Successful response to alpha-interferon 2b in a refractory IgM autoagglutinin-mediated hemolytic anemia.

We describe the beneficial effect of recombinant alpha 2b interferon in a woman with an idiopathic and refractory IgM-mediated autoimmune hemolytic anemia due to low-titer, high-thermal-amplitude cold agglutinins. The response was partial but sustained, 2 months after interruption of interferon, with hemoglobin concentrations ranging between 8.5 and 10 g/dl. In the literature, such rarely encountered hemolyzing warm-reacting agglutinins are described as causing severe hemolysis with a frequently fatal clinical outcome.