Increase of ICSBP-transcript numbers in a CML patient during in vivo IFN-α treatment, inversely correlated with bcr-abl-transcript (•), leukocyte (□), and lymphocyte (▪) numbers. At diagnosis (lane 0), and during treatment with hydroxyurea (lane 1: after 0.5 weeks; lane 2: 1 week) few ICSBPtranscripts were visible, although in this period the patient exhibited only 0% to 3% blast cells. During early IFN-α treatmentICSBP-transcript numbers increased (lane 3: 15 weeks; lane 4: 15 weeks), but decreased with progression to blast crisis (lane 5: 22 weeks; lane 6: 31 weeks; lane 7: 37 weeks, blast crisis with 60% blast cells; lane 8: 37 weeks, blast crisis, bone marrow). The mean of three experiments is displayed (±SEM). The patient exhibited an additional cytogenetic aberration, a monosomie 7, during blast crisis. BC, blast crisis.