Lysosomal enzymes in Behcet's syndrome

Pathological changes of venules and capillaries and perivascular infiltration with white cells suggestd participation of lysosomes in pathogenesis of Behcet's syndrome and kinetics of lysosomal enzymes in Behcet's syndrome were studied.Activities of cathepsin D, acid phosphatase and β-glucronidase in serum, which were lysosomal marker enzymes, were determined with bovine hemoglobin, p-nitrophenyl phosphate and p-nitrophenyl glucronide respectively as their matrices. With β-glucronidase the activities were significantly higher in patients with Behcet's syndrome than normal controls (p<0.05), and especially, higher values were detected in acute stage than quiet stage (p<0.05) .A serum factor which determines the labiability of the lysosomal membrane was examined as a causative factor of pathological kinetics of lysosomal enzymes. Rat liver lysosomal fraction was incubated with test sera and activities of released β-glucronidase were determined. Lysosomal membrane-labilizing ratio was defined as the percentage of released activity to the total activity of the fraction. The activities of thermolabile lysosomal membrane-labilizing serum factor, detected predominantly in the albumin fraction, were prominantly elevated in some patients with Behcet's syndrome compared with normal controls.Studies of lysosomal enzymes in Behcet's syndrome will serve promising roles in exploring pathogenesis but also in establishing diagnosis and treatment.