Early lymphoid blastic crisis following major karyotypic conversion in a chronic myeloid leukemia patient treated with interferon-a.

A major karyotypic conversion following interferon-alpha treatment delays or prevents blastic crisis in patients with chronic myeloid leukemia. We report here a 12-year-old boy with Ph1+ chronic myeloid leukemia who, after achieving a major karyotypic conversion following 12 months interferon-alpha treatment, developed an early lymphoid blastic transformation 7 months later while still under interferon-alpha therapy. A number of possible explanations for this quite unexpected event are discussed