IL-14 and IL-16 are expressed in the thyroid of patients with either Graves' disease or Hashimoto's thyroiditis.

OBJECTIVES: Cytokines have an important role in orchestrating the pathophysiology in autoimmune thyroid disease. The aim of the current study was to analyse the expression of interleukin (IL)-14 and IL-16 in the thyroid tissue of patients with Graves' disease (GD), Hashimoto's thyroiditis (HT) or multinodular goitre (MNG) and in that of normal individuals, in patients' intrathyroidal CD4(+) and CD8(+) T cells, and in patient and normal cultured thyroid follicular cells. METHODS: The expression of IL-14 and IL-16 mRNA and protein was investigated using reverse transcription-polymerase chain reaction (RT-PCR) amplification, and Western blotting and ELISAs, respectively. RESULTS: IL-14 mRNA expression was detected in thyroid tissue from 8/9 GD, 3/4 HT and 3/13 MNG patients and 1/6 normal individuals, and IL-16 mRNA expression in thyroid tissue from 9/9 GD, 4/4 HT and 9/13 MNG patients and 4/6 normal individuals. IL-14 mRNA expression was detected in intrathyroidal CD4(+) and CD8(+) T cells from 2/2 GD and 2/2 HT patients, while IL-16 mRNA was detected in samples from 1/2 HT patients but not in those from either patient with GD. IL-14 and IL-16 mRNA expression was found in thyroid follicular cells derived from 2/2 patient with GD and 1/1 normal individual. IL-14 protein was detected in thyroid tissue from 6/6 GD, 1/1 HT and 0/6 MNG patients and 0/6 normal individuals, and IL-16 protein in thyroid tissue from 6/6 GD, 1/1 HT and 1/6 MNG patients and 0/6 normal individuals. Expression of IL-14 protein was stimulated in thyroid follicular cells derived from two patients with GD and one normal individual by peripheral blood mononuclear cell (PBMC)-conditioned medium. Treatment of thyrocytes from two patients with GD and one normal individual with PBMC-conditioned medium and tumour necrosis factor (TNF)-α stimulated IL-16 protein expression. In normal thyrocytes, IL-16 protein synthesis was induced also by IL-1ß, IL-17A, IL-4 and transforming growth factor (TGF)-ß. CONCLUSIONS: The data provide evidence that the intrathyroidal production of IL-14 and IL-16 is associated with the pathogenesis of autoimmune thyroid disease. Thyroid follicular cells display the ability to express IL-14 and IL-16 mRNA and can be stimulated to express IL-16 protein, by a panel of cytokines, and IL-14 protein, by as yet unidentified factors.

Function-blocking autoantibodies to the melanin-concentrating hormone receptor in vitiligo patients.

Vitiligo is a common depigmenting skin disorder resulting from the loss of melanocytes in the cutaneous epidermis. Although the cause of the disease remains obscure, autoimmune mechanisms are thought to be involved. Recently, melanin-concentrating hormone receptor (MCHR)-binding autoantibodies have been identified in vitiligo patients. In the present study, we aimed to determine if MCHR autoantibodies could also affect receptor function either by direct activation or by blocking its response to melanin-concentrating hormone. The results indicated that 10/18 (56%) vitiligo patient IgG samples inhibited the function of MCHR expressed in a Chinese hamster ovary cell line. In contrast, neither control (n=20) nor SLE patient (n=10) IgG samples blocked receptor function. Compared with healthy controls, MCHR function-blocking autoantibodies were found at a significantly increased frequency in the vitiligo patient group (P=0.0004). No MCHR-activating autoantibodies were detected in any of the vitiligo patient, SLE patient or control IgG samples that were analysed. In addition, vitiligo patient IgGs were tested for MCHR autoantibodies that could mediate antibody-dependent cell-mediated cytotoxicity via the receptor. However, this could only be demonstrated in two vitiligo patient sera. Overall, this work has provided additional evidence that MCHR is a B-cell autoantigen in vitiligo and has demonstrated the existence of MCHR function-blocking autoantibodies further to the receptor-binding autoantibodies previously reported.

Characteristics of autoimmune thyroid disease occurring as a late complication of immune reconstitution in patients with advanced human immunodeficiency virus (HIV) disease.

