Background Chemokines are multifunctional mediators that control leukocyte recruitment into the inflammatory sites and enhance immune responses. It remains to be investigated which chemokines are important in Behcet's disease (BD).

Objectives The objective of this study was to investigate serum levels of (C-X-C motif) CXC chemokines in BD patients and its association with clinical manifestations and disease activity.

Methods Blood samples were collected from 109 BD patients and 34 age-, sex matched healthy controls (HCs). Twenty two follow-up samples were collected in BD patients. Serum CXC chemokines were assayed for the neutrophil chemoattractants (CXCL1 and CXCL8) and lymphocyte chemoattractants (CXCL9, CXCL10, CXCL12, CXCL13 and CXCL16) by using a multiplex assay. Cell surface makers such as CD3, CD4 and CXCR3 in peripheral blood mononuclear cells were investigated by flow cytometry. The clinical features including disease activity, laboratory tests and current medication were evaluated at the time of blood collection. C-X-C chemokine receptor 3 (CXCR3) expression in skin and intestinal lesions from BD patients were assessed via immunohistochemistry.

Results Serum levels of CXCL8, CXCL10 and CXCL12 were significantly higher in the BD patients than in HC (p=0.001, p=0.007 and p=0.003, respectively). Serum CXCL10 levels were significantly correlated with disease activity in both Behcet's Disease Current Activity Form (BDCAF) and Behcet's Syndrome Activity Score (BSAS) (rho =0.336, p<0.001 and rho =0.253, p=0.009, respectively) as well as with number of genital ulcer and erythema nodosum (EN) (rho =0.222, p=0.020 and rho =0.329, p<0.001, respectively). In follow-up BD patients, changes of serum CXCL10 levels were correlated with those of BDCAF (rho =0.425, p=0.048).

CXCR3 receptor expression was significantly increased on CD3 positive T cells versus CD3 negative cells in peripheral blood mononuclear cells of both BD patients and HCs (p=0.009 and p=0.031, respectively). Levels of serum CXCL10 were inversely correlated with percentage of CXCR3 expression on CD3 positive T cells in BD patients (rho = -0.523, p=0.022). In immunohistochemistry, the CXCR3 positive inflammatory cells were increased in skin lesions of BD patients than in those of HCs.

Conclusions These results suggest that CXCL10/CXCR3 axis contribute to pathogenesis of BD particularly mucocutaneous lesions. Measurement of serum CXCL10 may help to assess disease activity in BD patients.

Disclosure of Interest None declared