Analysis of anti-idiotypic antibodies against anti-microsomal antibodies in patients with thyroid autoimmunity

Anti-microsomal antibody (AMA) activity was inhibited in 14 of 16 sera and in all 12 IgG preparations from patients with postpartum thyroiditis following incubation with F(ab')2 fragments from normal polyspecific immunoglobulin for therapeutic use (ivIg). Similar results were observed with sera from seven of seven patients with Graves' disease and five of six patients with autoimmune hypothyroidism. Results of these competitive binding assays and affinity chromatography of AMA IgG on Sepharose-bound F(ab'), fragments from ivIg indicated that AMA antibodies reacted with ivIg through idiotypic-anti-idiotypic interactions. Eight out of 10 IgG preparations from patients with autoimmune thyroid disease also showed inhibition of AMA activity when coincubated with autologous IgM at various IgG:IgM molar ratios. These observations suggest that ivIg can inhibit anti-microsomal antibodies through idiotype-anti-idiotype interactions and that such interactions occur with IgM anti-idiotype antibodies in vivo, providing evidence of a role for idiotypic network regulation in the control of thyroid autoimmunity.

Antithyroid drugs and release of inflammatory mediators by complement-attacked thyroid cells

Thyroid cells are exposed to complement attack in Graves' disease and Hashimoto's thyroiditis, but are resistant to killing by homologous complement. We have examined the effects of sublethal complement attack on thyroid cells in vitro. Extracellular reactive oxygen metabolites were produced and prostaglandin E2, interleukin-1 alpha, and interleukin-6 were released after complement attack. Cells pretreated with interferon-gamma and interleukin-1 alpha, which increase expression of CD59, were more resistant to these effects of complement. Conversely, blockade of CD59 with monoclonal antibody increased complement-mediated oxygen radical production and release of prostaglandin E2, interleukin-1 alpha, and interleukin-6. The antithyroid drugs methimazole and propylthiouracil abolished or reduced oxygen radical production by complement-attacked thyroid cells and reduced cytokine release. These results suggest that sublethal complement attack in autoimmune thyroid diseases exacerbates tissue injury by causing thyroid cells to release potent phlogistic mediators, although some degree of protection may be afforded in vivo by cytokine-mediated upregulation of CD59. Antithyroid drugs, concentrated within thyroid cells, will prevent the release of these inflammatory molecules, which may in turn explain the amelioration of thyroiditis and remission of Graves' disease after such treatment.

T cell responses to synthetic TSH receptor peptides in Graves' disease

Twenty-eight peptides, representing the entire extracellular domain of the TSH receptor, were synthesised to investigate which parts of this autoantigen may be targets for the T cell response in Graves' disease (GD). T cells from 11 of 21 controls and 26 of 36 newly diagnosed GD patients proliferated in response to one or more peptides with a stimulation index (SI) of greater than 2.0 (chi 2 = 2.31, P greater than 0.1). The response of patients and controls to any of the individual peptides was also not statistically different. However, individual patients gave high SIs with certain peptides to which controls either gave an absent or very weak response. HLA-DR3 was not associated with any particular response to TSHR peptides. Three out of seven GD patients whose T cells were evaluated before and after treatment showed a response of this kind only early in the course of their disease. Intrathyroidal T cells from four GD patients did not give a consistent proliferative response to pools of five peptides, and depleting peripheral blood T cells of their CD8+ population did not affect the proliferative response. These results indicate that the T cell response to the TSH receptor in GD does not seem to be directed against any one particular epitope on the peptides we have tested which cover the extracellular domain.

Thyroid cells in Graves' disease and Hashimoto's thyroiditis stimulate allogeneic T cells when pretreated with phorbol ester

OBJECTIVE

To assess the capacity of thyroid follicular cells to function as antigen presenting cells, we have examined their ability to stimulate allogeneic T cells.

DESIGN

Thyroid follicular cells were pretreated with interferon-gamma or phorbol myristate acetate, washed thoroughly, and their capacity to induce allogeneic T cell proliferation was determined.

PATIENTS

Thyroid cells were prepared using thyroidectomy specimens from eight patients with Graves' disease, one with Hashimoto's thyroiditis and two with non-toxic multinodular goitre.

MEASUREMENTS

T cell 3H-thymidine incorporation was measured after a 16-hour incubation period with the isotope, 3 days after co-culture of T cells and thyroid cells.

RESULTS

Four of the eight thyroid cell preparations from thyroid autoimmunity patients failed to stimulate T cells, although there was a significant, weak stimulation for the whole group (P < 0.05): interferon-gamma pretreatment had no effect on this. Phorbol myristate acetate pretreatment significantly increased the ability of thyroid cells (from both autoimmune and multinodular glands) to stimulate T cells (P < 0.05); this was time and concentration dependent. Cell fixation after PMA treatment did not abolish this stimulatory activity, which could be transferred by supernatants from unfixed cells; exogenous interleukin-1 did not mimic the activity.

