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R S Bahn

Publications and source records attributed to R S Bahn.

At least 37 records · Page 2Linked to original sources
PubMed1996

Multivariate analysis of HLA loci in conjunction with a thyrotropin receptor codon 52 polymorphism in conferring risk of Graves' disease.

Recent reports have suggested that the HLA alleles DRB3*0101 or DQA1*0501 confer greater susceptibility to Graves' disease than does the DR3 allele. We have reported previously that a non-HLA-linked allele, a polymorphism in codon 52 of the human thyrotropin receptor gene, is highly associated with Graves' disease in females. To determine which of these four susceptibility alleles confers greater independent risk for the development of Graves' disease, we analyzed the alleles in 134 North American Caucasian females who have Graves' disease (n = 69) or are normal controls (n = 65) in a logistic regression model. While we found each of these alleles to be associated with Graves' disease when analyzed independently (corrected p < 0.01 for each of 4 alleles tested), only DR3 (p = 0.0001) and the thyrotropin receptor polymorphism (p = 0.0060) maintained a statistically significant independent association when assessed in conjunction with each of the other alleles in a logistic model. We conclude that DR3 confers the greatest susceptibility to Graves' disease (odds ratio = 7.6) of the alleles within the HLA locus, and that any association between DRB3*0101 or DQA1*0501 and Graves' disease may be a result of the tight linkage disequilibrium between these alleles and DR3. In addition, we found the non-HLA-linked thyrotropin receptor codon 52 polymorphism to confer significant independent risk of Graves' disease (odds ratio = 9.0). Further, because 6 of 6 individuals who possessed both DR3 and the thyrotropin receptor polymorphism had Graves' disease, while no individual in the normal control group possessed both alleles, study of a larger population to assess the potential synergism between these 2 alleles is warranted.

Alleles↗
PubMed1996

Lack of an association between alleles of interleukin-1 alpha and interleukin-1 receptor antagonist genes and Graves' disease in a North American Caucasian population.

Although an association between the human leukocyte antigen (HLA) allele DR3 and Graves' disease (GD) is well documented, the potential role of non-HLA-linked alleles in susceptibility to GD is an area of active investigation. In an attempt to study the potential role of two non-HLA susceptibility alleles in GD and Graves' ophthalmopathy, we examined 286 North American Caucasian individuals (145 normal controls and 141 individuals with GD) for the presence of the A2 allele of the interleukin-1 (IL-1) receptor antagonist gene. In addition, we examined a subset of this population (83 normal controls and 89 individuals with GD) for a specific polymorphism within exon 5 of the IL-1 alpha gene. We found the A2 allelic frequencies (0.25 and 0.23, respectively) and carriage rates (43% and 41%, respectively) in the two groups to be nearly identical. However, findings in the subgroup of patients with the extrathyroidal manifestations of GD (Graves' ophthalmopathy, pretibial dermopathy, and acropachy) suggested a trend toward a higher prevalence of the A2 allele in patients with more severe disease. The allelic frequency (0.28) and carriage rate (47%) of the IL-1 alpha exon 5 polymorphism in individuals with GD were nearly identical to those of the control population (0.28% and 45%, respectively). In summary, we were unable to demonstrate an association between these alleles and GD in our study population. We conclude that neither the A2 allele of the IL-1 receptor antagonist gene nor the IL-1 alpha exon 5 polymorphism confers increased susceptibility to GD.

Alleles↗
PubMed1996

Interleukin-1 (IL-1) receptor antagonist and soluble IL-1 receptor inhibit IL-1-induced glycosaminoglycan production in cultured human orbital fibroblasts from patients with Graves' ophthalmopathy.

