Background/Purpose: Diagnosis of Behçet´s disease (BD) is challenging because is based solely on clinical features. Articular involvement in this disease may mimic other diagnosis such as enteropathic arthritis manifestations. IgM anti-alpha-enolase antibodies (AAEA) were recently described in BD, however its clinical relevance is still undefined. Therefore, this study aimed to assess IgM AAEA in systemic BD and its possible association with clinical manifestations and disease activity.

Methods: Ninety-seven BD patients were compared to 36 enteropathic arthritis patients [Crohn’s disease (n=24) and ulcerative colitis (n=12)] and healthy controls (n=87). IgM AAEA was detected by immunoblotting using human alpha-enolase transfected cells whole lysate (Santa Cruz Biotechnology Inc., USA) as antigens. Disease activity was assessed by standardized indexes, BR-BDCAF for BD, SCCI for Crohn’s disease (CD) and HBI for ulcerative colitis (UC) together with c-reactive protein (CRP) levels. A longitudinal evaluation was performed in BD patients (n=56), with a minimum of two years interval, regarding IgM AAEA presence and disease activity scores.

Results: A higher IgM AAEA prevalence was found in BD compared to enteropathic arthritis and healthy controls (18.4% vs. 2.8% vs. 2.3%, p<0.001).  The frequency of IgM AAEA in active BD was significantly higher than in patients with inactive disease (30.2 vs. 7.4%, p=0.006). Further longitudinal analysis after at least two years confirmed a higher IgM AAEA frequency in active BD compared to inactive BD (45.5 vs. 13.3%, p=0.02). Reinforcing these findings, the mean BR-BDCAF scores and CRP levels were higher in IgM AAEA positive group at baseline (9.11 vs. 4.95, p=0.002 and 11.9 vs. 5.0mg/L, p=0.05) and post two years (5.0 vs. 2.1, p=0.01; 9.6 vs. 3.8mg/L, p=0.008). Regarding all clinical manifestations, we observed that the subgroup with articular symptoms presented higher IgM AAEA positivity on baseline and follow-up evaluations (26.3 vs. 5%, p=0.006; 54.5 vs. 15.6%, p=0.01).

Conclusion: Taken together these data suggest that IgM AAEA may be a novel marker for BD activity, particularly related to articular involvement. Further studies are necessary to confirm their usefulness in clinical practice to distinguish BD patients with articular involvement from patients with enteropathic arthritis manifestations.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/anti-alpha-enolase-antibodies-in-behcets-disease-a-marker-of-articular-disease-activity/