CONCLUSIONS

Thyroid cells expressing major histocompatibility complex class II molecules only weakly and inconsistently stimulate allogeneic T cells, compared to thyroid cells pretreated with phorbol myristate acetate, a difference which may be due to the expression of an unidentified co-stimulatory signal induced by phorbol ester.

The expression and role in T cell adhesion of LFA-3 and ICAM-2 on human thyroid cells

Thyroid follicular cells from patients with Graves' disease and Hashimoto's thyroiditis express intercellular adhesion molecule-1 (ICAM-1) and this is in part responsible for T cell adherence in vitro. To assess the potential role of other adhesion molecules in autoimmune thyroiditis, we investigated the expression and function of lymphocyte function-associated antigen-3 (LFA-3) and ICAM-2 on thyroid cells. Under basal culture conditions, a mean of 22.7% of Graves' thyroid cells (n = 8) expressed LFA-3 and this was enhanced by a mixture of T cell-derived cytokines and by IL-1, but not by TSH. LFA-3 was also demonstrated on Graves' (n = 4) and Hashimoto (n = 2) thyroid cells by immunohistochemical staining ex vivo. A small number of thyroid cells (mean 5.5%, n = 5) expressed ICAM-2 by flow cytometry but this was not altered by cytokines, and ICAM-2 could only be demonstrated on endothelial cells by immunohistochemical staining. It seems likely that contamination of primary thyroid cultures by such cells accounted for the small number of ICAM-2+ cells found using flow cytometry. Almost all of the cultured cells expressing LFA-3 or ICAM-2 also expressed ICAM-1, as assessed by dual staining. Blocking LFA-1, LFA-3, and ICAM-1 with monoclonal antibodies inhibited the adherence of T cells to thyroid follicular cells in assays of cell clustering; antibodies against ICAM-2 had no effect. These results show that two important adhesion receptor ligands, ICAM-1 and LFA-3, are expressed by thyroid cells in autoimmune thyroiditis and that these are likely to have functional importance in allowing T cells to bind to thyroid cell targets. This may play an important role in the initiation and maintenance of Graves' disease and Hashimoto's thyroiditis.

Detection of Defects in Rolling Element Bearings by Vibration Probability Density and Cross‐correlation Measurements

The usefulness of probability density and cross‐correlation of the vibration acceleration signal of rolling element bearings has been investigated. These measurements have been performed on ball bearings with and without simulated defects in their races after mounting them on a test rig. The measurement results show that both probability density and cross‐correlation of the bearings′ vibration signal can be used to detect defects in them.

Expression and function of membrane attack complex inhibitory proteins on thyroid follicular cells

Human thyroid cells are resistant to lysis by the homologous membrane attack complex. By immunohistochemical staining we here show that normal thyroid cells and those in Graves' disease and Hashimoto's thyroiditis express two membrane attack complex-inhibiting proteins, CD59 antigen and membrane attack complex-inhibiting protein/homologous restriction factor (MIP/HRF). In vitro, the expression of both molecules was enhanced by interleukin-1 (IL-1), tumour necrosis factor (TNF) and interferon-gamma (IFN-gamma) and cytokine-treated thyroid cells were more resistant to lysis by homologous complement. Blocking experiments with monoclonal antibodies against CD59 antigen and MIP/HRF showed that both molecules contributed but CD59 antigen was the more important in mediating resistance to complement attack. Expression of these proteins may be an important determinant of the severity of tissue injury produced by complement-fixing thyroid peroxidase antibodies in autoimmune thyroid disease.

T cell responses to synthetic thyroid peroxidase peptides in autoimmune thyroid disease

Sixteen peptides, representing four different extracellular regions of thyroid peroxidase (TPO) predicted to contain a high proportion of potential T cell epitopes, were synthesized to investigate which parts of this autoantigen may be targets for the T cell response in thyroid autoimmunity. Compared with 25 controls, peripheral blood T cells from 23-37% of 30 patients with Graves' disease or autoimmune hypothyroidism were stimulated significantly by three peptides, representing amino acids 415-432, 439-457 and 463-481 of the TPO sequence; T cells from individual patients were also stimulated by several other peptides. These results indicate that the T cell response to TPO is directed against several epitopes which may be recognized by different patients.

