Effects of testosterone on the development of autoimmune thyroiditis in two strains of chicken

Sex differences in monocyte expression of IL-6: role of autonomic mechanisms

Sex differences in the prevalence of inflammatory disorders exist, perhaps due to sex differences in cellular mechanisms that contribute to proinflammatory cytokine activity. This study analyzed sex differences of monocyte intracellular expression of IL-6 and its associations with reproductive hormones and autonomic mechanisms in 14 matched pairs of men and women ( n = 28). Monocyte intracellular IL-6 production was repeatedly assessed over two circadian periods. Sympathetic balance was estimated by heart rate variability and the ratio of power in the low-frequency (LF) to high-frequency (HF); vagal tone was indexed by the power of HF component. As compared to men, women showed greater monocyte expression of IL-6 across the circadian period. In addition, women showed lower sympathetic balance (LF/HF ratio), and greater levels of vagal tone (HF power). In women, but not men, sympathovagal balance was negatively associated with monocyte IL-6 expression, whereas vagal tone was positively associated with production of this cytokine. Levels of reproductive hormones were not related to monocyte IL-6 expression. The marked increase in monocyte expression of interleukin-6 in women has implications for understanding sex differences in risk of inflammatory disorders. Additionally, these data suggest that sex differences in sympathovagal balance or vagal tone may be a pathway to explain sex differences in IL-6 expression. Interventions that target autonomic mechanisms might constitute new strategies to constrain IL-6 production with impacts on inflammatory disease risk in women.

Effects of testosterone in the treatment of immune-mediated sensorineural hearing loss

Testosterones have beneficial effects not only on the modulation of expression of autoimmunity of B/W mice, but on other unrelated models such as autoimmune thyroiditis as well. This study was performed to evaluate the effect of testosterone in the treatment of immune-mediated sensorineural hearing loss (IMSNHL). To induce IMSNHL, 29 female Wistar rats were sensitized with bovine inner ear antigen three times weekly. Fourteen of 29 rats were injected subcutaneously three times a week with 250 microg of testosterone propionate from 1 week prior to the first sensitization to 1 week following the second booster sensitization. An auditory brain-stem response (ABR) test was performed prior to each antigen challenge and at 1, 2, 3, 4, 6 and 8 weeks following sensitization. On ABR testing, the testosterone-treated animals showed better results than the control animals with IMSNHL in the degree of hearing loss (10 to 20 dB vs. 10 to 40 dB) and incidence of hearing loss over 20 dB (25.0% vs. 53.3%). None of testosterone-treated animals showed a hearing loss over 20 dB, whereas 40% of the control animals with IMSNHL revealed hearing loss over 20 dB. These results suggest that testosterone propionate may be effective in the prevention of and early recovery from IMSNHL and may be used in the future as a one treatment modality for IMSNHL.

Immunological pattern in patients with 21-hydroxylase deficiency

The aim of this work was to perform an immunological study in six patients with 21 hydroxylase deficiency in mild form (M210HD) and in 2 patients with 21-hydroxylase deficiency in classical form (C210HD) and in their parents, in whom a previous HLA,C4,Bf typing demonstrated high prevalence of DR5 and phenotypic absence of fraction C4B of complement (C4BQO). This study contains the evaluation of C3, IgA, IgG, IgM levels, anticardiolipin antibodies (IgG and IgM) and circulating immunocomplexes. A study of lymphocyte subsets was also performed. Among M210HD 1 patient showed presence of anticardiolipin antibodies both IgM and IgG; this patient had shown antinuclear antibodies in a previous study. Among parents, some subjects showed presence of anticardiolipin antibodies and high levels of circulating immunocomplexes. No alterations in C3 and Ig levels were observed. A reduced percentage of CD4 suppressor-inducer (CD4-SI) (p < 0.05 in M210HD and in parents vs controls) and increased percentage of CD4 helper-inducer (CD4-HI) (p < 0.05 in both groups vs controls) were found. No alterations were evidenced in C210HD patients. Data about association between 21-hydroxylase deficiency and autoimmune diseases are rare. Our results confirm that 210HD could be associated to an unbalancement of immune system function and suggest that non immune genes, like 21-hydroxylase one, may influence the expression of autoimmune diseases at least in presence of peculial extended haplotypes.

