Skin window examination according to Rebuck and cutaneous pathergy tests in patients with Behcet's disease.

Comparative in vivo examinations of skin (cutaneous pathergy test, skin window technique over 24 h according to Rebuck) were carried out in 12 patients with Behçet's disease (BD) and in 13 healthy volunteers serving as controls. 10 out of 12 patients at active phases of BD showed a positive papular (-pustular) skin reactivity to needle prick or venepuncture. These 10 patients simultaneously revealed an increased chemotactic activity of polymorphonuclear leukocytes (PMNL) in vitro. In the controls all pathergy tests were negative and chemotaxis of PMNL was within normal range. The proportion of PMNL initially coming up to 100% in the skin window preparations, very rapidly decreased in patients with BD as compared to a distinctly slower drop in the controls. Conversely to the number of PMNL, the skin window cellular pattern was built up by monophagocytic cells replacing the PMNL. The phenomenon of 'rapid depletion of PMNL', from skin window can be considered an additional hint on the functional disturbance of the PMNL involved in the pathogenesis of BD.