Identification of pre-leukaemic haematopoietic stem cells in acute leukaemia.

In acute myeloid leukaemia (AML), the cell of origin, nature and biological consequences of initiating lesions, and order of subsequent mutations remain poorly understood, as AML is typically diagnosed without observation of a pre-leukaemic phase. Here, highly purified haematopoietic stem cells (HSCs), progenitor and mature cell fractions from the blood of AML patients were found to contain recurrent DNMT3A mutations (DNMT3A(mut)) at high allele frequency, but without coincident NPM1 mutations (NPM1c) present in AML blasts. DNMT3A(mut)-bearing HSCs showed a multilineage repopulation advantage over non-mutated HSCs in xenografts, establishing their identity as pre-leukaemic HSCs. Pre-leukaemic HSCs were found in remission samples, indicating that they survive chemotherapy. Therefore DNMT3A(mut) arises early in AML evolution, probably in HSCs, leading to a clonally expanded pool of pre-leukaemic HSCs from which AML evolves. Our findings provide a paradigm for the detection and treatment of pre-leukaemic clones before the acquisition of additional genetic lesions engenders greater therapeutic resistance

Molecular landscape and prognostic impact of FLT3 -ITD insertion site in acute myeloid leukemia : RATIFY study results

In acute myeloid leukemia (AML) internal tandem duplications of the FLT3 gene (FLT3- ITD) are associated with poor prognosis. Retrospectively, we investigated the prognostic and predictive impact of FLT3 -ITD insertion site (IS) in 452 patients randomized within the RATIFY trial, which evaluated midostaurin additionally to intensive chemotherapy. Next-generation sequencing identified 908 ITDs, with 643 IS in the juxtamembrane domain (JMD) and 265 IS in the tyrosine kinase domain-1 (TKD1). According to IS, patients were categorized as JMDsole (n = 251, 55%), JMD and TKD1 (JMD/TKD1; n = 117, 26%), and TKD1sole (n = 84, 19%). While clinical variables did not differ among the 3 groups, NPM1 mutation was correlated with JMDsole (P = 0.028). Overall survival (OS) differed significantly, with estimated 4-year OS probabilities of 0.44, 0.50, and 0.30 for JMDsole, JMD/TKD1, and TKD1sole, respectively (P = 0.032). Multivariate (cause-specific) Cox models for OS and cumulative incidence of relapse using allogeneic hematopoietic cell transplantation (HCT) in first complete remission as a time-dependent variable identified TKD1sole as unfavorable and HCT as favorable factors. In addition, Midostaurin exerted a significant benefit only for JMDsole. Our results confirm the distinct molecular heterogeneity of FLT3 -ITD and the negative prognostic impact of TKD1 IS in AML that was not overcome by midostaurin

Thrombotic Thrombocytopenic Purpura Associated with Pneumococcal Sepsis

The first documented case of thrombotic thrombocytopenic purpura (TTP) associated with pneumococcal septicemia is reported. This association has been previously demonstrated with hemolytic uremic syndrome. The patient presented with recurrent seizures, oliguric renal failure, fever, thrombocytopenia and microangiopathic hemolytic anemia; coagulation studies were normal. Blood and sputum cultures were positive for Streptococcus pneumoniae. The patient responded to therapy with plasmapheresis and antiplatelet agents as well as antibiotics. Coincident infection should be searched for in all cases of TTP.Peer Reviewe

Thrombotic thrombocytopenic purpura associated with pneumococcal sepsis

The first documented case of thrombotic thrombocytopenic purpura (TTP) associated with pneumococcal septicemia is reported. This association has been previously demonstrated with hemolytic uremic syndrome. The patient presented with recurrent seizures, oliguric renal failure, fever, thrombocytopenia and microangiopathic hemolytic anemia; coagulation studies were normal. Blood and sputum cultures were positive for Streptococcus pneumoniae. The patient responded to therapy with plasmapheresis and antiplatelet agents as well as antibiotics. Coincident infection should be searched for in all cases of TTP

