Associations exist between autoimmune thyroid disorders (AITD) and other organ specific autoimmune disorders, for example in autoimmune polyglandular syndromes type 1 and 2, that are rare genetic disorders.
However, thyroid function abnormalities and thyroid autoantibodies have been frequently described also in patients with systemic rheumatological autoimmune diseases, as Sjögren’s syndrome (SS), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), mixed cryoglobulinemia (MC), sarcoidosis, or psoriathic arthritis, highlighting the possibility of common pathogenic mechanisms among them. More recently, studies have evaluated longitudinally the incidence of new cases of thyroid autoimmunity and dysfunction, for example, in patients with SSc, or SS, or MC, showing a high incidence of new cases of hypothyroidism, thyroid dysfunction, anti-thyroperoxidase (AbTPO) positivity, and that the appearance of hypothyroidism was related to a borderline high initial thyroid-stimulating hormone level, AbTPO positivity, and a hypoechoic and small thyroid. These studies suggested that these patients should have periodic thyroid function follow-up. However other studies were not able to find any significant association, between many of the above mentioned autoimmune disorders and thyroid autoimmunity.
Many papers have also underlined the importance of a common genetic susceptibility (HLA, etc) in the pathogenesis of autoimmunity in patients with coexistence of AITD and other autoimmune manifestations. Furthermore epigenetics, or environmental factors could be implicated in the association of autoimmune disorders.
Serum and/or tissue CXCL10 expression is increased in organ specific autoimmune diseases, as autoimmune thyroiditis, Graves’ disease, type 1 diabetes, and/or systemic rheumatological disorders (like RA, SLE, SSc, MC), underlining the importance of a common immune-pathogenesis of these disorders, characterized by a Th1 prevalent autoimmune response.
These studies suggest that patients with systemic autoimmune disorders should have periodic thyroid follow-up, and appropriate treatments when needed.
The Research Topic will present a compendium of reviews on the association of different autoimmune diseases with thyroid autoimmunity, with a special attention to clinical manifestations, treatment, and pathogenesis.
This collection is the second volume of The Association of Other Autoimmune Diseases in Patients with Thyroid Autoimmunity