Acute myeloid leukemia (AML) is a group of highly-heterogeneous clonal diseases. Chemotherapy and hematopoietic stem cell transplantation are considered as effective treatment for AML. For high-risk AML patients, allogeneic hematopoietic stem cell transplantation is an effective therapeutic option. However, some AML patients may still face the problem of disease recurrence after hematopoietic stem cell transplantation. A majority of recurrent patients cannot be effectively treated by chemotherapy or secondary transplantation, which is the main cause of death after allogeneic hematopoietic stem cell transplantation. Therefore, it is of significance to strengthen follow-up of AML patients after allogeneic hematopoietic stem cell transplantation and implement appropriate measures to prevent postoperative recurrence. In this article, the monitoring, drug prevention and cell therapy of recurrence after allogeneic hematopoietic stem cell transplantation in high-risk AML patients were reviewed, aiming to provide reference for improving clinical prognosis of high-risk AML patients undergoing allogeneic hematopoietic stem cell transplantation.

Objective:To investigate the phylogenetic and antigenic characteristics of hemagglutinin (HA) gene of influenza B/Victoria lineage (BV) viruses in Beijing during the 2021-2022 influenza surveillance season, and to analyze whether the circulating BV viruses match the vaccine strain.Methods:Pharyngeal swab specimens from influenza like-illness (ILI) cases in the 2021-2022 influenza surveillance season were collected from surveillance network labs in Beijing and cultured in MDCK cells and chicken embryo to isolate BV viruses. Nucleic acids of the viruses were extracted, and the HA gene was amplified and sequenced. The nucleotide and amino acid sequence identity of the HA gene was analyzed using MEGA5.0 software. A phylogenetic tree of HA gene was constructed using the maximum likelihood method. The N-glycosylation sites in HA were predicted online. Three-dimensional structure of HA was constructed using SWISS-MODEL homologous modeling. Hemagglutination inhibition (HI) test was performed to analyze the antigenicity of BV viruses.Results:A total of 402 BV viruses were collected and 58 strains with full-length HA gene sequences were chosen for further analysis. Compared with the HA gene of this year′s vaccine strain (B/Washington/02/2019), there were 27 amino acid mutations, 11 of which were located in four different antigenic determinants. The phylogenetic analysis revealed that three subgroups of 1A.3, 1A.3a1, and 1A.3a2 co-circulated in Beijing with 54 strains (54/58, 93.10%) clustered to the Clade 1A.3a2, two strains (2/58, 3.45%) clustered to the Clade 1A.3a1, and two strains (2/58, 3.45%) in the same subgroup (Clade 1A.3) as the vaccine component BV strain in 2021-2022. Compared with the vaccine strain (B/Washington/02/2019), two BV strains had an additional N-glycosylation site at residue 197, while the other 56 strains showed no change in N-glycosylation sites. Antigenic analysis showed that 35 BV strains (35/58, 60.34%) were antigenically similar to the vaccine strain and 23 strains (23/58, 39.66%) were low-response strains.Conclusions:Three subgroups of BV viruses co-circulated in Beijing during the 2021-2022 influenza surveillance season. The predominant subgroup was Clade 1A.3a2 (93.10%), showing a certain genetic distance with the vaccine strain (B/Washington/02/2019). Nearly 40% (39.66%) of the viruses were low-response strains. This study indicated that continuous monitoring of the variations of influenza epidemic strains and timely providing laboratory basis for screening vaccine component strains were the basic technical guarantee for coping with influenza pandemic.

