Spontaneous recovery in a patient with acquired thrombotic thrombocytopenic purpura (TTP): observation of a 'subclinical' TTP state.

TTP is a haematologic emergency that requires urgent therapy to reduce morbidity and mortality. However, it is well documented that individuals with hereditary TTP and a proportion with acquired TTP in clinical remission can have low or nearly absent ADAMTS13 activity levels without evidence of microangiopathic haemolytic anaemia (MAHA) or thrombotic manifestations. Our patient represents a unique case of confirmed ADAMTS13 deficiency due to a documented inhibitor, leading to mild haemolytic anaemia and thrombocytopenia both of which recovered spontaneously. We propose that this scenario could represent a 'subclinical' TTP state that precedes the development of clinically significant disease.