OP-9 - Correlation between antiphospholipid antibodies and the coagulation-fibrinolysis system in women with a history of miscarriage - comparison between conventional antiphospholipid antibodies and neo-self antibodies.

Abstract

The clinical diagnostic criteria for antiphospholipid antibody syndrome (APS) include thrombosis and obstetric complications; alterations in the coagulation-fibrinolysis system due to pathogenic autoantibodies have been described as a common background for the clinical presentation of APS. Recently, autoantibodies against β2-glycoprotein I (β2GPI) in complex with HLA class II molecules (β2GPI/ HLA-DR) (neo-self antibodies) have been reported to be a novel autoantibody associated with APS. The present study investigated the relationship between conventional antiphospholipid antibodies and neoself antibodies and coagulation/fibrinolysis markers in women with a history of miscarriage. Serum antibody titres of conventional antiphospholipid antibodies (anti-cardiolipin IgG/IgM, anti-β2GPI and lupus anticoagulant) and neo-self antibodies were measured in 58 women with a history of miscarriage. Coagulation and fibrinolysis status was assessed by TAT, AT and D-dimer and APTT. In addition, the relationship with subsequent pregnancy outcome was investigated. Ten women were positive for conventional antiphospholipid antibodies and six were positive for neo-self antibodies, including one patient who was positive for both. 28 patients had elevated TAT levels and none of them showed APTT elongation. The frequency of elevated TAT was 80% (8/10) in the conventional antiphospholipid antibody-positive group and 83% (5/6) in the neo-self antibody-positive group. Those ratios were higher than the TAT positivity of 37% (16/43) in the antibodies-negative group. During the observational period, clinical pregnancy was confirmed in 23 cases, including 16 with TAT elevation. Among them, three cases resulted in early miscarriage, two of which had a TAT elevation, one of which was positive for neo-self-antibodies. Both the traditional antiphospholipid antibody-positive group and the neo-self antibody-positive group had a high frequency of TAT elevation. Alteration in coagulation/fibrinolytic system could be shared as the pathogenic background between the two groups and is possibly involved in the incidence of miscarriage.