P1658: clinical characteristics of a high-positive antiphospholipid syndrome

Topic: 34. Thrombosis and vascular biology - Biology & Translational Research Background: Antiphospholipid syndrome (APS) occupies one of the leading positions in the structure of the causes of thrombosis. The annual incidence of APS is 5 cases per 100,000 population, and the prevalence is about 40-50 cases per 100,000. According to the severity of clinical manifestations and complications, high-positive APS needs special attention. Aims: Assessment of clinical manifestations and complications of high-positive APS. Methods: 72 patients with APS aged 14 to 70 years were under follow-up. The average age of patients was 34 ± 6.82 years, women predominated - 73.6%. The follow-up period ranged from 6 months to 9 years. The diagnosis was verified in accordance with the Sydney classification criteria of APS (2006). Antibodies to cardiolipin and to β2-glycoprotein-1 (β2-GP-1) of the IgM and G classes were determined by enzyme-linked immunosorbent assay (ELISA). Plasma hemostasis indicators and lupus anticoagulant(LA)were determined using an ACL Elite pro coagulometer. High-positive APS was determined with an increase in antiphospholipid antibodies (APAB) of more than 60 IU/ml. In the presence of two (doublet) or three (triplet) types of APAB, category I was established, in the presence of one type of APAB, category II (IIa - BA; IIb - antibodies to cardiolipin; IIc - antibodies to β2-GP-1). In order to exclude congenital thrombophilia, the activity of antithrombin III, proteins C and S, and the level of homocysteine were assessed; molecular genetic testing (by PCR) was carried out for the presence of thrombogenic mutations. Results: High-positive APS was determined in 19% of women and 47% of men with primary APS. A total of 19 patients, which accounted for 26.4% of the observation group. Among the clinical manifestations, thrombosis of various localization prevailed (68.4%): veins of the lower extremities - 23.5%; veins of the upper extremities - 7.7%; portal vein pool - 15.3%, portal vein - 15.3%. Pulmonary embolism was diagnosed in 17.6% of patients. Recurrent miscarriage was observed in 30% of women. Of the non-criteria manifestations of APS is cerebrovascular accident of the ischemic type - in 11.7% of cases; immune thrombocytopenia - 11.7%. In 52.6% of patients, secondary autoimmune complications developed within 2-9 years, among which autoimmune coagulopathy prevailed (60%). Among other complications: hemorrhagic vasculitis, glomerulonephritis, autoimmune hemolytic anemia, aplastic anemia. In 57.9% of patients, the presence of two (double) types of AFAB was detected simultaneously; in 36.8% of cases - triplet and in 5.3% of cases - category IIa was verified. In 5.5% of cases, primary APS was accompanied by congenital thrombophilia: Heterozygous Leiden mutation (n=2) and heterozygous mutation of the prothrombin G20210A gene (n=2). Among patients with high-positive APS, congenital thrombophilia was detected in 11.5%. Summary/Conclusion: High-positive APS was observed in 1/3 of newly diagnosed APS cases. The risk of developing this variant of APS in men is twice as high. Venous thrombosis prevailed in the clinical picture, however, high-positive APS can onset with non-criteria manifestations, such as cerebrovascular accident, immune thrombocytopenia. In half of the cases, there is a risk of developing various immunocomplex and secondary autoimmune complications that worsen the prognosis of the disease. Keywords: Antiphospholipid syndrome, Venous thrombosis, Lupus anticoagulant