Viral infection has always been a significant challenge to human health. Transplant recipients, including those who have undergone solid organ transplantation and allogeneic hematopoietic stem cell transplantation, are at high risk of viral infection due to their weak immune function under immunosuppressive therapy. Unlike the general population, transplant recipients are prone to pneumonia and even severe pneumonia after respiratory viral infection, which requires close attention from clinicians. Therefore, this article reviews the clinical characteristics and special management of viral infection in this population, focusing on the epidemiological features of common respiratory viral infection in transplant recipients, early diagnosis and intervention after infection, severe warning signs and drug treatment strategies, for the reference of clinical colleagues.

Objective:In order to explore the impact of corona virus disease 2019(COVID-19)on the hospitalization of children with bronchiolitis and to improve clinicians′ understanding of the characteristics of bronchiolitis during the COVID-19 epidemic.Methods:This was a multicenter clinical study, and the data have been collected from 23 children′s medical centers in China.All the clinical data were retrospectively collected from children with bronchiolitis who were hospitalized at each study center from January 1, 2019 to December 31, 2021.The results included gender, age at hospitalization, length of stay, respiratory syncytial virus(RSV) test results, severity rating, ICU treatment, and the total number of children hospitalized with respiratory tract infection during the same period.The clinical data of children with bronchiolitis in 2019 before COVID-19 epidemic and in 2020、2021 during COVID-19 epidemic were statistically analyzed and compared.Results:According to a summary of data provided by 23 children′s medical centers, there were 4 909 cases of bronchiolitis in 2019, 2 654 cases in 2020, and 3 500 cases in 2021.Compared with 2019, the number of bronchiolitis cases decreased by 45.94% in 2020 and 28.70% in 2021.In 2019, 2020 and 2021, there were no significant differences in gender ratio, age, and duration of hospitalization.Compared with 2019, the ratio of bronchiolitis to the total number of hospitalizations for respiratory tract infection decreased significantly in 2020 and 2021( χ2=12.762, P<0.05; χ2=84.845, P<0.05).The proportion of moderate to severe bronchiolitis cases in both 2020 and 2021 was lower than that in 2019, and the difference was statistically significant ( χ2=4.054, P<0.05; χ2=8.109, P<0.05).There was no statistically significant difference in the proportion of bronchiolitis cases requiring ICU treatment between 2019, 2020, and 2021 ( χ2=1.914, P>0.05).In 2019, a total of 52.60%(2 582/4 909) of children with bronchiolitis underwent RSV pathogen testing, and among them, there were 708 cases with RSV positive, accounting for 28.00%.In 2020, 54.14%(1 437/2 654) of children with bronchiolitis underwent RSV pathogen testing, and there were 403 cases with RSV positive, accounting for 28.04%.In 2021, 66.80%(2 238/3 500) of children with bronchiolitis underwent RSV pathogen testing, and there were 935 cases with RSV positive, accounting for 41.78%.Compared with 2019 and 2020, the RSV positive rate in 2021 showed a significant increase( χ2=99.673, P<0.05; χ2=71.292, P<0.05). Conclusion:During the COVID-19 epidemic, the implementation of epidemic prevention and control measures reduced the hospitalization rate and severity of bronchiolitis, but did not reduce the positive rate of RSV detection.

