The main BCR-ABL mRNA transcript types and hematological features of newly diagnosed chronic myeloid leukemia in Burkina Faso

Abstract

Objective: Chronic myeloid leukemia (CML) is characterized by the Philadelphia chromosome with an abnormally shortened chromosome 22, which is the result of a reciprocal translocation of chromosomes 9 and 22 that creates BCR-ABL fusion transcripts. CML accounts for approximately 15% of all leukemia cases and 24.3% of hematological disorders in Burkina Faso. The present study identified the main BCR-ABL fusion transcript variants using multiplex PCR in CML patients and investigated the hematological features at the time of diagnosis. Patients and Methods: Total cellular RNA was extracted from 107 blood leukocytes using methods adapted from Chomczynsky and Sacchi (1987). A reverse transcription reaction was performed using a high capacity cDNA reverse transcription kit from Applied Biosystem (Ref 4368814) following the manufacturer’s instructions. BCR-ABL transcript types were investigated using a homemade PCR method that was adapted and optimized from published protocols. A single reaction with multiple primers was used in multiplex PCR to detect and investigate the type and frequency of CML in 41 enrolled patients. Results: The average age of patients was 39 years and ranged between 12 and 65 years. Two main transcript types were identified in 38 of the 41 patients included in the study. The most common transcripts were b2a2 (47.4%) and b3a2 (34.2%). Eight samples (18.4%) presented both types of transcripts. During the diagnosis, the average hemoglobin level, average white blood cell number and platelets in newly diagnosed CML patients were 8.3 g/dL; 270.1 G/L and 350.2 G/L, respectively. Conclusions: Multiplex-PCR allowed for the rapid, specific and simultaneous detection of the most frequent BCR-ABL variant transcripts. The present study showed a higher frequency of b2a2 than b3a2 transcripts in Burkina Faso CML patients. These findings will guide us in the choice of specific BCR-ABL variant primers for the monitoring of patients undergoing Imatinib treatment.

Keywords

• chronic myeloid leukemia
• bcr-abl variants
• multiplex pcr
• hematological features
• burkina faso