The lupus anticoagulant. A disease marker in antinuclear antibody negative lupus that is cross-reactive with autoantibodies to double-stranded DNA.
The lupus anticoagulant (LA) was demonstrated in 37% of 52 consecutive systemic lupus erythematosus (SLE) patients and patients with lupus-like syndromes, who were referred to our unit. The LA was found to be associated with a biologic false-positive VDRL (P less than 0.005), and the apparently paradoxical association of LA with vascular thromboses was confirmed (P less than 0.05). The presence of LA and a biologic false-positive VDRL defined a group of 7 antinuclear antibody negative patients with characteristic features of recurrent thromboses, spontaneous abortions, neurologic involvement, and renal disease. Further studies on 6 selected sera demonstrated LA in all 6 IgM fractions and in 3 of 6 IgG fractions. Inhibition of LA was shown in 6 of 9 Ig fractions after absorption with double-stranded DNA (dsDNA). Anticardiolipin antibody was shown by immunodiffusion in 3 LA positive IgG fractions from VDRL negative sera. Cardiolipin micelles partially inhibited anti-dsDNA binding of 4 IgG fractions, 3 of which were LA negative. In this report we discuss the overlapping specificities due to cross-reactivity between LA, anticardiolipin, and anti-dsDNA antibodies in human SLE, and we suggest that LA be considered equivalent to the biologic false-positive VDRL as a criterion for the diagnosis of SLE.
D000974:Antibodies, Antinuclear / Q000032:analysis*; D001666:Binding Sites, Antibody; D001779:Blood Coagulation Factors / Q000032:analysis / Q000037:antagonists & inhibitors*; D001780:Blood Coagulation Tests; D002308:Cardiolipins / Q000276:immunology; D003429:Cross Reactions; D004247:DNA / Q000276:immunology*; D005260:Female; D005428:Flocculation Tests; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D016682:Lupus Coagulation Inhibitor; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000276:immunology*; D008297:Male; D011233:Precipitin Tests
D000974:Antibodies, Antinuclear; D001779:Blood Coagulation Factors; D002308:Cardiolipins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D016682:Lupus Coagulation Inhibitor; D004247:DNA