With the development of health care,medical x-ray equipments have been applied extensively.In order to avoid the harm of X-ray to patients,radioprotection must be paid more attention, and radiation dosage should be minimized.

Objective:To investigate the infection spectrum revealed by metagenomics high-throughput next-generation sequencing (mNGS), and to provide a reference for infection diagnosis after allogeneic hematopoietic stem cell transplantation (allo-HSCT).Methods:A total of 64 patients who developed systemic or local infection symptoms after allo-HSCT in Hebei Yanda Lu Daopei Hospital from January 2018 to November 2018 were enrolled. Gene sequences of pathogenic microorganisms in blood, cerebrospinal fluid and bronchoalveolar fluid specimens were detected by using mNGS. The pathogenic microorganisms or suspected pathogens were determined based on the clinical manifestations of patients.Results:There were 97 samples of mNGS detection for 64 patients who underwent allo-HSCT. The most common gram-positive bacteria were staphylococcus haemolyticus (19 times) and staphylococcus (14 times), and the most common gram-negative bacterium was acinetobacter baumannii (8 times). The most common viruses were cytomegalovirus, EB virus and Torque teno virus (35, 22 and 23 times, respectively), and the most common fungi were malassezia globus (14 times) and candida parapsilosis (8 times). There were 3 mycobacterium tuberculosis complexes detected in 3 patients with acute myeloid leukemia who received allo-HSCT. Mycoplasma orale was detected in one patient's sputum, and none parasite was detected.Conclusion:mNGS can comprehensively reveal the infection spectrum of hematologic diseases after allo-HSCT, especially for pathogenic microorganisms that are rare or difficult to cultivate, and it can effectively help the diagnosis of clinically infectious pathogens.

OBJECTIVE: To detect fusion gene with pathological significance in a patient with refractory and relapsed acute B cell lymphoblastic leukemia (B-ALL) and to explore its laboratory and clinical characteristics. METHODS: Transcriptome sequencing was used to detect potential fusion transcripts. Other laboratory results and clinical data of the patient were also analyzed. RESULTS: The patient was found to harbor TCF3 exon 17-ZNF384 exon 7 in-frame fusion transcript. The minimal residual disease (MRD) has remained positive after multiple chemotherapy protocols including CD19-, CD22- targeted chimeric antigen receptor T cells immunotherapy. The patient eventually achieved complete remission and sustained MRD negativity after allogeneic hemopoietic stem cell transplantation (allo-HSCT). CONCLUSION Transcriptome sequencing can effectively detect potential fusion genes with clinical significance in leukemia. TCF3-ZNF384 positive B-ALL has unique laboratory and clinical characteristics, may not well respond to chemotherapy and immunotherapy, and is more likely to relapse. Timely allo-HSCT treatment may help such patients to achieve long-term disease-free survival. TCF3-ZNF384 positive B-ALL is not uncommon in pediatric patients but has not been effectively identified.
B-Lymphocytes ; Basic Helix-Loop-Helix Transcription Factors/genetics* ; Child ; Hematopoietic Stem Cell Transplantation ; Humans ; Laboratories ; Precursor Cell Lymphoblastic Leukemia-Lymphoma/therapy* ; Trans-Activators/genetics* ; Transcriptome

Objective:To investigate the molecular genetic and clinical characteristics of MEF2D-BCL9 fusion gene-positive acute B-cell lymphoblastic leukemia (B-ALL), and to provide the reference for the diagnosis and treatment of the disease.Methods:The medical record and experimental examination data of a 18-year-old female MEF2D-BCL9 fusion gene-positive B-ALL patient were retrospectively analyzed. The clinical manifestations and biological characteristics of MEF2D-BCL9 fusion gene-positive B-ALL were summarized.Results:This 18-year-old female patient was treated in a local hospital in December 2018 and was diagnosed as B-ALL. She achieved complete remission after chemotherapy and recurred at 6 months after the initial onset, and then she was admitted to Hebei Yanda Ludaopei Hospital in the 9 months after the initial onset.MEF2D-BCL9 fusion gene was detected through RNA-sequencing (RNA-seq) and verified by using polymerase chain reaction and Sanger sequencing. Bone marrow cell morphology was similar to mature B cells with vacuoles but without characteristic chromosome karyotype abnormalities. The patient achieved remission after VLD regimen chemotherapy, chimeric antigen receptor T-cell (CAR-T) therapy and bridged to allogeneic hematopoietic stem cell transplantation (allo-HSCT). She has maintained complete remission for 2 years at the last follow-up in February 2022.Conclusions:MEF2D-BCL9 fusion gene-positive B-ALL is characterized with high risk, early relapse and poor prognosis. These patients may benefit from CAR-T and allo-HSCT. It further emphasizes the importance of taking MEF2D-BCL9 fusion gene into the detection or identification by using RNA-seq, particularly for those newly diagnosed B-ALL patients in children and adolescents with specific bone marrow morphology.

