Objective:To explore the screening value of platelet parameters from blood cell analysis for MYH9-related disorders(MYH9-RD).Methods:A cross-sectional study was conducted with 38 patients diagnosed with MYH9-RD at Shenzhen Children's Hospital from May 1, 2016, to August 31, 2024, including 24 males and 14 females; the median age was 11.5 (3.8, 35) years; categorized by gene mutation location into "head region" ( n=8 ) and "tail region" ( n=30); and by clinical manifestations into " isolated hematological manifestations" ( n=16) and "hematological manifestations with extra-hematological involvement"( n=22). The control groups included 39 cases of immune thrombocytopenia (ITP), 38 cases of acute lymphoblastic leukemia (ALL), and 40 healthy individuals. Platelet-related parameters were detected by hematology analyzer, and platelet counts and sizes were confirmed by manually counting and microscopic observation. Kruskal-Wallis test was used to compare platelet parameters between MYH9-RD and control groups. Receiver operating characteristic (ROC) curves were used to assess the diagnostic efficacy of platelet parameters for MYH9-RD. Results:In MYH9-RD patients the median value of mean platelet volume (MPV) was 13.4 (11.2, 14.7) fl, immature platelet fraction (IPF) was 52.7% (43.5%, 58.0%), platelet large cell ratio(PLCR) was 57.6 %(45.0%, 62.9%), and microscopic large platelet ratio (PLCR-M) was 30.0% (25.0%, 30.0%).And those values weresignificantly higher than in ITP, ALL, and healthy controls (all P<0.05). Patients with MYH9 gene "head region" mutations had a lower platelet count [24.5 (15.0, 47.5)×10 9/L]than those with "tail region" mutations [69.0 (49.5, 86.3) ×10 9/L]( Z=-3.493, P<0.001), but a higher IPF ( t=2.024, P=0.044).Patients with "extra-hematological involvement had a lower platelet count than those with "isolated hematological manifestations" ( t=-2.015, P=0.043). The optimal cutoff value for diagnosing MYH9-RD with IPF was 26.7%, with a sensitivity of 100% and specificity of 98.7%; the area under the curve was 0.999 (95% CI 0.995-1.000), which was superior toMPV, PLCR and PLCR-M parameters. Conclusion:IPF is superior to other platelet parameters sush as MPV,showing high diagnostic efficacy in distinguishing MYH9-RD from ITP and ALL. It can be used as a simple and effective indicator for early screening of MYH9-RD.

Objective:To investigate factors influencing frequent episodes (≥ 4 episodes within 1 year) in children with moderate-to-severe atopic dermatitis (AD) in China.Methods:A national multicenter cross-sectional study was conducted. Patients under the age of 18 years diagnosed with moderate-to-severe AD were enrolled at dermatology clinics in 18 medical institutions across 12 provinces and municipalities in China between June 12 and August 8, 2023. At the time of the visit, their guardians completed a structured questionnaire covering demographic characteristics, clinical features of AD, personal and family history, factors associated with frequent episodes of moderate-to-severe AD, compliance with treatment, and disease awareness. Statistical analyses included t tests, one-way analysis of variance, rank-sum tests, and chi-square tests, with multiple-response analysis applied for multiple-choice questions. Results:A total of 965 valid questionnaires were collected, and 965 children with moderate-to-severe AD were included. Among them, there were 531 males and 434 females, 678 (70.3%) were aged 2 - < 12 years, 837 (86.7%) were from urban areas, the age at onset was 2.47 ± 3.03 years, and the median frequency of AD episodes in the past year was 4 times. These children were divided into 2 groups based on the median episode frequency: < 4-episode group (439 cases, 45.5%) and ≥ 4-episode group (526 cases, 54.5%). Compared with the < 4-episode group, children in the ≥ 4-episode group showed younger ages at onset (2.22 ± 2.98 years vs. 2.76 ± 3.06 years, P = 0.006) and higher proportions of patients with comorbid allergic diseases in both the children themselves (82.9% [436/526] vs. 69.7% [306/439], χ2 = 23.42, P < 0.001) and their relatives (66.0% [347/526] vs. 57.4% [252/439], χ2 = 7.46, P = 0.006). Children in the ≥ 4- episode group also had higher monthly usage of moisturizers (150 [30, 300] g vs. 60 [6, 200] g) and daily frequency of moisturizer use, greater disease awareness, but more severe fear of medication use (all P < 0.05). The region and the human development index level were both significantly associated with the episode frequency (both P < 0.001), with the highest proportion of children from South China in the ≥ 4- episode group (36.3%, 191/526). Children in the ≥ 4-episode group also had a longer duration of topical glucocorticoid use than those in the < 4-episode group ( Z = -2.21, P = 0.027). External triggers associated with AD episodes mainly included heat exposure (50.36%, 486/965), hot water bathing (40.73%, 393/965), seafood (23.52%, 227/965), and dust mites (33.37%, 322/965) . Conclusion:In children with moderate-to-severe AD in China, factors influencing frequent episodes may include residence in southern or economically developed regions, earlier age at onset, having a personal or family history of allergic diseases, and fear of medication use.