Adhesion molecule expression by the FRTL-5 rat thyroid cell line

We have examined the expression and function of rat CD54, a homologue of human intercellular adhesion molecule-1 (ICAM-1), by the continuously growing rat thyroid cell line FRTL-5. Approximately 10% of FRTL-5 cells express CD54 under basal conditions and this is not influenced by thyrotrophin. Expression of CD54 is increased by cytokines (gamma-interferon, tumour necrosis factor, interleukin-1) and by an activator of C-kinase, phorbol 12-myristate 13-acetate. Blocking ICAM-1 with a monoclonal antibody directed against this molecule significantly (P less than 0.01) reduced the binding of splenic lymphocytes to FRTL-5 cells but inhibition was consistently greater (P less than 0.01) in the presence of antibodies against a rat homologue of lymphocyte function-associated antigen-1, the receptor on T cells for ICAM-1. In no case was complete blocking of cluster formation observed. These results show that a pure line of rat thyroid cells can express an ICAM-1 homologue and this is directly enhanced by cytokines. Expression of this homologue is partially responsible for lymphocyte adhesion to thyroid cells, which is likely to be a major event in T cell recognition of thyroid antigens in autoimmune thyroiditis.

HLA associations with Hashimoto's thyroiditis

There is disagreement over the HLA-DR associations of Hashimoto's (goitrous) thyroiditis. We have studied 86 English Caucasian patients with this condition whose DR types were determined by restriction fragment polymorphism analysis. HLA-DR3 was significantly more frequent in these patients than in 100 controls (chi 2 = 7.09; P less than 0.01). The relative risk was 2.23 and aetiological fraction 0.29. HLA-DPB and DQB alleles were analysed in a proportion of these subjects by enzymatic DNA amplification and oligonucleotide probing. The only significant finding was an excess of HLA-DQw2 (in linkage disequilibrium with DR3) in the Hashimoto group (chi 2 = 7.43, P less than 0.007). These results do not support a difference between goitrous and atrophic thyroiditis based on respective associations with HLA-DR5 and DR3, but confirm a recent study in which HLA-DR3 was associated with Hashimoto's thyroiditis. However, it is possible that genes telomeric to DR3 may be involved in determining which type of thyroiditis a patient with autoimmune hypothyroidism develops.

Constrictive pericarditis masquerading as Budd-Chiari syndrome

Budd-Chiari syndrome (BCS) and constrictive pericarditis (CP) share many common clinical features. Over the last year we encountered three patients in whom CP clinically mimicked BCS. Two of the three did not even have raised jugular venous pressure. One patient with severe jaundice and hepatic coma ultimately died. Liver biopsy features were not discriminating. The final diagnosis of CP was established by echocardiography, chest computed tomography (CT), or cardiac catheterization. We conclude that in all patients with apparent BCS and atypical features, a noninvasive test like echocardiography or chest CT should be done to rule out treatable illness like CP before embarking on such invasive procedures as liver biopsy for diagnosis.

Mosquito fauna of certain areas of deltaic West Bengal--a preliminary report

Survey of mosquito fauna in certain areas of deltaic Bengal was conducted between September 1989 to February 1990. Anopheles vagus predominated in Canning study area and Anopheles hyrcanus in Budge Budge. Comparatively low densities of Anopheles annularis were recorded from Canning (6.05% of the total anophelines) and Budge Budge (7.36% of the total anophelines), respectively. C. vishnui, C. pseudovishnui and C. tritaeniorhynchus were collected from both Canning and Budge Budge study areas. C. pseudovishnui predominated in Canning and C. vishnui in Budge Budge. Amongst the three species of C. vishnui complex, C. triateniorhynchus ranked third in order of preponderance at both the study areas.

HLA antigens in Asian Indian patients with Graves' disease

A study of 57 Asian Indian patients with Graves' disease revealed a significant increase in the frequency of HLA-DQW2 (61.4%) as compared to the control population (22.6%) giving a relative risk of 5.4. Less prominent but statistically significant increase in the frequency of HLA-A10 (29.8% patients as opposed to 10.5% controls) and HLA-B8 (28.1% patients as opposed to 8.7% controls) was also observed. Further, patients carrying the phenotypes HLA-A10 and HLA-B8 were more prone to develop the disease at a younger age. Two HLA haplotypes, namely A10-B8 and B8-DR3, were found in significant linkage disequilibrium in our patients with Graves' disease. Patients carrying these haplotypes also had a tendency to develop the disease at an earlier age.

Role of cockroaches in allergy to house dust in Calcutta, India

Prick skin tests on 200 patients with a history of sensitivity to dust were done against house dust, cockroach, D. pteronyssinus, and D. farinae antigenic extracts. The frequency of positive reaction was 35% to cockroach, 59% to house dust, 84.7% to D. farinae, and 54% to D. pteronyssinus. Distinctively different prevalence of the three antigens, cockroach, house dust, and mites suggest that cockroach antigen is a specific antigen independent from house dust and mite antigens.

