Background Apoptosis is strictly programmed cell death of aged, disrupted or unnecessary cells. It has substantial role in the development and control of immune system. Its dysregulation may play a part in the pathogenesis of autoimmune disorders. Bcl-2 is an protooncogen of controlling apoptosis in immunocompetent cells.

Objectives Bcl-2 levels of peripheral mononuclear cells in patients with Behcet’s disease were investigated in order to have information about the apoptotic processes of this vasculitis which pathogenesis is unknown.

Methods Twenty-eight Behcet’s (mean age ± SD, 41.9 ± 7.8; 15 male,13 female), 21 familial Mediterranean fever (FMF), (mean age 34.5 ± 12.4; 9 male,12 female), 11 rheumatoid arthritis (RA) patients (mean age 44.9 ± 18.5; 1 male, 10 female) and 22 controls (mean age 37.7 ± 6.9; 11 male, 11 female) were taken into the study. Peripheral mononuclear cells of the subjects were isolated by phicol gradient method; after cell counts were standardised according to the kit instructions, the cells were lysed and Bcl-2 levels were studied by ELISA method.

Results Mean Bcl-2 levels of the Behcet’s patients (mean ± SEM, 78.58 ± 16.38 U/ml) were found significantly lower than that of the controls (161.70 ± 23.97 U/ml), (p = 0.006). No difference was found between the mean Bcl-2 levels of the active and inactive Behcet’s patients. The mean Bcl-2 level of Behcet group was not significantly different than those of the FMF (112.97 ± 29.97 U/ml) and the RA (82.63 ± 31.87 U/ml) groups. Mean Bcl-2 levels of the FMF (p = 0.061) and the RA (p = 0.076) groups were also not different than that of the controls.

Conclusion Low levels of Bcl-2 in peripheral mononuclear cells of Behcet’s patients might be a clue to the dysregulation of programmed cell death in mononuclear cells of this vasculitis.