Objective:To explore the key genes related to the development, progression and prognosis of acute myeloid leukemia (AML) based on bioinformatics, and to analyze their functions.Methods:The chip expression profile GSE84881 data set of AML patients including 19 AML samples and 4 normal tissue samples was downloaded from the gene expression omnibus (GEO) database. GEO online tool GEO2R was used to screen the differentially expressed genes (DEG). The DAVID online database was used to make gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis of DEG. The STRING online database was used to analyze the protein interaction (PPI) network of DEG, and the key genes were screened by using the Cytoscape software. The weighted gene co-expression network analysis (WGCNA) was used to build co-expressed network and obtain the central genes.LC-Bio online platform was used to construct Venn diagram and the key genes and central genes in PPI were crossed to finally obtain the true key genes. RNA-seq datasets GSE2191 and GSE90062 of human tissues were downloaded from GEO database to verify the screened key genes. Kaplan-Meier method was used to analyze the effects of key genes on the overall survival (OS) of AML based on the data of GEPIA database.Results:A total of 247 DEG were identified in GSE84881 data set, including 112 up-regulated genes and 135 down-regulated genes. According to the results of GO enrichment analysis, 247 DEG were mainly enriched in the regulation of signal transduction and cell proliferation in the biological process (BP); the cell composition (CC) revealed that these genes were mainly involved in the cytoplasm and exosomes; the molecular function (MF) analysis showed that these genes were mainly enriched in protein binding and calcium binding. Further KEGG pathway enrichment analysis showed that these 247 DEG were mainly involved in NOD-like receptor signal pathway and interleukin 17 (IL-17) signal pathway. And then the 12 key genes were obtained from PPI. WGCNA software was used to screen 13 central genes from GSE84881 dataset and finally 1 real key gene EGF was obtained after taking intersection. Kaplan-Meier method showed that OS time of AML patients in EGF high expression group was decreased than that in EGF low expression group, and the difference was statistically significant( P = 0.044). Conclusions:EGF may be an important diagnosis and treatment target of AML and may become a potential biomarker for clinical treatment and prognosis prediction of AML.

Objective:To explore the safety and advantages of non-cryopreserved sibling umbilical cord blood hematopoietic stem cell transplantation for major thalassaemia in children.Methods:From October 2016 to June 2021, 9 patients with major beta thalassaemia received non-cryopreserved hematopoietic stem cell transplantation of sibling umbilical cord blood at Zhongshan Hospital of Xiamen University. The pretreatment scheme, the process of stem cell implantation and follow-up were analyzed and summarized.Results:Among the 9 cases, there were 5 males and 4 females with a median age of 4(2~11)years. Median level of ferritin was 2 997(1 936~5 512)μg/L. At gestational weeks 12~16, each patient's mother underwent villi testing to confirm that the donor without thalassaemia major was complete HLA-matched with the patient. All of them received an intensive conditioning regimen made up of cyclophosphamide(CTX), fludarabine and busulfan(Bu). Graft-versus-host disease(GVHD) was prevented by cyclosporine A(CSA)and mycophenolate mofetil(MMF)with or without methotrexate(MTX). Except for one failed implant, 8 cases were successfully engrafted. Median time of neutrophil implantation was 19.5(15~26)days, median time of platelet implantation 32(22~34)days and median time of erythrocyte implantation 30.5(18~37)days. Up until September 1, 2021, the median follow-up period was 27(3~59)months and the rate of successful engraftment 88.89%. There was no transplant-related mortality. Overall survival was 100% and thalassaemia-free survival 88.89%. Two patients developed grades Ⅱ skin acute GVHD(22.2%). No grade Ⅲ-Ⅳ GVHD or chronic GVHD occurred. Epstein-Barr virus infection occurred in 1 case.No infection of cytomegalovirus occurred.Conclusions:For major thalassaemia in children, stem cell transplantation of non-cryopreserved sibling cord blood is both safe and feasible with a high implantation rate and a low incidence of GVHD.

