Thyrocytes from Autoimmune Thyroid Disorders Produce the Chemokines IP-10 And Mig and Attract CXCR3+ Lymphocytes

Abstract

To better understand the selective migration of lymphocytes in autoimmune thyroid disorders (AITDs), we analyzed thyroid samples and demonstrated an enhanced expression of the chemokines interferon (IFN)-inducible protein (Ip)-10 and regulated on activation normal T lymphocyte expressed and secreted (RANTES) in thyroids from AITD patients. Ip-10 and monokine induced by IFN-γ (Mig) were expressed in vivo in thyroid follicular cells (TFCs) from AITD thyroids. Interestingly, Ip-10 mRNA, although not basally detected in cultured TFCs, was strongly induced by IFN-γ and synergistically increased by TNF-α addition. Furthermore, high levels of Ip-10 protein were detected in the supernatants of IFN-γ-stimulated TFCs. Likewise, Mig protein was strongly induced in TFCs by the same stimuli as Ip-10. Unlike Ip-10 and Mig, the expression of RANTES was induced mainly by TNF-α. In addition, intrathyroidal lymphocytes from AITD patients showed higher expression of CXCR3, CCR2, and CCR5 chemokine receptors than autologous peripheral blood lymphocytes. T lymphoblasts expressing CXCR3 showed an increased migration to supernatants from stimulated TFCs, which was abolished by specific antibodies to the chemokines Ip-10 and Mig, as well as to their receptor CXCR3. Taken together, these data suggest a potential role of TFCs, through the production of the chemokines Ip-10, Mig and RANTES, in regulating the recruitment of specific subsets of activated lymphocytes in AITDs.