Adhesion molecule expression in erythema nodosum-like lesions in Behcet's disease - A histopathological and immunohistochemical study

Behcet's (BD) is a systemic inflammatory disease with histological evidence for vasculitis. Leucocyte-leucocyte and leucocyte-endothelial cell interactions are critical in inflammatory reactions that are influenced by the expression, activation and shedding of adhesion molecules. We investigated the expression of some adhesion molecules (E- and L-selectin, VLA-4, ICAM-1, PECAM-1, VCAM-1 and CD18 and CD11c chains of beta-2 integrins) on endothelial and inflammatory cells by immunohistochemistry on cryostat sections of erythema nodosum lesions taken from 15 patients with BD and 12 patients with erythema nodosum of unknown cause. Hematoxylin-eosin stained sections of all specimens were also assessed. The major histopathological findings were perivascular mononuclear cell infiltration and secondary vasculitic changes with no difference between the two groups (P>0.05). However, the frequency of thrombophlebitis was higher in BD (P<0.001). Endothelial and inflammatory cell adhesion molecule expression did not show any significant difference between groups (P>0.05). Although VCAM-1 expression and intensity on endothelial cells of BD patients seemed to be lower, this did not reach statistical significance (P=0.056), We concluded that subcutaneous thrombophlebitis is an important feature of erythema nodosum like lesions in BD, which is almost impossible to understand by physical examination alone. Colchicine, which is known to have some influence on adhesion molecules, might have affected our results, as these showed no significant difference regarding adhesion molecules between the two groups.