Circulating immune complexome analysis identified anti-tubulin-α-1c as an inflammation associated autoantibody with promising diagnostic value for Behcet’s Disease

Background Behcet's disease (BD) is a chronic, multisystem-involved vasculitis and its pathogenesis remains elusive. No specific serological markers for BD diagnosis have been established. Identification of novel diagnostic biomarkers will be helpful in timely diagnostic and treatment for Behcet's disease. Objective To screen novel autoantigens or autoantibodies with potential diagnostic value in circulating immune complexes (CICs) from BD patients. Methods A proteomic strategy for immune complexome analysis was developed, in which CICs were separated from serum sample of 10 BD patients and 10 healthy controls and then subjected to Orbitrap mass spectrometry for autoantigen profiling. Anti-tubulin-α-1c antibody levels were further determined by enzyme-linked immunosorbent assay (ELISA) in sera of patients with BD, systemic lupus erythematosus (SLE), recurrent aphthous ulcers (RAU), ANCA associated systemic vasculitis (AASV), Takayasu's arteritis (TA) and 59 healthy controls. Result A total of 17 potential antigens were identified in CICs from BD patients, but not in HC. The autoantibody to one of the identified antigens, tubulin-α-1c, was significantly increased in BD patients compared with that in healthy and disease controls. The sensitivity and specificity of tubulin-α-1c antibody in the diagnosis of BD in this study were 61.36% and 88.4%, respectively. Further analysis demonstrated that anti-tubulin-α-1c was associated with complications of deep venous thrombosis and erythema nodosum in BD. The levels of anti-tubulin-α-1c were also significantly correlated with the BD inflammation and disease activity markers ESR, CRP and BVAS. Conclusion Anti-tubulin-α-1c antibody is a promising biomarker in diagnosis and severity evaluation of BD and in indicating the risk of deep venous thrombosis and erythema nodosum. The immune complexome analysis by proteomic CIC autoantigen screening is a feasible way of identifying novel biomarkers in BD.