Correlation of DNA load, genotyping, and clinical phenotype of Mycoplasma pneumoniae infection in children.

Introduction: This study aimed to investigate the correlation between Mycoplasma pneumoniae (MP)-DNA load in the bronchoalveolar lavage fluid (BALF) of children with MP pneumonia (MPP) and its subtypes, relevant laboratory data, imaging, extrapulmonary complications in infected children, and its clinical significance in evaluating the disease. Methods: Children hospitalized with MPP at Tianjin Children's Hospital between December 2017 and December 2020 were selected for the study, excluding those with mixed viral, bacterial, and fungal infections. Children were divided into low- and high-load groups according to the MP DNA load in BALF using real-time quantitative fluorescence polymerase chain reaction (PCR). After a successful MP culture, positive specimens were subjected to PCR-Restriction fragment length polymorphism and Multiple-locus variable number tandem repeat analysis typing. Basic data, clinical information, laboratory data, and radiological results were collected from all children included in the study. Results: The PI-I type dominated the different load groups. Children in the low-load group had more wheezing and shortness of breath; however, children in the high-load group had a higher length of hospitalization, maximum fever temperature, higher chills/chilliness, incidence of abdominal pain, and higher C-reactive protein (CRP), procalcitonin (PCT) and aspartate aminotransferase (AST) levels. Children in the high-load group were more likely to have imaging changes such as pleural effusion, and the incidence of respiratory infections and extrapulmonary complications was higher than that of those in the low-load group. We applied Spearman's correlation analysis to clarify the relationship between MP DNA load and the clinical severity of MPP. We found that MP DNA load was positively correlated with length of hospitalization, maximum fever temperature, CRP, PCT, Interleukin-6 (IL-6), and AST levels, and negatively correlated with fever and cough durations, white blood cell count (WBC), and proportion of monocytes (MONO). The degree of correlation was as follows: length of hospitalization > IL-6 > cough duration > AST > fever duration > PCT > WBC > proportion of MONO > maximum fever temperature > CRP levels. Conclusions: MP DNA load was not correlated with MP typing but was significantly correlated with the children's clinical phenotype. Therefore, the MP DNA load helps in the early diagnosis of infection and can better predict disease regression.

Interleukin-6 serum levels are independently associated with severe adenovirus pneumonia in children: a cross-sectional study.

Background: This study aimed to explore the potential association between interleukin-6 (IL-6) serum levels and severe adenovirus pneumonia (SAP) in children. Methods: A retrospective hospital-based cross-sectional study was conducted on children with SAP who presented to the Tianjin Children's Hospital between January 2019 and December 2020. Serum IL-6 levels were categorized into quintiles (Q1-5). The primary outcome variable was the occurrence of SAP. The patients' clinical features, laboratory findings, and radiographic characteristics were also assessed, and a descriptive bivariate analysis was carried out. Multivariable logistic regression analysis was applied to evaluate the relationship of IL-6 with SAP after adjustment for confounders. The nonlinear relationship between IL-6 and SAP was also analyzed. P value <0.05 was considered statistically significant. Results: In total, 542 patients met our inclusion criteria (223 males and 319 females). The mean IL-6 serum level was 38.51 pg/mL (range, 1.50-659.2 pg/mL). After adjustment for confounders, the odds ratio (OR) per SD (standard deviation) increase in IL-6 was 1.66 [95% confidence interval (CI): 1.14, 2.41]. The multivariable-adjusted OR (95% CI) of SAP across the Q1-Q5 categories of IL-6 were as follows: 1.00 (reference), 1.17 (0.59, 2.35), 1.79 (0.88, 3.63), 2.31 (1.12, 4.76), and 2.85 (1.32, 6.14) (P for trend =0.002). The risk of SAP increased with the IL-6 serum level up to 40.78 pg/mL (adjusted OR 1.029, 95% CI: 1.008-1.051; P=0.007); however, when the IL-6 level exceeded 40.78 pg/mL, it had no association with the risk of SAP (OR 1.003, 95% CI: 0.996-1.010; P=0.384). Conclusions: Our findings suggest that the serum level of IL-6 is associated with the risk of SAP in children. The levels of IL-6 in children should therefore be of concern to clinicians.

Establishment of a predictive nomogram and its validation for severe adenovirus pneumonia in children.

