Indirect evidence of hemolysis has been described in patients with autoimmune thrombocytopenic purpura. In order to collect more data, another method to assess red blood cell destruction in these patients was employed: measurement of free haptoglobin levels. In 17 individuals with autoimmune thrombocytopenic purpura the levels of free haptoglobins were assessed after carefully ruling out microangiopathic hemolysis, systemic lupus erythematosus or overt Evans syndrome. Abnormally low levels of free haptoglobins were found in five individuals (29%) as indirect evidence of hemolysis. The long-term thrombocytopenia-free status was lower in patients with low haptoglobin levels than in those with normal levels (40 versus 58%). These data, added to previous evidence, support the observation of Evans made 50 years ago: "there is a spectrum-like relationship between primary thrombocytopenia and haemolytic anemia".". Accordingly, the concept of "attenuated" variants of the Evans syndrome could be entertained.
Keywords: Autoimmune; Evans syndrome; Haemolysis; Haptoglobin; Purpura; Thrombocytopenic.