Chemokines and autoimmune thyroid diseases.

Chemokines are a family of small, structurally related molecules that regulate cell trafficking of various types of leukocytes through interactions with their seven-transmembrane, G protein-coupled receptors. Their major function is the recruitment of leukocytes to inflammation sites, but they also play roles in tumor growth, angiogenesis, organ sclerosis, and autoimmunity. A variety of evidence has accumulated to support the concept that thyroid follicular cells as well as intrathyroidal lymphocytes are able to produce CC and CXC chemokines, which, in turn, promote the initiation and maintenance of an inflammatory process resulting in autoimmune thyroid diseases (AITD). Overexpression of several chemokines in AITD has been demonstrated. Moreover, alterations of CCL2, CCL5, CXCL9, and CXCL10 have been shown in circulation of many patients with AITD. In subjects with Graves' disease, antithyroid drug treatment, radioactive iodine ablation, and thyroidectomy can significantly reduce CXCL10 levels. The measurement of chemokines in serum of AITD patients might provide a useful parameter for the evaluation and prediction of disease activity and progression. Further experimental and clinical studies will expand our understanding of the clinical implications of chemokine detection and the effects of chemokines on the pathogenesis of AITD.