Objective To investigate the correlation between HLA-DM gene polymorphism and antibody response induced by poliomyelitis vaccine.Methods 355 healthy infants aged 2 to 3 months in Guangxi Zhuang Autonomous Region were selected as the study objects,and 10 SNPs of DMA exon 3 and DMB exon 2/3 were genotyped by Sanger sequencing.The correlation between DMA and DMB genes and poliomyelitis vaccine-induced antibody response was analyzed at allele,genotype and haplotype levels.Results In the type Ⅰ antibody response induced by polio vaccine,the frequencies of DMA*01:02,DMB*01:01,DMB*01:01/DMB*01:01 and DMA*01:02-DMB*01:01 were higher in the non-seroconversion group than in the seroconversion group(P<0.05).In the polio type Ⅱ antibody response,the frequencies of DMA*01:02,DMA*01:02/DMA*01:02,DMB*01:01/DMB*01:01 and DMA*01:02-DMB*01:01 were higher in the non-seroconversion group than in the seroconversion group(P<0.05).Conclusion Alleles DMA*01:02 and DMB*01:01 may be associated with type Ⅰ and type Ⅱ antibody responses induced by poliomyelitis vaccine.

Objective:To analyze the epidemiological features of respiratory syncytial virus (RSV) infection in Beijing, and monitor the sequence variations in RSV glycoprotein (G) gene and clinical features of infected children.Methods:Respiratory tract specimens were collected from children with acute respiratory infection in the Children′s Hospital Affiliated to Capital Institute of Pediatrics from January 1, 2023 to December 31, 2023. RSV-positive specimens screened by multiple nucleic acid testing were subjected to PCR to amplify the full-length RSV G gene. A phylogenetic tree was constructed after gene sequencing to analyze RSV subtypes and trace G gene variants. Clinical data were retrieved from the medical record system to analyze the clinical features of children with RSV infection in Beijing.Results:A total of 5 489 respiratory specimens were collected from 3 046 male patients and 2 443 female patients. The average age of the patients was 4.36 years. A total of 589 RSV-positive specimens (10.7%, 589/5 489) were detected with 349 from male patients and 240 from female patients. The average age of children with RSV infection was (2.51±2.78) years and the median age was 0.48 years. RSV had been circulating among children in Beijing since March 2023 with two epidemic peaks in May (24.6%, 122/496) and December (18.2%, 126/693). The predominant subtype of RSV in the first half of 2023 was subtype A, but it was replaced by subtype B from November 2023. Phylogenetic analysis revealed a novel G gene of RSV subtype B (RSV-B-BA9-954bp) with a length of 954 bp, which belonged to a new cluster in the phylogenetic tree. The percentage of patients admitted to the Intensive Care Unit (ICU) was higher in children with new variant of RSV subtype B infection than in those with common RSV subtype B infection [44.1% (15/34) vs 25.2% (31/123), χ 2=4.600, P=0.032], while the counts of white blood cells and the levels of C-reactive protein were lower in the children with new variant infection ( P<0.05). Conclusions:RSV has been prevalent among children in Beijing since March 2023 with two epidemic peaks. The predominant A subtype is gradually replaced by to B subtype. A new variant of RSV B G gene (RSV-B-BA9-954bp) is detected among the children.

Objective:To analyze the differentially expressed genes of human respiratory syncytial virus (RSV) subtype A genotype ON1, a predominant genotype in Beijing, after infecting A549 cells using transcriptomic sequencing, and provide potential targets for RSV prevention and treatment.Methods:A local strain (61397-ON1) identified by whole-genome sequencing as ON1 genotype of RSV subtype A was selected to infect A549 cells. Total mRNA was extracted, and the differentially expressed genes in infected and uninfected A549 cells were screened by transcriptomic sequencing. GO analysis and KEGG pathway analysis were performed. Besides, six genes with differential expression ratio greater than two times were randomly selected for qRT-PCR verification.Results:There were 1 632 differentially expressed genes between infected and uninfected A549 cells, of which 807 genes were up-regulated and 825 genes were down-regulated. The differentially expressed genes were mainly involved in immune response-related biological processes such as cytokine response and positive regulation of MAPK cascades, and were enriched in MAPK signaling pathway, NOD-like receptor signaling pathway, p53 signaling pathway, TNF signaling pathway, IL-17 signaling pathway and NF-κB signaling pathway. The results of qRT-PCR for six differentially expressed genes were consistent with the trend of transcriptome data.Conclusions:The differentially expressed genes of RSV A subtype ON1 genotype after infecting A549 cells are mainly involved in cytokine response and immune-related signaling pathways. This study provides basic data for further study of the molecular mechanism of RSV infection and the development of prevention and treatment strategies.

