Correlation of Serum Amyloid-A Levels, Clinical Manifestations, Treatment, and Disease Activity in Patients with Behçet's Disease.

Background: Behçet's disease (BD) is an inflammatory disorder potentially leading to life- and sight-threatening complications. No laboratory marker correlating with disease activity or predicting the occurrence of disease manifestations is currently available.

Objectives: To determine an association between serum amyloid-A (SAA) levels and disease activity via the BD Current Activity Form (BDCAF), to evaluate disease activity in relation to different SAA thresholds, to examine the association between single organ involvement and the overall major organ involvement with different SAA thresholds, and to assess the influence of biologic therapy on SAA levels.

Methods: We collected 95 serum samples from 64 BD patients. Related demographic, clinical, and therapeutic data were retrospectively gathered.

Results: No association was identified between SAA levels and BD disease activity (Spearman's rho = 0.085, P = 0.411). A significant difference was found in the mean BDCAF score between patients presenting with SAA levels < 200 mg/L and those with SAA levels > 200 mg/L (P = 0.027). SAA levels > 200 mg/L were associated with major organ involvement (P = 0.008). A significant association was found between SAA levels > 150 mg/dl and ocular (P = 0.008), skin (P = 0.002), and mucosal (P = 0.012) manifestations. Patients undergoing biologic therapies displayed more frequently SAA levels < 200 mg/L vs. patients who were not undergoing biologic therapies (P = 0.012).

Conclusions: Although SAA level does not represent a biomarker for disease activity, it might be a predictor of major organ involvement and ocular disease relapse at certain thresholds in patients with BD.