This study analyzed the epidemiological characteristics and trends of respiratory syncytial virus (RSV) infections among inpatients with acute respiratory infections (ARI) in a children′s hospital in Shenzhen City inpatients from 2020 to 2023. From January 2020 to December 2023, multiple reverse transcription polymerase chain reaction (RT-PCR) combined with capillary electrophoresis fragment analysis technology was used to detect the nucleic acids of 12 respiratory pathogens, including RSV, in hospitalized children diagnosed with ARI. The patients were divided into six age groups: 0 to <6 months, 6 months to <1 year, 1 to <2 years, 2 to <5 years, 5 to <10 years, and 10 to <18 years. A total of 53 033 children were tested, including 6 830 RSV positive cases, with an overall positivity rate of 12.88%. The annual RSV positivity rates from 2020 to 2023 were 20.04%, 16.18%, 4.89%, and 13.33%, respectively, with statistically significant differences between the years ( χ2=1 185.994, P<0.001). The positive rate of RSV detection decreased with increasing age across all years (all P trend<0.05). From 2020 to 2023, the proportion of RSV-positive cases aged 2 to 5 years and older showed an increasing trend ( P trend<0.001 for all years). Compared to 2023, the median age of RSV-infected children was lower in 2020 ( Z=7.826, P<0.001) and 2021 ( Z=6.106, P<0.001). The proportion of severe infections requiring ICU admission did not change significantly across all years ( χ2=0.179, P=0.981). The RSV epidemic season in 2020 mainly occurred during 28-43 weeks, and in 2021, it spanned from 22-43 weeks. However, in 2022, the season was delayed until the 49th week and lasted for three weeks. In 2023, the seasonal epidemic appeared earlier, starting in the 14th week and lasting for 28 weeks. From 2020 to 2023, the rate of RSV co-infections with other pathogens (mycoplasma pneumoniae, human parainfluenza virus, human bocavirus, human coronavirus, human metapneumovirus, and influenza A) significantly increased (all P trend<0.01). In conclusion, the epidemiological characteristics of RSV infections in Shenzhen Children′s Hospital changed from 2020 to 2023. In 2022, there were only delayed, low-intensity and short-lived seasonal epidemics. However, in 2023, there was an earlier and prolonged epidemic, with increased infections in children aged 2 to 5 years and older and a rise in co-infections, while the proportion of severe infections requiring ICU admission remained unchanged.