Experimental evidence from animal models has provided a framework for our current understanding of autoimmune disease pathogenesis and supports the importance of genetic predisposition, molecular mimicry, and immune dysregulation. However, only recently has evidence emerged to support the role of immune dysregulation in human organ-specific autoimmune disease. In the current study of the "late" manifestation of autoimmune thyroid disease (AITD) in a cohort of human immunodeficiency virus (HIV)-positive patients following highly active antiretroviral therapy (HAART), we discuss how immune dysregulation and factors associated with the immunopathology of HIV infection fit the current understanding of autoimmunity and provide a plausible basis for our clinical observations. De novo diagnoses of thyroid disease were identified between 1996 and 2002 in 7 HIV treatment centers (5/7 centers completed the study). Patients were diagnosed as clinical case entities and not discovered through thyroid function test screening. Paired plasma specimens were used to demonstrate sequential rise in thyroid antibodies. Seventeen patients were diagnosed with AITD (median age, 38 yr; 65% were of black African or black Caribbean ethnicity; and 82% were female). The median duration of immune reconstitution was 17 months. Graves disease (GD) was diagnosed in 15 of 17 patients. One patient developed hashithyrotoxicosis with atypically raised C-reactive protein, and another developed hypothyroidism. One GD patient had associated secondary hypoadrenalism. The estimated combined prevalence of GD for 4 treatment centers for female patients was 7/234 and for males was 2/1289. The denominator numbers were matched controls, from 4 centers able to provide data, who commenced HAART during the same time (January 1996 to July 2002) and who did not develop clinical AITD. The mean baseline pre-HAART CD4 count was 67 cells/mL, and the mean increase from nadir to AITD presentation was 355 cells/mL. AITD patients were more likely than controls (95% confidence interval, chi-square test) to be severely compromised at baseline (as defined by a CD4 count < 200 cells/mL or the presence of an acquired immunodeficiency syndrome [AIDS]-defining diagnosis), and to experience greater CD4 increments following HAART. AITD may be a late manifestation of immune reconstitution in HIV-positive patients taking HAART, and immune dysregulation may be an important factor.

Detection and localization of chemokine gene expression in autoimmune thyroid disease.

OBJECTIVE: Autoimmune thyroid disease (Hashimoto's thyroiditis and Graves' disease) is characterized by lymphocytic infiltration of the thyroid gland. Chemokines are cytokines with chemoattractant properties for a range of immune effector cells and might therefore play a significant role in the initiation and maintenance of the autoimmune process. The aim of this study was to analyse chemokine gene expression in autoimmune thyroid tissue and in cultured thyroid follicular cells (TFC). DESIGN AND PATIENTS: Immunocytochemistry and reverse-transcriptase polymerase chain reaction (RT-PCR) amplification were used to analyse the expression of monocyte chemoattractant protein (MCP)-1, RANTES (regulated upon activation, normal T cell expressed and secreted), macrophage inflammatory protein (MIP)-1 alpha, MIP-1 beta, interferon (IFN)-gamma-inducible protein (IP)-10 and monokine induced by IFN-gamma (Mig) in thyroid tissue from patients with Hashimoto's thyroiditis (n = 4), Graves' disease (n = 6) and nonautoimmune multinodular goitre (n = 4). Chemokine gene expression was also examined in cultured TFC by RT-PCR. RESULTS: Expression of MCP-1, RANTES, MIP-1 alpha, MIP-1 beta, IP-10 and Mig was demonstrated in all Hashimoto's and most Graves' thyroid specimens but very little expression was detected in the nonautoimmune goitre samples. In thyroid tissue from Graves' disease patients, positive staining for chemokines was largely restricted to the lymphocytic cell infiltrate. Within thyroid tissue from Hashimoto's patients, there was evidence for the expression of all chemokines by thyroid follicular cells, suggesting a role for local chemokine synthesis by the glandular epithelial cells in the recruitment of inflammatory cells into the gland in autoimmunity. The present work also showed that expression all the chemokine genes analysed could be induced in cultured thyroid cells by IFN-gamma and interleukin (IL)-1 alpha. Expression of all the chemokines examined was not stimulated by TSH. CONCLUSION: We postulate that TFC may play a role in the pathogenesis of autoimmune thyroid disease as they are able to express the chemokines MIP-1 alpha, MIP-1 beta, MCP-1, RANTES, IP-10 and Mig that would promote the infiltration of immune cells into the thyroid gland.

Mutations of the PDS gene, encoding pendrin, are associated with protein mislocalization and loss of iodide efflux: implications for thyroid dysfunction in Pendred syndrome.

Pendred syndrome (PDS) is an autosomal recessive disorder characterized by deafness and goiter. Phenotypic heterogeneity is observed in affected individuals, and thyroid dysfunction is particularly variable. The syndrome is caused by mutations in the PDS (SLC26A4) gene, encoding an anion transporter pendrin, which localizes to the apical membrane of thyroid follicular cells. PDS is thought to enable efflux iodide into the follicle lumen. More than 50 diseases causing mutations of PDS have been reported. Here we have investigated the effect of nine PDS missense mutations on pendrin localization and iodide transport with the view to understanding their functional impact. As demonstrated by transient expression of green fluorescent protein-tagged pendrin mutant constructs in mammalian cell lines, appropriate trafficking to the plasma membrane was observed for only two mutants. The remaining PDS mutants appear to be retained within the endoplasmic reticulum following transfection. Iodide efflux assays were performed using human embryonic kidney 293 cells transfected with mutant pendrin and cotransfected with sodium iodide transporter to provide a mechanism of iodide uptake. The results indicated loss of pendrin iodide transport for all mislocalizing mutations. However, PDS mutants are associated with variable thyroid dysfunction in affected subjects. We concluded that additional genetic and/or environmental factors influence the thyroid activity in Pendred syndrome.