BACKGROUND: Severe adenovirus pneumonia (SAP) of children is prone to multi-system complications, has the high mortality rate and high incidence of sequelae. Severity prediction can facilitate an adequate individualized treatment plan. Our study try to develop and evaluate a predictive nomogram for children with SAP. METHODS: An observational study was designed and performed retrospectively. The data were categorized as training and validation datasets using the method of credible random split-sample (split ratio =0.7:0.3). The predictors were selected using Lasso (least absolute shrinkage and selection operator) logistic regression and the nomogram was developed. Nomogram discrimination was assessed using the receiver operating characteristic (ROC) curve, and the prediction accuracy was evaluated using a calibration curve. The nomogram was also evaluated for clinical effectiveness by the decision curve analysis (DCA). A P value of <0.05 was deemed statistically significant. RESULTS: The identified predictors were fever duration, and interleukin-6 and CD4+ T cells and were assembled into the nomogram. The nomogram exhibited good discrimination with area under ROC curve in training dataset (0.79, 95% CI: 0.60-0.92) and test dataset (0.76, 95% CI: 0.63-0.87). The nomogram seems to be useful clinically as per DCA. CONCLUSIONS: A nomogram with a potentially effective application was developed to facilitate individualized prediction for SAP in children.

Analysis of the predicting factors of recurrent wheezing in infants.

BACKGROUND: Clinically, asthma in children under 5 years old is under estimated because lack of diagnostic criteria. The current study was, therefore, designed to identify the predicting factors for recurrent wheezing in infants. METHODS: One hundred forty-five infants under 3-year old hospitalized with respiratory diseases were enrolled into this study. Patients were followed up for one-year period after being discharged from the hospital and were, then, divided into recurrent wheezing group and non-recurrent wheezing group based on whether there was recurrent wheezing or not. Wheezing or recurrent wheezing was specifically monitored in addition to blood tests for allergic and respiratory diseases. RESULTS: The prevalence of eczema and respiratory syncytial virus (RSV) infection were significantly higher in recurrent wheezing group than in control group (74.2% vs 45.8%; 32.3% vs. 13.3%, respectively, both P < 0.05); the percentage of blood eosinophil and serum eosinophil-derived neurotoxin (EDN) concentration at admission were also higher in recurrent wheezing group than in control group (3.10 ± 2.54% vs. 1.31 ± 1.15%; 68.67 ± 55.05 ng/mL vs. 27. 36 ± 19.51 ng/mL; respectively, both P < 0.001). Multivariate logistic regression analysis on eosinophil count and serum EDN concentration in predicting recurrent wheezing revealed that the eosinophil count showed the lowest sensitivity (51.6%) and highest specificity (90.4%), with the area under the ROC curve (AUC) of 0.752 ± 0.041; and that, in contrast, the serum EDN showed the highest sensitivity (88.7%) and lowest specificity (56.6%), with AUC of 0.795 ± 0.037. CONCLUSION: Combination of eosinophil count and serum EDN measurement may be better to predict the risk of recurrent wheezing in early life of childhood.

Phenotypes of the inflammatory cells in the induced sputum from young children or infants with recurrent wheezing.

BACKGROUND: To identify inflammatory cell types by phenotypic analysis of the inflammatory cells in the induced sputum. METHODS: This retrospective study included 1232 children and infants, who were assigned into mild/moderate groups (326) and severe group (602) by clinical symptom scores. Phenotypes of sputum inflammatory cells were analyzed using liquid-based thin-cytologic test and eosinophil-derived neurotoxin (EDN) was quantified by ELISA. RESULTS: Blood eosinophil count, serum total IgE level, and allergen detection rate were significantly higher in the severe group. In the 905 cases of qualified sputum, 526 cases exhibited at least one type of inflammatory cells, including neutrophil (343, 65.2%), eosinophil (161, 30.6%), and mixed granulocytes (22, 4.2%). Levels of neutrophils and eosinophils were significantly higher in the severe group than mild/moderate group, and eosinophil was predominant in the severe group. Serum EDN was 104.8 ± 39.4 µg/l in the eosinophil phenotype group, 112.6 ± 41.2 µg/l in the mixed group, 88.2 ± 36.6 µg/l in the neutrophil phenotype group, and 60.9 ± 34.6 µg/l in the paucigranulocytic phenotype group. CONCLUSION: Induced-sputum inflammatory cell count may be used to determine phenotype of wheezing. The criteria of classifying adult asthma could be applicable for children and infants.