Follow-up study on 24 patients with nomifensine-induced immune haemolytic anaemia

There is as yet only scarce information regarding the natural history and long-term clinical sequelae of patients who survive the acute complications of severe drug-related immune haemolysis, the effect of the mode of drug administration for sensitization and possible alterations of serological characteristics of drug-dependent antibodies during the postsensitization period. We therefore followed 24 patients with nomifensine-induced haemolytic anaemia for up to 6 years after the haemolytic attack. All patients had suffered from a severe haemolytic episode. None of the patients showed any abnormal findings upon reinvestigation (complete history and physical examination; extended biochemical and haematological laboratory status), particularly with respect to renal function. Drug-dependent antibodies remained detectable in 19 of 21 sera, while drug-independent autoantibodies, demonstrable in six patients during the acute phase of haemolysis, could no longer be detected. With regard to the mode of drug administration, the majority of patients (15 out of 24) had developed the haemolysis at the beginning (immediately after a single dose) or during a second course of drug therapy (n = 8 and 7, respectively). The immune response did not appear to be dose- or time-dependent. This study confirms the benign long-term prognosis of patients who survive life-threatening complications in drug-induced immune haemolytic anaemia. In addition, it indicates that drug-dependent antibodies may remain detectable over long periods of time, and that irregular drug administration might be associated with a higher risk of drug sensitization.