ESPE Abstracts

Background: Chronic autoimmune thyroiditis (cAIT) and Graves’ disease (GD) are the most common autoimmune disorders in children. Proinflammatory cytokine such as IL-6 has been generally associated with the induction of inflammation and autoimmunity. Osteoprotegerin, a soluble glycoprotein and a member of the tumor necrosis factor receptor (TNFR) family, play an important role in bone homeostasis and in vasculature.

Objective and hypotheses: The aim of the study was to determine concentrations of IL-6 and OPG in autoimmune thyroid disease (AITD) in children.

Method: We studied serum IL-6 and OPG (ELISA) in 22 newly diagnosed children with cAIT (mean: TSH 46.7 μIU/ml↑, fT4 0.54 ng/dl↓, fT3 2.10 pg/ml; ATPO 2597 IU/ml↑, and ATG 533 IU/ml↑), 22 GD children (mean: TSH 0.01 μIU/ml↓, fT4 4.24 ng/dl↑, fT3 19.01 pg/ml↑; TRAb 24 U/l↑ ATPO 2280 IU/ml↑, ATG 426 IU/ml↑) and 20 healthy subjects with normal fT₄, fT₃, TSH, and negative antithyroid Abs.

Results: In our study no significant difference was observed between IL6 serum concentrations in studied groups (P=0.48; Kruskal–Wallis test). OPG concentrations were significantly higher (ANOVA P=0.013; Newman–Keuls P<0.01) in children with GD: (mean±S.D.) (4.48±2.01 pmol/l) compared to control group (3.02±1.17 pmol/l); whereas no significant difference between children with cAIT (3.79±1.28 pmol/l) vs control group (Newman–Keuls P>0.05) and cAIT vs GD (Newman–Keuls P>0.05) was observed. In children with hyperthyroidism we identified significant positive correlation between OPG and IL6 (r=0.51; P<0.05). ROC curve indicates good efficacy of OPG to discriminate groups of hyperthyroid and healthy children (AUC=0.716; P=0.017) at cut-off point of 4.54 pmol/l with low sensitivity (54.5%) but high specificity (95%). In these groups of children AUC of IL6 did not differ significantly from 0.5 (P=0.435).

Conclusion: Based on performed study we suggest that OPG may be considered as a marker of hyperthyroidism in GD children.