Bronchoalveolar lavage in children. ERS Task Force on bronchoalveolar lavage in children. European Respiratory Society

The utility of elective flexible bronchoscopy to improve quality of life and clinical outcomes for children: A systematic review

INTRODUCTION

Elective flexible bronchoscopy (FB) is now widely available and standard practice for a variety of indications in children with respiratory conditions. However, there is limited evidence regarding the utility of elective FB in children. This systematic review (SRs) aimed to determine the utility of FB on its impact in clinical decision making and quality of life (QoL).

METHODS

We searched Pubmed, Cochrane central register of controlled trials, Embase, World Health Organization Clinical Trials Registry Platform and Cochrane database of SRs from inception to April 20, 2023. We included SRs and randomized controlled trials (RCTs) that used parallel group design (comparing use of elective FB vs. no FB, or a wait-list approach [early FB vs. usual wait FB]) in children aged ≤ 18 years. Our protocol was prospectively registered and used Cochrane methodology for systemic reviews of interventions.

RESULTS

Our search identified 859 articles; 102 duplicates were removed, and 753 articles were excluded by title and abstract. Four full text articles were reviewed and subsequently excluded, as none met the inclusion criteria outlined in our patient, intervention, comparator, outcome measures framework.

CONCLUSIONS

There is a paucity of high-quality RCT evidence to support the routine use of elective FB in children with respiratory conditions. However, available retrospective and a single prospective study demonstrate the high utility of FB in the elective pediatric setting.

REGISTRATION

PROSPERO CRD42021291305.

A novel syndrome of silent rhinovirus-associated bronchoalveolitis in children with recurrent wheeze

BACKGROUND

Rhinovirus (RV) infections trigger wheeze episodes in children. Thus, understanding of the lung inflammatory response to RV in children with wheeze is important.

OBJECTIVES

This study sought to examine the associations of RV on bronchoalveolar lavage (BAL) granulocyte patterns and biomarkers of inflammation with age in children with treatment-refractory, recurrent wheeze (n = 616).

METHODS

Children underwent BAL to examine viral nucleic acid sequences, bacterial cultures, granulocyte counts, and phlebotomy for both general and type-2 inflammatory markers.

RESULTS

Despite the absence of cold symptoms, RV was the most common pathogen detected (30%), and when present, was accompanied by BAL granulocytosis in 75% of children. Compared to children with no BAL pathogens (n = 341), those with RV alone (n = 127) had greater (P < .05) isolated neutrophilia (43% vs 16%), mixed eosinophils and neutrophils (26% vs 11%), and less pauci-granulocytic (27% vs 61%) BAL. Children with RV alone furthermore had biomarkers of active infection with higher total blood neutrophils and serum C-reactive protein, but no differences in blood eosinophils or total IgE. With advancing age, the log odds of BAL RV alone were lower, 0.82 (5th-95th percentile CI: 0.76-0.88; P < .001), but higher, 1.58 (5th-95th percentile CI: 1.01-2.51; P = .04), with high-dose daily corticosteroid treatment.

CONCLUSIONS

Children with severe recurrent wheeze often (22%) have a silent syndrome of lung RV infection with granulocytic bronchoalveolitis and elevated systemic markers of inflammation. The syndrome is less prevalent by school age and is not informed by markers of type-2 inflammation. The investigators speculate that dysregulated mucosal innate antiviral immunity is a responsible mechanism.

Association between arachidonate lipoxygenase 15,c.-292 C > T gene polymorphism and non-cystic fibrosis bronchiectasis in children: a pilot study on the effects on airway lipoxin A4 and disease phenotype

BACKGROUND

Persistent airway inflammation is a central feature of bronchiectasis. Arachidonate 15-lipoxygenase (ALOX-15) controls production of endogenous lipid mediators, including lipoxins that regulate airway inflammation. Mutations at various positions in ALOX-15 gene can influence airway disease development. We investigated association between ALOX-15,c.-292 C > T gene polymorphism and bronchiectasis unrelated to cystic fibrosis in Egyptian children. Also, lipoxin A4 (LXA4) level in bronchoalveolar lavage (BAL) was studied in relation to polymorphism genotypes and disease phenotypes determined by clinical, pulmonary functions, and radiological severity parameters.

METHODS

This was an exploratory study that included 60 participants. Thirty children with non-cystic fibrosis bronchiectasis (NCFB) were compared with 30 age and sex-matched controls. ALOX-15,c.-292 C > T polymorphism was genotyped using TaqMan-based Real-time PCR. LXA4 was measured in BAL using ELISA method.

RESULTS

There was no significant difference between patients and controls regarding ALOX-15,c.-292 C > T polymorphism genotypes and alleles (OR = 1.75; 95% CI (0.53-5.7), P = 0.35) (OR = 1; 95% CI (0.48-2), p = 1). BAL LXA4 level was significantly lower in patients, median (IQR) of 576.9 (147.6-1510) ng/ml compared to controls, median (IQR) of 1675 (536.8-2542) (p = 0.002). Patients with severe bronchiectasis had a significantly lower LXA4 level (p < 0.001). There were significant correlations with exacerbations frequency (r=-0.54, p = 0.002) and FEV1% predicted (r = 0.64, p = 0.001). Heterozygous CT genotype carriers showed higher LXA4 levels compared to other genotypes(p = 0.005).

CONCLUSIONS

Low airway LXA4 in children with NCFB is associated with severe disease phenotype and lung function deterioration. CT genotype of ALOX-15,c.-292 C > T polymorphism might be a protective genetic factor against bronchiectasis development and/or progression due to enhanced LXA4 production.

