Interferon Alfa-2b Antibodies and Clinical Resistance in a Patient with Hairy Cell Leukemia

A patient with hairy cell leukemia is described who, during the course of treatment of his disease with interferon αb, developed antibodies to the drug. Coincident with antibody development, clinical resistance to the effect of alfa interferon was noted Despite an increasing dose of interferon, no signs of disease response were noted and the patient required a change in therapy to deoxycoformycin. Although similar findings have been described in patients treated with interferon alfa-2a, this is the first report of clinical resistance associated with neutralizing antibody formation in a hairy cell leukemia patient treated with interferon alfa-2b.