Serum levels of sP-selectin and sL-selectin in children and adolescents with Graves' disease

The targeting and recruitment of inflamatory cells to vascular endothelium in Graves' disease (GD) is mediated by L-selectin (leucocyte endothelial cell adhesion molecule-1) and P-selectin (platelet activation-dependent granule-external membrane protein). The aim of this study was to estimate the serum concentrations of soluble L-selectin and soluble P-selectin in patients with (GD) before and during methimazole treatment. ELISA method was used to determine the concentrations of P-, L-Selectin and antithyroglobulin and antithyroid peroxidase antibodies, while the anti-TSH receptor autoantibodies (TRAbs) were evaluated using a radio receptor assay (RRA). The serum levels of sL-selectin and sP-selectin were markedly elevated in patients with GD before treatment with methimazole (p <0.0001 for both) and after 8 weeks of therapy (p <0,001 for sL-selectin and p <0,014 for sP-selectin). After 24 months of therapy, serum concentrations of these adhesion molecules were normalized. Serum levels of sP-selectin and sL-selectin in patients with GD correlated with the serum concentrations of triiodothyronine (r=0,42, 0,56, respectively) and thyroxine (r=0.6; r=0.71, respectively). Moreover, we observed a positive correlation between serum levels of TPO-Abs, TG-Abs, TRAbs and sL-selectin (r=0.64; 0.61; 0.49 respectively) and betwen sP-selectin and TPO-Abs (r=0,42, respectively). We conclude that the antithyroid antibodies involved in the pathogenesis of Graves' disease cause the elevation of the levels of the selectins, which act as mediators of leukocyte inflow and adhesion to the tissue of the thyroid gland. The evaluation of the serum level of soluble forms of adhesion molecules in children and adolescents with hyperthyroidism allows control over the autoimmune process.