Graves' Hyperthyroidism Is Antibody-Mediated But Is Predominantly a Th1-Type Cytokine Disease

We wish to comment on an assumption commonly made that Graves' disease and Hashimoto's thyroiditis are distinguished by immune responses involving T-cell helper type 1 and type 2 (Th1 and Th2), respectively. For example, the title of a paper recently published in the JCEM refers to this perceived Th1/Th2 dichotomy in thyroid autoimmune disorders (1). In the abstract, Marique et al (1) state that “Hashimoto's thyroiditis and Graves' disease are thyroid disorders driven by Th1 and Th2 responses, respectively,” and subsequently they state that Graves' disease “is driven by the humoral immune response and Th2 cytokines (IL-4 and IL-10)”. The authors are not alone in adopting this viewpoint which we, ourselves, did in earlier years. Subsequently, we (and possibly others) have been unsuccessful in convincing the thyroid community that these assumptions are incorrect. The purpose of this Commentary is to summarize key points of information in order to enhance insight into the pathogenesis of these complex, fascinating, and extremely common disorders.