Reversal of infection with Mycobacterium avium intracellulare by treatment with alpha-interferon in a patient with hairy cell leukemia.

A patient with debilitating hairy cell leukemia and documented Mycobacterium avium intracellulare infection unresponsive to standard antituberculous therapy who was treated with alpha-interferon is described. A rapid clinical response with correction of underlying pancytopenia and eradication of the atypical mycobacteria infection was found. No deleterious effects from alpha-interferon therapy were found. The associated resolution of anergy and the sterilization of bone marrow suggest that the reversal of host cellular immune defects led to the eventual control of this patient's infection.