Thyrotrophin Receptor Antibody: Objective and Quantitative Inflammatory Indicator in Patients With Thyroid Eye Disease.

Context: Accurate assessment of the inflammatory status in thyroid eye disease (TED) is crucial for diagnosis and treatment; however, this assessment remains challenging.

Objectives: To study whether thyrotrophin receptor antibody (TRAb) can be utilized as a quantitative and objective indicator of the inflammatory status in patients with TED.

Methods: We gathered and analyzed TRAb and clinical characteristics from 226 consecutive TED patients. Additionally, we examined 27 inflammatory cytokines in the orbital adipose tissue of 41 patients and assessed the alterations in TRAb following IV methylprednisolone (IVMP) therapy in 40 patients.

Results: The 226 TED patients included 116 females and 110 males, with a mean age of 46.4 ± 12.2 years. The correlation between TRAb and clinical activity score (CAS) was the most pronounced (r = 0.427; P < .001). TRAb was identified as the most influential factor for CAS. Subsequent investigation into the relationship between TRAb and pathological inflammation revealed that TRAb exhibited a significant positive correlation with 7 proinflammatory cytokines [Interleukin (IL)-8, chemokine (C-C motif) ligand 3 (CCL-3), serpin E1, platelet-derived growth factor (PDGF)-AB, IL-12p70, IL-21, and PDGF-BB] and a significant negative correlation with 1 anti-inflammatory cytokine [bone morphogenetic protein 7 (BMP-7)]. IL-8, CCL-3, serpin E1, PDGF-AB, and IL-1β were significantly upregulated in the orbital adipose tissue of TRAb-positive patients compared to TRAb-negative patients. In contrast, BMP-7 demonstrated an opposite trend. Additionally, TRAb and CAS significantly decreased following IVMP therapy, with a significant correlation between the extent of reduction in TRAb and CAS.

Conclusion: TRAb significantly correlated with both CAS (clinical inflammation indicator) and inflammatory cytokines (pathological inflammation marker). Consequently, we propose, for the first time, that TRAb may serve as an objective and quantitative biomarker for assessing inflammation in TED.