Sandra Guerra Xavier

JAK2V617F mutation in patients with thrombosis: to screen or not to screen?

Introduction:  Thrombotic complications are a main concern in patients with myeloproliferative neoplasms. Recently, a gain‐of‐function mutation of the gene encoding the JAK2 tyrosine kinase that results in a valine‐to‐phenylalanine substitution at position 617 (V617F) has been described. Since the description of the JAK2‐V617F mutation and its finding in patients with splanchnic vein thrombosis without an overt myeloproliferative neoplasm, many groups have studied the prevalence of this mutation in patients with unexplained venous and arterial thrombosis.

Low prevalence of the JAK2V617F in patients with ischemic stroke or cerebral venous thrombosis.

Quebec platelet disorder (QPD) is an autosomal dominant bleeding disorder associated with increased risks for bleeding and the expression and storage of urokinase plasminogen activator (u-PA) in platelets, despite normal u-PA in plasma (reviewed in [1]). In the recent article on QPD published in this journal [1], QPD was proposed to result from defective u-PA regulation by megakaryocytes. However, the levels of u-PA in other QPD cells and urine have not been reported. Individuals with QPD are at increased risk of experiencing bleeding following hemostatic challenges, and approximately 50% experience episodic, spontaneous hematuria, which is associated with higher levels of platelet u-PA [2]. As urine normally contains significant amounts of u-PA (40–80 mg/ml) [3], we investigated whether individuals with QPD have an increased urinary u-PA as a potential contributor to their urinary tract bleeding.

Gene rearrangement study for minimal residual disease monitoring in children with acute lymphocytic leukemia

Objective To detect markers for minimal residual disease monitoring based on conventional polymerase chain reaction for immunoglobulin, T-cell receptor rearrangements and the Sil-Tal1 deletion in patients with acute lymphocytic leukemia. Methods Fifty-nine children with acute lymphocytic leukemia from three institutions in Minas Gerais, Brazil, were prospectively studied. Clonal rearrangements were detected by polymerase chain reaction followed by homo/heteroduplex clonality analysis in DNA samples from diagnostic bone marrow. Follow-up samples were collected on Days 14 and 28-35 of the induction phase. The Kaplan-Meier and multivariate Cox methods were used for survival analysis. Results Immunoglobulin/T-cell receptor rearrangements were not detected in 5/55 children screened (9.0%). For precursor-B acute lymphocytic leukemia, the most frequent rearrangement was IgH (72.7%), then TCRG (61.4%), and TCRD and IgK (47.7%); for T-acute lymphocytic leukemia, TCRG (80.0%), and TCRD and Sil-Tal deletion (20.0%) were the most common. Minimal residual disease was detected in 35% of the cases on Day 14 and in 22.5% on Day 28-35. Minimal residual disease on Day 28-35, T-acute lymphocytic leukemia, and leukocyte count above 50 x 109/L at diagnosis were bad prognostic factors for leukemia-free survival in univariate analysis. Relapse risk for minimal residual disease positive relative to minimal residual disease negative children was 8.5 times higher (95% confidence interval: 1.02-70.7). Conclusion Immunoglobulin/T-cell receptor rearrangement frequencies were similar to those reported before. Minimal residual disease is an independent prognostic factor for leukemia-free survival, even when based on a non-quantitative technique, but longer follow-ups are needed.

Philadelphia-negative chronic myeloproliferative neoplasms

Chronic myeloproliferative diseases without the Philadelphia chromosome marker (Ph-), although first described 60 years ago, only became the subject of interest after the turn of the millennium. In 2001, the World Health Organization (WHO) defined the classification of this group of diseases and in 2008 they were renamed myeloproliferative neoplasms based on morphological, cytogenetic and molecular features. In 2005, the identification of a recurrent molecular abnormality characterized by a gain of function with a mutation in the gene encoding Janus kinase 2 (JAK2) paved the way for greater knowledge of the pathophysiology of myeloproliferative neoplasms. The JAK2 mutation is found in 90-98% of polycythemia vera and in about 50% essential thrombocytosis and primary myelofibrosis. In addition to the JAK2 mutation, other mutations involving TET2 (ten-eleven translocation), LNK (a membrane-bound adaptor protein); IDH1/2 (isocitrate dehydrogenase 1/2 enzyme); ASXL1 (additional sex combs-like 1) genes were found in myeloproliferative neoplasms thus showing the importance of identifying molecular genetic alterations to confirm diagnosis, guide treatment and improve our understanding of the biology of these diseases. Currently, polycythemia vera, essential thrombocytosis, myelofibrosis, chronic neutrophilic leukemia, chronic eosinophilic leukemia and mastocytosis are included in this group of myeloproliferative neoplasms, but are considered different situations with individualized diagnostic methods and treatment. This review updates pathogenic aspects, molecular genetic alterations, the fundamental criteria for diagnosis and the best approach for each of these entities.

Use of inflammatory molecules to predict the occurrence of fever in onco-hematological patients with neutropenia.

