T helper (Th) 17 cells and interleukin (IL)-17 play a significant role in the pathogenesis of autoimmune thyroid disease (AITD). However, it has recently become clear that Th17 cells are more heterogeneous and exhibit two different phenotypes, whereas IL-23 and IL-1β are crucial for the generation of pathogenic Th17 lymphocytes. We aimed to investigate the association between IL-17 and Th17-promoting cytokines in AITD by studying the immunoexpression patterns of IL-17, IL-23, and IL-1β in thyroid tissue. Following thyroidectomy, 29 patients with AITD (21 cases of Hashimoto’s thyroiditis (HT) and 8 cases of Graves’ disease (GD)) and 18 patients with colloid goiter, as controls, were enrolled in this study, and immunohistochemistry was performed. The expression level of IL-17 in thyrocytes was significantly higher in HT and GD patients than in colloid goiter patients. Immunopositivity for both IL-23 and IL-1β was significantly increased in HT patients compared to GD and colloid goiter patients. However, no difference was found between IL-23 or IL-1β expression in patients with GD and colloid goiter. A positive correlation between IL-17 and IL-23 as well as IL-17 and IL-1β expression was observed in HT patients (r = 0.574, p = 0.007 and r = 0.461, p = 0.036, respectively). In the GD group, IL-17 was positively correlated with IL-1β (r = 0.817, p = 0.013) but not with IL-23 expression. We found increased IL-23 and IL-1β expression in the HT group but not in the GD group. Furthermore, both interleukins were correlated with IL-17 immunopositivity in thyroid tissue, suggesting that pathogenic Th17-promoting cytokines may play a role in HT pathogenesis.

Th17 cells together with their hallmark cytokine interleukin (IL)-17 were identified as crucial contributing factors in the pathogenesis of thyroid autoimmunity. The cytokine-regulated tight junction (Tj) disruption is thought to be essential in the initiation and/or development of several diseases. Still, the role of IL-17 maintaining Tj integrity in autoimmune thyroid diseases (AITDs) has not yet been evaluated. We aimed to investigate integrity of the thyroid follicle by studying immunoexpression of cellular Tj – zonula occludens (ZO)-1 and claudin-1 proteins coupled to IL-17A and CD68 detection in AITD patients compared with controls. Thirty-five adult patients undergoing thyroidectomy and presenting 18 cases of Hashimoto thyroiditis (HT), 7 of Graves’ disease (GD) as well as 10 subjects of colloid goiter without autoimmune component served as controls were enrolled in this study. An immunohistochemical analysis including IL-17A, ZO-1, claudin-1, and CD68 detection was performed in each case. The correlation of IL-17A with Tj and CD68 in patients with AITD was also analyzed. Apart from inflammatory cells, we evidenced a stronger expression level of IL17A in the thyroid follicular cells in HT patients when compared with GD or colloid goiter. A significant reduction of ZO-1 immunoreactivity was observed in the thyrocytes in HT patients, whereas no significant differences were found in claudin-1 expression in HT and GD compared with colloid goiter patients. A significantly higher number of thyroid follicles with CD68-positive cells was found in HT patients than that in patients with GD or colloid goiter. In HT patients, the expression of IL-17A in the follicular cells was positively correlated with CD68 immunopositivity, whereas no association with claudin-1 or ZO-1 expression was found. GD patients did not reveal any significant correlation of IL-17A with Tj and CD68. Strong overexpression of IL-17A observed in the thyroid epithelial cells is associated with the presence of intrafollicular CD68-positive cells in HT patients. We evidenced the changes in molecules of thyrocyte junctional complexes highlighting impairment of the thyroid follicle integrity in HT, but no association with IL-17A was found.