Objective:To explore the pathogenic agents of acute respiratory infection (ARI) in children in Beijing.Methods:In the cross-sectional study, 3 groups of children from different departments were enrolled from Feb 6 th, 2023 (6 th week) to May 28 th (21 th week), 2023, including influenza-like case group from emergency department for nucleic acid testing of influenza virus (Flu) and human metapneumovirus (HMPV), the outpatient ARI group under nucleic acid testing for Flu, respiratory syncytial virus (RSV), adenovirus (ADV), and parainfluenza virus (PIV), and the inpatient ARI group under nucleic acid testing for Flu, RSV, HMPV, ADV, human bocavirus (HBoV), Rhinovirus (Rh), PIV, coronavirus (HCoV), Mycoplasma pneumoniae (Mp) and Chlamydia pneumonia (Cp). Results:There were 320 influenza-like cases enrolled, including 192 males and 128 females, aged 4.7 (3.6, 6.9) years, and 117 cases (36.6%) positive for Flu A, which contained similar proportion of pandemic H1N1 (H1N1) 47.0% (55/117) and H3N2 53.0% (62/117), and 13 cases for HMPV 4.1% (13/320). The rate of Flu reached its peak at the 10 th week, with H1N1 as the predominant one from the 6 th to 9 th week (10.0%-50.0%) and then H3N2 from the 10 th to 16 th week (15.0%-90.0%). HMPV was detected from the 15 th week 5.0% (1/20), and then reached to 30.0% (6/20) at the 20 th week. In the outpatient ARI group, 7 573 were enrolled, including 4 131 males and 3 442 females, aged 4.0 (2.1, 5.3) years, and the highest positive rate for RSV 32.9% (2 491/7 573), followed by Flu A 12.1% (915/7 573). The dominant one was Flu A in weeks 6-14 (23.2%-74.7%), then RSV in the 15 th week 24.8% (36/145). In the inpatient ARI group, 1 391 patients were enrolled, including 804 males and 587 females, aged 3.3 (0.4, 5.8) years, and the highest positive rate for Rh 18.7% (260/1 391), followed by RSV 12.4% (173/1 391), Flu A 10.2% (142/1 391, of which 116 cases (81.7%) were H1N1, and 26 cases (18.3%) were H3N2) and HMPV 3.1% (43/1 391). H1N1 was detected from the 7 th week 10% (6/60), to peak in the 11 th week 31.8% (21/66). H3N2 was detected from the 8 th week 1.5% (1/68), and then kept in low level. The proportion of H1N1 among Flu was 81.7% (116/142) in the inpatient ARI group. RSV was detected from 12 th week 1.3% (1/80), reaching 30.4% (35/115) at 19 th week. The positive rate of HMPV reached 12.1% (14/116) at 21 th week. Conclusions:In the spring of 2023, the first one in Beijing is the Flu epidemic, with H1N1 being the predominant one in the early stage and H3N2 in the later stage. Then, there is a postponed RSV epidemic and an increased HMPV detection. In addition, nucleic acid testing for outpatient children should be strengthened to provide early warning of epidemics.

Objective:To investigate the spectrum of pathogenic agents in pediatric patients with acute respiratory infections (ARI) during the outbreak of coronavirus infectious diseases 2019 (COVID-19).Methods:Three groups of children were enrolled into the prospective study during January 20 to February 20, 2020 from Capital Institute of Pediatrics, including children in the exposed group with ARI and epidemiological history associated with COVID-19 from whom both pharyngeal and nasopharyngeal swabs were collected, children in the ARI group without COVID-19 associated epidemiological history and children in the screening group for hospital admission, with neither COVID-19 associated epidemiological history nor ARI. Only nasopharyngeal swabs were collected in the ARI group and screening group. Each group is expected to include at least 30 cases. All specimens were tested for 2019-nCoV nucleic acid by two diagnostic kits from different manufacturers. All nasopharyngeal swabs were tested for multiple respiratory pathogens, whilst the results from the ARI group were compared with that in the correspondence periods of 2019 and 2018 used by t or χ 2 test. Results:A total of 244 children were enrolled into three groups, including 139 males and 105 females, the age was (5±4) years. The test of 2019-nCoV nucleic acid were negative in all children, and high positive rates of pathogens were detected in exposed (69.4%, 25/36) and ARI (55.3%, 73/132) groups, with the highest positive rate for mycoplasma pneumoniae (MP) (19.4%, 7/36 and 17.4%, 23/132, respectively), followed by human metapneumovirus (hMPV) (16.7%, 6/36 and 9.8%, 13/132, respectively). The positive rate (11.8%, 9/76) of pathogens in the screening group was low. In the same period of 2019, the positive rate of pathogens was 83.7% (77/92), with the highest rates for respiratory syncytial virus (RSV) A (29.3%, 27/92), followed by influenza virus (Flu) A (H1N1) (19.6%, 18/92) and adenovirus (ADV) (14.1%, 13/92), which showed significant difference with the positive rates of the three viruses in 2020 (RSV A: χ 2=27.346, P<0.01; FluA (H1N1): χ 2=28.083, P<0.01; ADV: χ 2=7.848, P=0.005) . In 2018, the positive rate of pathogens was 61.0% (50/82), with the highest rate for human bocavirus (HBoV) (13.4%, 11/82) and followed by ADV (11.0%, 9/82), and significant difference was shown in the positive rate of HBoV with that in 2020 (χ 2=6.776, P=0.009). Conclusions:The infection rate of 2019-nCoV is low among children in Beijing with no family clustering or no close contact, even with epidemiological history. The spectrum of pathogens of ARI in children during the research period is quite different from that in the previous years when the viral infections were dominant. MP is the highest positively detected one among the main pathogens during the outbreak of COVID-19 in Beijing where there is no main outbreak area.