An accumulation of glycosaminoglycans (GAG) is a feature characteristic of orbital connective tissues from patients with Graves' ophthalmopathy (GO) that leads directly to the clinical expressions of the disease. Interleukin-1 (IL-1), produced by macrophages and fibroblasts within the diseased orbit, stimulates GAG synthesis by orbital fibroblasts. We designed the current study to determine whether particular agents might block this effect and thus be useful in the treatment of GO. Orbital fibroblast cultures were grown to confluence and incubated for 48 h with IL-1 (1-10 U/mL) alone or IL-1 (10 U/mL) in combination with IL-1 receptor antagonist (IL-1ra; 1-40 ng/mL) or soluble IL-1 receptor (sIL-1R; 0.25-10 micrograms/mL). Cells were labeled with [3H]glucosamine and processed for GAG quantitation. The addition of IL-1 alone stimulated GAG synthesis by 73-176% (mean, 104%; P < 0.05). Significant inhibition of IL-1-stimulated GAG synthesis was observed after treatment of normal fibroblasts with IL-1ra at a concentration of 5 ng/mL (12.5-fold molar excess; mean, 33%; P < 0.05); essentially complete inhibition was achieved at 40 ng/mL (100-fold molar excess; mean, 86%; P < 0.05). Significant inhibition of GAG synthesis by sIL-1R was observed at a concentration of 0.5 microgram/mL (720-fold molar excess; mean, 79%; P < 0.05), and inhibition was essentially complete at 1 microgram/mL (1440-fold molar excess; mean, 89%; P < 0.05). IL-1ra and sIL-1R are potent inhibitors of IL-1-induced GAG production by cultured human orbital fibroblasts. Our results suggest that these two compounds, shown in early trials to be safe when administered parenterally, may be useful in the prevention or treatment of GO.

Cells, Cultured↗
PubMed1996

Lack of an independent association between the human leukocyte antigen allele DQA1*0501 and Graves' disease.

The association between the human leukocyte antigen (HLA) serotype DR3 and Graves' disease (GD) in Caucasian populations is well known. However, an even stronger association has been reported recently, especially in the male population, between the closely linked HLA allele DQA1*0501 and GD. We postulated that the reported association between DQA1*0501 and GD may be a result of the linkage of this allele with DR3 and may not represent an independent association. Accordingly, we screened a population of North American Caucasians (n = 218), including patients with GD (n = 101, 32 males, 69 females) and individuals with documented normal thyroid function (n = 117, 51 males, 66 females), for the presence of the DQA1*0501 allele and those alleles corresponding to the DR3 serotype (DRB1*03). Screening was accomplished using sequence specific PCR. A significant association was documented in the total study population between DR3 positivity and GD (P = 0.0002), but not between DQA1*0501 positivity and GD (P = 0.06). After gender stratification, significant associations were found only in the female population (DR3, P = 0.0004; DQA1*0501, P = 0.012) and not in the male population (DR3, P = 1.0; DQA1*0501, P = 1.0). Additionally, in those DR3 negative female subjects (n = 100), there was no independent association between DQA1*0501 positivity (n = 26) and GD (p = 0.82). P-values were corrected, where appropriate, for gender stratification and/or the number of HLA alleles tested. In conclusion, our results demonstrate a lack of independent association between the presence of the HLA allele DQA1*0501 and GD. We suggest that the apparent association between this allele and GD in the female population may be the result of its' close linkage to DR3.

Alleles↗
PubMed1996

Tissue eosinophilia and eosinophil degranulation in Riedel's invasive fibrous thyroiditis.

The etiology of Riedel's invasive fibrous thyroiditis (IFT) has remained obscure. This rare disorder has been confused in the past with the more common fibrous variant of Hashimoto's disease. The typical histological features of IFT, in particular the presence of an invasive fibrosclerotic process in conjunction with a prominent chronic inflammatory infiltrate, suggest that the release of fibrogenic cytokines and other factors from these cellular infiltrates may play an important role in the pathogenesis of this condition. Our observations in routinely processed tissue sections obtained from patients with documented IFT of striking tissue eosinophilia led us to hypothesize that eosinophils and their products may play a role in the evolution of this disease. Immunofluorescence staining with affinity-purified polyclonal rabbit antibody directed against human eosinophil granule major basic protein revealed marked tissue eosinophilia and abundant extracellular deposition of major basic protein in all specimens from 16 patients with IFT. By contrast, only occasional eosinophils and no extracellular major basic protein were detected in control thyroid tissues obtained from patients with multinodular goiter, Graves' disease, Hashimoto's disease, and normal thyroid tissue. The presence of marked eosinophil infiltration and extracellular major basic protein deposition in IFT and other associated fibrosclerotic conditions suggests a role for eosinophils and their products in propagating the fibrogenesis seen in IFT.