[Clinical practice guidelines for bronchoalveolar lavage in Chinese children (2024)]

Bronchoalveolar lavage (BAL) has become an important technique in the diagnosis and treatment of respiratory diseases in children. In order to standardize the clinical application of BAL in children, the Branch of Pediatric Critical Care Physicians of Chinese Medical Association, in collaboration with other institutions, has developed the "Clinical practice guidelines for bronchoalveolar lavage in Chinese children (2024)" based on the principles of the World Health Organization guidelines and the formulation/revision principles of the Chinese clinical practice guidelines (2022 edition). This guideline provides 30 recommendations to guide the operational procedures of BAL in children.

Early life surfactant protein-D levels in bronchoalveolar lavage fluids of extremely preterm neonates

Surfactant protein-D (SP-D) is a hydrophilic protein with multiple crucial anti-inflammatory and immunological functions. It might play a role in the development and course of pulmonary infections, acute respiratory distress syndrome, and other respiratory disorders. Only few small neonatal studies have investigated SP-D: we aimed to investigate the links between this protein, measured in the first hours of life in extremely preterm neonates, and clinical outcomes, as well its relationship with pulmonary secretory phospholipase A2 (sPLA2). Bronchoalveolar lavage fluids were obtained within the first 3 h of life. SP-D and sPLA2 were measured with ELISA and radioactive method, respectively; epithelial lining fluid concentrations were estimated with urea ratio. Clinical data were prospectively collected. One hundred extremely preterm neonates were nonconsecutively studied. SP-D was significantly raised with increasing gestational age (24-26 wk: 68 [0-1,694], 27 or 28 wk: 286 [0-1,328], 29 or 30 wk: 1,401 [405-2,429] ng/mL, overall P = 0.03). SP-D was significantly higher in cases with clinical chorioamnionitis with fetal involvement (1,138 [68-3,336]) than in those without clinical chorioamnionitis with fetal involvement (0 [0-900] ng/mL, P < 0.001). SP-D was lower in infants with bronchopulmonary dysplasia (BPD) (251 [0-1,550 ng/mL]) compared with those without bronchopulmonary dysplasia (BPD) or who died before its diagnosis (977 [124-5,534 ng/mL], P = 0.05) and this was also significant upon multivariate analysis [odds ration (OR): 0.997 (0.994-0.999), P = 0.024], particularly in neonates between 27- and 28-wk gestation. SP-D significantly correlated with the duration of hospital stay (ρ = -0.283, P = 0.002), invasive ventilation (ρ = -0.544, P = 0.001), and total sPLA2 activity (ρ = 0.528, P = 0.008). These findings help understanding the role of SP-D early in life and support further investigation about the role of SP-D in developing BPD.NEW & NOTEWORTHY Surfactant protein-D increases with gestational age and is inversely associated with BPD development. These results have been obtained in the first hours of life of extremely preterm neonates with optimal perinatal care.

Predictive power of chest radiography for infectious or inflammatory lung disease

OBJECTIVE

Children frequently present with chronic cough, recurrent respiratory infections, and dysphagia. These symptoms are poor predictors of significant inflammatory lung disease, such as from chronic aspiration. Bronchoalveolar lavage (BAL) is the gold standard for identification of lung infection and airway inflammation but is expensive and requires sedation. Chest X-rays (CXR) are inexpensive, low-radiation tests that do not require sedations and can document findings associated with infectious or inflammatory lung disease. The accuracy of CXR to predict or exclude infectious or inflammatory lung disease has not been directly evaluated and is unknown.

METHODS

Retrospective cohort of all pediatric patients who underwent FFB with BAL within 2 weeks of a CXR. Blinded CXR images reviewed for findings consistent with inflammatory disease by two senior pediatric radiologists. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for CXR to identify significant inflammation and/or infection on BAL were calculated.

RESULTS

Three hundred and forty-four subjects included. Two hundred and sixty-three had positive CXR (77%), 183 had inflammatory BAL (53%), and 110 had infection (32%). The sensitivity of CXR changes for BAL inflammation, infection, and either inflammation or infection was 84.7, 90.9, and 85.3, respectively. The PPV of CXR was 58.9, 38.0, and 59.7. The NPV of CXR was 65.0, 87.5, and 66.3.

CONCLUSIONS

Although CXR are inexpensive, do not require sedation, and are of low radiation dose, the ability of an entirely normal CXR to exclude active inflammatory or infectious lung disease is limited.

Ocular sarcoidosis in adults and children: update on clinical manifestation and diagnosis

Sarcoidosis-associated uveitis, is the predominant ocular sarcoidosis presentation, which affects both adults and children. For adults, international ocular sarcoidosis criteria (IWOS) and sarcoidosis-associated uveitis criteria (SUN) are defined. However, for children they are not yet established internationally. Due to the specificity of pediatric manifestations of sarcoidosis, this task is even more challenging. In children, sarcoidosis is subdivided into Blau syndrome and early-onset sarcoidosis (BS/EOS) affecting younger children (< 5 years) and the one affecting older children with clinical presentation resembling adults. Differential diagnosis, clinical work-up as well as diagnostic criteria should be adapted to each age group. In this article, we review the clinical manifestation of sarcoidosis-associated uveitis in adults and children and the sensitivity and specificity of various ocular sarcoidosis diagnostic modalities, including chest X-ray and CT, FDG PET-CT, gallium-67 scintigraphy, bronchoalveolar lavage fluid, genetic testing for NOD2 mutations and serum biomarkers, such as ACE, lysozyme and IL2R.

