Background: Adamantiades-Behçet's disease is a chronic systemic disorder associating oral and genital ulcerative lesions with ocular and cutaneous manifestations. Previous publications report increased superoxide production by neutrophils and macrophages, increases in cytokines and malondialdehyde (MDA), as well as low levels of enzymatic antioxidant defenses.
Aim: We looked for another marker of oxidative stress in Adamantiades-Behçet's disease: the presence of clastogenic factors (CF) in patients' plasma. In addition, we determined plasma endproducts of lipid peroxidation (MDA).
Patients and methods: We studied 20 patients and 20 controls. The clastogenic activity was evaluated by means of cytogenetic methods. This test (CF test) detects circulating prooxidants, due to their clastogenic effects after exposure of lymphocyte cultures of healthy persons to plasma ultrafiltrates from patients. The clastogenic prooxidants are lipid peroxidation products and cytokines, in particular TNF-alpha. Lipid peroxidation was evaluated by the Yagi method.
Results: The CF test was positive in 18 out of 20 patients, while it was negative in all 20 control persons. The mean increase in chromosomal breaks was 10.6 +/- 3.8 in cultures exposed to patients' plasma and 1.3 +/- 2.4 for cultures receiving control plasma (p <0.001). The clastogenic effect of patients' plasma ultrafiltrates was significantly inhibited by superoxide dismutase (EC 1.15.1.1), suggesting an important role of the superoxide radical in the clastogenic pathway. Thiobarbituric-acid-reactive substances (expressed as nanomoles MDA per milliliter) were also significantly increased in these patients: 10.6 +/- 3.2 for patients and 6.6 +/- 1.4 for controls (p <0.001).
Conclusion: The presence of CF in the plasma of patients, indicating the presence of circulating prooxidants with chromosome-damaging effects, confirms an oxidative stress in Adamantiades-Behçet's disease. The anticlastogenic effect of superoxide dismutase in vitro suggests the implication of the superoxide radical. MDA levels were also significantly increased in patients.