Background Serum mannose-binding lectin (MBL) is a recognition molecule of the lectin pathway of complement with antimicrobial and anti-inflammatory actions. Several polymorphisms have been reported for the MBL2 gene. These variants are associated with low MBL serum concentration and are risk factors of infectious diseases, atherosclerosis and autoimmune diseases (1).Systemic lupus erythematosus patients with associated antiphospholipid syndrome have a higher prevalence of MBL-deficient genotypes.(2). Patients with primary antiphospholipid syndrome (PAPS) have carotid intima-media thickness, a marker of accelerated atherosclerosis. However, the role of MBL-deficient genotypes in PAPS is unclear.
Objectives To investigate the prevalence of MBL-deficient genotypes in PAPS and its association with carotid intima-media thickness (IMT).
Methods Blood samples were obtained from 48 patients with PAPS and matched with 111 healthy controls by age and gender, in a relation 1:2. Demographic, clinical data, cardiovascular risk factors and antibody profile were recorded. Total DNA was extracted from total blood with DNA isolation kit for mammalian blood (ROCHE). PCR-RFLP (Restriction Fragment Length Polymorphisms) reactions were performed on 50 ng of genomic DNA. MBL exon 1 PCR products were incubated with Mbo II, Ban I at 37°C, and Mwo I at 60°C for 1 h. MBL promoter gene region PCR products were incubated with Drd I and Btg I overnight at 37°C. The products were analyzed by electrophoresis using silver staining of polyacrylamide gel electrophoresis. Colour Doppler with high resolution B mode carotid ultrasonography was performed in patients to measure intima-media thickness (IMT).
Conclusions This study shows a high prevalence of MBL-deficient genotypes in the promotor region of the MBL2 gene (LX/LY, LXA/A) in patients with PAPS. However, MBL variant alleles were not significantly associated with carotid IMT. The accelerated atherosclerosis in PAPS could be consequence of genetic, immunological, and environmental risk factors. A prospective study is necessary in order to confirm these results.
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Disclosure of Interest None Declared