reversible therapy-related dysplastic hematopoiesis following beta interferon therapy in multiple sclerosis patients: report of 2 cases.

background: interferon beta-la and -1b have been increasingly used for the treatment of multiple sclerosis (ms). the most frequent systemic adverse effects are flu-like symptoms. laboratory abnormalities include asymptomatic leukopenia and elevated hepatic transaminases. myelodysplastic syndrome (mds) refers to a spectrum of hematological disorders which can occur in different situations. several hematological abnormalities have been reported following interferon therapy. methods: we report two cases of secondary mds after long term interferon therapy by using the laboratory data and bone marrow results. conclusion: both of our cases were reversible; although treatment with ifnβ-1a and-1b is safe and well tolerated in the majority of population, we should be careful about this premalignant hematological disorder.