Utilizing metagenomic next-generation sequencing for diagnosis and lung microbiome probing of pediatric pneumonia through bronchoalveolar lavage fluid in pediatric intensive care unit: results from a large real-world cohort

Background

Metagenomic next-generation sequencing (mNGS) is a powerful method for pathogen detection in various infections. In this study, we assessed the value of mNGS in the pathogen diagnosis and microbiome analysis of pneumonia in pediatric intensive care units (PICU) using bronchoalveolar lavage fluid (BALF) samples.

Methods

A total of 104 pediatric patients with pneumonia who were admitted into PICU between June 2018 and February 2020 were retrospectively enrolled. Among them, 101 subjects who had intact clinical information were subject to parallel comparison of mNGS and conventional microbiological tests (CMTs) for pathogen detection. The performance was also evaluated and compared between BALF-mNGS and BALF-culture methods. Moreover, the diversity and structure of all 104 patients' lung BALF microbiomes were explored using the mNGS data.

Results

Combining the findings of mNGS and CMTs, 94.06% (95/101) pneumonia cases showed evidence of causative pathogenic infections, including 79.21% (80/101) mixed and 14.85% (15/101) single infections. Regarding the pathogenesis of pneumonia in the PICU, the fungal detection rates were significantly higher in patients with immunodeficiency (55.56% vs. 25.30%, P =0.025) and comorbidities (40.30% vs. 11.76%, P=0.007). There were no significant differences in the α-diversity either between patients with CAP and HAP or between patients with and without immunodeficiency. Regarding the diagnostic performance, the detection rate of DNA-based BALF-mNGS was slightly higher than that of the BALF-culture although statistically insignificant (81.82% vs.77.92%, P=0.677) and was comparable to CMTs (81.82% vs. 89.61%, P=0.211). The overall sensitivity of DNA-based mNGS was 85.14% (95% confidence interval [CI]: 74.96%-92.34%). The detection rate of RNA-based BALF-mNGS was the same with CMTs (80.00% vs 80.00%, P>0.999) and higher than BALF-culture (80.00% vs 52.00%, P=0.045), with a sensitivity of 90.91% (95%CI: 70.84%-98.88%).

Conclusions

mNGS is valuable in the etiological diagnosis of pneumonia, especially in fungal infections, and can reveal pulmonary microecological characteristics. For pneumonia patients in PICU, the mNGS should be implemented early and complementary to CMTs.

Mediators of systemic sclerosis-associated interstitial lung disease (SSc-ILD): systematic review and meta-analyses

Systemic sclerosis-associated interstitial lung disease (SSc-ILD) is rare, poorly understood, with heterogeneous characteristics resulting in difficult diagnosis. We aimed to systematically review evidence of soluble markers in peripheral blood or bronchoalveolar lavage fluid (BALF) as biomarkers in SSc-ILD.

METHOD

Five databases were screened for observational or interventional, peer-reviewed studies in adults published between January 2000 and September 2021 that assessed levels of biomarkers in peripheral blood or BALF of SSc-ILD patients compared with healthy controls. Qualitative assessment was performed using Critical Appraisal Skills Programme (CASP) checklists. Standardised mean difference (SMD) in biomarkers were combined in random-effects meta-analyses where multiple independent studies reported quantitative data.

RESULTS

768 published studies were identified; 38 articles were included in the qualitative synthesis. Thirteen studies were included in the meta-analyses representing three biomarkers: KL6, SP-D and IL-8. Greater IL-8 levels were associated with SSc-ILD in both peripheral blood and BALF, overall SMD 0.88 (95% CI 0.61 to 1.15; I2=1%). Greater levels of SP-D and KL-6 were both estimated in SSc-ILD peripheral blood compared with healthy controls, at an SMD of 1.78 (95% CI 1.50 to 2.17; I2=8%) and 1.66 (95% CI 1.17 to 2.14; I2=76%), respectively.

CONCLUSION

We provide robust evidence that KL-6, SP-D and IL-8 have the potential to serve as reliable biomarkers in blood/BALF for supporting the diagnosis of SSc-ILD. However, while several other biomarkers have been proposed, the evidence of their independent value in diagnosis and prognosis is currently lacking and needs further investigation.

PROSPERO REGISTRATION NUMBER

CRD42021282452.

Metagenomic next-generation sequencing of bronchoalveolar lavage fluid from children with severe pneumonia in pediatric intensive care unit

Background

Severe pneumonia due to lower respiratory tract infections (LRTIs) is a significant cause of morbidity and mortality in children. Noninfectious respiratory syndromes resembling LRTIs can complicate the diagnosis and may also make targeted therapy difficult because of the difficulty of identifying LRTI pathogens. In the present study, a highly sensitive metagenomic next-generation sequencing (mNGS) approach was used to characterize the microbiome of bronchoalveolar lavage fluid (BALF) in children with severe lower pneumonia and identify pathogenic microorganisms that may cause severe pneumonia. The purpose of this study was to use mNGS to explore the potential microbiomes of children with severe pneumonia in a PICU.

Methods

We enrolled patients meeting diagnostic criteria for severe pneumonia admitted at PICU of the Children’s Hospital of Fudan University, China, from February 2018 to February 2020. In total, 126 BALF samples were collected, and mNGS was performed at the DNA and/or RNA level. The pathogenic microorganisms in BALF were identified and correlated with serological inflammatory indicators, lymphocyte subtypes, and clinical symptoms.

