PREVALENCE OF BETA(2)-GLYCOPROTEIN-I ANTIBODY IN SYSTEMIC LUPUS-ERYTHEMATOSUS PATIENTS WITH BETA(2)-GLYCOPROTEIN-I DEPENDENT ANTIPHOSPHOLIPID ANTIBODIES

Objective-To investigate whether beta(2)-glyceprotein I antibody (aGPI ) exists in sera that are positive for antiphospholipid antibodies (aP L). Methods-Thirty six patients with systemic lupus erythematosus (SLE ) and 20 healthy volunteers were recruited. GPI independent and depend ent aPL (anticardiolipin (aCL), antiphosphatidylserine, antiphosphatid ylinositel, antiphosphatidic acid) were measured using a conventional enzyme Linked immunosorbent assay (ELISA). aGPI was measured by an ELI SA using a gamma irradiated plate coated with purified GPI. Results-Tw enty of 36 SLE patients were positive for at least one of the GPI-depe ndent aPL. Five of these 20 were also positive for aGPI. Another five of the 20 showed low GPI dependency aCL antibodies; however, three of these patients required GPI for binding to phosphatidylserine, phospha tidylinositol, or both. Conclusion-We confirmed the existence of aGPI in patients with true GPI dependent aPL. From these results, we recomm end the use of a gamma irradiated plate with GPI as antigen for the de tection of phosphate true GPI dependent aPL or aGPI. microlitres