Deficient activity of von Willebrand factor-cleaving protease in thrombotic thrombocytopenic purpura in the setting of adult-onset Still's disease

SIR, Adult-onset Still's disease (AOSD) is a systemic autoimmunedisorder of unknown aetiology and pathogenesis, characterizedby high spiking fever, a salmon-pink evanescent rash and polyarthritis.Although the aetiology and pathogenesis of this disease arenot fully understood, several lines of evidence suggested thatimmunological mechanism play important roles in the pathogenesis[1]. Thrombotic thrombocytopenic purpura (TTP) is a potentially life-threateningdisorder characterized by haemolytic anaemia, consumptive thrombocytopenia,disturbance of consciousness, fever and renal damage. A majorbreakthrough in the understanding of the pathogenesis of TTPis the discovery of deficient