Interleukin 8 in Behçet's disease

Activated peripheral polymorphonuclear leukocytes (PMNs) and infiltration of PMNs into the lesions are characteristic findings of Behçet's disease (BD). A variety of cytokines, including interleukin 8 (IL-8), have been shown to activate PMNs. To investigate the role of IL-8 in the development of BD lesions, IL-8 production in vivo and in vitro was examined in 25 BD patients. IL-8 levels measured by ELISA in the non stimulated culture supernatants of peripheral mononuclear cells (MNCs) were higher in patients with active BD than in those with inactive BD or normal controls. Without LPS stimulation, IL-8 mRNA expression in incubated MNCs detected by Northern blot analysis was higher in active BD patients than in controls. Polarization assay confirmed the accelerated activity of PMN isolated from patients with active BD. However, these PMNs did not respond to IL-8 as strongly as to FMLP (an exogenous stimulator); a possible reason is that the PMNs of these patients are constantly exposed to IL-8 in vivo. Immunohistochemically, MNCs, endothelial cells and fibroblasts in BD lesions were positively stained by anti-IL-8 antibody. These data indicate that the production of IL-8 may be accelerated in inactive BD and that IL-8 may play an important role in the pathogenesis of BD.