Results

mNGS of BALF identified potentially pathogenic bacteria in children with severe pneumonia in the PICU. An increased BALF bacterial diversity index was positively correlated with serum inflammatory indicators and lymphocyte subtypes. Children with severe pneumonia in the PICU had the potential for coinfection with viruses including Epstein–Barr virus, Cytomegalovirus, and Human betaherpesvirus 6B, the abundance of which was positively correlated with immunodeficiency and pneumonia severity, suggesting that the virus may be reactivated in children in the PICU. There was also the potential for coinfection with fungal pathogens including Pneumocystis jirovecii and Aspergillus fumigatus in children with severe pneumonia in the PICU, and an increase in potentially pathogenic eukaryotic diversity in BALF was positively associated with the occurrence of death and sepsis.

Conclusions

mNGS can be used for clinical microbiological testing of BALF samples from children in the PICU. Bacterial combined with viral or fungal infections may be present in the BALF of patients with severe pneumonia in the PICU. Viral or fungal infections are associated with greater disease severity and death.

Diagnostic workup of childhood interstitial lung disease

Childhood interstitial lung diseases (chILDs) are rare and heterogeneous diseases with significant morbidity and mortality. An accurate and quick aetiological diagnosis may contribute to better management and personalised treatment. On behalf of the European Respiratory Society Clinical Research Collaboration for chILD (ERS CRC chILD-EU), this review summarises the roles of the general paediatrician, paediatric pulmonologists and expert centres in the complex diagnostic workup. Each patient's aetiological chILD diagnosis must be reached without prolonged delays in a stepwise approach from medical history, signs, symptoms, clinical tests and imaging, to advanced genetic analysis and specialised procedures including bronchoalveolar lavage and biopsy, if necessary. Finally, as medical progress is fast, the need to revisit a diagnosis of "undefined chILD" is stressed.

Pulmonary function of children with tracheomalacia and associated clinical factors

OBJECTIVES

Spirometry is easily accessible yet there is limited data in children with tracheomalacia. Availability of such data may inform clinical practice. We aimed to describe spirometry indices of children with tracheomalacia, including Empey index and flow-volume curve pattern, and determine whether these indices relate with bronchoscopic features.

METHODS

From the database of children with tracheomalacia diagnosed during 2016-2019, we reviewed their flexible bronchoscopy and spirometry data in a blinded manner. We specially evaluated several spirometry indices and tracheomalacia features (cross-sectional lumen reduction, malacic length, and presence of bronchomalacia) and determined their association using multivariable regression.

RESULTS

Of 53 children with tracheomalacia, the mean (SD) peak expiratory flow (PEF) was below the normal range [68.9 percent of predicted value (23.08)]. However, all other spirometry parameters were within normal range [Z-score forced expired volume in 1 s (FEV₁ ) = -1.18 (1.39), forced vital capacity (FVC) = -0.61 (1.46), forced expiratory flow between 25% and 75% of vital capacity​​​​​​ (FEF_25%-75% ) = -1.43 (1.10), FEV₁ /FVC = -1.04 (1.08)], Empey Index = 8.21 (1.59). The most common flow-volume curve pattern was the "knee" pattern (n = 39, 73.6%). Multivariable linear regression identified the presence of bronchomalacia was significantly associated with lower flows: FEV₁ [coefficient (95% CI) -0.78 (-1.54, -0.02)], FEF_25%-75% [-0.61 (-1.22, 0)], and PEF [-12.69 (-21.13, -4.25)], all p ≤ 0.05. Other bronchoscopic-defined tracheomalacia features examined (cross-sectional lumen reduction, malacic length) were not significantly associated with spirometry indices.

CONCLUSION

The "knee" pattern in spirometry flow-volume curve is common in children with tracheomalacia but other indices, including Empey index, cannot be used to characterize tracheomalacia. Spirometry indices were not significantly associated with bronchoscopic tracheomalacia features but children with tracheobronchomalacia have significantly lower flow than those with tracheomalacia alone.

Secretory phospholipase A2 expression and activity in preterm clinical chorioamnionitis with fetal involvement

Secretory phospholipase A2 (sPLA2) regulates the first step of inflammatory cascade and is involved in several pathological processes. sPLA2 also plays a role in preterm labor and parturition, since they are triggered by inflammatory mediators such as prostaglandins. Interestingly, chorioamnionitis (i.e.: the presence of intrauterine inflammation) is also often associated with preterm birth. We aimed to verify if chorioamnionitis with fetal involvement modifies sPLA2 activity and expression profile in mothers and neonates delivered prematurely. We collected maternal plasma and amniotic fluid, as well as bronchoalveolar lavage fluid from preterm neonates born to mothers with or without clinical chorioamnionitis with fetal involvement. We measured concentrations of sPLA2 subtype-IIA and -IB, total enzyme activity and proteins. Urea ratio was used to obtain epithelial lining fluid concentrations. Enzyme activity measured in maternal plasma (p<0.001) and amniotic fluid (p<0.001) was higher in chorioamnionitis cases than in controls. This was mainly due to the increased production of sPLA2-IIA as the subtype -IB was present in a smaller amount and was similar between the two groups; sPLA2-IIA was increased in epithelial lining fluid (p=0.045) or increased, although without statistical significance, in maternal plasma (p=0.06) and amniotic fluid (p=0.08) of chorioamnionitis cases. Cytokines known to increase sPLA2-IIA expression (TNF-a, IL-1b) or whose expression was increased by sPLA2-IIA (IL-8) were higher in histologically confirmed chorioamnionitis (TNF-a (p=0.028), IL-1b (p<0.001) and IL-8 (p=0.038)). These data represent the basis for future studies on sPLA2-IIA inhibition to prevent deleterious consequences of chorioamnionitis and preterm birth.

