Frequency of bcr-abl transcripts among sudanese patients with persistent myeloid leukocytosis: a diagnostic aide for chronic myeloid leukemia in low-income countries

BCR-ABL leukemic fusion gene types in chronic myeloid leukemia (CML) correlate with the disease clinical course and outcome. There is limited reported data regarding the frequency and types of BCR-ABL leukemic gene in the Sudan. This study aims to determine the frequency and types of BCR-ABL fusion transcripts and investigate their possible diagnostic role in patients with persistent myeloid leukocytosis. Following informed consent, one hundred and fifty-one patients with persistent myeloid leukocytosis for >8 weeks and in the absence of infection were enrolled. Peripheral blood was used for RNA extraction and RT-PCR technique with specific primers was used for BCR-ABL amplification. Ninety-seven per cent of patients (147/151; 97.4%) had BCR-ABL transcripts. The frequencies of BCR-ABL transcripts were 53.7% for b3a2, 27.3% for b2a2 and 19% for other atypical and co-expressed transcripts. Platelets counts were significantly higher in patients with the b3a2 positive transcript compared to those with the b2a2 (p=0.02). All patients with BCR-ABL transcripts and persistent myeloid leukocytosis were diagnosed as CML and were treated accordingly with good response. BCR-ABL fusion gene is seen in the great majority (97.4%) of Sudanese patients with persistent myeloid leukocytosis and is a good diagnostic aide for CML.