<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>Elevated immunoglobulin G4 (IgG4) serum antibodies are an important feature of IgG4-related disease. However, IgG4 antibodies can play a role in autoimmune thyroid disorders. In this study, we aimed to evaluate the impact of serum IgG4 levels on clinical features of Graves’ disease (GD). We recruited 60 patients with GD (48 patients without thyroid eye disease, 12 patients with moderate-to-severe Graves’ orbitopathy [GO], and 25 healthy control subjects). The prevalence of high IgG4 serum concentration was 4.2% among GD patients without GO and 33.33% in patients with moderate-to-severe GO. The group with GO had significantly higher median IgG4 levels (87.9 mg/dL) than the control group (41.2 mg/dL, <italic>P</italic> = 0.034) and the GD without GO group (30.75 mg/dL, <italic>P</italic> &lt; 0.001). Patients with thyroid nodules had lower IgG4 levels than patients without thyroid nodules, but the difference was not statistically significant (35.7 [24.8; 41.53] mg/dL vs. 43 [30.1; 92.7] mg/dL, <italic>P</italic> = 0.064). IgG4 as a diagnostic tool for moderate-to-severe GO had the following parameters: area under the curve (AUC): 0.851 (<italic>P</italic> &lt; 0.001), at the cut-off value of 49 mg/dL, negative predictive value: 100%, positive predictive value: 48%, sensitivity: 100%, specificity: 73%. There were no significant differences between the high and normal IgG4 groups in thyroid hormones, antithyroid antibodies, and ultrasound features. Serum IgG4 levels are associated with some of the clinical features of GD and can help in the diagnostic process of the disease. More research is needed to better understand the pathophysiology of IgG4 involvement in GD.</p>
</abstract>

Elevated immunoglobulin G4 (IgG4) serum antibodies are an important feature of IgG4-related disease. However, IgG4 antibodies can play a role in autoimmune thyroid disorders. In this study, we aimed to evaluate the impact of serum IgG4 levels on clinical features of Graves’ disease (GD). We recruited 60 patients with GD (48 patients without thyroid eye disease, 12 patients with moderate-to-severe Graves’ orbitopathy [GO], and 25 healthy control subjects). The prevalence of high IgG4 serum concentration was 4.2% among GD patients without GO and 33.33% in patients with moderate-to-severe GO. The group with GO had significantly higher median IgG4 levels (87.9 mg/dL) than the control group (41.2 mg/dL, P = 0.034) and the GD without GO group (30.75 mg/dL, P < 0.001). Patients with thyroid nodules had lower IgG4 levels than patients without thyroid nodules, but the difference was not statistically significant (35.7 [24.8; 41.53] mg/dL vs. 43 [30.1; 92.7] mg/dL, P = 0.064). IgG4 as a diagnostic tool for moderate-to-severe GO had the following parameters: area under the curve (AUC): 0.851 (P < 0.001), at the cut-off value of 49 mg/dL, negative predictive value: 100%, positive predictive value: 48%, sensitivity: 100%, specificity: 73%. There were no significant differences between the high and normal IgG4 groups in thyroid hormones, antithyroid antibodies, and ultrasound features. Serum IgG4 levels are associated with some of the clinical features of GD and can help in the diagnostic process of the disease. More research is needed to better understand the pathophysiology of IgG4 involvement in GD.

Clinical Significance of IgG4 Serum Concentration in Graves’ Disease

Department of Endocrinology, Metabolism and Internal Medicine

Archivum Immunologiae et Therapiae Experimentalis

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

{"article-title":"Clinical Significance of IgG4 Serum Concentration in Graves\u2019 Disease"}

Elevated immunoglobulin G4 (IgG4) serum antibodies are an important feature of IgG4-related disease. However, IgG4 antibodies can play a role in autoimmune...

Clinical Significance of IgG4 Serum Concentration in Graves’ Disease

Published Online: Jul 20, 2024

Page range: -

Received: Mar 21, 2024

Accepted: Jun 20, 2024

DOI: https://doi.org/10.2478/aite-2024-0015

Keywords
IgG, IgG4, Graves’ disease, Thyroid eye disease, IgG4-related disease

© 2024 Michal Olejarz et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Clinical Significance of IgG4 Serum Concentration in Graves’ Disease

Published Online: Jul 20, 2024

Page range: -

Received: Mar 21, 2024

Accepted: Jun 20, 2024

DOI: https://doi.org/10.2478/aite-2024-0015

KeywordsIgG, IgG4, Graves’ disease, Thyroid eye disease, IgG4-related disease

© 2024 Michal Olejarz et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Keywords
IgG, IgG4, Graves’ disease, Thyroid eye disease, IgG4-related disease