Lipid hydroperoxides (LOOHs) are by product of lipid peroxidation. Paraoxonase (PON), arylesterase (ARE), free sulphydryl (SH) groups and ceruloplasmin (CP) are enzymes or proteins with antioxidant characteristics. This study aims to determine the levels of LOOHs, the levels of SH, the activities of PON1, ARE and CP in active and inactive Behçet's disease (BD) patients.

The study included 21 BD cases (10 active and 11 inactive) and 23 healthy volunteers. The levels of LOOHs and SH and the activities of PON1, ARE and CP were determined.

The level of LOOHs was found to be significantly high, while level of SH and activities of PON1, ARE and CP were observed as significantly low in the BD group, when compared with the control group (p<0.001, for each). There was a significant negative correlation between the level of LOOHs and the activity of ARE in the BD group (r=-0.46, p<0.05). An increase in the level of LOOHs and a decrease in the activities of PON1, ARE and CP were observed in the active BD group when compared with the inactive BD group, but differences were not statistical significant (p>0.05, for each).

Results of the study indicate the impaired oxidant/antioxidant balance in BD. PON1 and ARE possess anti-atherosclerotic characteristics in addition to antioxidant ones. Accordingly, development of atherosclerosis in addition to tissue injury in BD seems to be inevitable due to the decrease in antioxidant levels resulting from increased oxidative stress.