Serum antibodies against the insulin-like growth factor-1 receptor (IGF-1R) in Graves’ disease and Graves’ orbitopathy

• Published in: Journal of endocrinological investigation Vol. 42; no. 4; pp. 471 - 480
• Main Authors: Marinò, M., Rotondo Dottore, G., Ionni, I., Lanzolla, G., Sabini, E., Ricci, D., Sframeli, A., Mazzi, B., Menconi, F., Latrofa, F., Vitti, P., Marcocci, C., Chiovato, L.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.04.2019; Springer Nature B.V
• Subjects: Autoantibodies; Endocrinology; Graves' disease; Insulin; Insulin-like growth factor I; Insulin-like growth factors; Investigations; Medicine; Medicine & Public Health; Metabolic Diseases; Original Article; Population studies; Serum levels; Thyroiditis; Thyroid autoimmunity; Thyroid eye disease; Graves’ disease; Graves’ ophthalmopathy; Insulin-like growth factor-1 receptor; Autoimmune thyroiditis; Graves’ orbitopathy; Thyroid
• ISSN: 1720-8386; 0391-4097; 1720-8386
• DOI: 10.1007/s40618-018-0943-8

Background A role of the insulin-like growth factor-1 receptor (IGF-1R) in the pathogenesis of Graves’ orbitopathy (GO) has been proposed, but the existence and function of anti-IGF-1R-antibodies (IGF-1R-Abs) are debated. Methods We designed a cross-sectional investigation to measure serum IGF-1R-Abs by a commercial assay in consecutive patients with Graves’ disease (GD) compared with healthy subjects and patients with autoimmune thyroiditis (AT). A total of 134 subjects were screened including 27 healthy subjects, 80 GD patients (54 of whom with GO), and 27 AT patients. The main outcome measure was the prevalence of positive serum IGF-1R-Abs in GO, compared with GD without GO and with the other study groups. Results Having established a cut-off value at 55.2 ng/ml for positive tests, positive IGF-1R-Abs were more frequent in GD (25%), than in AT (3.7%, P  =  0.003) and healthy subjects (0%, P  =  0.006). Within GD, there was no difference between patients with or without GO. Serum levels of IGF-1R-Abs differed across the study population ( P  < 0.0001), reflecting their higher concentrations in GD ( P  < 0.0001 vs both AT and healthy subjects), but with no difference between patients with or without GO. In patients with GO, there was an inverse correlation between serum IGF-1R-Abs and CAS ( R  = − 0.376, 95% CI: from − 0.373 to − 0.631; P  = 0.005), the significance of which remains to be investigated. Conclusions Serum autoantibodies against the IFG-1R are present in one-fourth of GD patients, regardless of the presence of GO. Further functional studies are needed to investigate the significance of their inverse correlation with GO activity.