Frequência da mutação JAK2V617F em pacientes com trombocitose no interior do RS

Abstract

Myeloproliferative neoplasms (MPN) are unique hematopoietic stem-cell disorders, resulting in an increased proliferation of single or multilineage mature hematopoietic cells. JAK2V617F mutation is a diagnostic criterion for MPN, indicated in cases of erythrocytosis or thrombocytosis with undetermined causes. This study aims to characterize the cases of outpatients with thrombocytosis, regarding their hematological profile and the presence of JAK2V617F mutation. We selected 260 outpatients attended in a private clinical laboratory in Santa Maria, RS, for a blood count exam, within a 9-month period. These patients were older than 18 years and their platelet counts results ≥ 450.000 /mm3. Data regarding demographic profile (sex and age) and hematological profile (blood count parameters) were made available. Their blood samples were submitted to DNA extraction and JAK2V617F mutation detection by ARMS system. Statistical analysis was performed by classifying patients into two groups: positive for JAK2V617F mutation (JP group) and negative for the mutation (JN group). Demographic and hematological data from both groups were compared using SPSS program, version 20. Results of p<0.05 were considered statistically significant. Thrombocytosis was present in 1.0% of outpatients. Of these, 7.7% were positive for JAK2V617F mutation. Patients of the JP group had age (p = 0.039), platelet (p <0.001) and erythrocytes (p <0.0001) counts and hematocrit (p <0.0001) and hemoglobin (p <0.0001) levels significantly higher than JN. There was no difference in the frequency of the mutation among gender. The hematological profile of JP group showed combined erythrocytosis and leukocytosis in 35% and 45% of patients, respectively. Trilineage cellular hyperplasia was present in 20% and isolated thrombocytosis in 15% of patients in this group. The presence of JAK2V617 in Brazilian outpatients with thrombocytosis was substantial. Its presence was significantly associated with specific changes in the hematological profile of these patients, such as increased erythrocyte mass and hemoglobin and hematocrit levels. In these cases, the use of this mutation as a screening test for MPN is relevant and might help the early diagnosis of these malignancies.