Objective:To investigate factors influencing frequent episodes (≥ 4 episodes within 1 year) in children with moderate-to-severe atopic dermatitis (AD) in China.Methods:A national multicenter cross-sectional study was conducted. Patients under the age of 18 years diagnosed with moderate-to-severe AD were enrolled at dermatology clinics in 18 medical institutions across 12 provinces and municipalities in China between June 12 and August 8, 2023. At the time of the visit, their guardians completed a structured questionnaire covering demographic characteristics, clinical features of AD, personal and family history, factors associated with frequent episodes of moderate-to-severe AD, compliance with treatment, and disease awareness. Statistical analyses included t tests, one-way analysis of variance, rank-sum tests, and chi-square tests, with multiple-response analysis applied for multiple-choice questions. Results:A total of 965 valid questionnaires were collected, and 965 children with moderate-to-severe AD were included. Among them, there were 531 males and 434 females, 678 (70.3%) were aged 2 - < 12 years, 837 (86.7%) were from urban areas, the age at onset was 2.47 ± 3.03 years, and the median frequency of AD episodes in the past year was 4 times. These children were divided into 2 groups based on the median episode frequency: < 4-episode group (439 cases, 45.5%) and ≥ 4-episode group (526 cases, 54.5%). Compared with the < 4-episode group, children in the ≥ 4-episode group showed younger ages at onset (2.22 ± 2.98 years vs. 2.76 ± 3.06 years, P = 0.006) and higher proportions of patients with comorbid allergic diseases in both the children themselves (82.9% [436/526] vs. 69.7% [306/439], χ2 = 23.42, P < 0.001) and their relatives (66.0% [347/526] vs. 57.4% [252/439], χ2 = 7.46, P = 0.006). Children in the ≥ 4- episode group also had higher monthly usage of moisturizers (150 [30, 300] g vs. 60 [6, 200] g) and daily frequency of moisturizer use, greater disease awareness, but more severe fear of medication use (all P < 0.05). The region and the human development index level were both significantly associated with the episode frequency (both P < 0.001), with the highest proportion of children from South China in the ≥ 4- episode group (36.3%, 191/526). Children in the ≥ 4-episode group also had a longer duration of topical glucocorticoid use than those in the < 4-episode group ( Z = -2.21, P = 0.027). External triggers associated with AD episodes mainly included heat exposure (50.36%, 486/965), hot water bathing (40.73%, 393/965), seafood (23.52%, 227/965), and dust mites (33.37%, 322/965) . Conclusion:In children with moderate-to-severe AD in China, factors influencing frequent episodes may include residence in southern or economically developed regions, earlier age at onset, having a personal or family history of allergic diseases, and fear of medication use.

This study analyzed the epidemiological characteristics and trends of respiratory syncytial virus (RSV) infections among inpatients with acute respiratory infections (ARI) in a children′s hospital in Shenzhen City inpatients from 2020 to 2023. From January 2020 to December 2023, multiple reverse transcription polymerase chain reaction (RT-PCR) combined with capillary electrophoresis fragment analysis technology was used to detect the nucleic acids of 12 respiratory pathogens, including RSV, in hospitalized children diagnosed with ARI. The patients were divided into six age groups: 0 to <6 months, 6 months to <1 year, 1 to <2 years, 2 to <5 years, 5 to <10 years, and 10 to <18 years. A total of 53 033 children were tested, including 6 830 RSV positive cases, with an overall positivity rate of 12.88%. The annual RSV positivity rates from 2020 to 2023 were 20.04%, 16.18%, 4.89%, and 13.33%, respectively, with statistically significant differences between the years ( χ2=1 185.994, P<0.001). The positive rate of RSV detection decreased with increasing age across all years (all P trend<0.05). From 2020 to 2023, the proportion of RSV-positive cases aged 2 to 5 years and older showed an increasing trend ( P trend<0.001 for all years). Compared to 2023, the median age of RSV-infected children was lower in 2020 ( Z=7.826, P<0.001) and 2021 ( Z=6.106, P<0.001). The proportion of severe infections requiring ICU admission did not change significantly across all years ( χ2=0.179, P=0.981). The RSV epidemic season in 2020 mainly occurred during 28-43 weeks, and in 2021, it spanned from 22-43 weeks. However, in 2022, the season was delayed until the 49th week and lasted for three weeks. In 2023, the seasonal epidemic appeared earlier, starting in the 14th week and lasting for 28 weeks. From 2020 to 2023, the rate of RSV co-infections with other pathogens (mycoplasma pneumoniae, human parainfluenza virus, human bocavirus, human coronavirus, human metapneumovirus, and influenza A) significantly increased (all P trend<0.01). In conclusion, the epidemiological characteristics of RSV infections in Shenzhen Children′s Hospital changed from 2020 to 2023. In 2022, there were only delayed, low-intensity and short-lived seasonal epidemics. However, in 2023, there was an earlier and prolonged epidemic, with increased infections in children aged 2 to 5 years and older and a rise in co-infections, while the proportion of severe infections requiring ICU admission remained unchanged.

