Which antibody is positive in Graves' eye disease (Graves' ophthalmopathy)?

From the Guidelines

In Graves' eye disease, the most relevant positive antibody is the antithyroid peroxidase antibody, as indicated by recent clinical guidelines 1. When evaluating patients with suspected thyroid eye disease, it is essential to consider the underlying autoimmune processes that contribute to the condition.

• The antithyroid peroxidase antibody and antithyroglobulin antibody are commonly tested in patients with thyroid eye disease, as they can help confirm the diagnosis and guide treatment decisions 1.
• Orbital imaging, such as CT or MRI scans, can also be useful in assessing extraocular muscle thickening and other orbital changes associated with thyroid eye disease 1.
• While other antibodies, such as thyroid-stimulating immunoglobulin (TSI) and thyroglobulin antibodies (TgAb), may also be present in some cases, the antithyroid peroxidase antibody is a key diagnostic marker for thyroid eye disease, according to the most recent evidence 1.
• It is crucial to note that the diagnosis and management of Graves' eye disease require a comprehensive approach, taking into account the patient's overall clinical presentation, laboratory results, and imaging findings 1.

From the Research

Antibodies in Grave Eye Disease

• The antibody that is positive in Grave eye disease is Thyroid-Stimulating Antibody (TSAb) 2, 3.
• TSAb is believed to cause hyperthyroidism of Graves' disease and is used to diagnose Graves' disease and to follow Graves' patients 2.
• Thyrotropin-binding inhibitor immunoglobulin (TBII) is also used as a marker for Graves' disease, but it is more related to hyperthyroidism than to ophthalmopathy 3.
• The presence of TSAb is correlated with the severity of Graves' ophthalmopathy, while TBII is correlated with hyperthyroidism 3.
• Other studies have also shown that TSAb and TBII can be used to diagnose Graves' disease and to predict its clinical course 4, 5, 6.

Relationship between Antibodies and Grave Eye Disease

• TSAb is significantly correlated with the severity of Graves' ophthalmopathy, while TBII is not 3.
• The sum of the scores of eyelid swelling, proptosis, and extraocular muscle enlargement is taken as a measure of the overall severity of the Graves' ophthalmopathy, and TSAb is significantly correlated with this score 3.
• TBII is more related to hyperthyroidism than to ophthalmopathy, and is correlated with free triiodothyronine (FT3) and free thyroxine (FT4) levels 3.

Clinical Value of Antibody Assays

• The simultaneous measurement of both TSAb and TBII is clinically useful, since TSAb and TBII reflect two different aspects of TRAb 2.
• TSAb and TBII assays have high sensitivity and specificity for the diagnosis of Graves' disease, and are equally sensitive and specific 2.
• The clinical value of TSAb and TBII assays in establishing the diagnosis of Graves' disease and in predicting its clinical course has been demonstrated 2, 4, 5, 6.