Effectiveness of alpha-interferon therapy and bcr-abl transcripts in patients with chronic myeloid leukemia (CML)

Polymerase chain reaction (PCR) was used to study bcr-abl transcripts in 36 CML patients. 13 of them have received recombinant or natural alpla-interferon, 15 were treated with myelosan or hydroxyurea and 8 - combination of cytostatics. Rearrangement types b3a2, b2a2 and e1a2 occurred in 22, 5 and 5 out of 36 patients, respectively. Two patients displayed coexpression b3a2+b2a2, and one - b3a2+e1a2. Gene rearrangement type remained unidentified in one case. The majority of patients with new-onset blast transformation (in 6 of 8) had transcript e1a2. Alpha-interferon therapy produced the largest number of complete remissions, cytogenetic among them (reduction of pH′-clone by 15-87%), in patients with the rearrangement type b3a2. The least therapeutic response was noted in patients with coexpression b3a2+b2a2. Cytogenetic response to alpha-interferon therapy was as a rule absent in patients with type b2a2. No significant correlation was registered between the type of bcr-abl rearrangement and duration of CML chronic phase, survival, clinical course and/or hematological parameters.