Validation of nasal tracheal aspiration in children with lung disease

Background

Nasal tracheal aspiration (NTA) is a frequently used diagnostic method to assess of infections in the lower airways. However, the validity of the method has not previously been compared to bronchoalveolar lavage (BAL) in non-intubated children with a lung disease. We hypothesised that NTA performed by health professionals using the nares vocal cord distance to be placed at the entrance of the trachea, will result in same finding of bacteria in the lower airways as the gold standard of BAL.

Methods

In a prospective study, 173 paired samples of NTA and BAL were obtained between June 2016 to August 2018. Samples were collected from all patients undergoing bronchoscopy with spontaneous breathing during general anaesthesia. This study compares the microbiological results from the cultures obtained by investigating complete concordance i.e. identical pathogenic bacteria and coherence i.e. absence or presence of pathogenic bacteria growth between NTA and BAL.

Results

Samples were collected in 164 patients, 158 children between 21 days and 18 years of age and six young adults still treated at the paediatric department. The overall similarity (complete agreement) was found in 49% [41–56], sensitivity was 35% [27–45], specificity was 66% [55–76], positive predictive value was 36% [27–46] and negative predictive value was 64% [54–64] concerning complete pathogenic bacteria concordance. If we only considered coherence growth of pathogenic bacteria, similarity was 71% [63–79], sensitivity was 74% [64–81], specificity was 66% [55–76], positive predictive value was 75% [65–82] and negative predictive value was 65% [54–75]. Patients with cystic fibrosis showed a similarity of 88% [73–95], a sensitivity of 92% [76–99], a specificity of 71% [36–95], a positive predictive value of 92% [76–99] and a negative predictive value of 71% [36–95] concerning coherence growth of pathogenic bacteria.

Conclusion

The study indicates that NTA compared to BAL as the gold standard is not clinically useful to assess positive findings of specific bacteria in the lower airway tract. Statistically significantly increased sensitivity and positive predictive value were found in cystic fibrosis patients concerning coherence growth. The clinical usage of NTA remains important as negative findings are of clinical value. However, BAL continues to be preferred as a significantly superior diagnostic tool.

Detection of Pneumocystis jirovecii Pneumonia in Infants with Non-Human Immunodeficiency Virus Admitted to Pediatric Intensive Care Using Metagenomics Next-Generation Sequencing

Objective

This study aimed to investigate the characteristics of the non-human immunodeficiency virus (HIV) pneumocystis pneumonia (PCP) via the microbial composition of Pneumocystis jirovecii pneumonia in the lower respiratory tract in infants with severe pneumonia who were hospitalized in the study’s pediatric intensive care unit (PICU).

Methods

The clinical characteristics of 16 infants with non-HIV PCP (the PCP group) and 33 infants with severe pneumonia (the control group) who were hospitalized at the same time in the PICU were analyzed retrospectively. Using metagenomic next-generation sequencing (mNGS), the bronchoalveolar lavage fluid (BALF) of the two groups was analyzed, and the microbial results and clinical data were compared.

Results

Compared with the control group, the infants in the PCP group had a lower incidence of cough (25% vs 78.8%; P < 0.05), a greater history of surgery (50.0% vs 39.1%; P < 0.05), and a more significant decrease in C3, C4, and CD4/CD8 ratios (all P < 0.05). The pathogenic bacteria in the BALF included P. jirovecii, respiratory syncytial virus, cytomegalovirus (CMV), and Staphylococcus aureus. The predominance of viral infection in the PCP group was significantly higher than in the control group (P < 0.05), especially CMV (43.5% vs 15.2%; P < 0.05). The top five symbiotic microorganisms detected in the BALF of the 49 infants were Streptococcus, Propionibacterium, Rothia, Staphylococcus, and Moraxella. There was no significant difference in the relative abundance of common symbiotic microorganisms between the two groups (all P > 0.05).

Conclusion

Non-HIV PCP has a higher incidence in PICU infants with severe pneumonia, especially those with underlying diseases or who are immunocompromised, which are clinically difficult to treat. A BALF analysis using mNGS is helpful for early and clear diagnoses. It also helps to clarify the distribution of pathogenic and lower respiratory tract colonizing bacteria in infants with severe pneumonia.

Interstitial lung disease in infancy and early childhood: a clinicopathological primer

Children's interstitial lung disease (chILD) encompasses a wide and heterogeneous spectrum of diseases substantially different from that of adults. Established classification systems divide chILD into conditions more prevalent in infancy and other conditions occurring at any age. This categorisation is based on a multidisciplinary approach including clinical, radiological, genetic and histological findings. The diagnostic evaluation may include lung biopsies if other diagnostic approaches failed to identify a precise chILD entity, or if severe or refractory respiratory distress of unknown cause is present. As the majority of children will be evaluated and diagnosed outside of specialist centres, this review summarises relevant clinical, genetic and histological findings of chILD to provide assistance in clinical assessment and rational diagnostics.

