Occurrence of thyrocyte HLA class II expression in a wide variety of thyroid diseases: relationship with lymphocytic infiltration and thyroid autoantibodies.

The proteins of the major histocompatibility system (HLA in humans) play an essential role in the regulation of immune responses due to their involvement in the presentation of antigen to T lymphocytes. Thyroid follicular cells (thyrocytes) from patients with Graves' disease and Hashimoto's thyroiditis demonstrate increased expression of HLA class I and aberrantly or inappropriately express class II antigens, a phenomenon that may play an important role in the pathogenesis of these autoimmune diseases. To establish if these changes in the expression of HLA molecules are characteristic of thyroid autoimmune disease, the immunopathological features (including class I and class II antigen expression) of 100 thyroidectomy specimens from patients with nonautoimmune thyroid disease were studied by indirect immunofluorescence, and the results compared with the findings in specimens from 14 patients with Graves' disease and 12 subjects undergoing laryngectomies for carcinoma. Increased class I product expression was found in 61% of all tissues studied, with maximal occurrence in papillary carcinomas (100%) and Graves' disease (86%), but it was also detected in 50% of the glands containing nodular lesions and in 16% of the control glands. Inappropriate class II molecule expression was found in Graves' disease (71%), hyperplastic nodules (53%), multinodular glands (44%), papillary carcinomas (38%), and 16% of the control glands. In summary, an increase in inappropriate HLA class I and class II expression was very common in nonautoimmune thyroid glands, but it generally occurred in the context of lymphocytic infiltration and thyroid autoantibodies (i.e. focal thyroiditis). Multiple correlation analyses of these 4 phenomena indicated heterogeneity in the mechanism leading to the inappropriate expression of thyrocyte class II antigens in the different conditions studied.

[Anthropometric changes and nitrogen balance in patients with morbid obesity treated with very low calorie diet]. / Modificaciones antropométricas y balance de nitrógeno en pacientes con obesidad mórbida tratados con dieta muy baja en calorías.

BACKGROUND: Morbid obesity is associated with increased morbidity and mortality. In these patients, weight reduction reduces associated morbidity and increases life expectancy. The aim of the present study was to evaluate the anthropometric changes in a group of patients treated with a very low caloric diet and to assess nitrogen balance and clinical and biological tolerance. METHODS: Overall 65 patients were prospectively evaluated (12 males and 53 females with a mean age of 45 +/- 7 years. Mean initial weight was 110 +/- 21 kg, with a Quetelet index of 43 +/- 7 kg/m2. They were treated as inpatients during 42 days exclusively with a very low caloric diet. They also followed a physical exercise program during one hour daily. RESULTS: The weight reduction was 15 +/- 4 kg (p less than 0.0001) with a reduction in fat mass of 9 +/- 2 kg (p less than 0.0001) and a reduction in fat-free mass of 6 +/- 3 kg (p less than 0.0001). The Quetelet index was reduced in 5 +/- 1 points (p less than 0.0001). There was also a reduction in the muscle adipose index from 1 +/- 0.2 to 0.7 +/- 0.2. The nitrogen balance remained negative throughout the 42 study days, although with a clear trend towards equilibrium. There were significant reductions in blood glucose, proteinemia, total cholesterol and subfractions. Triglycerides did not show significant changes. Clinical tolerance was excellent in all cases except 4 who withdraw from treatment because of nausea and vomiting. CONCLUSIONS: In this study, very low caloric diet achieved satisfactory weight reduction, basically at the expense of adipose tissue, reflected in a reduction of the muscle adipose index. Nitrogen balance remained negative throughout the treatment but with a trend towards normalization. Tolerance was excellent in 61 of the 65 cases (94%).

[The use of molecular epidemiologic markers in the study of an epidemic outbreak of legionnaires' disease of nosocomial origin]. / Utilidad de los marcadores epidemiológicos moleculares en el estudio de un brote epidémico de enfermedad del legionario de origen nosocomial.

BACKGROUND: Epidemiological investigations of Legionella infections are based, since recently, on molecular techniques that are more sensitive and specific than phenotypic traits. We were interested in these methods for subtyping isolates of L. pneumophila serogroup 1 and confirm the epidemic spread of an outbreak of legionnaires' disease at the Universitary Hospital Germans Trias i Pujol (HUGTiP) in Badalona. METHODS: Environmental samples taken from domestic water, heating and cooling water systems and oxygen humidifiers were examined. Clinical and environmental isolates of L. pneumophila serogroup 1 were compared by analysis of genomic DNA by restriction endonucleases. RESULTS: We could found L. pneumophila serogroup 1 and 9 in domestic hot water and heating systems and L. micdadei in cooling water system. Cleavage of genomic DNA showed that all restriction fragment patterns coming from clinical and environmental isolates of L. pneumophila serogroup 1 were identical and different from isolates belonging to the same species and serogroup but coming from community area. CONCLUSIONS: Molecular analysis of clinical and environmental isolates of L. pneumophila serogroup 1 has allowed to identify a reservoir related to a nosocomial outbreak of legionnaires' disease at the HUGTiP, and a clonal population of L. pneumophila serogroup 1 in environmental samples genotypically identical to the clinical ones.

