Antibodies against oxidized low density lipoproteins in pregnant women

Oxidized low density lipoproteins (oxLDL) formed in vivo induce a humoral immune response. Oxidative modification of LDL renders it immunogenic and a heterogeneous population of specific anti-oxLDL antibodies is produced. These antibodies could represent a biological marker of oxidative stress and serve as markers of atherosclerosis. Autoantibodies against oxLDL (oLAb) have been detected in human subjects practically of every age. oLAb also appear in the blood of pregnant women. Some studies have shown that the levels of antibodies to oxLDL were elevated in women with established preeclampsia. The present study was aimed to estimate the oLAb IgG levels in the first and second trimester of pregnancy. Furthermore, we estimated the correlation between maternal serum (MS) levels of oLAb and alpha-1-fetoprotein (MS AFP), human chorionic gonadotrophin (MS HCG) and trophoblast-specific-beta-1-glycoprotein (MS SP1), because these proteins are determined as a part of prenatal biochemical screening for fetal congenital abnormalities. Our study deals with the oLAb changes in women with pregnancy-induced hypertension. We also investigated the correlation between oLAb IgG and anticardiolipin antibodies IgG (ACA) in the serum of pregnant women. We examined 40 pregnant women attending Institute for Mother and Child Care for their antenatal care as outpatients. Routine blood samplings between the 9-13th week of pregnancy and 16-18th week of pregnancy were performed as a part of biochemical prenatal screening for fetal congenital abnormalities (Group 1). Their mean age was 27 +/- 4.1 years. Furthermore, we examined 26 women in the second or third trimester with pregnancy-induced hypertension (Group 2). Group 2 was compared with 49 pregnant women in the second or third trimester who were normotensive (Group 3). We used commercial standardized ELISA kits for determination of oLAb IgG, ACA IgG, MS AFP and MS HCG, MS SP1 was analyzed by single radial immunodiffusion. We did not find any differences in the levels of oLAb IgG in the first and second trimester in the women of Group 1. The correlation between oLAb and ACA IgG was not statistically significant (Spearman coefficient r=0.22, p=0.1). The correlation between oLAb IgG with MS AFP, MS HCG and MS SP1 was not statistically significant. Weak negative correlation for AFP and HCG was suggested both in the first and in the second trimester. The levels of oLAb IgG in the group of women with pregnancy-induced hypertension were significantly lower than in the group of normotensive women (348 +/- 388 U/ml v.s. 579 +/- 400 mU/ml, p<0.01). We can conclude that the levels of oLAb do not differ in the first and second trimester of gravidity. However, we cannot exclude the possible influence of an inverse relationship between oLAb IgG titers and the synthesis of fetoplacental antigens. This finding is important especially in the context of the results of prenatal biochemical screening. Pregnancy-induced hypertension is associated with lower levels of oLAb. Weak cross-reactivity between oLAb and anticardiolipin antibodies may exist but there is a possibility that there are two different populations of antibodies reacting with various antigens.