Cell Degranulation↗
PubMed1995

Nongoitrous (type I) amiodarone-associated thyrotoxicosis: evidence of follicular disruption in vitro and in vivo.

Treatment with the antiarrhythmic agent amiodarone results in alterations in thyroid hormone metabolism, and can induce either hypothyroidism or hyperthyroidism (amiodarone-associated thyrotoxicosis, AAT). AAT occurs in patients both with and without preexisting goiter. In our study of the nongoitrous variety, the effect in vitro of amiodarone treatment and of concurrent treatment with potential inhibitors on thyroid cells (FRTL-5) was assessed by measuring the release of radiolabeled chromium (51Cr). In addition, thyroid histopathology was evaluated in autopsy specimens from six amiodarone-treated patients who had no pretreatment evidence of thyroid disease. Histopathologic examination revealed minimal or no evidence of thyroid follicular damage in specimens from amiodarone-treated euthyroid patients (n = 4). In contrast, moderate to severe follicular damage and disruption were present in glands from patients with AAT (n = 2). Studies in vitro showed amiodarone to be cytotoxic to thyroid cells; this effect was inhibited by treatment with dexamethasone (10(-3) mmol) or perchlorate (2.5 micrograms/mL). In summary, we demonstrate evidence in vitro and in vivo of amiodarone-induced thyroid follicular damage and disruption in specimens from patients with nongoitrous AAT and in cultured normal thyroid cells. In addition, we demonstrate inhibition of this effect following treatment in vitro with dexamethasone or perchlorate. Our findings support the concept that nongoitrous (type I) AAT results from direct drug toxicity with disruption of thyroid follicles and subsequent release of preformed thyroid hormone.

Adult↗
PubMed1995

Normal function in vivo of a homozygotic polymorphism in the human thyrotropin receptor.

We have demonstrated previously and association between a polymorphism in the human thyrotropin receptor gene and an increased prevalence of autoimmune thyroid disease in individuals bearing this polymorphic allele. The polymorphism involves the nucleotide base substitution of a cytosine for the wild-type adenine at the first position of codon 52 and is found generally in the heterozygotic state. Such change results in the substitution of a threonine for the wild-type proline at this position in the receptor protein sequence. The resulting protein would lack a beta turn (at position 52) in a potential loop conformation, and thus would have a significantly altered three-dimensional conformation. The biologic consequences of this conformational change in the receptor are unknown, but may involve altered function or immunogenicity. We report here two individuals with normal thyroid function who are homozygous for the thyrotropin receptor polymorphism, suggesting that the altered receptor is able to respond normally to thyrotropin with respect to the maintenance of the euthyroid state.

Adenine↗
PubMed1995

A polymorphism in the extracellular domain of the thyrotropin receptor is highly associated with autoimmune thyroid disease in females.

We and others have described previously a polymorphism at the first position of codon 52 (C52 --> A52) of the human thyrotropin receptor (hTSHr) gene. To determine its potential significance, we studied female (n = 100) and male (n = 25) patients with autoimmune thyroid disease (Graves' disease, n = 91; Hashimoto's thyroiditis, n = 34) and normal individuals [n = 121, female (n = 69), male (n = 52)]. Screening was performed using AciI restriction enzyme digestions of PCR-amplified genomic DNA. All codon 52 polymorphisms were verified by direct DNA sequencing. Data were analyzed using Chi-square or Fisher exact tests and p-values were corrected for multiple comparisons. Our studies demonstrated that this polymorphism is highly associated with autoimmune thyroid disease in the female population (corrected p = 0.008). We found no such association in the male population. Within females, there was a greater association between Graves' disease and the polymorphism (corrected p = 0.017) than between Hashimoto's thyroiditis and the polymorphism (corrected p = 0.090). The polymorphism was present in a higher proportion of Graves' disease patients with Graves' ophthalmopathy and pretibial dermopathy (40%) or Graves' ophthalmopathy, pretibial dermopathy, and acropachy (60%), than in patients with Graves' disease alone (15%), or Graves' disease and Graves' ophthalmopathy alone (17%). In conclusion, a polymorphism (C52 --> A52) of the hTSHr is associated with autoimmune thyroid disease in females.