ILD of childhood is comparable by name only to lung disease in adults. A dedicated interdisciplinary team is required to achieve the best possible outcome. This review summarises the current clinicopathological criteria and associated genetic alterations.https://bit.ly/3mpxI3b

Diagnostic Value of IP-10 Level in Plasma and Bronchoalveolar Lavage Fluid in Children with Tuberculosis and Other Lung Diseases

Objectives: IP-10 has been proposed as a new diagnostic biomarker for Mycobacterium tuberculosis infection (MTBI). However, data on IP-10 concentration in bronchoalveolar lavage fluid (BALF) for pediatric tuberculosis are lacking. Aim: To determine IP-10 levels in unstimulated BALF and plasma in children with and without MTBI. Methods: IP-10 concentrations in BALF and plasma were measured in children hospitalized with suspected tuberculosis or other respiratory disease and scheduled for bronchoscopy. Thirty-five children were enrolled: 13 with suspected tuberculosis and 22 controls. The association between IP-10 and age was examined. Results: The IP-10 expression was increased in BALF compared to plasma (p = 0.008). We noticed higher BALF IP-10 levels in children with asthma, interstitial lung disease, and lung anomaly than in children with MTBI and other respiratory tract infections, but the differences were statistically insignificant. There was a moderate correlation between plasma and BALF IP-10 concentrations (rs = 0.46, p = 0.018). No correlation between IP-10 level and age was detected. Conclusions: IP-10 is detectable in unstimulated BALF in children with respiratory diseases, reaches higher concentrations in unstimulated BALF vs plasma, and does not correlate with age. However, it could not discriminate MTBI from other respiratory diseases.

Advances in the Rapid Diagnostic of Viral Respiratory Tract Infections

Viral infections are a significant public health problem, primarily due to their high transmission rate, various pathological manifestations, ranging from mild to severe symptoms and subclinical onset. Laboratory diagnostic tests for infectious diseases, with a short enough turnaround time, are promising tools to improve patient care, antiviral therapeutic decisions, and infection prevention. Numerous microbiological molecular and serological diagnostic testing devices have been developed and authorised as benchtop systems, and only a few as rapid miniaturised, fully automated, portable digital platforms. Their successful implementation in virology relies on their performance and impact on patient management. This review describes the current progress and perspectives in developing micro- and nanotechnology-based solutions for rapidly detecting human viral respiratory infectious diseases. It provides a nonexhaustive overview of currently commercially available and under-study diagnostic testing methods and discusses the sampling and viral genetic trends as preanalytical components influencing the results. We describe the clinical performance of tests, focusing on alternatives such as microfluidics-, biosensors-, Internet-of-Things (IoT)-based devices for rapid and accurate viral loads and immunological responses detection. The conclusions highlight the potential impact of the newly developed devices on laboratory diagnostic and clinical outcomes.

Bronchoalveolar lavage profiles in uncontrolled wheezy children compared by asthma predictive index

OBJECTIVE

The asthma predictive index (API) predicts later asthma in preschoolers with frequent wheeze. We hypothesized that airway cytology differs between API positive (API+)/negative (API-) children with uncontrolled/recurrent wheezing with dominance of eosinophils in API+ and neutrophils in API- groups respectively. The main objective of this study is to compare bronchoalveolar lavage (BAL) cell profiles in API+/API- children with recurrent wheezing unresponsive to inhaled corticosteroids (ICS).

DESIGN

Retrospective analysis of BAL in 43 children, 3-36 months (median: 14 months) receiving ICS (31 API+, 12 API-). BAL cell differential counts, bacterial/viral cultures, and lipid-laden macrophage percentages were analyzed. Cell counts presented as median (range).

RESULTS

Neutrophil percentages were increased in both groups (API- 16% [1%-76%]; API+ 42% [1%-95%]; p = NS). Cell percentages were similar for lymphocytes (API- 12% [1%-30%]; API+ 7% [1%-37%]), and macrophages (API- 67.5% [12%-97%]; API+ 41% [2%-94%]). Eosinophil percentages were low in both groups (API- 1% [1%-2%]; API+ 1% [1%-11%]). There was no difference in cellular distributions using absolute cell counts comparing API groups. Bacterial cultures were positive in 18 (60%) API+ and 5 (41%) API- patients (p = 0.10).

CONCLUSION

Cell profiles do not differ between API groups in children ≤36 months with recurrent wheezing unresponsive to ICS. Neutrophil percentages and total granulocyte count correlate with positive bacterial cultures independent of API status. Persistent bacterial bronchitis likely plays an important role in the persistence of symptoms unresponsive to ICS therapy regardless of API status with a trend to more positive cultures in API positive children.

Retrospective Review of Flexible Bronchoscopy in Pediatric Cancer Patients

The use of flexible bronchoscopy (FB) with bronchoalveolar lavage (BAL) to diagnose and manage pulmonary complications has been shown to be safe in adult cancer patients, but whether its use is safe in pediatric cancer patients remains unclear. Thus, to describe the landscape of FB outcomes in pediatric cancer patients and to help define the populations most likely to benefit from the procedure, we undertook a retrospective review of FBs performed in patients younger than 21 years treated at our institution from 2002 to 2017. We found that a greater volume of total fluid instilled during BAL was significantly associated with increased probabilities of positive BAL culture (p=0.042), positive bacterial BAL culture (p=0.037), and positive viral BAL culture (p=0.0496). In more than half of the FB cases, findings resulted in alterations in antimicrobial treatment. Our study suggests that for pediatric cancer patients, FB is safe, likely provides diagnostic and/or therapeutic benefits, and has implications for treatment decisions.

Benefits and risks of bronchoalveolar lavage in severe asthma in children

Background

Although bronchoscopy can be part of the exploration of severe asthma in children, the benefit of bronchoalveolar lavage (BAL) is unknown. The present study aimed to decipher whether systematic BAL during a flexible bronchoscopy procedure could better specify the characteristics of severe asthma and improve asthma management.