Androgen treatment prevents diabetes in nonobese diabetic mice

The nonobese diabetic (NOD) mouse strain provides a model system for human autoimmune diabetes. This disease model is extensively used not only to examine the etiology and pathogenesis of diabetes, but also as a means to evaluate therapies. In NOD mice, the disease progresses from insulitis to islet destruction and clinical diabetes in a high percentage of female mice. In this study, androgen therapy, begun after the onset of insulitis, was found to prevent islet destruction and diabetes without eliminating the islet inflammation in female NOD mice. However, diabetes can be adoptively transferred into such hormone-treated recipients. The prevention of disease onset by androgen is likely due to the hormonal alteration of the development or function of the immune cells necessary for islet destruction.

The influence of pregnancy and reproductive span on the occurrence of autoimmune thyroiditis

A study comparing the reproductive histories of 89 women affected by Hashimoto's thyroiditis (HT) with 89 matched controls has been carried out to determine whether endogenous hormones contribute to the development of the disease. There was no evidence of an association between HT and parity and no trend to an increasing disease risk with increasing parity. However, patients with HT had a longer reproductive span. There was a significant trend to a lower risk with later age at menarche (relative risk (RR) of menarche at 13-14 years compared with less than or equal to 12 years = 0.71, and greater than or equal to 15 years compared with less than or equal to 12 years = 0.45), and an increased risk with a later menopause (greater than or equal to 51 years compared with less than or equal to 50 years, RR = 3.00, P less than 0.025). An additional finding was an increased hysterectomy rate among the cases. These observations may be explained if the hyperoestrogenic state associated with a longer reproductive span acted to modulate the immune process in autoimmune thyroid disease.

Effects of gender and sex steroids on the immune response

Elevated immune responses and the higher incidence of autoimmune diseases in female (compared to male) humans and animals have been known for a long time. However, the scientific interest in this interrelationship has been limited both amongst immunologists and endocrinologists. It is mainly in the last ten years that investigations in this area have been intensifying. A number of fairly recent review articles confirm the increased interest in various aspects of this "interdiscipline" [1-4]. In the present paper we should like to make a new assessment of the state of knowledge. We shall firstly discuss heteroimmune response differences between males and females in humans, rodents and birds and then the roles of gender and sex hormones in autoimmune disease in various species. The general conclusions are the following. Gender and sex hormones have a clear effect on various hetero- and auto-immune responses but the mechanisms of action are still unknown; starting from sex hormones, steroids can be devised which have favourable effects on immune processes but lack undesirable hormonal effects; such hormonomimetics should be, in principle, applicable for the treatment of autoimmune disease.

Identification of T cells in early dermal lymphocytic infiltrates in avian scleroderma

University of California, Davis (UCD) line 200 chickens spontaneously develop a progressive fibrotic syndrome with features similar to those observed in human autoimmune connective tissue diseases, including fibrosis, vascular occlusion, and lymphocytic infiltration of the comb, skin, digits, and viscera. Beginning at 2 weeks post hatch, line 200 chickens develop intense lymphocytic infiltration of the comb and dorsal neck skin. To further characterize the nature of these cellular infiltrates, weekly serial skin biopsy specimens from line 200 and control birds were examined using hematoxylin and eosin staining and indirect immunofluorescence with a library of mouse anti-chicken monoclonal antibodies specific for lymphocyte markers. In situ staining performed on serial skin sections revealed the presence of large groups of T cells beginning at 2 weeks of age. Further characterization of these infiltrates demonstrated the presence of both T helper and T cytotoxic/suppressor cells with a mean +/- SD T4:T8 ratio of 1.44 +/- 0.29 by 4 weeks of age. As the lesions progressed, the infiltrates also contained distinct groups of B cells as characterized by MUI 36. In addition, the lesions were strongly positive for B-L (Ia) antigen, which was noted on B cells, monocytes/macrophages, activated T cells, and fibroblasts. The skin sections were negative for 2 different macrophage monoclonal antibodies at all time-points. Upon extraction from affected skin, 42.0 +/- 13.06% (mean +/- SD) of these cells were positive for B-L, 35.10 +/- 6.51% were T cells, and 31.25 +/- 3.14% were recognized by MUI 36. Although positive staining for IgG was not found in these extracted cells, 7% of the isolated cells were positive for surface IgM.

