AB0609 Correlation between plasma lipoprotein phospholipase a2 (LP-PLA2) and anti phospho lipid antibody(APL-AB) in patients with connective tissue diseases

Background Plasma Lp-PLA2 has both anti-inflammatory and pro-inflammatory activity in vascular-related pathologies and is an independent risk predictor for coronary heart disease and stroke because of its important role in atherosclerosis and thrombosis. However, vasculitis is a common pathological feature of connective tissue disease. Objectives Therefore, the aim of this study was to investigate the association of plasma Lp-PLA2 level with antinuclear antibody (ANA) titer, karyotype, anti-cardiolipid antibody (ACA) and anti-β2GP1 antibody and lupus anticoagulant (LA, including PT-IgG and PT-IgM). Methods Outpatient and inpatient with connective tissue diseases from Department of Rheumatology of the Third Affiliated Hospital of Sun Yat-sen University from 2015 to 2016 were randomly selected. Venous blood was collected, plasma Lp-PLA2 level was measured by Elisa method. ANA titer and karyotype were detected by indirect immunofluorescence assay. ACA, anti-β2GP1 antibody, PT-IgG and PT-IgM were detected by Elisa method. SPSS23.0 statistical software was used for statistical analysis. Results A total of 176 patients with connective tissue disease including 38 males (21.59%) and 138 females (78.41%) were enrolled in this study, and the average age was 42.22±17.31 years. The mean plasma level of Lp-PLA2 was (363.96±203.19 ng/ml). There was no significant difference in Lp-PLA2 level between different genders (p=0.072), and LP-PLA2 level have no correlation with age (p=0.098). The ANA titers were classified as negative (35.80%), weakly positive 1: 100 (11.93%), positive 1: 100 (18.75%), positive 1: 320 (12.50%), positive 1: 1000 and positive 1: 3200 (9.66%). There was no significant difference in plasma Lp-PLA2 level between different titers of ANA (p=0.088). ANA karyotypes included nucleolus type (0.88%), centromere type (3.54%), cytoplasm type (7.96%), homogeneity (29.20%) and granularity (58.41%). Also, there was no significant difference in plasma Lp-PLA2 level between different karyotypes (p=0.153). The average level of ACA was 12.88±23.87 RU/ml and there was no significant correlation between plasma Lp-PLA2 level and ACA level (p=0.839). Anti-β2GP1 antibodies were classified as negative ( 18 U/ml). PT-IgM were all negative and there was no significant difference in plasma Lp-PLA2 level between PT-IgG negative (96.59%) and positive (3.41%) patients (p=0.279). Conclusions Plasma Lp-PLA2 level in patients with connective tissue disease have no significant correlation with age, gender, ANA titer, karyotype, ACA, anti-β2GP1 antibody and LA. The role of plasma Lp-PLA2 in connective tissue disease may be different from APL-Ab. Disclosure of Interest None declared