ANTIBODY-TITERS AGAINST OXIDIZED LDL ARE NOT ELEVATED IN PATIENTS WITH FAMILIAL HYPERCHOLESTEROLEMIA

Antibodies against oxidized low density lipoproteins (Ox-LDLs) have be en proposed to be independent predictors of atherosclerosis developmen t. The main aims of the current study were to (1) compare antibody tit ers to Ox-LDL in patients with heterozygous familial hypercholesterole mia (n=51) with those in matched controls (n=45) and (2) analyze wheth er the antibody titers were related to the extent of atherosclerosis, as assessed cross-sectionally and prospectively by ultrasonography in the 2 study groups. Antibody titers were determined with a solid-phase ELISA, and plates were coated with the antigens Ox-LDL or malondialde hyde-treated LDL (MDA-LDL) as well as with the postcoat only (5% dry m ilk powder). Antibody titers were expressed as absorbance [(value in p atient serum minus that in postcoat) divided by (Internal Standard Ser um minus postcoat)]. There were no significant differences in antibody titers against Ox-LDL or MDA-LDL between the group of patients with f amilial hypercholesterolemia and the controls. In cross-sectional comp arisons, no significant associations were observed between the intima- media thickness of the carotid or femoral arteries and antibody titers against Ox-LDL or between plaque occurrence and these titers. Patient s with a history of myocardial infarction had significantly lower IgM titers against Ox-LDL compared with patients without a history of myoc ardial infarction and with controls. In conclusion, mean values for an tibody titers against Ox-LDL were not increased in the patient group c ompared with a healthy control group, and no positive, significant rel ationship was observed between antibody titers and the extent of ather osclerosis, as measured by ultrasound, in the carotid or femoral arter ies. Taken together, these findings indicate that the relationship bet ween the autoimmune response to Ox-LDL and the extent of atheroscleros is is more complex than previously anticipated.