Comparision of Allogeneic Hematopoietic Stem Cell Transplantation between Children with Thalassemia of Different Ages / 中国实验血液学杂志

OBJECTIVE@#To investigate the difference of therapeutic effects on children with thalassemia at different age after hematopoietic stem cell transplantation.@*METHODS@#The clinical data of children with thalassemia treated in our hospital were retrospectively analyzed. The children were divided into 2-5 years old group and 6-12 years old group. The success rate of implantation, transplant-related mortality, GVHD incidence, and other transplant-related complications, as well as thalassemia-free survival (TFS) were compared between the two groups.@*RESULTS@#The incidence of GVHD, hemorrhagic cystitis and severe oral mucositis after transplantation in the 2-5 years old group were significantly lower than those in the 6-12 years old group, while there was no statistically significant difference in the TFS between the two groups.@*CONCLUSION@#Children in the low age (2-5 years old) group show fewer complications and higher quality of life after transplantation, therefore, stem cell transplantation at 2-5 years old is more conducive to rehabilitation of the children with thalassemia.

DNMT3A gene mutations in acute myeloid leukemia / 中国实验血液学杂志

Epigenetic changes, including abnormal DNA methylation, have been identified to play significant roles in tumor initiation and progression. Recently, mutations of DNMT3A were identified in acute myeloid leukemia (AML), which possibly caused changes in DNA methylation, and indicated a poor prognosis. Sequencing analysis showed that most of the mutations were single nucleotide variations, including a hotspot Arg882. DNMT3A mutations were detected in about 20% AML patients, and closely associated with the age over 60, the M(4), M(5) subtypes and intermediate-risk cytogenetics. Others showed that these alterations also present in myelodysplastic syndrome (MDS) and primary myelofibrosis (PMF) prior to development of the obvious leukemia, indicating that these mutations might contribute to leukemogenesis. However, its prognostic value of minimal residual disease and role of therapeutic targets are still unclear, focusing on a large cohort of AML patients will solve these issues. In this review, the achievement in studying DNMT3A gene mutation are summarized, and the latest research progress is briefly discussed.

Evaluation of methods for detection of NPM1 gene mutations in acute myeloid leukemia / 中国实验血液学杂志

The purpose of this study was to establish real-time based methods for detection of NPM1 gene mutation in acute myeloid leukemia (AML). Primers/probes were designed according to the clustered region of NPM1 mutations on exon 12. Two real-time PCR assays, including high resolution melting curve (HRM) and allele-specific PCR (AS-PCR), were developed and clinically evaluated with 89 AML samples, which were parallelly detected by capillary electrophoresis (CE) and sequencing. The results showed that a total of 17 mutation-positive samples were detected, including type A (15 cases), type B (1 case) and type Nm (1 case). HRM assay could detect all mutant types, and the analytical sensitivity was around 5%. In contrast, AS-PCR assay detected only 95% mutant types, but its sensitivity was as high as 0.01%. It is concluded that considering the characteristics of each method as well as the clinical evaluation results, HRM may be used for screening of NPM1 mutations at diagnosis, while the AS-PCR can be used for the MRD quantification during follow-up.

Simultaneous detection of FLT3-ITD and NPM1 gene mutations in acute myeloid leukemia by double PCR / 中国实验血液学杂志

Objective of this study was to establish a method for simultaneous detection of FLT3/ITD and NPM1 gene mutations in AML. A double PCR was firstly designed and optimized to amplify both exon 12 of NPM1 and exon 14-intron 14-exon 15 of FLT3, with the aim of detecting almost all reported mutations. After optimization, a touchdown PCR was chosen for the multiplex PCR procedure, with the primer concentrations of NPM1 and FLT3-ITD being 200 nmol/L and 152 nmol/L respectively. The PCR amplicons were separated by capillary electrophoresis and the presence of mutants was recognized by the size difference between the mutants and wild-type products. The areas of mutant peak and wild-type peak were used to calculate the mutant/wild-type ratio. All the positive mutated samples were confirmed by sequencing. The results showed that 17 patients with NPM1 mutation, 15 patients with FLT3-ITD mutation, 6 patients with both NPM1 and FLT3-ITD mutations were found among 93 patents. 7 patients with M₂, 4 patients with M₄, 5 patients with M₅ and 1 patients with M₆ were found out of 17 patients with NPM1 mutation, in which 10 patients were male and 7 patients were female, 15 patients were with type A, 1 patients was with type B and 1 patients was with type Nm, strikingly 1 CML patient in blast crisis was found to carry a type A mutation. Among 15 patients with FLT3-ITD mutation 1 patient with M₁, 8 patients with M₂, 2 patients with M₂, 2 patients with M₃, 1 patient with M₄, 3 patients with M₅ were found, in which 5 patients were male and 10 patients were female. Sequencing results further confirmed the accuracy and reliability of this method. It is concluded that a novel method with the ability to detect both FLT3-ITD and NPM1 mutations has been developed when genomic DNA was templated. This method is fast, easy, accurate and capable to calculate the mutant/wild-type ratio.