Objective:To explore the efficacy and safety of unrelated mismatched hematopoietic stem cell transplantation(HSCT)for thalassemia major.Methods:For this retrospective cohort study, 15 patients with β-thalassemia major underwent unrelated mismatched HSCT between January 2018 and April 2022. There were 8 males and 7 females with a median age of 7(3-12)years and a median ferritin level of 3 417.3(223-14 485)μg/L. The conditioning regimens on the basis of fludarabine(Flu), busulfan(Bu)and cyclophosphamide(CTX)and GVHD prophylaxis on the basis of cyclosporine(CsA), mycophenolate mofetil(MMF), anti-human thymocyte immunoglobulin(ATG)plus low-dose post-cyclophosphamide(PTCy)and mesenchymal stem cells were offered.Results:Up until April 1, 2022, 15 children were successfully implanted during a median follow-up period of 24.1(11-49)months and all of them achieved stable donor chimerism. The median time to neutrophil and platelet engraftment were 12(11-22)and 14(8-38)days respectively. Except for 2 deaths, 13 cases survived. The estimated 2-year probability of overall survival(OS)and thalassemia-free survival(TFS)were both 86.67%. There were 5 cases of acute graft versus host disease (aGVHD) below grade Ⅱ, 2 cases of grade Ⅲ to Ⅳ aGVHD, and 3 cases of localized chronic graft versus host disease (cGVHD) after transplantation. No gengralized cGVHD occurred. Both cytomegalovirus and Epstein-Barr virus were activated in five recipients.Conclusions:Unrelated mismatched donor HSCT is both safe and feasible for thalassemia major.

Acute lymphoblastic leukemia (ALL) is a malignant tumor dominated by B-cell or T-cell proliferation, of which 80% is the malignant proliferation of B-lymphocytes, and it can be more commonly seen in children. Studies have found that ALL is often accompanied by abnormal molecular biological phenotypes. The study of the molecular biological characteristics of ALL helps the precise diagnosis, prognostic analysis, pathogenesis research and the discovery of new diagnostic markers and therapeutic targets. This article summarizes several molecular markers of adult acute B-lymphoblastic leukemia discovered in recent years, and reviews the clinical significance.

Objective:To clarify the M protein ( emm gene) types and drug susceptibility characteristic variations of Group A Streptococcus (GAS) in children in Beijing. Methods:The GAS strains isolated from throat swab samples of children diagnosed with scarlet fever and pharyngeal infection in scarlet fever etiology surveillance sentinel hospitals in 16 districts of Beijing in 2018, 2019 and 2021 were analyzed retrospectively.PCR amplification and sequencing were used for emm genotyping, and the minimum inhibitory concentrations (MIC) of 10 antibiotics were determined by the broth microdilution method.The data were analyzed using χ2 test and Fisher′ s exact method between groups. Results:A total of 557 GAS strains were collected, and 11 emm genotypes ( emm1, emm3, emm4, emm6, emm11, emm12, emm22, emm75, emm89, emm128, and emm212) were detected.Of 557 strains, 238 trains were of emm1 type (42.73%), 271 strains were of emm12 type (48.65%) and 48 strains were of other emm types (8.62%). The detection rates of emm1, emm12 and other emm type genes in 2018, 2019, and 2021 were [37.50% (105/280 strains), 57.14% (160/280 strains), 5.36% (15/280 strains)], [49.05% (129/263 strains), 39.54% (104/263 strains), 11.41% (30/263 strains)], and [28.57% (4/14 strains), 50.00% (7/14 strains), 21.43% (3/14 strains)], respectively.In children infected with emm12 in 2018 and 2019, there were more children under 6 years old than children over 6 years old (62.50% vs.46.88%, 46.36% vs.30.36%) (χ 2=7.182, 6.973; all P<0.05). Drug susceptibility testing results suggested that 225 randomly selected GAS strains were all 100.00% sensitive to 7 antibiotics including Penicillin, Levofloxacin, Meropenem, Linezolid, Cefotaxime, Cefepime and Vancomycin.The rates of resistance to Erythromycin, Tetracycline and Clindamycin were [88.57% (93/105 strains), 87.62% (92/105 strains), 86.67% (91/105 strains)], and [94.34% (100/106 strains), 94.34% (100/106 strains), 87.74% (93/106 strains)] in 2018 and 2019, respectively.The test strains were 100.00% (14/14 strains) resistant to the above 3 antibiotics in 2021.MIC 50 and MIC 90 values of Penicillin in 2018, 2019, and 2021 were (0.03 mg/L, 0.03 mg/L), (0.03 mg/L, 0.06 mg/L), and (0.06 mg/L, 0.06 mg/L), respectively.Among 225 GAS strains, 207 strains had drug resistance and were resistant to more than one drug.Specifically, 94.69% (196/207 strains) were resistant to Erythromycin, Tetracycline and Clindamycin.About 4.35% (9/207 strains) were resistant to both Erythromycin and Clindamycin.A total of 0.97% (2/207 strains) were resistant to Erythromycin and Tetracycline. Conclusions:The emm genotypes of GAS in children in Beijing are diverse in 2018, 2019 and 2021.The dominant genotypes are emm12 and emm1, and emm12 is the main epidemiological type.GAS strains maintain highly resistant to Erythromycin, Clindamycin and Tetracycline, and sensitive to Penicillin and other antibiotics.However, MIC 50 and MIC 90 of Penicillin shows an ascending trend.