Febrile neutropenia remains a frequent complication in onco-hematological patients, and changes in the circulating level of inflammatory molecules (IM) may precede the occurrence of fever. The present observational prospective study was carried out to evaluate the behavior of plasma tumor necrosis factor alpha (TNF-α), soluble TNF-α I and II receptors (sTNFRI and sTNFRII), monocyte chemoattractant protein-1 [MCP-1 or chemokine (c-c motif) ligand 2 (CCL2)], macrophage inflammatory protein-1α (MIP-1α or CCL3), eotaxin (CCL11), interleukin-8 (IL-8 or CXCL8), and interferon-inducible protein-10 (IP-10 or CXCL10) in 32 episodes of neutropenia in 26 onco-hematological patients. IM were tested on enrollment and 24-48 h before the onset of fever and within 24 h of the first occurrence of fever. Eight of 32 episodes of neutropenia did not present fever (control group) and the patients underwent IM tests on three different occasions. sTNFRI levels, measured a median of 11 h (1-15) before the onset of fever, were significantly higher in patients presenting fever during follow-up compared to controls (P = 0.02). Similar results were observed for sTNFRI and CCL2 levels (P = 0.04 for both) in non-transplanted patients. A cut-off of 1514 pg/mL for sTNFRI was able to discriminate between neutropenic patients with or without fever during follow-up, with 65% sensitivity, 87% specificity, and 93% positive predictive value. Measurement of the levels of plasma sTNFRI can be used to predict the occurrence of fever in neutropenic patients.

Evaluation of the European LeukemiaNet recommendations for predicting outcomes of patients with acute myeloid leukemia treated in low- and middle-income countries (LMIC): A Brazilian experience

BACKGROUND Current results regarding treatment outcomes in acute myeloid leukemia (AML) point to significant differences between low- and middle-income countries (LMIC) and high-income countries (HIC). Excluding well-known socioeconomic issues, genetic markers important for prognosis have not been properly incorporated into the clinical practice so far and their usefulness outside of well-controlled clinical trials remain unknown. METHODS Here, we assessed the clinical significance of the European LeukemiaNet (ELN) recommendations in 196 consecutive patients with AML in a real-life setting. All patients were younger than 60 years of age (49% male) and treated with conventional chemotherapy for induction and consolidation in three Brazilian Institutions that well represent Brazilian geographic and socioeconomic diversity. FINDINGS Multivariable analysis showed that ELN recommendations had a slight association with complete remission achievement (odds ratio: 0.74, 95% confidence interval, CI: 0.53-1.01; P=0.06), but were independently associated with poor overall survival (OS) (hazard ratio, HR: 1.3, 95% CI: 1.1-1.54; P=0.002), disease-free survival (DFS) (HR: 1.42, 95% CI: 1.03-1.95; P=0.028) and event-free survival (EFS) (HR: 1.24, 95% CI: 1.06-1.47; P=0.007), considering initial leukocyte counts and age as confounders. ELN recommendations had no impact on cumulative incidence of relapse (P=0.09). INTERPRETATION Our results suggest that within the context of LMIC, the prognostic markers recommended by ELN may be useful to predict patients clinical outcomes; however, the OS, DFS and EFS were shorter than the reported in Europe and US for the respective risk groups.

Comparison between qualitative and real-time polymerase chain reaction to evaluate minimal residual disease in children with acute lymphoblastic leukemia

Introduction Minimal residual disease is an important independent prognostic factor that can identify poor responders among patients with acute lymphoblastic leukemia. Objective The aim of this study was to analyze minimal residual disease using immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements by conventional polymerase chain reaction followed by homo-heteroduplex analysis and to compare this with real-time polymerase chain reaction at the end of the induction period in children with acute lymphoblastic leukemia. Methods Seventy-four patients diagnosed with acute lymphoblastic leukemia were enrolled. Minimal residual disease was evaluated by qualitative polymerase chain reaction in 57 and by both tests in 44. The Kaplan–Meier and multivariate Cox methods and the log-rank test were used for statistical analysis. Results Nine patients (15.8%) were positive for minimal residual disease by qualitative polymerase chain reaction and 11 (25%) by real-time polymerase chain reaction considering a cut-off point of 1 × 10−3 for precursor B-cell acute lymphoblastic leukemia and 1 × 10−2 for T-cell acute lymphoblastic leukemia. Using the qualitative method, the 3.5-year leukemia-free survival was significantly higher in children negative for minimal residual disease compared to those with positive results (84.1% ± 5.6% versus 41.7% ± 17.3%, respectively; p-value = 0.004). There was no significant association between leukemia-free survival and minimal residual disease by real-time polymerase chain reaction. Minimal residual disease by qualitative polymerase chain reaction was the only variable significantly correlated to leukemia-free survival. Conclusion Given the difficulties in the implementation of minimal residual disease monitoring by real-time polymerase chain reaction in most treatment centers in Brazil, the qualitative polymerase chain reaction strategy may be a cost-effective alternative.

Characterization of NPM1, FLT3, and IDH1 mutations in adult patients with acute myeloid leukemia: a Brazilian cohort study

Nath alia Gomide Cruz*, Ana Fl avia Tib urcio Ribeiro*, Ana Beatriz Firmato Gl oria, Saman Abbas, Juliana Godoy Assumpç~ao, Silvana Maria Eloi Santos, Suely Meireles Rezende, Sandra Guerra Xavier and Evandro M. Fagundes Faculty of Medicine, Universidade Federal de Minas Gerais and Fundaç~ao HEMOMINAS, Belo Horizonte, Brazil; Department of Internal Medicine, Faculty of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Hematology Unit, University Hospital, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Huffington Center on Aging, Baylor College of Medicine, Houston, TX, United States; Molecular Hematology Laboratory, Hospital das Clinicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Department of Clinical Pathology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil