on the use of thyroxine replacement may reduce the incidence of undertreatment or overtreatment.

Carbimazole and the autoimmune response in Graves' disease

Microsomal antibodies and antibodies directed toward the receptor for thyroid-stimulating hormone (TSH) decreased in parallel while patients with Graves' disease were taking carbimazole, whereas no significant changes were observed during treatment with placebo or propranolol. The changes in autoantibody levels during carbimazole treatment were independent of changes in serum thyroxine and could have been due to a direct effect of the drug on autoantibody synthesis. Evidence for this suggestion was provided when low doses of methimazole (the active metabolite of carbimazole) were found to inhibit thyroid-autoantibody production in cultured lymphocytes. Since thyroid lymphocytes are probably a major site of thyroid-antibody synthesis in Graves' disease and methimazole is concentrated in the thyroid during treatment, a local action of the drug on antibody production seems likely. This possibility could be important in the use of carbimazole to control hyperthyroidism.

Further observations on radioimmunoassay for thyroglobulin-binding capacity in human serum

A simplified radioimmunoassay for measuring thyroglobulin-binding capacity in human serum is described. Thyroglobulin (Tg) is labelled with lactoperoxidase (specific activity 5 microCi/microgram) which makes it possible to measure a binding capacity of more than 10 ng/ml of serum. The standard curve is plotted measuring the percentage of bound 125I-Tg against the dilution of 1 mg/ml Tg capacity from a pool of Tg antibodies from different individual serum samples. When polyethyleneglycol and a second antibody were compared in their precipitation of the immune complexes, the latter provided a better precipitation. The stability of the labelled Tg stored at --20 degrees C was checked at different intervals of time by ultracentrifugation and immunoreactivity. It was found that the labelled Tg can be used up to one month after iodination. Fragments produced during storage at --20 degrees C only partially reacted with Tg antibodies. Screening of 300 serum samples was performed by haemagglutination and binding capacity; of 45 positive serum samples, 28 were positive only by binding capacity, thus demonstrating that this method is far more sensitive, accurate and precise than those currently employed.

HLA antigens and thyroid autoantibodies in patients with Graves' disease and their first degree relatives

Patients with Graves' disease (n = 105) had an increased frequency of HLA-B8 (40%) and a reduced frequency of HLA-B12 (24.8%) when compared with random controls (n = 117; 24.8% and 40.2% respectively). Comparison of patients with their first degree relatives (n = 118) shows the frequency deviations in these antigens to be characteristic of the families from which patients with Graves' disease are drawn, rather than of the disease itself. The haplotypes, identified in eight-six patients and 113 relatives, indicate that the excess of HLA-B8 in patients and their relatives is primarily due to the halpotype 1-8. The relative risk for an HLA-B8 individual of developing Graves' disease is 2.02, whilst the relative risk for an individual of haplotype 1-8 is 4.23. No significant associations were found between the incidence of any HLA antigen or combination thereof and the presence or absence of thyroglobulin and thyroid microsomal antibodies, or antibodies which interact with the TSH receptor.

A study of triplets with Hashimoto's thyroiditis

Genetic predisposition to Hashimoto's thyroiditis is suggested by its striking aggregation in families and its occurrence in twins. The manifestations range from overt clinical and biochemical hypothyroidism to the detection of thyroid autoantibodies in healthy, symptom-free individuals and their relatives. So far as the authors are aware, the finding of Hashimoto's thyroiditis in identical triplets has not previously been reported and they therefore present the cases of Faith, Hope and Charity, 63-year-old triplet sisters.

Thyroglobulin and microsomal autoantibody production by cultures of Hashimoto peripheral blood lymphocytes

Peripheral blood lymphocytes from patients with Hashimoto's thyroiditis have been cultured for 2--3 weeks in Marbrook flasks. During this period, readily detectable amounts of thyroglobulin and microsomal antibodies were synthesized by the cells and secreted into the culture medium. Gel filtration studies indicated that the autoantibodies produced in culture were of a similar molceular weight to the serum antibodies and this provided evidence that autoantibody synthesis in vitro was representative of autoantibody synthesis in vivo. Our data suggest that this culture technique may be used to make a detailed investigation of the human autoimmune disease process.

Humoral immune stimulation and antiepithelial antibodies in Yersinia infection

Results consistent with a general humoral immune stimulation were found when 127 sera from 89 patients with Yersinia enterocolitica infection were studied. Significantly increased gammaglobulin concentrations and elevated isohemagglutinin titers were seen in these sera as compared to sera from normal blood donors and patients with streptococcal infection. Antinuclear and anti-smooth muscle antibodies were demonstrated in both yersinia and streptococcal infection. The prevalence of non-organ specific antiepithelial antibodies reacting with gastrointestinal and thyroid epithelial cells was significantly increased in yersinia infection.

Comparison of radioassay and haemagglutination methods for anti-thyroid microsomal antibodies

Parallel measurements of circulating anti-thyroid microsomal (anti-M) antibodies by radioassay and haemagglutination were performed on subjects with or without thyroid disorders. Three-quarters (75.4%) of control subjects had undetectable antibody levels (less than 10 u/ml) by radioassay and only 3.1% had concentrations of greater than or equal to 75 u/ml. Abnormally elevated levels (greater than or equal to 75 u/ml) were found in most of the patients with Hashimoto's thyroiditis (94.1%) or idiopathic myxoedema (86.7%), in the majority (75.0%) of those with Graves' disease and only in a minority of those with other thyroid disorders. The percentage of positive sera by haemagglutination was very similar in all groups to that of abnormal values observed in the radioassay. Direct comparison of parallel tests on a total of 631 sera revealed a highly significant correlation (r = 0.91, P less than 0.001) between the two methods, but elevated antibody titres by haemagglutination were found in some sera with negative radioassays. All these sera were from a single patient with thyroid carcinoma associated with Hashimoto's thyroiditis and had elevated levels of anti-thyroglobulin (anti-Tg) antibodies. Evidence that such discrepancies were due to anti-Tg antibodies reacting with microsomal-bound Tg was provided by the demonstration that the haemagglutination produced by these sera could be completely inhibited by the addition of Tg. A similar inhibition was observed with two rabbit antisera to human Tg, but not with sera from patients with thyroid autoimmune disorders containing high levels of anti-microsomal anti-bodies.

Response to thyrotrophin-releasing hormone in atrial dysrhythmias

Seventy-eight clinically euthyroid patients with atrial dysrhythmias, either established or paroxysmal, and sixty-three patients in sinus rhythm with coronary disease were screened for hyperthyroidism using thyroid function tests including the thyroid-stimulating hormone (TSH) response to thyrotrophin-releasing hormone (TRH). All had normal levels of serum thyroxine (T4) apart from three with dysrhythmias who were found to have hyperthyroidism. Twenty per cent of patients with atrial dysrhythmias and 10% of those in sinus rhythm had exaggerated TSH response to TRH. Thirty-six per cent of patients with an exaggerated response of TSH to TRH had significant titres of thyroid auto-antibodies compared with 15% with positive antibodies in those with normal TSH response to TRH. Auto-immune thyroid disease may be more closely related to heart disease than has previously been recognized. Rapid atrial dysrhythmias may occur in the presence of a normal serum thyroxine, high levels of TSH and positive thyroid antibodies.

The secretion of thyrotrophin with impaired biological activity in patients with hypothalamic-pituitary disease

We describe here two patients with hypothyroidism due to pituitary-hypothalamic disease in whom basal thyrotrophin (TSH) levels measured by radioimmunoassay (RIA) were elevated yet when measured by a cytochemical bioassay (CBA) were found to be normal. This finding and the absence of the normal rise of thyroid hormones in response to thyrotrophin-releasing hormone (TRH) mediated release of TSH confirms for the first time the secretion of TSH with impaired biological activity. Primary thyroid disease as a cause for the elevated immunoreactive TSH was excluded by the absence of circulating thyroid antibodies and by a normal thyroidal radioiodine uptake response to exogenous TSH.

Thyroid hormone concentrations in a large scale community survey. Effect of age, sex, illness and medication

Total thyroid hormone concentrations have been measured in the course of a large scale community survey to determine the distribution of these variables in the normal population and to assess the effect of age, sex, previously undectected thyroid disease and medication upon these parameters. 2779 subjects were studied. Serum T4 concentrations were normally distributed. A progressive increase in T4 levels with age was noted in the males, and a smaller increase in females which was concealed by the raised T4 values secondary to oral contraceptive therapy in females under the age of 45. Serum T3 levels were also normally distributed. There was a small reduction in T3 with age in the males but this fall was not seen in the females. T3 values were relatively higher in females under the age of 45 but this increase was not noted after exclusion of subjects taking an oral contraceptive. The changes in thyroid hormone concentrations with age are relatively minor (particularly with respect to T3) in a randomly selected sample from an English town. It is suggested that the changes reported by other authors reflect the process of selection used, and the high frequency of undetected thyroid disease, other illness and medication in hospital-based communities.