Transcriptome sequencing (RNA-seq) has unique advantages in analyzing gene fusion, splicing mutations, and gene expression profiles. Single-cell RNA-seq provides powerful tools to reveal cellular heterogeneity in normal and tumor tissues. With the widespread application of high-throughput gene sequencing technology and the rapid reduction in cost, RNA-seq is increasingly used in hematological malignancies research. This article introduces the related research progress in conjunction with reports at the 61st American Society of Hematology Annual Meeting.

Objective: To analyze the incidence and mutation characteristics of FLT3 gene mutation and clinical efficacy of tyrosine kinase inhibitor (TKI) in patients with mixed phenotype acute leukemia (MPAL). Methods: A total of 48 patients with MPAL who were admitted to Hebei Yanda Lu Daopei Hospital from June 2015 to February 2018 were retrospectively analyzed. The common mutated 58 genes in hematologic malignancies were detected by using amplicon-targeted next generation sequencing, of which internal tandem duplication (ITD) and point mutation occurred in the hotspot region of exon 14, 15 and 20 in FLT3 gene. Multiplex polymerase chain reaction (PCR) analysis was used to detect 35 gene fusions in hematological neoplams. Results: There were 7 cases of FLT3 mutation in 48 MPAL patients, which were all ITD mutations. The median length of the inserts of FLT3-ITD was 48 bp, and one MPAL patient carried 2 multiple length inserts simultaneously, and the median variant allele frequency (VAF) was 40.5% (7.9%-84.7%). There were no statistically significant differences in clinical and genetic characteristics between FLT3 mutation-positive and FLT3 mutation-negative MPAL patients (both P > 0.05). Among 7 FLT3 mutation-positive MPAL patients, 4 cases were often accompanied with RUNX1 mutation. A total of 4 MPAL patients with FLT3-ITD-positive received sorafenib or sunitinib combined chemotherapy, and 3 of them achieved complete remission. Conclusions ITD mutation is the main part in the FLT3 mutation of MPAL patients. FLT3-ITD-positive MPAL patients are often accompanied with RUNX1 mutation, which may benefit from targeted therapy with FLT3 kinase inhibitor.

Whether Fanconi anemia (FA) heterozygotes are predisposed to bone marrow failure and hematologic neoplasm is a crucial but unsettled issue in cancer prevention and family consulting. We retrospectively analyzed rare possibly significant variations (PSVs) in the five most obligated FA genes, BRCA2, FANCA, FANCC, FANCD2, and FANCG, in 788 patients with aplastic anemia (AA) and hematologic malignancy. Sixty-eight variants were identified in 66 patients (8.38%). FANCA was the most frequently mutated gene (n = 29), followed by BRCA2 (n = 20). Compared with that of the ExAC East Asian dataset, the overall frequency of rare PSVs was higher in our cohort (P = 0.016). BRCA2 PSVs showed higher frequency in acute lymphocytic leukemia (P = 0.038), and FANCA PSVs were significantly enriched in AA and AML subgroups (P = 0.020; P = 0.008). FA-PSV-positive MDS/AML patients had a higher tumor mutation burden, higher rate of cytogenetic abnormalities, less epigenetic regulation, and fewer spliceosome gene mutations than those of FA-PSV-negative MDS/AML patients (P = 0.024, P = 0.029, P = 0.024, and P = 0.013). The overall PSV enrichment in our cohort suggests that heterozygous mutations of FA genes contribute to hematopoietic failure and leukemogenesis.
Anemia, Aplastic/genetics* ; Epigenesis, Genetic ; Fanconi Anemia/genetics* ; Germ Cells ; Hematologic Neoplasms/genetics* ; Humans ; Leukemia, Myeloid, Acute/genetics* ; Retrospective Studies