Avaliação funcional de neutrófilos circulantes em portadores de leucemia mielóide crônica antes e após o início do tratamento com mesilato de imatinibe

Abstract

Objective: To evaluate neutrophil function in patients with chronic myeloid leukemia (CML) before and after initiation of treatment with imatinib mesylate (MI). Material and Methods: The study included 13 patients diagnosed with CML (new cases), with a mean age of 51 years, of both sexes, selected at the hematology outpatient clinic of the Ophir Loyola Hospital, Belém-PA. In this group three blood samples were taken. The first collection at the time of diagnosis with the untreated patient (Group B1), the second collection after one month of IM treatment (Group B2) and the third collection after four months of treatment (Group B3). The control group (Group A) consisted of 13 healthy volunteers of both sexes. In addition to the blood count and leukogram, the phagocytosis assays and the cytochemical test for spontaneous reduction of nitroazul tetrazolium (NBT) were also performed to evaluate the neutrophil oxidative metabolism. Results: The evaluation of phagocytic function indicated statistical difference when compared Group A with Groups B1, B2 and B3, p = 0.0001. Groups B1, B2 and B3 presented lower phagocytic indices (IFs) with 2.07 ± 0.5; 1.99 ± 0.4 and 1.97 ± 0.6 respectively, compared to Group A with 3.72 ± 0.8. In the oxidative metabolism evaluation there was no statistical difference between group A with groups B1, B2 and B3, p = 0.2997. Discussion: The results showed that untreated patients had lower IF compared to the control group. This means that even if the patient has innumerable cells of the proliferative process, these cells have their functions diminished. Patients treated with MI also had lower IF compared to the control group. Although the number of leukocytes and neutrophils decreased in these patients, the phagocytic capacity of these cells remained decreased. There was no statistical difference regarding the activation of oxidative metabolism in the NBT reduction test. This means that the production of ROS by the NADPH oxidase system does not change independently of MI treatment. Conclusion: There was a reduction in the amount of circulating neutrophils after initiation of IM treatment. The phagocytic function of neutrophils remained decreased after initiation of IM treatment. Neutrophil oxidative metabolism does not change independently of MI treatment. Therefore, additional studies are important to evaluate the exact mechanism of function alteration involved in these patients to allow a better orientation regarding the therapy used.