[Venous thrombosis, circulating anticoagulant and systemic lupus erythematosus. Two cases reported in two identical HLA sisters (author's transl)].

The observation of two cases of thrombophlebitis of the calf which occurred in two sisters within a period of three years is reported. The investigation revealed in both cases the presence of a circulating anticoagulant with anti-prothrombinase activity in association with biological signs of systemic lupus erythematosus (L.E.): anti-DNA antibodies, decreased complement levels, false positive BW reactions. In one patient, the skin biopsy showed a continuous IgM band on immuno-fluorescence. After respectively 4 years and 18 months follow-up both patients are still free from clinical symptoms. A review of the literature is presented and the clinical and etiological significance of the presence of a circulating anticoagulant, its relationship with L.E., particularly with "latent" L.E. (presence of biological signs only), and its association with thrombophlebitis are discussed.