Objective:To explore the screening value of platelet parameters from blood cell analysis for MYH9-related disorders(MYH9-RD).Methods:A cross-sectional study was conducted with 38 patients diagnosed with MYH9-RD at Shenzhen Children's Hospital from May 1, 2016, to August 31, 2024, including 24 males and 14 females; the median age was 11.5 (3.8, 35) years; categorized by gene mutation location into "head region" ( n=8 ) and "tail region" ( n=30); and by clinical manifestations into " isolated hematological manifestations" ( n=16) and "hematological manifestations with extra-hematological involvement"( n=22). The control groups included 39 cases of immune thrombocytopenia (ITP), 38 cases of acute lymphoblastic leukemia (ALL), and 40 healthy individuals. Platelet-related parameters were detected by hematology analyzer, and platelet counts and sizes were confirmed by manually counting and microscopic observation. Kruskal-Wallis test was used to compare platelet parameters between MYH9-RD and control groups. Receiver operating characteristic (ROC) curves were used to assess the diagnostic efficacy of platelet parameters for MYH9-RD. Results:In MYH9-RD patients the median value of mean platelet volume (MPV) was 13.4 (11.2, 14.7) fl, immature platelet fraction (IPF) was 52.7% (43.5%, 58.0%), platelet large cell ratio(PLCR) was 57.6 %(45.0%, 62.9%), and microscopic large platelet ratio (PLCR-M) was 30.0% (25.0%, 30.0%).And those values weresignificantly higher than in ITP, ALL, and healthy controls (all P<0.05). Patients with MYH9 gene "head region" mutations had a lower platelet count [24.5 (15.0, 47.5)×10 9/L]than those with "tail region" mutations [69.0 (49.5, 86.3) ×10 9/L]( Z=-3.493, P<0.001), but a higher IPF ( t=2.024, P=0.044).Patients with "extra-hematological involvement had a lower platelet count than those with "isolated hematological manifestations" ( t=-2.015, P=0.043). The optimal cutoff value for diagnosing MYH9-RD with IPF was 26.7%, with a sensitivity of 100% and specificity of 98.7%; the area under the curve was 0.999 (95% CI 0.995-1.000), which was superior toMPV, PLCR and PLCR-M parameters. Conclusion:IPF is superior to other platelet parameters sush as MPV,showing high diagnostic efficacy in distinguishing MYH9-RD from ITP and ALL. It can be used as a simple and effective indicator for early screening of MYH9-RD.

Objective:To explore the risk factors for lymphoproliferative disorders (PTLD) in children with thalassemia major (TM) after allogeneic hematopoietic stem cell transplantation (allo-HSCT).Methods:This was a retrospective case-control study.A total of 482 children with TM who underwent allo-HSCT at Shenzhen Children′s Hospital between January 2020 and December 2022 were selected and classified into the PTLD and non-PTLD groups according to the occurrence of PTLD.The risk factors for PTLD after allo-HSCT in children with TM were analyzed, and the diagnostic efficiency of relevant risk factors for PTLD was analyzed by receiver operating characteristic (ROC) curve.Results:A total of 25 out of 482 patients (5.2%, 25/482) developed PTLD about 114 (54-271) days after allo-HSCT.Among them, 12 cases (12/25, 48.0%) occurred within 100 days, and 22 cases (22/25, 88.0%) occurred within 1 year after allo-HSCT.Univariate analysis showed that there were significant differences in gender composition, type of transplant donor, number of natural killer cells and B lymphocytes in peripheral blood at 30 days after allo-HSCT, positive rate of plasma Epstein-Barr virus deoxyribonucleic acid (EBV-DNA) and incidence rate of acute graft-versus-host disease (aGVHD) between the 2 groups (all P<0.05).Multivariate Logistic regression analysis showed that female ( OR=3.196, 95% CI: 1.144-8.929), positive plasma EBV-DNA ( OR=17.523, 95% CI: 5.449-56.344) and aGVHD ( OR=3.156, 95% CI: 1.161-8.575) were independent risk factors for PTLD after allo-HSCT in TM children (all P<0.05).The ROC curve analysis showed that positive plasma EBV-DNA had an excellent accuracy in predicting the occurrence of PTLD after allo-HSCT (sensitivity was 0.796, specificity was 0.800, area under the curve was 0.803).If combined with aGVHD and gender, the area under the curve for the prediction of PTLD increased to 0.831. Conclusions:Female, positive plasma EBV-DNA and aGVHD are independent risk factors for PTLD after allo-HSCT in children with TM.It provides useful early warnings for the prediction and prevention of PTLD.

