Anti-alpha-enolase antibodies in Behçet's disease: a marker of mucocutaneous and articular disease activity?

OBJECTIVES: To assess IgM anti-alpha-enolase antibodies (AAEA) in systemic Behçet's disease (BD) and its possible association with clinical manifestations and disease activity.

METHODS: Ninety-seven consecutively selected BD patients were compared to 36 enteropathic spondyloarthritis (ESpA) [24 Crohn's disease (CD) and 12 ulcerative colitis (UC)] patients and 87 healthy controls. IgM AAEA was detected by immunoblotting. Disease activity was assessed by standardised indexes, Brazilian BD Current Activity Form (BR-BDCAF) for BD and Harvey-Bradshaw Index (HBI) for CD and UC patients. A second evaluation was performed in BD patients (n=56), regarding IgM AAEA presence, disease activity scores and C-reactive protein (CRP).

RESULTS: Higher IgM AAEA prevalence was found in 97 BD (17.7%) compared to ESpA (2.8%) and healthy controls (2.3%), p<0.001. IgM AAEA frequency was higher in active BD compared to inactive BD (30.2% vs. 7.4%, p=0.006), a finding confirmed in the second cross-sectional evaluation of 56 of these BD patients (45.5% vs. 13.3%, p=0.02). Mean BR-BDCAF scores were higher in IgM AAEA positive group on both evaluations (9.1 ± 5.4 vs. 4.9 ± 4.9, p=0.002; 5.0 ± 4.9 vs. 2.2 ± 2.9, p=0.01, respectively). BD patients with mucocutaneous and articular symptoms presented higher IgM AAEA positivity in the first and second evaluations (64.7% vs. 27.5%, p=0.005; 36.4% vs. 7.1%, p=0.039 respectively).

CONCLUSIONS: Our data support the notion that alpha-enolase is a target antigen in BD, particularly associated with disease activity, mucocutaneous and articular involvement. In addition, IgM AAEA may distinguish BD from ESpA, especially in patients with high disease activity.