Alterations in the Reactive Oxygen Species in Peripheral Blood of Chronic Myeloid Leukaemia Patients from Northern India.

Introduction: There is a significant difference in the Reactive Oxygen Species (ROS) levels of Chronic Myeloid Leukaemia (CML) patients before and during treatment with Tyrosine Kinase Inhibitors (TKIs). This is because high ROS levels support oncogenic phenotype of CML by inducing proliferation pathway and accumulation of further genetic mutations. Often the measurement is done on WBC or serum for ascertaining one type of ROS species, but measurement of global ROS in fresh whole blood will give more accurate estimation of ROS. Aim: To measure global ROS in peripheral blood of CML patients. Materials and Methods: A case control study was undertaken to measure ROS in peripheral blood of CML patients from Northern India. CML patients on TKIs (n= 40 on imatinib herein called treated) and untreated (n= 17, who were not on any TKIs or alternative medicine, called as treatment naive) and 52 healthy controls were also enrolled. Chemiluminescent assay was carried out using luminol as signal enhancer in 400 mu l of blood to measure ROS. The chemiluminescence was measured as Relative Light Units (RLU)/sec/10(4) WBC. Data was presented in terms of mean +/- SE or geometric mean (95% Confidence Interval) for continuous variables and percentage for categorical variables. Groups were compared using two sample t- test for continuous variables and chi- square test for categorical variables. Results: The WBC profile and ROS levels of patients taking TKIs were quite similar and showed no significant difference (p< 0.999) compared to healthy controls. In contrast, significant increase was observed in the ROS levels of CML patients not on TKIs (untreated) compared to patients under treatment (p< 0.029) and healthy controls (p< 0.007). We also observed that the absolute ROS values and WBC counts were higher in untreated patients compared to patients on TKIs and healthy controls, even though mean ROS value was less. Conclusion: To ascertain the alterations in ROS levels of CML patients before and during treatment with TKIs, it is better to measure global ROS in fresh whole blood by chemiluminescent method using luminol. Luminol assay is a quick, easy and inexpensive method to measure global ROS. Patient under treatment with TKIs show significant decrease in ROS levels almost similar to the levels measured in healthy controls yet the mechanisms by which this decrease occurs needs to be elucidated.