Do antibodies to beta2-glycoprotein 1 contribute to the better characterization of the antiphospholipid syndrome?
The aim of this study was to determine if the measurement of anti-beta2-glycoprotein I antibodies (abeta2-GPI) in serum levels contributes to the better characterization of the clinical situation of patients with antiphospholipid syndrome (APS). For this purpose abeta2-GPI of both isotypes was measured in 42 patients with APS and 32 SLE patients without APS. Clinical records of all patients were thoroughly reviewed. The presence of abeta2-GPI was correlated with the clinical manifestations of APS and compared with the presence of anticardiolipin antibodies (aCL) and lupus anticoagulant (LA) activity. There was a positive correlation between levels of aCL and abeta2-GPI for both IgG and IgM isotypes (rho of Spearman=0.82 and 0. 64 respectively, P=0.0001). Both antibodies presented significantly higher titres in LA positive patients (P<0.05). The specificity for APS was 91% for IgG abeta2-GPI vs 75% for IgG aCL and 87% for IgM abeta2-GPI vs 81% for IgM aCL. 68% of patients with thrombosis of 100% of patients with thrombocytopenia showed positive tests for all three markers (aCL, LA, abeta2-GPI). Simultaneous presence of circulating LA and high titres of both aCL and abeta2-GPI identify a subset of patients with primary APS (PAPS) who have a more severe clinical course of the disease. Although the specificity of abeta2-GPI IgG is higher than that of aCL IgG, when all three tests are performed abeta2-GPI testing provides only additional information to that of aCL and LA. Therefore, we concluded that the abeta2-GPI test should not be considered as a substitute for conventional LA or aCL assays. However, performance of abeta2-GPI seems to be important in PAPS with high aCL titres, to alert the physician about the risk for the worst course of the illness.
Detkov
Immunology Unit, Hospital La Paz, Madrid, Spain.
Gil-Aguado
A
A
Lavilla
P
P
Cuesta
M V
MV
Fontán
G
G
Pascual-Salcedo
D
D
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000918:Antibody Specificity; D016736:Antiphospholipid Syndrome / Q000276:immunology*; D001323:Autoantibodies / Q000276:immunology*; D005260:Female; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000276:immunology; D016682:Lupus Coagulation Inhibitor / Q000276:immunology; D008297:Male; D008875:Middle Aged; D053482:beta 2-Glycoprotein I
D001323:Autoantibodies; D006023:Glycoproteins; D007132:Immunoglobulin Isotypes; D016682:Lupus Coagulation Inhibitor; D053482:beta 2-Glycoprotein I