Thyroid-stimulating immunoglobulins in ophthalmic Graves' disease

Thyroid-stimulating immunoglobulins (TSI) have been detected by receptor assay in the sera of 43% of patients with ophthalmic Graves' disease. Comparison of the receptor assay studies with thyroid function tests indicated that in several patients the antibodies detected by receptor assay were biologically inactive. In other patients, thyroid function appeared to be under TSI control with hyperthyroidism prevented by autoimmune destruction of the thyroid.

Identification of subgroups of euthyroid graves's ophthalmopathy

We attempted to determine if euthyroid Graves's ophthalmopathy is a single entity or a heterogeneous group of disorders. Activity of long acting thyroid stimulator protector occurred in 31 of 33 patients with Graves's hyperthyroidism but in only nine of 17 with euthyroid Graves's ophthalmopathy. Of the euthyroid patients, six had protector activity and thyroid non-suppressibility; firm goiters and high titers of thyroid antibodies were the rule in this group. We believe that these patients have three autoimmune diseases: Hashimoto's thyroiditis, Graves's thyroid disease and Graves's ophthalmopathy. Five euthyroid patients had no detectable protector activity or thyroid antibodies and had normal thyroid suppressibility; the thyroid was generally normal in size and consistence. These patients are interpreted as having "isolated" Graves's ophthalmopathy without any autoimmune thyroid disease. The remaining six patients showed dissociation between protector activity and thyroid non-suppressibility and cannot be classified as yet. Euthyroidism in Graves's ophthalmopathy may have more than one cause.

A long-term follow up of patients with autoimmune thyroid disease

A survey in a general practice in the North-East of England in 1963 detected thyroglobulin antibodies in 16.2% of women and 4.3% of men. High titres of antibodies were found in 4.6% of women and 1.6% of men. Forty six subjects with thyroglobulin antibodies (from an original total of fifty-two) were studied in 1972 and forty of these were studied further in 1975. These subjects were compared with a group of age- and sex-matched controls from the original survey. Three of the subjects had developed overt hypothyroidism by 1975 and a raised serum thyroid-stimulating hormone (TSH) concentration was found more frequently in euthyroid subjects peviously found to be antibody positive. There was a striking difference in the antibody studies in that only 26% of the previously antibody positive subjects had thyroglobulin antibodies in 1972 and 30% in 1975. A raised serum TSH concentration was found to correlate with cytoplasmic a-tibodies and particularly with the combination of cytoplasmic and thyroglobulin antibodies.

Measurement of circulating thyroid microsomal antibodies by the tanned red cell haemagglutination technique: its usefulness in the diagnosis of autoimmune thyroid diseases

Thyroid-microsomal antibodies were quantitated by a new technique utilizing tanned sheep red blood cells coated with human thyroid microsomal antigens. This haemagglutination assay (MCHA) correlated with the immunofluorescent antibody (FAB) but not with the thyroglobulin haemagglutination antibodies (TGHA) assay. Of forty-one patients with Hasmimoto's thyroiditis, thirty-nine (95%) were MCHA but only twenty-four (59%) TGHA positive. Titres were similar for the hypothyroid and euthyroid patients. Patients less than 20 years of age had either negative (50%) or low titre (less than 1:160) TGHA but 100% positive MCHA at titres greater than 1:1280. Of twenty-one patients with Graves' disease eighteen (86%) were MCHA and six (29%) TGHA positive. Of thirty-two patients without thyroid disease eleven (34%) were MCHA and/or TGHA positive. On the basis of family history and associated abnormalities, in eight of eleven, positive antibodies may have been due to subclinical Hashimoto's thyroiditis. Fourteen subjects of a control group (10%) were MCHA positive. Seven of ten examined had goitres. MCHA is a simple and quantitative test, useful in the diagnosis of autoimmune thyroid diseases.