Introduction: To assess the usefulness of circulating IL-16 and RANTES measurements as markers of Graves' orbitopathy (GO) activity and to estimate the role of these cytokines in GO pathogenesis.
Material and methods: 42 individuals were divided into four groups: Group 1 comprised 15 euthyroid patients with clinical symptoms of GO who underwent corticosteroid therapy consisting of intravenous infusions of methylprednisolone (MP) and teleradiotherapy (TR); Group 2 comprised ten patients with hyperthyroid GD (Gtx); Group 3 comprised ten patients with GD in euthyreosis (Geu); and Group 4 comprised seven healthy volunteers age- and sex-matched to Groups 1-3. Serum samples were collected 24 hours before the first dose of MP, 24 hours after the first dose of MP, before TR, and at the end of therapy. Serum IL-16 and RANTES were determined by ELISA and TSH-Rab by RIA.
Results: Serum IL-16 levels in patients with GO were significantly elevated at the end of therapy: 346 pg/mL (257-538) compared to IL-16 values before treatment: 250 ng/mL (211-337) and to the control group. RANTES serum concentrations did not significantly differ between studied groups, and immunosuppressive treatment did not influence its level. A negative correlation between TSH-Rab and RANTES was found in all studied groups (R = -0.32, p 〈 0.01).
Conclusions: Our data suggests that IL-16 may exert an immunoregulatory effect in Graves' orbitopathy. Serum measurements of both IL-16 and RANTES may be clinically useful; however, establishing their place in the diagnostics and treatment monitoring of GO needs further research.