With characteristics of high infectivity, diverse transmission routes and high variation, norovirus is the main pathogen of sporadic cases and outbreaks of acute gastroenteritis, resulting in a serious disease burden. This paper summarizes the latest progress in epidemiological research of norovirus infection from aspects of disease burden caused by acute gastroenteritis, virus variation and predominant strains, prevention and control measures, and immunization and vaccine development

Objective: To understand the antigenicity and genetic characterization of influenza B virus HA gene in B/Victoria-lineage virus (BV) in Beijing during 2017-2018. Methods: Thirty BV virus strains isolated from MDCK cell culture by 17 laboratories in Beijing were collected. The antigenicity was analyzed by comparing with the vaccine strain recommended by WHO. The total viral nucleic acid was extracted and HA gene was amplified by RT-PCR and sequenced. The phylogenetic tree was constructed by HA and mutant sites were analyzed. Results: Among 30 strains of BV, 23 strains (76.7%) were low-reactive strains, other 7 strains (23.3%) were related to the vaccine. The phylogenetic analysis showed that the HA gene of all 30 strains located in Clade 1A branch. In addition, amino acid mutations occurred in 8 sites, and 6 of them located in the antigen determining region. Conclusions There was a correlation between the high proportion of low-reactive antigenicity and 6 aa variation in antigenic determinants involved in HA region of BV influenza virus between 2017-2018, which provides an important laboratory basis for the recommendation of BV influenza vaccine.

Objective: To observe the efficacy and safety of intensive cladribine-based conditioning regimen for allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children with major thalassemia. Methods: Retrospective analysis was performed for the clinical data of 12 children with major thalassemia undergoing allo-HSCT from March 2017 to July 2018. All of them were diagnosed definitely and the median age at transplantation was 5 years (range: 2-13 years), including HSCT from HLA-matched unrelated donor (n=8), HLA8/10-matched unrelated donor (n=1), HLA-matched sibing donor (n=2) and haploidentical donor (n=1). They received a new intensive conditioning regimen of cyclophosphamide (CTX), cladribine, busulfan (Bu) and antithymocytic globulin. The median doses of mononuclear cell (MNC) and CD34 positive cell were 10.97×10⁸/kg (range: 5.72-12.49×10⁸/kg) and 12.2×10⁶/kg (range: 6.7-22×10⁶/kg). Graft-versus-host disease (GVHD) was prevented by cyclosporine A (CSA), methotrexate (MTX) and mycophenolate mofetil (MMF). Results: Engraftment succeeded (n=11) and failed (n=1). The median time of neutrophil and platelet engraftment was 11 days (range: 8-17 days) and 13 days (range: 8-37 days) respectively. There were grade II acute GVHD (n=6) and grade IV intestinal acute GVHD (n=1) at 35 days post-transplantation. The latter one finally died of severe infection at 70 days post-transplantation. Two recipients of DLI developed limited chronic GVHD. Three cases (25%) developed cytomegaloviremia. None suffered from severe transplantation-related complications, such as cytomegalovirus diseases, hepatic veno-occlusive disease (HVOD), hemorrhagic cystitis or septicemia, etc. The median follow-up time was 15(8-18) months. Among 11 survivors, ten became transfusion-independent. Conclusions Cladribine-based conditioning regimen is both safe and effective for allo-HSCT in children with major thalassemia. However, vigorous immunosuppression may increase the risks of infection and viral activation after transplantation.