Background: Anti-beta 2-glycoprotein I antibodies (a beta 2GPI) were studied in patients with diseases or clinical symptoms related to antiphospholipid antibodies (aPl) with the aim of establishing a relationship between both antibodies and these clinical manifestations.
Methods: The a beta 2GPI antibodies were determined by enzymeimmunoassay in a group of 94 altruist blood donors and 135 patients (98 with systemic lupus erythematosus, 21 cases of primary antiphospholipid syndrome, 10 cases with idiopathic Sneddon syndrome and 6 with Q fever). The lupus anticoagulating-type aPl antibodies were determined in the same subjects by kaolin coagulation time and the Russell's viper venom time while anticardiolipin-type IgG, IgM and IgA isotypes were determined by enzymeimmunoassay. The a beta 2GPI antibodies were related with the aPl antibodies, fetal losses and history of thrombosis by a contingency table with Yates correction in the first two parameters and means comparison by the Students' t test for the history of thrombosis.
Results: The aPl and a beta 2GPI antibodies in the control group were negative. In the group of patients the latter antibodies were positive in 33.6% (33 cases) of the patients with lupus, 57% (12 cases) of the patients with primary antiphospholipid syndrome, in one of the patients with the Sneddon syndrome and in none of the patients with Q fever. The aPl antibodies were positive in 26.5% of the patients with lupus and in 100% of the cases with primary antiphospholipid syndrome or Q fever and negative in all the cases with idiopathic Sneddon syndrome. A significant relationship was found between the a beta 2GPI antibodies and thrombotic manifestations (p = 0.01) or obstetric complications (p < 0.04). A dependent relationship was observed in both autoantibodies (aPl and a beta 2GPI) (p < 0.01).
Conclusions: There is a significant relationship between the antiphospholipid antibodies and the anti-beta 2-glycoprotein I antibodies in addition to a relationship with thrombotic symptoms or obstetric complications.