PREVALENCE OF ANTI-BETA(2)-GLYCOPROTEIN-I AND ANTI-PROTHROMBIN ANTIBODIES IN 2174 PATIENTS AND 107 HEALTHY CONTROLS

Prevalences of anticardiolipin (aCLA), anti-beta(2)-glycoprotein I (an ti-beta(2)-GPI) and anti-prothrombin IgG antibodies were determined by ELISA in 2174 patients and 107 blood donors. Among patients, 137 had systemic lupus erythematosus (SLE), while 683 displayed at least one c linical or biological feature suggestive of antiphospholipid syndrome: 497 patients had thrombosis, 51 patients had experienced at least 3 m iscarriages or a foetal death at more than 12 weeks of gestation, 67 h ad thrombocytopenia, 50 had lupus anticoagulants (LA), 13 had thrombos is and LA, 3 had thrombocytopenia and LA and 2 had a history of foetal lass and LA. Connective tissue or related disorders were present in 5 95 patients, 759 others were suffering from miscellaneous diseases and cases of HIV infection were excluded from the study. Prevalences of a CLA and anti-beta(2)-GPI antibodies were increased in patients with SL E and/or LA in comparaison to all other groups (p < 0.001). In these p atients, anti-beta(2)-GPI antibodies were often associated with aCLA, 34 (77%) of 44 patients with anti-beta(2)-GPI antibodies also having a CLA (p < 0.001). In other patients the reverse was true, anti-p,GPI an tibodies being infrequent and when present rarely associated with aCLA (p < 0.001). The prevalence of sera with anti-beta(2)-GPI antibodies but no aCLA was similar in all patient groups and in blood donors. The se results suggest that at least two types of antiphospholipid contain ing sera exist, those containing only one kind of antibody (aCLA or an ti-beta(2)-GPI antibodies, type 1) which are poorly specific and those associating aCLA and anti-beta(2)-GPI antibodies (type 2), highly spe cific for SLE and/or LA. The prevalence of anti-prothrombin antibodies was increased in patients with SLE and/or LA (p < 0.01) and in those with an unexplained prolongation of APTT (p < 0.01). In the latter cas e, since these antibodies were not associated with LA, aCLA or anti-be ta(2)-GPI antibodies, this indicates that anti-prothrombin antibodies may interfere in the APTT test and should therefore be screened in pat ients presenting an unexplained prolongation of APTT.