Objective:To explore the detection of potentially pathogenic bacteria (PPB) in the nasopharynx of children with respiratory syncytial virus (RSV) bronchiolitis and the influence of PPB types on disease severity.Methods:In this retrospective cohort study, clinical data of patients hospitalized for RSV bronchiolitis at Department of Respiratory Medicine, Children′s Hospital of Soochow University between January 1, 2017 and December 31, 2019 were retrospectively analyzed.The virus, Mycoplasma pneumoniae and bacteria in nasopharyngeal secretion of children were detected.They were classified into <3 months group, 3-<6 months group, 6 months-<1 year group and 1-2 years group based on the age.In addition, they were further classified into RSV infection group, RSV+ G + group, RSV+ G - group and RSV+ G + + G - group based on detected PPB in the nasopharynx.Comparison of RSV + PPB frequency between groups was performed by Chi- squared test, clinical characteristics were compared by using Mann- Whitney U test. Results:A total of 280 patients with RSV bronchiolitis were included in the study, involving 113 cases (40.4%) with PPB in the nasopharynx.The most-common detection bacterium was Streptococcus pneumoniae.The detection rate of Streptococcus pneumoniae increased with age ( χ2=12.609, P=0.005), while that of Staphylococcus aureus decreased with age ( χ2=8.387, P=0.034). Compared with RSV group, patients in RSV+ G - group had a longer length of stay, higher rate of fever and shortness of breath, higher oxygen supplement and higher C-reactive protein (CRP) (all P<0.05). Compared with RSV group, patients in RSV+ G + group were older, and they had higher rate of fever, higher percentage of neutrophil, lower percentage of lymphocyte and higher CRP (all P<0.05). Conclusions:PPB in nasopharynx can be detected in about 40% of children hospitalized with RSV bronchiolitis, and nasopharynx complicated with PPB infection may affect the severity of RSV bronchiolitis.

Objective:Standardized sample resources and high-quality clinical big data are important resources for medical research, only through resource sharing can maximize its utilization.Which can be utilized to the max only through resource sharing.Methods:This paper attempts to explore the sharing mechanism of the resource sharing platform and proposes some aspects such as the platform construction background, management regulations, legal ethical system, data sharing principles, benefit distribution, etc.This article attempts to explore the sharing mechanism based on the resource sharing platform of the respiratory disease biobank, proposes the contents that should be included in the sharing mode.Detailed information including the platform construction background, management procedures, legal and ethical system, data sharing principles and benefit distribution should take into consideration in the operating mechanism of the platform.Results:Establishing a resource sharing platform matches the development of clinical research in China.The tailored sharing model which is suitable for the field of respiratory diseases will also guide the rapid development of clinical research.Conclusions:The construction of a respiratory disease biobank sharing platform is conducive to promoting the opening and sharing of biological samples and information resources in the context of big data.

Chest tightness variant asthma(CTVA) is a newly recognized and special type of bronchial asthma, with the only main clinical manifestation of chest tightness or sighing respiration, but without wheezing and other typical symptoms of bronchial asthma.At the same time, the patients with CTVA are likely to be misdiagnosed in clinic practices.There are few studies on CTVA in children.This article focuses on hot issues about the clinical features, pathoge-nesis, diagnosis and treatment of CTVA, which hopes to enhance the diagnosis and treatment level of CTVA in children.

Objective:To understand the present situation of the construction of standardized asthma clinic for children in China, to explore the problems existing in the process of construction, and to promote the healthy development of standardized clinic construction.Methods:The process and current situation of the construction of standar-dized asthma clinics for children in China were reviewed and investigated, and the practical significance of the China Children′s Asthma Action Plan (CCAAP) in the construction of standardized asthma clinics for children was explored.Results:(1)By December 2020, 1 289 standardized asthma clinics for children and 135 regional demonstration centers had been built; 56 training sessions had been held, with a total of 2 560 doctors and 650 nurses trained, covering 2 560 hospitals across the country; and 4 518 patient education sessions were held.Online publicity covers a total of 1 million person-times, with an annual average of 1.33 million patients.(2)CCAAP improved the quality control level of standardized asthma clinic and promoted the standardized management of children.Conclusions:Through process optimization, professional evaluation, individual health education and real-time disease monitoring, standardized asthma clinic for children with asthma can effectively enhance asthma management awareness of children and their parents, improve disease awareness, and promote better control of asthma.It is an effective management model of asthma in children at present, and it is worthy of clinical promotion.CCAAP plays a good role in the construction of standardized outpatient clinic for asthma in children.The construction of standardized asthma clinic for children in China has achieved remarkable results, and the development trend is good in the future.