Effects of elevated gonadotropin levels on thyroid function in the male rat

In order to determine if thyroid disease in hypogonadal men is the result of chronic elevation of serum gonadotropins, thyroid histology and serum thyroid hormone levels were evaluated in male rats that had been castrated either 2 weeks or 15 months previously. Despite significantly elevating serum LH levels, castration did not affect thyroid structure or function. Serum total T4 levels were reduced with age in both short and long-term castrate animals but returned to the levels seen in young rats when testosterone was replaced. Testosterone replacement also increased free T4 levels in both the young and old castrate rats. Neither age nor testosterone replacement affected serum T3 or TSH levels.

Abnormal testicular function in men with primary hypothyroidism

Myxedema in men is thought to cause infertility and impotence. Testicular function was investigated in eight consecutive men with primary hypothyroidism (autoimmune thyroiditis in five patients and amiodarone therapy in three patients). All had impotence that preceded the onset of hypothyroidism and did not improve with thyroid therapy. Gonadal function tests showed a hypergonadotropic state in five patients and hypogonadotropic hypogonadism in three patients including one with no response to luteinizing hormone-releasing hormone. Luteinizing hormone bioactivity was decreased in six patients and increased in two subjects who also had increased luteinizing hormone immunoreactivity. Serum testosterone and testosterone/estradiol-binding globulin concentrations were low in four of the patients. It is concluded that abnormalities of gonadal function are common in men with primary hypothyroidism.

Effect of testosterone treatments for varying periods on autoimmune development and on specific infiltrating leukocyte populations in the thyroid gland of obese strain chickens

Spontaneous autoimmune thyroiditis (SAT) is detectable by 2 weeks of age in the obese (OS) strain of chicken, and by 6 weeks virtually all of these animals have severe lymphoid infiltration of the thyroid. During the interval from hatching to 6 weeks of age, testosterone implants were administered for varying periods. All treatment groups were terminated at 6 weeks. Testosterone administered shortly after hatching increased thymus weight, depressed bursa weight, and reduced the severity of SAT, as measured by lymphoid infiltration of the thyroid and circulating thyroglobulin autoantibody concentrations. Birds supplemented with testosterone at later intervals exhibited depressed bursa and thymus weight; however, the severity of SAT was not affected. In a second experiment, the treated group was administered testosterone for the first 2 weeks after hatching. Thyroids were histologically examined at 2 and 6 weeks using a panel of five monoclonal antibodies (anti-Ia, anti-IgM, anti-IgG, anti-T cell, and antithymocyte). Compared with untreated controls, testosterone treatment reduced the frequency of Ia+ cells, T cells, and IgG+ cells in the thyroid. This treatment did not affect the frequency of IgM+ cells, and perhaps slightly increased the frequency of thymocytes. These results suggest that testosterone's suppressive effects are associated with changes in thymic development and effector T-cell and regulator T-cell activity.

Sex steroid and glucocorticoid receptors in the bursa of Fabricius of obese strain chickens spontaneously developing autoimmune thyroiditis

The female sex develops autoimmune disease far more often than the male. This is claimed to be due to differences in peripheral sex steroid levels. We have examined in the bursa of Fabricius of Obese strain (OS) chickens, which spontaneously develop autoimmune thyroiditis, as well as in their healthy counterparts androgen(AR)-, estrogen(ER)-, progestin(PR)- and glucocorticoid(GR)-receptors in an attempt to elucidate possible further pathomechanisms, namely at the target site of steroid hormones. The characterization (affinity, specificity, association- and dissociation-rate, sedimentation behaviour) of all four types of receptors revealed no difference between sex or strain. Furthermore, the ontogeny study of the receptor capacity and affinity from the 7th embryonic day (i.e. before lymphocyte settlement) until bursa involution, again showed no difference between OS and healthy chickens of either sex. Thus, it can be concluded that the principal sex dependency of the susceptibility to autoimmune disease results predominantly from differences in sex steroid levels per se, although alterations in mechanisms beyond the cytosolic receptor level can presently not be excluded.