Circulating CXCL9 and CXCL10 as markers of activity of Graves' orbitopathy during treatment with corticosteroids and teleradiotherapy

The aim of the study was to assess the usefulness of circulating chemokines CXCL9 and CXCL10 measurements as surrogate markers of GO activity and as a guideline in therapeutic decision-making. Forty-two individuals were divided into 4 groups: 1. 15 euthyroid patients with clinical symptoms of orbitopathy (GO) who underwent corticosteroid therapy consisting of intravenous infusions of methylprednisolone (MP) and teleradiotherapy (TR); 2. 10 patients with hyperthyroid GD (Gtx); 3. 10 patients with GD in euthyreosis (Geu); and 4. 7 healthy volunteers age and sex-matched to groups 1-3. The serum samples were collected 24 h before MP, 24 h after first dose of MP, before TR and at the end of therapy. Serum CXCL9 and CXCL10 were determined by ELISA and TSH-Rab by RIA. There were significant reductions in CXCL9 and CXCL10 serum concentrations during CS and TR treatment as compared both to control group and to basal values in GO patients. Moreover, CXCL9 concentration was significantly diminished in comparison to controls in GO patients who were identified later as corticosteroid-respondent (p<0.001). In this latter group of patients, CXCL9 was also found to be significantly reduced 24 h after first dose of MP as compared to non-respondents (p<0.02). The high-degree positive correlation between CXCL9 and CXCL10 was found (R=0.8; p<0.001). Our results suggest that the increased concentrations of CXCL9 (and CXCL10), at least in part, reflect the activity of orbital inflammation and therefore these chemokines could serve as a guideline in therapeutic decision-making in patients with Graves' orbitopathy.