Objective:To study the macrolides resistance of Mycoplasma pneumoniae(MP) in Suzhou area, and try to explore the relationship between drug resistance and refractory Mycoplasma pneumoniae pneumonia (RMPP). Methods:From a series of hospitalized children who were diagnosed as Mycoplasma pneumoniae pneumonia (MPP) from October 2013 to September 2014 in Suzhou area, 48 children were treated with Azithromycin (10 mg/kg, once a day, intravenous drip for 5-7 days), and the clinical symptoms and chest imaging were still progressing so they were clinically diagnosed as RMPP, and 34 children who were successfully treated with macrolides antibiotics (MA) were clinically diagnosed as general MPP (GMPP). MP DNA was extracted from the airway secretion of children in the two groups, and the point mutations of 2063 and 2064 of 23S rRNA were sequenced, and according to the MP 23S rRNA sequencing results, the children were divided into macrolides antibiotic resistant MP group (MRMP) and macrolides antibiotic sensitive MP group (MSMP). The clinical characteristics of the two groups were compared. Results:In the MRMP group, the incidence of RMPP was 62.2% (46/74 cases), while in MSMP group, the incidence of RMPP was 25.0% (2/8 cases). The point mutation of MP 23S rRNA had no significant effect on the occurrence of RMPP ( χ2=2.719, P=0.099). Compared with MRMP group, MSMP group presented shorter fever time and less glucocorticoid use.No significant differences between the two groups were found in chest imaging examination, as well as some laboratory results, including the total number and classification of white blood cell (WBC), C-reactive protein (CRP), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and creatine kinase isoenzyme (CK-MB). Conclusions:The fever duration of MPP lasted more than 1 week, suggesting the possibility of macrolides resistance of MP, but macrolides resistance did not aggravate the occurrence of RMPP.It is unreliable to judge the MRMP by chest imaging features and laboratory results.

Objective:To investigate the etiology of necrotizing pneumonia (NP) in children and the clinical characteristics of NP caused by different pathogens in China.Methods:A retrospective, case-control study was performed in children with NP who were admitted to 13 hospitals in China from January 2008 to December 2019. The demographic and clinical information, laboratory data, etiological and radiological findings were analyzed. The data were divided into three groups based on the following years: 2008-2011, 2012-2015 and 2016-2019, and the distribution characteristics of the pathogens in different period were compared. Meanwhile, the pathogens of pediatric NP in the southern and northern China were compared. And the clinical characteristics of the Mycoplasma pneumoniae (MP) NP and the bacterial NP were also compared. T-test or Mann-Whitney nonparametric test was used for comparison of numerical variables, and χ 2 test was used for categorical variables. Results:A total of 494 children with NP were enrolled, the median ages were 4.7 (0.1-15.3) years, including 272 boys and 222 girls. Among these patients, pathogens were identified in 347 cases and the pathogen was unclear in the remaining 147 cases. The main pathogens were MP (238 cases), Streptococcus pneumoniae (SP) (61 cases), Staphylococcus aureus (SA) (51 cases), Pseudomonas aeruginosa (13 cases), Haemophilus influenzae (10 cases), adenovirus (10 cases), and influenza virus A (7 cases), respectively. MP was the most common pathogen in all three periods and the proportion increased yearly. The proportion of MP in 2016-2019 was significantly higher than that in 2012-2015 (52.1% (197/378) vs. 36.8% (32/87), χ 2= 6.654, P=0.010), while there was no significant difference in the proportion of MP in 2012-2015 and that in 2008-2011 (36.8% (32/87) vs. 31.0% (9/29), χ2=0.314, P=0.575).Regarding the regional distribution, 342 cases were in the southern China and 152 in the northern China. Also, MP was the most common pathogen in both regions, but the proportion of MP was higher and the proportion of SP was lower in the north than those in the south (60.5% (92/152) vs. 42.7% (146/342), χ 2=13.409, P<0.010; 7.9% (12/152) vs. 14.3% (49/342), χ 2= 4.023, P=0.045). Comparing the clinical characteristics of different pathogens, we found that fever and cough were the common symptoms in both single MP and single bacterial groups, but chest pain was more common (17.0% (34/200) vs. 6.1% (6/98), χ 2=6.697, P=0.010) while shortness of breath and wheezing were less common in MP group (16.0% (32/200) vs. 60.2% (59/98), χ 2=60.688, P<0.01; 4.5% (9/200) vs. 21.4% (21/98), χ 2=20.819, P<0.01, respectively). The white blood cell count, C-reactive protein and procalcitonin in the bacterial group were significantly higher than those in the MP group (14.7 (1.0-67.1)×10 9/L vs. 10.5 (2.5-32.2)×10 9/L, 122.5 (0.5-277.3) mg/L vs. 51.4 (0.5-200.0) g/L, 2.13 (0.05-100.00) μg/L vs. 0.24 (0.01-18.85) μg/L, Z=-3.719, -5.901 and -7.765, all P<0.01). Conclusions:The prevalence of pediatric NP in China shows an increasing trend during the past years. MP, SP and SA are the main pathogens of NP, and the most common clinical symptoms are fever and cough. The WBC count, C-reactive protein and procalcitonin in bacterial NP are significantly higher than those caused by MP.