[Defects of adrenal steroidogenesis in patients with hirsutism]. / Defectos de la esteroidogénesis adrenal en pacientes con hirsutismo.

BACKGROUND: To determine the frequency and the type of adrenal steroidogenic abnormalities in hirsute women. SUBJECTS AND METHODS: ACTH test was performed during follicular phase in 127 hirsute and 40 normal (control) women. Before ACTH injection we measured in serum by RIA: 17-OH-pregnenolone (17-OH-P5), 17-OH-progesterone (17-OH-P4), androstenedione (AN), cortisol (CT), 11-deoxycortisol (DCT), dehydroepiandrosterone (DHEA) and its sulphate (DHEAS), total (TT) and free (FT) testosterone, oestradiol (E2), progesterone (PR), androstenediol glucuronide (AG), LH, FSH and prolactin. After 60 min of ACTH injection 17-OH-P5, 17-OH-P4, AN, DHEA, CT and DCT were measured. Net increment of stimulated steroids and the ratios 17-OH-P5/17-OH-P4, DHEA/AN, 17-OH-P4/CT, 17-OH-P5/CT and DCT/CT were calculated. Pelvic ultrasonographic exploration was done when irregular menses were reported. RESULTS: Up to 31% of the patients presented enzymatic defects in adrenal steroidogenesis. Diagnostic criteria for enzyme defects were established. Late-onset 21-hydroxylase deficiency was diagnosed in 6 (4.5%) patients, HLA typing of these patients demonstrated that 4 out of 6 had B14-DR1. Sixteen women (12.6%) displayed a 17-OH-P4 response and the net increment 2 SD above the normal mean concentration, which are diagnostic criteria for late-onset 21-hydroxylase deficiency carriers. We diagnosed a 3 beta-hydroxysteroid dehydrogenase defect when 17-OH-P5 and DHEA responses, their net increment and the 17-OH-P5/17-OH-P4 and 17-OH-P5/CT ratios were 2 SD above the normal mean after ACTH: 14 women were diagnosed. 11 beta-hydroxylase deficiency diagnosis was made when DCT response, its net increment and the DCT/CT ratio after ACTH were 2 SD above the normal mean: 7 women were detected. Associated biosynthetic defects were described. CONCLUSIONS: One third of our patients with hirsutism presented anomalous response to ACTH, consistent with enzymatic abnormalities in adrenal steroidogenesis.

Transcription of a broad range of self-antigens in human thymus suggests a role for central mechanisms in tolerance toward peripheral antigens.

The role of the thymus in the induction of tolerance to peripheral antigens is not yet well defined. One impending question involves how the thymus can acquire the diversity of peripheral nonthymic self-Ags for the process of negative selection. To investigate whether peripheral Ags are synthesized in the thymus itself, we have determined the expression of a panel of circulating and cell-bound peripheral Ags, some of which are targets of autoimmune diseases, at the mRNA level in total thymic tissue and in its main cellular fractions. Normalized and calibrated RT-PCR experiments demonstrated the presence of transcripts of nonthymic self-Ags in human thymi from 8 days to 13-yr-old donors. Out of 12 glands, albumin transcripts were found in 12; insulin, glucagon, thyroid peroxidase, and glutamic acid decarboxylase (GAD)-67 in six, thyroglobulin in five, myelin basic protein and retinal S Ag in three, and GAD-65 in one. The levels of peripheral Ag transcripts detected were age-related but also showed marked interindividual differences. Cytokeratin-positive stromal epithelial cells, which are a likely cellular source for these, contained up to 200 transcript copies of the most expressed peripheral Ags per cell. These results implicate the human thymus in the expression of wide representation of peripheral self-Ags and support the view that the thymus is involved in the establishment of tolerance to peripheral Ags. The existence of such central mechanism of tolerance is crucial for the understanding of organ-specific autoimmune diseases.

Chronic administration of amiodarone and thyroid function: a follow-up study.

In order to evaluate the effects of amiodarone on thyroid function in chronically treated patients, 43 consecutive patients, who had been taking a mean weekly dose of 1420 +/- 488 mg for more than 9 months (mean 16.5 months), were studied. In a first evaluation, three patients with hypothyroidism and two with hyperthyroidism were discovered. In the remaining 38 patients, mean T4 (131 +/- 38 nmol/L) and rT3 (0.85 +/- 0.3 nmol/L) levels were significantly higher than reference values (p less than 0.05 and p less than 0.001, respectively), and mean T3 levels (1.89 +/- 0.73 nmol/L) were significantly lower (p less than 0.001). Thirteen patients showed hyperresponsiveness to thyrotropin-releasing hormone (TRH) stimulation testing. In a second evaluation, performed 12 to 18 months later, two new cases of hypothyroidism were discovered. T3 levels showed significantly lower values (p less than 0.02) than in the first evaluation, whereas basal thyroid-stimulating hormone levels and levels 30 and 60 minutes after TRH stimulation were significantly higher than those in the first evaluation (p less than 0.001). Five new hyperresponders to TRH were found. In the present series, the progressive appearance of clinical thyroid dysfunction with an elevated total incidence (16%) is demonstrated. Moreover, a progressively high prevalence of hyperresponsiveness to TRH stimulation is shown. These findings indicate that chronic amiodarone administration may carry a high risk of thyroid dysfunction.

