Abstract
Introduction Chronic myeloid leukemia (CML) is characterized by the presence of the BCR-ABL fusion gene with constitutive tyrosine kinase activity that activates many signaling pathways contributing to the abnormal growth and survival of leukemic cells. Basophilia is a strong independent prognostic variable that correlates with the phase of CML. In CML, basophils are difficult to be identified by their morphology due to their immaturity or low frequency by tyrosine kinase inhibitors (TKIs) therapy. It is important to predict responses to therapy and to monitor levels of minimal residual disease in CML patients by cytogenetics and PCR. However, these parameters are expensive and require special technologies. Thus, the aim of the current study was to clarify whether the serum level of the basophil-marker histamine correlates with hematologic, cytogenetic, and molecular responses in CML patients and with the achievement of the optimal response to TKI therapy.
Patients and methods The histamine level was measured by enzyme-linked immunosorbent assay in 48 CML patients, together with cytogenetic analysis at diagnosis and after 6 months from the start of imatinib treatment. Molecular study of BCR-ABL was also performed at 6 months.
Results Histamine levels were upregulated in CML patients at diagnosis compared with the healthy control group and correlated with the total leukocytic count, the absolute peripheral blood basophil count, and the percent of bone marrow basophils. After 6 months of imatinib treatment, histamine levels were significantly reduced in CML patients compared with the levels at diagnosis and were still significantly higher than in controls. Histamine levels at 6 months correlated significantly with PCR measurements for BCR-ABL. A significant difference in histamine levels was found between patients according to their hematological, cytogenetic, and molecular responses. Also, it differed significantly among TKI response groups (optimal, warning, failure).
Conclusion We found that the serum histamine level may serve as a cheap early predictor of cytogenetic and molecular remission as well as the response to imatinib. However, we could not encourage measuring serum histamine as an alternative to PCR for BCR-ABL for the monitoring of minimal residual disease. (C) 2015 The Egyptian Society of Haematology.