Clinical significance of IgE in bronchial asthma

Total mean serum IgE levels of 63 patients (aged 16-49 years) suffering from bronchial asthma and 64 control subjects (aged 19-40 years) were estimated by RIA method. Mean serum IgE level of patients and control subjects was 1132 +/- 643 units/ml and 43 +/- 26 units/ml respectively. The difference between the two values was statistically significant (p less than 0.001). Four per cent of the patients had serum IgE levels within normal limits. No significant correlation was found between mean serum IgE level of the patients and the duration of the disease. Differences in mean serum IgE level of male and female patients and control subjects was not statistically significant. The mean serum IgE level of patients in the age group of 21-40 years was highest (F = 1.33, p less than 0.05). Significantly elevated levels of serum IgE were observed in patients with both personal and family history of atopic disease in comparison to patients with only personal or family history only (p less than 0.05). As such the estimated raised level of IgE was significant in view of the severity of atopic asthma.

Density of Culex vishnui and appearance of JE antibody in sentinel chicks and wild birds in relation to Japanese encephalitis cases

In the District of Burdwan, a rural area of West Bengal State, India, Japanese encephalitis (JE) virus is endemic. In one village a longitudinal survey was conducted in order to find out whether associations could be established between the density of the vector mosquito Culex vishnui in two types of resting places, the incidence of infections in sentinel chicks exposed at monthly intervals, the prevalence of antibodies in wild birds and the occurrence of clinical infections in the human population. The experiment lasted from August 1981 till August 1982. Meteorologically a summer season (March-June), a rainy season (July-October) and a winter season (November-February) are distinguished. In the sentinel chicks infections were observed in all three seasons; in wild birds antibodies were prevalent throughout the year; these observations suggest perennial transmission of the virus in its maintenance cycle. Human infections were observed periodically with, in August 1982, a pronounced peak; this may point to fluctuations in the level of circulation of the virus in its maintenance cycle and spillover to the human population at times of peak circulation. The peaks may be related to the influx of young non-immune birds and newborn mammals into the animal population in summer. Further studies, including virus isolation attempts from mosquitoes and nestling birds, are required to prove this hypothesis.

Thrombin receptors define responsiveness of cholesterol-modified platelets

The microviscosity of human platelet membranes was changed by incubating platelets with liposomes containing various ratios of cholesterol and lecithin. Binding of 125I-thrombin to the modified platelets was measured together with platelet aggregation and secretion. In cholesterol-normal platelets (mole ratio of cholesterol to phospholipid (C:PL) = 0.553; eta = 2.40 poise), weighted nonlinear least squares curve fitting indicated that a model involving two classes of sites was adequate to describe the binding isotherm (K1 = 8.3 X 10(8) M-1; R1 = 150 sites/platelet; K2 = 6.4 X 10(6) M-1; R2 = 16,000 sites/platelet). In cholesterol-enriched platelets (C:PL = 0.857; eta = 3.05 poise), the apparent affinities for the two classes of sites decreased to 55 and 53%, respectively, while the binding capacities increased to 170 and 160%, respectively. In contrast, in the cholesterol-depleted platelets (C:PL = 0.435; eta = 2.03 poise), the affinities increased to 220 and 180%, respectively, while the binding capacities decreased to 53 and 46%, respectively. In cholesterol-enriched, cholesterol-normal, and cholesterol-depleted platelets, the thrombin concentrations required for half-maximal aggregation were 0.17, 0.35, and 0.52 nM, respectively, while the values for half-maximal secretion of [14C]serotonin were 0.17, 0.40, and 0.55 nM, respectively. Plots of receptor occupancy versus biological response showed that maximum response in cholesterol-enriched, cholesterol-normal, and cholesterol-depleted platelets occurred with occupancy of 30, 50, and 70% of the high affinity sites, respectively. In all three treatment groups, occupancy of 40-50 high affinity sites results in 50% aggregation. These results show that (i) modification of platelet membrane microviscosity results in changes in the number and affinity of both high and low affinity thrombin receptors, (ii) the change in receptor number rather than affinity is the determinant for platelet responsiveness, and (iii) the changes in membrane microviscosity do not appear to alter the coupling between occupied receptor and subsequent bioresponse.

Fly borne Vibrio parahaemolyticus in Calcutta

V. parahaemolyticus has been detected from flies in all months of the year in Calcutta. The mean percentage of isolation is: housefly 14.1, blue bottle fly 18.5, external washing 10.1, viscera 22.6, flies of sweet shops 9.7 and those from fish market 22.7. Flies revealed higher (4.4%) isolation of Kanagawa postive V. parahaemolyticus strains than those of water and fish specimens (0.8%) studied previously. Strains negative to Kanagawa test but simulating enteropathogenic serotypes are recorded in 8.0% isolates. Possibility of fly borne contamination from the sources like human faeces, sewage and fish is discussed.