Objective:To investigate the clinical characteristics and risk factors of bronchiolitis obliterans (BO) after adenovirus pneumonia.Methods:Clinical data of 266 children with adenovirus pneumonia hospitalized in Children′s Hospital of Soochow University from January 2011 to December 2017 were retrospectively analyzed.Accor-ding to whether they developed BO, children with adenovirus pneumonia were divided into the BO group and the non-BO group.Clinical features of the BO group and the non-BO group were compared by t test, rank sum test or chi square test.Risk factors were analyzed by Logistic regression approach. Results:Among 266 children with adenovirus pneumonia included, 37 patients were developed into BO group, and their age was significantly younger than that of the non-BO group [12.0(8.0, 17.5) months vs.32.0(13.0, 48.0) months, P<0.001]. Compared with the non-BO group, there were more proportion of preterm infants[10.8%(4/37 cases) vs.3.1%(7/229 cases), P=0.028], more instances of comorbidities [21.6%(8/37 cases) vs.4.4%(10/229), P<0.001] and more children with allergic diseas[35.1%(13/37 cases) vs.20.1%(46/229 cases), P=0.041] in the BO group, and the difference was statistically significant.The duration of fever in the BO group was significantly longer than that of the non-BO group [10(4.0, 13.5) d vs.6(4.0, 9.0) d, P=0.011] children with symptoms of wheezing, shortness of breath, and hypoxemia in the BO group were significantly more than the non-BO group[81.1%(30/37 cases) vs.27.9%(64/229 cases), P<0.001; 64.9%(24/37 cases) vs.5.7%(13/229 cases), P<0.001; 59.5%(22/37 cases) vs.6.6%(15/229 cases), P<0.001]. The platelet count, IgG level, and CD3 -CD 19+ lymphocyte percentage were significantly higher in the BO group than the non-BO group [(364±104)×10 9/L vs.(297±105)×10 9/L, P=0.001; 6.74(4.92, 10.16) g/L vs.5.93(1.00, 8.04) g/L, P=0.016; (33.5±15.3)% vs.(26.1±10.2)%, P=0.008]. In contrast, the percentage of CD3 + CD4 + lymphocytes in the BO group was lower than the non-BO group[(29.1±8.0)% vs.(32.5±9.4)%, P=0.044], the difference was statistically significant.The BO group had a higher rate of mixed bacterial infection than the non-BO groups[37.8%(14/37 cases) vs.16.6%(38/229 cases), P=0.003]. An age<26 months, comorbidities, premature birth history, wheezing, shortness of breath, and hypoxemia were independent risk factors for BO after adenovirus pneumonia( OR=4.808, 30.667, 7.558, 3.909, 8.842, 8.607, all P<0.05). Conclusions:An age of less than 26 months, a history of premature delivery comorbidities, wheezing, shortness of breath and hypoxemia, are independent risk factors for BO after adenovirus pneumonia.Children with above manifestations should receive high resolution CT as soon as possible to determine whether it is BO.