Aims Thyroid orbitopathy (TO) is an autoimmune inflammatory disorder characterised by several ocular manifestations. Several autoantigens have been proposed to be involved in the pathogenesis of TO, but the autoantigen system and the mechanism of TO would be rather complex. In this study, an immunoproteomic method was used to survey novel autoantigens expressed in the orbital fat tissue of patients with TO.

Methods We used immunoproteomic, ELISA and immunohistochemical staining methods to survey novel autoantigens expressed in the orbital fat tissue of patients with TO.

Results Six protein spots showing high reactivity with the serum from the patients with TO were detected as candidate orbital autoantigens, and two of them (carbonic anhydrase 1 (CA1) and alcohol dehydrogenase 1B (ADH1B)) were further verified by ELISA and immunohistochemical staining. We found that CA1 and ADH1B could attribute target autoantigens in this autoimmune disease. We discovered anti-CA1 and anti-ADH1B antibody prevalence to be higher in patients with TO (68.57%/51.43%) or Graves’ disease (GD) (72%/48%) than in healthy controls respectively. Immunohistochemical staining study revealed the significantly enhanced expressions of CA1 and ADH1B in orbital fat of TO compared with that in healthy controls.

Conclusions We found that CA1 and ADH1B could attribute target autoantigens in this autoimmune disease. The high prevalence of these autoantibodies against CA1 and ADH1B in patients with TO and GD clarifies the potential clinical role for anti-CA1 and anti-ADH1B antibodies as biomarkers for GD and TO.