Cytokine Signature Differences in Major Phenotypic Groups of Behçet Disease

Behçet disease (BD) has heterogeneous presentations, mainly mucocutaneous, vascular, and ocular manifestations. The mechanisms associated with different phenotypes have not been clarified. We aimed to investigate the expression of innate and adaptive immunity-related cytokines in these 3 main BD phenotypes in active and untreated states and remission after treatment to be able to develop a cytokine-based treatment algorithm.

Serum samples were isolated from 41 patients with newly diagnosed active BD (aBD), which consisted of 19 mucocutaneous aBD, 11 ocular aBD (o-aBD), and 11 vascular aBD patients, 35 patients in remission (rBD), and 9 healthy controls (HC). Serum levels of each cytokine were measured with sandwich enzyme-linked immunosorbent assay and analyzed as both raw measurements and corrected levels for each 1 million white blood cells.

The study included 41 aBD patients (female/male [F/M]: 9/32; median age, 29 years), 35 rBD patients (F/M: 9/26; median age, 29 years), and 9 HC (F/M: 3/6; median age, 28 years). The serum interferon γ level was significantly higher in the aBD group than in the rBD (116 vs. 92 pg/mL, p = 0.022). The serum interleukin 35 (IL-35) level was significantly higher in the HC group compared with aBD and rBD ( p = 0.05). IL-17-related cytokines were lower in o-aBD. With treatment, they increased in o-aBD but decreased in mucocutaneous aBD and vascular aBD patients.

This study supports the involvement of both innate and T H 1-predominated adaptive immune responses across all BD phenotypes. The IL-17 and T H 17-related immune responses appear less prominent in ocular BD, which may explain the ineffectiveness of IL-17 blockade in treating ocular BD. These findings support the need for further studies using comprehensive gene expression analyses to develop targeted treatment strategies for BD phenotypes.