Base Sequence↗
PubMed1995

Analysis of T-cell antigen receptor variable region gene usage in patients with thyroid-related pretibial dermopathy.

It is unknown whether T cells infiltrating the pretibial skin of patients with thyroid-related pretibial dermopathy represent a primary immune response or participate in a nonspecific inflammatory process. To characterize these T cells at the molecular level, we examined the T-cell antigen receptor variable region gene usage in pretibial skin biopsy specimens obtained from patients with early and late stages of pretibial dermopathy and from individuals with unrelated inflammatory conditions of the pretibial skin. RNA extracted from pretibial biopsy specimens and peripheral blood lymphocytes was reverse transcribed and amplified with the polymerase chain reaction and 22 V alpha and 23 V beta gene-specific oligonucleotide primers. The resulting T-cell receptor (TcR) V alpha and V beta transcripts were verified by Southern hybridization analysis using TcR C-region-specific, digoxigenin-labeled oligonucleotide probes. Compared with matched peripheral blood lymphocytes, the pretibial TcR V alpha and V beta gene repertoire expressed was heterogeneous but revealed marked restriction of V alpha and V beta gene usage in samples derived from patients with active inflammatory pretibial dermopathy of recent onset. In contrast, greater diversity of the TcR V alpha gene repertoire and loss of TcR V beta gene restriction were noted in patients with long-standing, clinically inactive pretibial dermopathy. TcR V gene usage in pretibial tissue and peripheral blood lymphocyte samples obtained from control subjects was unrestricted. Limited variability of TcR V gene usage in early pretibial dermopathy may reflect a primary immune response of antigen-specific T lymphocytes infiltrating the pretibial skin in thyroid-related pretibial dermopathy.

Adult↗
PubMed1995

The fibroblast is the target cell in the connective tissue manifestations of Graves' disease.

A controversy exists concerning whether the extraocular muscle cell or the fibroblast is the autoimmune target in Graves' ophthalmopathy (GO). Although the extraocular muscle bodies are grossly enlarged in GO, the muscle cells themselves are histologically intact. Within the muscle bodies, as well as in the fatty connective tissue of the orbit, there is an accumulation of glycosaminoglycans (GAG). These hydrophilic mucopolysaccharides are made by fibroblasts. In this commentary, I will present evidence that the fibroblast, and not the extraocular muscle cell, is the autoimmune target in GO and in the other connective tissue manifestations of Graves' disease (pretibial dermopathy and acropachy). This argument is based on clinical evidence, on histochemical and biochemical evidence of fibroblast stimulation in GO, and on functional evidence that patients' orbital lymphocytes recognize autologous orbital fibroblasts, and not eye muscle extract.

Antibody Formation↗
PubMed1995

Analysis of retroorbital T cell antigen receptor variable region gene usage in patients with Graves' ophthalmopathy.

