IMMUNE-RESPONSE AGAINST MODIFIED LOW-DENSITY LIPOPROTEINS IN PATIENTSWITH NON-INSULIN-DEPENDENT DIABETES-MELLITUS

Background: Diabetes mellitus is a risk factor atherosclerosis. Low de nsity lipoproteins are considered a key factor in the formation of ath eroma and the immune system has an important contribution to this proc ess. Aim: To quantify the immune response against modified low density lipoproteins in patients with non insulin dependent diabetes mellitus . Material and methods: LDLs obtained from blood of healthy subjects, were glycated or altered with malondialdehyde and used as antigens. Se rum autoantibodies against these LDLs were measured by ELISA in 22 pat ients with non insulin dependent diabetes mellitus aged 46 to 67 years old and 13 healthy controls aged 41 to 65 years old. Basal and LDL st imulated tumor necrosis factor a production in vitro, by peripheral le ukocytes of diabetics and controls was also measured. Results: The rat io of glycated LDL/native LDL antibodies was higher in diabetics than in controls (9.37 +/- 2.72 and 0.41 +/- 0.11 respectively p<0.05) and the ratio of MDA modified LDL/native LDL antibodies was not significan tly different (8.64 +/- 3.83 and 2.14 +/- 1.26 respectively, NS). Tumo r necrosis or production by leukocytes was higher in diabetics than in controls in basal conditions (53.3 +/- 15.3 and 26.9 +/- 14.7 arbitra ry units (a.u.) respectively), when stimulated with native LDL (46.5 /- 5 and 24.3 +/- 9.4 a.u. respectively), when stimulated with malondi aldehyde modified LDL (50 +/- 16.2 and 24.4 +/- 7.7 a.u. respectively) or when stimulated with glycated LDL (38.3 +/- 8.8 and 14.4 +/- 7.5 a .u. respectively). Conclusions: Diabetic patients have an enhanced imm une response against low density lipoproteins, factor that could contr ibute to the accelerated atherogenesis of this disease.