Ambulatory consolidation chemotherapy for acute myeloid leukemia with antibacterial prophylaxis is associated with frequent bacteremia and the emergence of fluoroquinolone resistant E. Coli

Abstract Background Ambulatory consolidation chemotherapy for acute myeloid leukemia (AML) is frequently associated with bloodstream infections but the spectrum of bacterial pathogens in this setting has not been well-described. Methods We evaluated the emergence of bacteremias and their respective antibiotic susceptibility patterns in AML patients receiving ambulatory-based consolidation therapy. Following achievement of complete remission, 207 patients received the first cycle (C1), and 195 the second cycle (C2), of consolidation on an ambulatory basis. Antimicrobial prophylaxis consisted of ciprofloxacin, amoxicillin and fluconazole. Results There were significantly more positive blood cultures for E. coli in C2 as compared to C1 (10 vs. 1, p=0.0045); all E. coli strains for which susceptibility testing was performed demonstrated resistance to ciprofloxacin. In patients under age 60 there was a significantly higher rate of Streptococccus spp. bacteremia in C2 vs. C1; despite amoxicillin prophylaxis all Streptococcus isolates in C2 were sensitive to penicillin. Patients with Staphylococcus bacteremia in C1 had significantly higher rates of Staphylococcus bacteremia in C2 (p=0.009, OR=8.6). Conclusions For AML patients undergoing outpatient-based intensive consolidation chemotherapy with antibiotic prophylaxis, the second cycle is associated with higher rates of ciprofloxacin resistant E. coli, penicillin-sensitive Streptococcus bacteremias and recurrent Staphylococcus infections

Differential survival improvement for patients 20-29 years of age with acute lymphoblastic leukemia

Objective: To compare improvement in survival from 1986 to 2009 for acute lymphoblastic leukemia (ALL) patients 1-14, 15-19 and 20-29 years in Ontario and United States.Methods: This population-based analysis used data from Ontario Cancer Registry (OCR) and Surveillance Epidemiology and End Results (SEER).Results: In OCR, there was steady improvement in survival by period of diagnosis in all three age groups. In SEER, there was no improvement in survival for patients aged 20-29 years.Conclusions: Survival in Ontario and the United States has improved for patients with ALL aged 1-19 years. However, survival has improved among patients aged 20-29 years only in Ontario

Serum Voriconazole Level Variability in Patients with Hematological Malignancies Receiving Voriconazole Therapy

INTRODUCTION: Voriconazole plasma concentrations have been correlated with oral dosing in healthy subjects, but have been poorly characterized in ill patients with hematological malignancies receiving intensive chemotherapy.METHODS: The relationship between orally administered voriconazole, plasma concentrations and liver toxicity was examined in a cohort of 69 primarily acute leukemia patients undergoing intensive chemotherapy.RESULTS: Oral administration of voriconazole was associated with significant interpatient variability, with voriconazole steady-state concentrations ranging from 0 μg/mL to 16.6 μg/mL. Approximately 20% of patients achieved steady-state concentrations ud_less_than1 μg/mL. When adjusted for weight, patients receiving higher voriconazole doses tended toward higher plasma concentrations; however, there was no significant relationship between the plasma concentration and genotype, age, sex or use of concomitant proton pump inhibitors. Voriconazole concentrations were correlated with higher serum alkaline phosphatase levels at day 6 to 8, and with higher bilirubin and aspartate aminotransferase levels at day 14 to 16, but not with other liver enzyme levels.CONCLUSION: In ill patients with acute leukemia and related disorders undergoing treatment with oral voriconazole, there is a poor correlation between the voriconazole dose and plasma concentrations, and many patients achieve levels that are considered to be subtherapeutic. The findings support the routine use of therapeutic drug monitoring in these patients.Peer Reviewe