Use of FRTL-5 for the study of thyroid antibodies involved in goitrogenesis

Some authors have suggested a role of autoimmunity in the pathogenesis of iodine deficiency disorders (IDD). For this purpose we have searched for thyroid adenylate cyclase stimulating antibody (TSAb) and thyroid growth stimulating antibody (TGSAb) in patients with endemic goiter (EG) and endemic cretinism (EC). Immunoglobulins G preparations (IgGs) were tested in FRTL-5 cells. TSAb were calculated as percent of cAMP increase over basal production and TGSAb were expressed as percent of increase of 3H-thymidine incorporation and DNA content in FRTL-5 cells. Our results show that IgGs from goitrous patients were devoid of TSAb and TGSAb activities, while in the same conditions IgGs from patients with Graves' disease had the ability to stimulate cAMP production and 3H-thymidine incorporation in FRTL-5 cells. These data argue against a direct role of TSAb and TGSAb in the pathogenesis of IDD.