Reduction of the susceptibility to infective endocarditis with time in animals with endocavitary catheters.

In a previous study we showed that the lesions of non-bacterial thrombotic endocarditis induced by means of implantation of a catheter in the left ventricle (LV) of the rabbit, undergo inner connectivization and surface endothelialization, which are completed within 2-3 months. In the present study we have investigated whether these histological changes lead to a variation in susceptibility to infective endocarditis (IE). After studying two control groups, we compared the incidence of IE in four groups of 15 rabbits each, inoculated with Streptococcus mitis I, 10, 35 and 70 days after implantation of a catheter in the LV. The frequency of infection was shown to be progressively reduced from 100% to 26.7%. This demonstrates that endothelialization of the catheter and the sterile vegetations protect the animals from IE.

Expression of intercellular adhesion molecule-1 in thyroid follicular cells in autoimmune, non-autoimmune and neoplastic diseases of the thyroid gland: discordance with HLA.

The presence of intercellular adhesion molecule-1 (ICAM-1) on epithelial cells facilitates their recognition by specific T lymphocytes. To assess the possible role of ICAM-1 in the recognition of thyroid follicular cells by T cells in thyroid autoimmune disease, we investigated the expression of ICAM-1 in thyrocytes from thyroid glands affected by Graves' disease, in glands with non-autoimmune pathology and normal glands using immunofluorescence staining on cryostat sections and on dispersed cell preparations. Sequential tissue sections from glands affected by Graves' disease (n = 15), multinodular goitre (MNG, n = 26), benign nodules (n = 11), primary carcinomas (n = 12) and control thyroid glands (n = 5) were stained for ICAM-1, HLA class I, HLA class II, CD3 and thyroid peroxidase (TPO). Weak and patchy ICAM-1 expression was found in the thyrocytes of 4/15 (27%) Graves' disease and of 1/26 (4%) multinodular goitre glands. In contrast, ICAM-1 expression was detected in the thyrocytes of 5/11 (45%) benign nodules and of 8/12 (67%) thyroid carcinomas in which it was sometimes strong. Thyrocytes in the five control glands were negative. These results correlated well with flow cytometry data from 23 of these glands which showed that ICAM-1 expression in thyrocytes from Graves' patients was, when present, 'dull', while in some malignant thyrocytes it was 'bright'. In preparations of thyrocytes from Graves' disease glands we found a striking discordance between the high levels of expression of HLA class I and HLA class II and the low expression of ICAM-1. This is surprising since in vitro the expression of these three molecules is equally induced by IFN-gamma and TNF-alpha. These results suggest that additional factors are involved in the induction of the inappropriate HLA class II expression observed in the thyrocytes of glands affected by Graves' disease.

Hyperexpression of transporter in antigen processing-1 (TAP-1) in thyroid glands affected by autoimmunity: a contributing factor to the breach of tolerance to thyroid antigens?

According to the 'aberrant HLA expression' hypothesis, endocrine autoimmunity is driven by presentation of self antigens by target cells over-expressing HLA molecules. In autoimmune thyroid diseases (AITD), thyroid follicular cells (thyrocytes) over-express HLA class I and HLA class II molecules. Since efficient presentation of endogenous peptides via class I requires transporters that translocate endogenous peptides from the cytoplasm to the endoplasmic reticulum, i.e. transporters associated with antigen processing (TAP) -1 and -2, the capability of thyrocytes to express TAP and whether TAP is hyperexpressed in AITD glands are issues relevant to the above hypothesis. Results from immunofluorescence and Northern blotting studies on primary thyrocyte cultures and on a thyroid cell line demonstrate that thyrocytes express constitutively TAP-1 at a low level, and that this expression is readily induced by interferon-gamma (IFN-gamma) and to a lesser extent by IFN-alpha. In AITD, but not in non-autoimmune glands, thyrocytes hyperexpress TAP-1, as demonstrated by both immunohistopathology and flow cytometry. The cytokine pattern does not bear, as assessed by reverse transcriptase-polymerase chain reaction (RT-PCR), a clear relationship with TAP-1 expression. These results have broad implications and suggest that the core concept of the 'aberrant HLA expression' hypothesis of endocrine autoimmunity could be incorporated in the currently prevailing view of 'autoimmunity by breach of peripheral tolerance'.