Objective To analyze the etiological characteristics and the variation of pathogens spectrum in hospitalized children with a-cute respiratory tract infection(ARTI)before and after COVID-19 under"the level B of management for class B"of infectious diseases(Level B for Class B)in Shenzhen,in order to provide reference for the clinical diagnosis,treatment and prevention of ARTI.Meth-ods The ARTI cases from January 8,2022 to July 30,2022 were selected as before"Level B for Class B",and the cases from Janu-ary 8,2023 to July 30,2023 were selected as after"Level B for Class B".The pharyngeal swab samples submitted for analyzing 11 common pathogens,such as COVID-19,influenza virus(Ⅳ),respiratory syncytial virus(RSV)and mycoplasma pneumoniae(MP)in the children with ARTI admitted to Shenzhen Children's Hospital.Results SARS-CoV-2 were detected as positive in 347 cases,a-mong which 225 cases were before"Level B for Class B"including 29 cases combined with other pathogens(12.89％,29/225)and human parainfluenza viruses(HPIV)was the most common(31.03％,9/29).After"Level B for Class B",SARS-CoV-2 were detec-ted as positive in 122 cases,including 28 cases combined with other pathogens(22.95％,28/122),and RSV was the most common(28.57％,8/28).There was a statistical difference between the positive rate of SARS-CoV-2 combined with other pathogens before and after"Level B for Class B"(X2=5.834,P=0.016).After"Level B for Class B",the total pathogen detection rate(positive for at least one pathogen)was 60.82％(2 864/4 709)in the spring(January 8,2023 to April 30,2023),and influenza virus A(IVA)(22.64％,1 066/4 709),rhinovirus(HRV)(19.86％,935/4 709)and RSV(13.29％,626/4 709)were the main pathogens,and there were 301 cases(6.39％,301/4 709)of mixed infections.In the summer(May 1,2023 to July 30,2023),the total detection rate of pathogens was 70.26％(4 012/5 710),among which RSV(21.63％,1 235/5 710),MP(13.91％,794/5 710),HPIV(10.05％,574/5 710)were the main pathogens,and there were 710 cases(12.43％,710/5 710)of mixed infections,all of which were significantly higher than the same period before"Level B for Class B".The difference was statistically significant(P＜0.05).Conclusion After"Level B for Class B"for COVID-19,the detection rate of 11 common pathogens increased significantly and the pathogen spectrum of ARTI changed significantly.

Objective:To establish the biology reference interval (RI) of peripheral blood procalcitonin (PCT) for children between 3 days and 6 years old in China.Methods:Totally 3 353 reference individuals with apparent health or no specific diseases were recruited in 18 hospitals throughout the country during October 2020 to May 2021. Reference individuals were divided into four groups: 3-28 days, 29 days - 1 year, 1-3 years and 4-6 years. Vein blood or capillary blood were collected by percutaneous puncture from every reference individual. The PCT level in serum and the capillary whole blood were assayed by Roche Cobas e601 and Norman NRM411-S7 immunoanalyzer. Outliers were deleted and 95th percentiles of every group were provided as RIs. Man-Whitney U test or Kruskal-Wallis test were used performed to assess the difference among different gender, age or method groups. Results:The difference of PCT distribution between male and female is not statistically significant, but the difference between serum and capillary whole blood is statistically significant. The differences between age groups are significant too. For Roche e601, serum PCT RI of 3-28 days group is <0.23 μg/L, 29 days - 6 years are <0.11 μg/L. For NRM411, Serum PCT RI of 3-28 days group is <0.21 μg/L, 29 days - 1 year: <0.09 μg/L, 1 - 6 years: <0.10 μg/L. For whole blood PCT, RI of 3-28 days group is <0.26 μg/L, 29 days - 6 years is <0.15 μg/L.Conclusions:Serum and capillary whole blood PCT have different RIs, however, capillary whole blood PCT testing is valuable in pediatric application. Children in 3-28 days show higher PCT levels than other age group. To establish the RIs and understand the differences among different groups are essential for the interpretation and clinical application of peripheral blood PCT testing results.