Neutrophilic phlebitis is characteristic of intestinal Behçet's disease and simple ulcer syndrome

To characterize the histological features of intestinal Behcet's disease and simple ulcer syndrome and to clarify the possible mechanisms involved in their development by analysing the type of inflammatory infiltrates in the diseased intestine and the expression of adhesion molecules on endothelial cells.

Tissue samples from 10 patients diagnosed as having intestinal Behcet's disease or simple ulcer syndrome were studied. Immunohistochemical studies were performed on paraffin-embedded tissue using a labelled streptavidin-biotin method. In all cases, phlebitis was remarkably seen in submucosal inflammatory lesions, but the adjacent arteries were not affected. Inflammatory infiltrates around the affected vessels consisted of neutrophils and mononuclear cells, and neutrophils predominated over CD68+ macrophages and lymphocytes. The majority of mononuclear cells were CD3+ T cells, and CD4+ cells were more frequent than CD8+ T cells. As for adhesion molecule expression, intercellular adhesion molecule-1, but not vascular cell adhesion molecule-1, was expressed in most endothelial cells of the vessels with phlebitis, some of which were also positive for HLA-DR.

Neutrophilic phlebitis may be involved in the pathogenesis of intestinal Behcet's disease and simple ulcer syndrome.