Treatment with alpha interferon associated with the development of paraneoplastic pemphigus

The use of interferon (INF) is usually considered safe, the major side-effect being a flu-like syndrome. However, with its ability to alter immune responsiveness, INF has been associated with the induction of autoimmune diseases. We report a patient with Waldenstrom's macroglobulinaemia who developed a generalized blistering eruption after treatment with systemic INF-α 2A (INF) for multiple skin cancers. The patient's skin showed histological features, immunofluorescence findings, and immunoprecipitation diagnostic of paraneoplastic pemphigus. Despite aggressive treatment the patient died. In our patient, the use of INF was temporally related to the development of paraneoplastic pemphigus. Although interferon has been shown to induce other autoimmune diseases, to our knowledge this is only the second report of a patient treated with an interferon who subsequently developed a fatal autoimmune blistering disorder. Paraneoplastic pemphigus is a recently described autoimmune bullous disorder with a poor prognosis. The mechanism by which INF triggered the paraneoplastic pemphigus is not known.