To date, it has remained unclear whether orbit-infiltrating T cells in patients with Graves' ophthalmopathy (GO) represent a primary immune response in which a limited number of T cell clones driving the disease are activated against specific antigens, or whether they participate in a non-specific inflammatory process. To characterize these T cells at the molecular level, we examined the T cell antigen receptor (TcR) V gene repertoire in situ in retroorbital tissue specimens obtained from patients with early and late stages of clinically severe GO and from patients with non-GO orbital conditions. Ribonucleic acid extracted from orbital tissue and peripheral blood lymphocytes (PBL) was reverse transcribed and amplified using the polymerase chain reaction and 22 V alpha and 24 V beta gene-specific oligonucleotide primers. The resulting TcR V alpha and V beta transcripts were verified by Southern hybridization analysis using TcR C region-specific, digoxigenin-labeled oligonucleotide probes. Compared with matched PBL, the retroorbital TcR V alpha and V beta gene repertoire expressed was heterogeneous, but revealed marked restriction of V gene usage in samples derived from retroorbital connective tissue and extraocular muscle of all eight patients with severe GO of short duration studied. In contrast, greater diversity of the TcR V beta gene repertoire and loss of TcR V alpha gene restriction was noted in four patients with late GO undergoing reconstructive eye muscle surgery. Unrestricted TcR V gene usage was demonstrated in orbital tissue and PBL samples obtained from control subjects. These results suggest that retroorbital TcR V gene usage is variable but markedly restricted during the earlier stages of GO. With increasing disease duration, greater diversity of the TcR V gene repertoire appears to develop, and oligoclonality of the T cell response may be lost. Selection of patients with early stages of GO will be important when further dissecting TcR usage and antigen specificity of orbit-infiltrating T lymphocytes in GO.

Adult↗
PubMed1995

Modulation of cellular functions in retroorbital fibroblasts using antisense oligonucleotides targeting the c-myc protooncogene.

PURPOSE: To examine the signal transduction pathways involved in the activation of orbital fibroblast effector functions relevant to the pathogenesis of Graves' ophthalmopathy (GO). To determine, using antisense technology, whether the c-myc protooncogene is involved in cell proliferation and glycosaminoglycan (GAG) synthesis in cultured orbital fibroblasts (OF). METHODS: The effects of a 16-mer c-myc antisense phosphorothioate oligodeoxynucleotide (S-ODN) on OF monolayers derived from orbital connective tissue of patients with severe GO (n = 6) and healthy individuals (n = 3) were investigated. Quiescent OF monolayers were treated with serum or cytokines and were exposed to increasing concentrations of a c-myc antisense S-ODN and several control S-ODN. Cell proliferation was quantitated by direct cell counting and by immunocytochemistry for the nuclear Ki-67 antigen. Glycosaminoglycan synthesis was examined by [3H] GAG analysis. The effects of the c-myc antisense S-ODN and control S-ODN on c-myc mRNA and protein product levels were analyzed using reverse-transcriptase polymerase chain reaction, immunocytochemistry, and immunoblotting, respectively. RESULTS: Transient suppression of c-myc mRNA and the c-myc protein product by a c-myc antisense S-ODN (2 to 8 microM) strongly inhibited cell proliferation and GAG synthesis in OF derived from patients with GO and healthy individuals. These effects occurred in a dose-dependent manner and were specific for the c-myc antisense S-ODN used. Cell morphology or viability were not affected. CONCLUSIONS: The c-myc protooncogene and its protein product are involved in the proliferative and metabolic activities of OF exposed to serum or cytokines in vitro. C-myc appears to be an essential component of at least two OF cellular activities likely to contribute to the orbital tissue alterations in GO.

Base Sequence↗
PubMed1994

A genomic point mutation in the extracellular domain of the thyrotropin receptor in patients with Graves' ophthalmopathy.

