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Scientific Articles

Serum Immunoglobulin G4 Levels and Graves’ Disease Phenotype

key information

source: Endocrine

year: 2017

authors: Martin CS, Sirbu AE, Betivoiu MA, Florea S, Barbu CG, Fica SV


We investigated, at diagnosis, the relationship between serum immunoglobulin G4 levels and the main characteristics of Graves’ disease: hyperthyroidism severity, goiter size, presence of active Graves’ ophthalmopathy, antithyroid antibodies status, and titer.

This prospective study included 80 newly diagnosed Graves’ disease patients. The main parameters measured at diagnosis: thyroid-stimulating hormone, free thyroxine, free triiodothyronine, total triiodothyronine, thyroglobulin, antithyroid peroxidase antibodies, anti-thyroglobulin antibodies, thyroid-stimulating hormone receptor antibodies, immunoglobulin G4.

In Graves’ disease patients, serum immunoglobulin G4 levels were higher than in general population (p = 0.028) and higher in men compared to women (p = 0.002). Only one female patient with intense hypoechoic goiter, high anti-thyroglobulin antibody, and antithyroid peroxidase antibody titers had an elevated serum immunoglobulin G4 level at diagnosis. Patients with immunoglobulin G4 levels above the 75th percentile (>237.52 mg/dl, N = 20) were younger at Graves’ ophthalmopathy onset (p < 0.001), had higher antithyroid peroxidase antibody (p = 0.01), and anti-thyroglobulin antibody levels (p = 0.006) and required shorter duration of the first methimazole treatment cycle (p = 0.041) than patients with immunoglobulin G4 below the 75th percentile. At diagnosis, patients with immunoglobulin G4 levels above the 90th percentile (>286.28 mg/dl, N = 8) had lower total triiodothyronine values (p = 0.001) than patients with IgG below the 90th percentile. No significant correlations were found between smoking status (p = 0.58), goiter size (p = 0.50), the presence of ophthalmopathy (p = 0.42) or thyroid-stimulating hormone receptor antibody titers (p = 0.45) and the mean value of immunoglobulin G4 levels at diagnosis.

Our data suggest that Graves’ disease patients with elevated immunoglobulin G4 levels at diagnosis have a phenotype characterized by higher anti-thyroglobulin antibody and antithyroid peroxidase antibody titers, less severe T3 hyperthyroidism, younger age at ophthalmopathy onset and require a shorter duration of the first methimazole treatment cycle.

organization: Carol Davila University of Medicine and Pharmacy, Romania; Elias Hospital, Romania

DOI: 10.1007/s12020-016-1157-5