Thrombosis and fetal loss in primary antiphospholipid syndrome versus systemic lupus erythematous

ABSTRACT

Antiphospholipid syndrome [APS] is characterized by recurrent arterial and venous thrombosis, fetal losses and occasional thrombocytopenia. APS commonly occurs in the context of connective tissue diseases mainly SLE, but may occur as a primary diseases i.e. primary antiphospholipid syndrome [PAPS]. We studied 30 SLE and 13 PAPS patients to compare the incidence of thrombosis and fetal losses in both groups and to correlate it to anti-cardiolipin antibodies [ACL] measured with the conventional ELISA assay. ACL IgG was significantly higher in PAPS patients, as compared to SLE patients. However, ACL IgM was not statistically different between the two groups. Eight out of ten PAPS patients had 22 abortions [80%] compared to 11 abortions in seven out of twenty six SLE patients [28%]. This difference significantly correlated with both ACL IgG and IgM [p<0.05]. Eight out of thirteen PAPS patients had 10 thrombo-embolic events [70%] compared to three events out of thirty SLE patients [10%]. This difference significantly correlated with ACL IgG [p<0.05] but not ACL IgM [p>0.05]. No significant difference was detected for the mean either ACL IgG or IgM levels in PAPS patients when divided into two subgroups according to the incidence of abortions and / or thromboembolic events. In SLE, such groups ACL IgM was significantly higher in the subgroup that did not have any abortive events when compared to those who had abortions. This indicates that ACL IgM is a poor predictor of future fetal losses in SLE patients. We concluded that ACL IgG, but not IgM is higher in PAPS than SLE patients. We also showed that the incidence of recurrent abortions and thrombosis are higher in PAPS than in SLE patients. This correlated to the level of ACL IgG and IgM in abortions, but to ACL IgG only in thrombosis. We also believe that the conventional ELISA assay for ACL is not a sensitive test, as it can identify some ACL that are unrelated to thrombosis. Therefore, we suggest using the new ACL assays which react either directly to beta2-GP1 or beta2-GPI dependent cardiolipin for more sensitive assessment of the risk of thrombosis and/or fetal losses in those patients