Peripheral Blood HPC Counts Are Augmented in CML Patients with Cytogenetic Findings of Disease as Compared to Patients in Cytogenetic Remission.

Chronic Myeloid Leukemia (CLM) is a stem cell disease characterized by inhibition of apoptosis and increased proliferation of bone marrow (BM) compounds. Evaluation of hematopoetic precursors cells on the peripheral blood (PB) of these patients show a high prevalence of leukemic CD34⁺ cells. Recently it was demonstrated that measurement of HPC by IMI channel on Sysmex showed an acceptable correlation between Hematopoetic Progenitors CD34+ cells counts. The aim of this work was to compare precursor cells (HPC) numbers in the PB of CML patients with disease and under remission. For this we studied 61 CML patients that had been treated with different protocols. From these 22 were in cytogenetic remission but 39 still presented more than 5% BM cells with Philadelphia chromosome (Ph+). Although the normal levels of CD34⁺ HPC in PB is considered to be very low, we considered less than 0.05% of leukocytes as normality. HPC in PB were counted using an automated peripheral blood counter (Sysmex XE-2100). We found that Ph+ CML patients had a significant increased number of PB HPC compared to CML patients under remission (with a confidence interval of 95%, and a corrected Yates analyses with X² 16.78 and p<0.0001). The increase in PB HPC was not related with the number of white cells counts at moment of the exam. These findings suggest that the presence of a high number of PB HPC in CML can be used as a non-invasive marker of the disease, more reliable than total and differential leukocyte count.