Objective: Low iodine intake during pregnancy may cause thyroid dysfunction, which results in inadequate fetal brain development. In the absence of a universal salt iodization programme, we conducted a nationwide survey of iodine deficiency in pregnant women in Latvia.Design: A countrywide twenty-cluster survey, with at least twenty women per cluster. Participants completed a questionnaire on dietary habits concerning iodine intake (n 739). Thyroid function (thyroid-stimulating hormone, free thyroxine and thyroperoxidase antibodies) was measured (n 550). Urinary iodine was measured using the ammonium persulfate method (n 696).Setting: The survey was performed in all regions of Latvia during the spring and autumn seasons in 2013.Subjects: Pregnant women (n 829).Results: The median creatinine (Cr)-standardized urinary iodine concentration (UIC) was 80·8 (interquartile range (IQR) 46·1–130·6) µg/g Cr or 69·4 (IQR 53·9–92·6) µg/l during pregnancy, and 81 % of pregnant women had UIC levels below the WHO recommended range of 150–250 µg/g Cr. The UIC was lowest during the first trimester of pregnancy, 56·0 (IQR 36·4–100·6) µg/g Cr, reaching higher concentrations of 87·5 (IQR 46·4–141·7) µg/g Cr and 86·9 (IQR 53·8–140·6) µg/g Cr in the second and third trimesters, respectively. Women taking supplements containing ≥150 µg iodine (6·8 % of respondents) had non-significantly higher UIC than did women without supplementation (96·2 v. 80·3 µg/g Cr, respectively, P=NS). Thyroperoxidase antibody concentration did not correlate significantly with UIC: Spearman’s ρ=−0·012, P=0·78.Conclusions: The median UIC indicates iodine deficiency in pregnant women in Latvia. Iodine supplementation (150 µg daily) and regular UIC monitoring should be suggested to overcome iodine deficiency and to reach the recommended levels without inducing autoimmune processes.

Autoimmune thyroid disease (AITD), including Graves’ disease (GD) or Hashimoto’s thyroiditis (HT), occurs due to genetic susceptibility and environmental factors, among which the role of stressful events remains controversial. This study investigated the relationship between the number and impact of stressful life events in AITD patients with selenium status, and the Th1/Th2/Th17 immune response. The study population included three groups: HT (n = 47), GD (n = 13), and a control group (n = 49). Thyroid function parameters, autoantibody levels, and the plasma levels of cytokines, selenium, selenoprotein P (SeP), and glutathione peroxidase 3 (GPx) activity were measured. Participants filled out the Life Experiences Survey. No significant differences in the number of stressful life events were found among the patients with HT, GD, and the controls. A higher (median (interquartile range)) negative stress level (8 (4–12)) than a positive stress level (3 (1–9)) was found in the HT group. The HT group showed a correlation between SeP and the positive stress level: r_s = −0.296, p = 0.048, and the GD group between GPx and the negative stress level (r_s = −0.702, p = 0.011). Significant positive correlations between thyroid peroxidase antibody level and the total number of major life events (p = 0.023), the number of major life events in the last 7–12 months, and the number of major life events with no impact and a negative stress level were found. We suggest that the measurements of Th2-related cytokines and selenoproteins could be used as biomarkers for the development of AITD in cases where stress is considered a component cause of the pathogenic mechanism of the disease.

The most common autoimmune disorders with clinically opposite manifestations are hypothyroidism in Hashimoto’s thyroiditis and hyperthyroidism in Graves’ disease. The healthcare burden of thyroid disease is substantial, resulting in substantial health care costs. The aim of the present analysis is to assess the use of thyroid medications in Latvia from 2011 to 2014 by age and gender. Our study used reimbursed medication prescriptions data, collected by the National Health Service of Latvia. The main indicator was the number of prevalent users of thyroid medications each year from 2011 to 2014, stratified by age and gender. From 2011 to 2014, the number of thyroxine users per 100 000 revealed a statistically significant increase in all age and gender groups, except in 0- to 9-year-old girls. The number of Thiamazole users among men increased in the age group from 40 to 89 years and in women age groups above 49 years. Increasing sales of both thyroid hormones and antithyroid medications are also observed in Estonia and Lithuania, indicating that growing thyroid morbidity is an issue in the whole region. The substantial increase in number of patients highlights the necessity for national guidelines on the use of thyroid function tests and standards of medical care.

In the absence of a mandatory salt iodisation programme, two nationwide cross-sectional cluster surveys revealed persisting iodine deficiency among Latvian schoolchildren during the spring season and a noteworthy iodine deficiency in pregnant women in Latvia; these deficiencies warrant intervention. The consequences of mild-to-moderate iodine deficiency during pregnancy and lactation can adversely affect foetal brain development. Data from a Latvian population survey revealed the consumption of approximately 100 μg of iodine per day through foods and iodised salt. Therefore, strategies to increase the consumption of iodine-containing products should be implemented, particularly for children. In addition, to meet the increased iodine requirement during pregnancy, pregnant women should take daily supplements containing 150 μg iodine from the earliest time possible. All women of childbearing age should be advised to increase their dietary iodine intake by using iodised table salt and iodine-rich products: seafood, milk and milk products. For women with pre-existing thyroid pathologies, the medical decision should be considered on a case-by-case basis. Urinary iodine concentration monitoring among schoolchildren and pregnant women and neonatal thyrotropin registry analysis every five years would be an appropriate strategy for maintaining iodine intake within the interval that prevents iodine deficiency disorders.