Orbital and pretibial fibroblasts are targets of autoimmune attack in Graves' ophthalmopathy (GO) and pretibial dermopathy (PTD). The fibroblast autoantigen involved in these peripheral manifestations of Graves' disease and the reason for the association of GO and PTD with hyperthyroidism are unknown. RNA encoding the full-length extracellular domain of the TSH receptor has been demonstrated in orbital and dermal fibroblasts from patients with GO and normal subjects, suggesting a possible antigenic link between fibroblasts and thyrocytes. RNA was isolated from cultured orbital, pretibial, and abdominal fibroblasts obtained from patients with severe GO (n = 22) and normal subjects (n = 5). RNA was reverse transcribed, and the resulting cDNA was amplified by the polymerase chain reaction, using primers spanning overlapping regions of the entire extracellular domain of the TSH receptor. Nucleotide sequence analysis showed an A for C substitution in the first position of codon 52 in 2 of the patients, both of whom had GO, PTD, and acropachy. Genomic DNA isolated from the 2 affected patients, and not from an additional 12 normal subjects, revealed the codon 52 mutation by direct sequencing and AciI restriction enzyme digestions. In conclusion, we have demonstrated the presence of a genomic point mutation, leading to a threonine for proline amino acid shift in the predicted peptide, in the extracellular domain of the TSH receptor in two patients with severe GO, PTD, acropachy, and high thyroid-stimulating immunoglobulin levels. RNA encoding this mutant product was demonstrated in the fibroblasts of these patients. We suggest that the TSH receptor may be an important fibroblast autoantigen in GO and PTD, and that this mutant form of the receptor may have unique immunogenic properties.

Adult↗
PubMed1994

Thyrotropin receptor antisera for the detection of immunoreactive protein species in retroocular fibroblasts obtained from patients with Graves' ophthalmopathy.

Autoimmunity against the TSH receptor (hTSH-R) is known to be the proximate cause of thyroidal activation in Graves' disease, but has not been definitively linked to extrathyroidal manifestations of this disorder, such as ophthalmopathy and pretibial myxedema. In an effort to increase our knowledge concerning mechanisms responsible for Graves' ophthalmopathy, we used antiserum directed against a highly immunogenic portion of the hTSH-R (amino acids 352-367; P1) to assess the presence of this receptor or immunologically related protein in cultured human retroocular fibroblasts obtained from patients with Graves' ophthalmopathy. Immunoenzymatic and immunofluorescent studies revealed specific staining of both cytoplasmic and cell membrane-associated protein in discrete vesicles. To further evaluate the immunoreactive species present in these cells, immunoblotting experiments were performed using hTSH-R-specific antisera (anti-P1) and sera obtained from patients with Graves' disease. Several protein bands were identified using both anti-P1 and Graves' disease patient sera, including species at mol wt of 95, 71, and 18 kilodaltons, the possible significance of which is discussed. The results support the hypothesis that immunity against the hTSH-R or related proteins contributes to the ophthalmopathy of Graves' disease.

Amino Acid Sequence↗
PubMed1994

Modulation of Graves' orbital fibroblast proliferation by cytokines and glucocorticoid receptor agonists.

PURPOSE: Paracrine/autocrine interactions between orbital fibroblasts (OF) and infiltrating lymphocytes/macrophages are thought to play a central role in the evolution of Graves' ophthalmopathy (GO). Compounds capable of stimulating the proliferation and synthetic capacities of OF may be of particular importance to these processes, because fibroblasts are known to both produce and respond to certain paracrine factors. METHODS: The effects of interleukin-1 alpha, interleukin-2, interleukin-4, interleukin-6, insulin-like growth factor I, transforming growth factor beta, and platelet-derived growth factor on OF monolayers derived from orbital fatty connective tissue and extraocular muscle endomysium of patients with severe GO undergoing orbital decompression (n = 3), and from connective tissue of normal persons (n = 3) were investigated. Stimulation of proliferation in growth-arrested OF was determined using immunocytochemical staining for the cell-proliferation-related nuclear antigen recognized by a monoclonal anti-Ki 67 antibody. In addition, the effects of OF coincubation with one of the aforementioned compounds and hydrocortisone (10(-7) M), the selective glucocorticoid receptor agonist RU 28362 (10(-7) M), or the glucocorticoid receptor antagonist RU 38486 (10(-7) M) were assessed. RESULTS: Under baseline conditions (0.1% fetal bovine serum), the proportion of proliferating cells was significantly higher in GO-OF compared with normal OF (p < 0.001). Significant stimulation of GO-OF proliferation was observed with interleukin-1 alpha (10 U/ml), interleukin-4 (1 ng/ml), insulin-like growth factor I (10 ng/ml), transforming growth factor beta (10 ng/ml), platelet-derived growth factor (1 ng/ml), and 1% or 15% fetal bovine serum (all P < 0.01), but not with interleukin-2 (10 U/ml) and interleukin-6 (100 U/ml). Compared with GO-OF, proliferation of normal OF was stimulated by fetal bovine serum to a similar degree, by interleukin-4, insulin-like growth factor I, transforming growth factor beta, and platelet-derived growth factor to a significantly lesser degree (all P < 0.01), and was unaffected by interleukin-1 alpha, interleukin-2, and interleukin-6. Compared with normal OF, either glucocorticoid receptor agonists, but not testosterone or progesterone, specifically inhibited the cytokine-stimulated proliferation of GO-OF to a significantly greater degree (P < 0.01). CONCLUSIONS: The enhanced proliferative capacity of GO-OF at baseline and in response to certain cytokines could play a role in the evolution of the clinical manifestations in GO. Inhibition of cytokine-activated cellular functions may be one mechanism by which glucocorticosteroids exert clinically useful effects in GO.