Material and methods

The study took place in two departments of a university hospital in Paris. Children who underwent flexible bronchoscopy for the exploration of severe asthma between April 2017 and September 2019 were retrospectively included.

Results

In total, 203 children were included, among whom 107 had a BAL. BAL cell count was normal in most cases, with an increasing number of eosinophils with age, independently from the atopic status of the patients. Compared with bronchial aspiration only, BAL increased the rate of identified bacterial infection by 1.5. Nonatopic patients had more bacterial infections (p<0.001). BAL induced a therapeutic modification only for azithromycin and omalizumab prescriptions. The practice of a BAL decreased bronchoscopy tolerance (p=0.037), especially in the presence of tracheobronchial malacia (p<0.01) and when performed in a symptomatic patient (p=0.019).

Discussion and conclusion

Although BAL may provide interesting information in characterising severe asthma, in most cases its impact on the patient's management remains limited. Moreover, BAL can be poorly tolerated and should be avoided in the case of tracheobronchial malacia or current asthma symptoms.

Bronchoalveolar lavage can help characterise severe asthma in children. However, it can be poorly tolerated and, in most cases, its impact on the patient's management remains limited.https://bit.ly/39XOlMt

Diagnostic Accuracy of Nasopharyngeal Swab Cultures in Children Less Than Five Years with Chronic Wet Cough

Background: It is necessary to find a non-invasive and accurate procedure to predict persistent bacterial bronchitis (PBB) causative organisms and guide antibiotic therapy. The study objective was to compare the diagnostic accuracy of nasopharyngeal swab cultures with bronchoalveolar lavage (BAL) cultures in children with PBB. Methods: Nasopharyngeal swab and BAL fluid specimens were collected and cultured for bacterial pathogens prospectively from less than five-year-old children undergoing flexible bronchoscopy for chronic wet cough. Results: Of the 59 children included in the study, 26 (44.1%) patients had a positive BAL bacterial culture with neutrophilic inflammation. Prevalence of positive cultures for any of the four common respiratory pathogens implicated in PBB (Moraxella catarrhalis, Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae) was significantly higher (p = 0.001) in NP swabs compared to BAL fluids (86.4% and 44.1% of PBB cases, respectively). NP swab cultures for any of the four main bacterial pathogens had 85% (95% CI: 65–96%) and 48% (95% CI: 31–66%) sensitivity and specificity of detecting PBB, respectively. Positive and negative predictive values were 56% (95% CI: 47–65%) and 80% (95% CI: 60–91%), respectively. In conclusion, in children less than 5 years of age with chronic wet cough (PBB-clinical), a negative NP swab result reduces the likelihood of lower airway infection; however, a positive NP swab does not accurately predict the presence of lower airway pathogens. Flexible bronchoscopy should be considered in those with recurrent PBB-clinical or with clinical pointers of central airway anomalies.

Non-neoplastic respiratory fluid cytology including cell differential counts for interstitial lung disease

Bronchioloalveolar lavage (BAL) is a non-invasive and well-tolerated procedure that plays a key role in the diagnosis of a variety of non-neoplastic pulmonary diseases, including acute respiratory failure, infection, diffuse parenchymal lung disease (DLPD), paediatric and occupational lung disease, and in the evaluation of the lung allograft. A variety of analytic techniques are commonly performed on BAL fluid, including cytology, cell differential count, microbiology and virology, as well as a number of additional techniques in specific circumstances.

Assessing Pediatric Feeding Disorders by Domain in Complex Aerodigestive Patients

Objective: Pediatric feeding disorder (PFD) is defined as impaired oral intake, associated with dysfunction in at least one of four domains: medical, nutritional, feeding skill, and/or psychosocial. The pediatric aerodigestive patient presents with conditions impacting airway, breathing, feeding, swallowing, or growth. The objective of the study was to determine the prevalence of PFD and dysfunctional domain, in the aerodigestive patient presenting to a tertiary aerodigestive clinic.

Methods: Twenty-five charts from patients enrolled in Mayo Clinic Children’s Center Aerodigestive Program were retrospectively reviewed for documentation of dysfunction within the four feeding disorder domains. Results from the aerodigestive triple scope, functional endoscopic evaluation of swallow (FEES), and videofluoroscopic swallow study (VFSS) were recorded. Height and weight z-scores were compared between the initial assessment and 6-12 months later.

Results: Median age was 20 months (range 2-81 months). Of the patients, 100% (n = 25) had dysfunction in at least one PFD domain. The domain identified most frequently was medical dysfunction (96%; n = 24). Feeding dysfunction was observed in 76% (n = 19). Psychosocial dysfunction was observed in 76% (n = 19). Nutritional dysfunction was observed in 60% (n = 15). Dysfunction in three or greater domains was seen in 80% (n = 20). Weight z-score increased in 76% (n = 19) of patients 6 to 12 months after the initial aerodigestive evaluation.

Conclusion: Aerodigestive patients frequently have PFD and utilizing the consensus definition of PFD at intake may enhance clinical assessment and therapeutic evaluation, and provide a framework to measure outcomes in this heterogeneous patient population.

Role of Flexible Bronchoscopy in Ventilator-Dependent Neonates

Objective

To assess the usefulness and safety of flexible bronchoscopy in ventilated neonates with extubation failure.

Method

This was a prospective observational study. Flexible bronchoscopy was done in eligible patients with failure of extubation form invasive ventilation. The main outcome measure was to find the presence of any anatomic or dynamic abnormalities of the airways of these patients and the organism profile of bronchoalveolar lavage (BAL) fluid.

