Lupus anticoagulant: a clinical and laboratory study of 100 cases

The clinical and laboratory features of 100 patients with lupus anticoagulant (LA) are reviewed. Subjects were divided into three groups according to their age (1-5, 15-35, 45-89 years). Female prevalence was observed in each group and overall F/M ratio was 3/1. An underlying autoimmune disease (principally lupus erythematosus) was found in 47 cases (10% of the children, 80% of the 15-35-year-old patients and 37% of the elderly patients). Biological criteria for the LA diagnosis were prolonged activated partial thromboplastin time and diluted thromboplastin time (1.3 x control), not corrected after addition of control to patient's plasma. Thromboplastin time was normal in 77 patients. Other types of coagulation inhibitors were eliminated by specific factor assays (with a 10-fold increase of cephalin concentration when necessary). Twenty-three thrombotic episodes were observed. No significant difference was found in the incidence of thrombosis between the autoimmune and non-autoimmune disease group, but the age when first thrombosis occurred was clearly lower in the former. Fourteen obstetrical accidents were noted in eight women but 13 pregnancies terminated without accident. Four patients experienced haemorrhagic complications; they all presented with a severe thrombocytopenia associated with the LA. In our experience, LA is a frequent coagulation abnormality, associated in about half of the cases with a clearly defined autoimmune disease. Clinical presentation appears as notably different according to the patient's age; it is particularly noteworthy that in nine out of 10 children, LA disappeared spontaneously within 6 months.