Antibodies, Monoclonal↗
PubMed1993

[Detection, localization and modulation of hyaluronic acid/CD44 receptor expression in patients with endocrine orbitopathy].

Accumulation of hyaluronic acid within the orbital tissues represents a histological hallmark of Graves' ophthalmopathy. The hyaluronic acid/CD44-receptor plays a key role in the binding and metabolism of hyaluronic acid, and affects numerous cellular functions of potential relevance to the pathogenesis of Graves' ophthalmopathy, including cell proliferation, migration, and adhesive interactions between connective tissue components and immunocompetent cells. Using a highly sensitive immunoperoxidase technique and monoclonal antibodies directed against the standard CD44 molecule, we examined the expression and modulation of hyaluronic acid/CD44 receptors in cryostat sections of orbital biopsy specimens derived from patients with severe Graves' ophthalmopathy and normal individuals. Modulation of CD44 by cytokines and affinity-purified IgGs derived from patients with Graves' ophthalmopathy was studied in extracts of fibroblast monolayers following stimulation in vitro, using SDS-polyacrylamid gel electrophoresis and immunoblotting. Strong immunoreactivity for CD44 was present in all specimens derived from patients with Graves' ophthalmopathy and was detected in fibroblasts residing in retroorbital connective tissue, in extracellular matrix components and in mononuclear cell infiltrates. By contrast, in normal orbital specimens, CD44 immunoreactivity was faint and present only in occasional connective tissue cells. Recombinant IL-1 alpha, TNF alpha, IGF-1 and GO-IgGs significantly stimulated CD44 expression in Graves' retroocular fibroblasts (range: 168 to 588%; all p < 0.05). By contrast, EGF, IL-6, control IgGs and 15% fetal calf serum failed to alter CD44 expression. Treatment of monolayers with IFN gamma resulted in weak inhibition of CD44 expression. In conclusion, the hyaluronic acid/CD44 receptor is expressed at elevated levels in Graves' orbital connective tissue in situ.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1993

Detection of TSH receptor RNA in cultured fibroblasts from patients with Graves' ophthalmopathy and pretibial dermopathy.

Fibroblasts are target cells for the autoimmune process in Graves' ophthalmopathy and pretibial dermopathy. Because the autoantigen involved in the hyperthyroidism of Graves' disease is the TSH receptor, we sought to determine whether RNA encoding this receptor might be present in retroocular and pretibial fibroblasts. RNA was reverse transcribed and the resulting cDNA was amplified by the polymerase chain reaction using primers spanning a region of the extracellular domain of the human TSH receptor. The predicted amplified product, verified by direct sequencing, was detected when RNA was derived from fibroblasts, but not from the nonfibroblast cells studied. The demonstration in fibroblasts of RNA encoding this important autoantigen in Graves' disease suggests that the TSH receptor might play a role in the pathogenesis of the connective tissue manifestations of this disease.

Base Sequence↗