Results

Forty-eight babies (68.8% preterm) were enrolled in the study. The most common finding on bronchoscopy was airway edema seen in 13 (27%) patients. BAL culture was positive in 29 (74%) patients. Overall treatment was modified in 35 (73%) patients based on bronchoscopy findings/BAL culture. Majority of infants (83.3%) tolerated the procedure very well.

Conclusion

Flexible bronchoscopy provides useful information in the management of newborn babies with extubation failure.

Pediatric flexible bronchoscopy: A single-center report

INTRODUCTION

Pediatric flexible laryngotracheal bronchoscopy (FB) is an integral part of diagnostics and treatment at tertiary pediatric respiratory centers.

AIM

FBs performed between 2013 and 2018 at our Pediatric Allergy and Respiratory Medicine Unit of the Department of Women's and Children's Health at Padua University were examined in terms of the indications, findings, and adverse events.

MATERIALS AND METHODS

The electronic medical records of pediatric patients who underwent FB at least once between 1 January 2013 and 31 December 2018 were considered. Patients' clinical data, indications for FB, anatomical findings, information derived from bronchoalveolar lavage (BAL) and bronchial brushing, and possible adverse events were analyzed.

RESULTS

There were 447 pediatric FBs performed in 428 patients (aged from 1 month to 18 years) for diagnostic purposes (92.4%), to clear secretions (3.6%), or to monitor a known condition (4.0%). The main indications were recurrent lower respiratory tract infections (LRTI, 32.2%) and chronic wet cough (9.4%). Lower airway malacia was the most common abnormal finding in these two groups (36.1% and 28.6%, respectively). BAL bacterial culture was positive in 55 children (39.6%) with recurrent LRTI and in 25 (59.5%) with chronic wet cough, being Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis the microorganisms most commonly isolated. FB proved a safe procedure and was well tolerated.

CONCLUSIONS

Pediatric FB is an essential tool at our tertiary pediatric respiratory center. It helps establish the anatomical conditions underlying several chronic respiratory conditions and any correlated microbiological findings, with a significant impact on further patient management.

Application across species of a one health approach to liquid sample handling for respiratory based -omics analysis

Airway inflammation is highly prevalent in horses, with the majority of non-infectious cases being defined as equine asthma. Currently, cytological analysis of airway derived samples is the principal method of assessing lower airway inflammation. Samples can be obtained by tracheal wash (TW) or by lavage of the lower respiratory tract (bronchoalveolar lavage (BAL) fluid; BALF). Although BALF cytology carries significant diagnostic advantages over TW cytology for the diagnosis of equine asthma, sample acquisition is invasive, making it prohibitive for routine and sequential screening of airway health. However, recent technological advances in sample collection and processing have made it possible to determine whether a wider range of analyses might be applied to TW samples. Considering that TW samples are relatively simple to collect, minimally invasive and readily available in the horse, it was considered appropriate to investigate whether, equine tracheal secretions represent a rich source of cells and both transcriptomic and proteomic data. Similar approaches have already been applied to a comparable sample set in humans; namely, induced sputum. Sputum represents a readily available source of airway biofluids enriched in proteins, changes in the expression of which may reveal novel mechanisms in the pathogenesis of respiratory diseases, such as asthma and chronic obstructive pulmonary disease. The aim of this study was to establish a robust protocol to isolate macrophages, protein and RNA for molecular characterization of TW samples and demonstrate the applicability of sample handling to rodent and human pediatric bronchoalveolar lavage fluid isolates. TW samples provided a good quality and yield of both RNA and protein for downstream transcriptomic/proteomic analyses. The sample handling methodologies were successfully applicable to BALF for rodent and human research. TW samples represent a rich source of airway cells, and molecular analysis to facilitate and study airway inflammation, based on both transcriptomic and proteomic analysis. This study provides a necessary methodological platform for future transcriptomic and/or proteomic studies on equine lower respiratory tract secretions and BALF samples from humans and mice.

Large scale cytokine profiling uncovers elevated IL12-p70 and IL-17A in severe pediatric acute respiratory distress syndrome

The specific cytokines that regulate pediatric acute respiratory distress syndrome (PARDS) pathophysiology remains unclear. Here, we evaluated the respiratory cytokine profile in PARDS to identify the molecular signatures associated with severe disease. A multiplex suspension immunoassay was used to profile 45 cytokines, chemokines and growth factors. Cytokine concentrations were compared between severe and non-severe PARDS, and correlated with oxygenation index (OI). Partial least squares regression modelling and regression coefficient plots were used to identify a composite of key mediators that differentially segregated severe from non-severe disease. The mean (standard deviation) age and OI of this cohort was 5.2 (4.9) years and 17.8 (11.3), respectively. Early PARDS patients with severe disease exhibited a cytokine signature that was up-regulated for IL-12p70, IL-17A, MCP-1, IL-4, IL-1β, IL-6, MIP-1β, SCF, EGF and HGF. In particular, pro-inflammatory cytokines (IL-6, MCP-1, IP-10, IL-17A, IL-12p70) positively correlated with OI early in the disease. Whereas late PARDS was characterized by a differential lung cytokine signature consisting of both up-regulated (IL-8, IL-12p70, VEGF-D, IL-4, GM-CSF) and down-regulated (IL-1β, EGF, Eotaxin, IL-1RA, and PDGF-BB) profiles segregating non-severe and severe groups. This cytokine signature was associated with increased transcription, T cell activation and proliferation as well as activation of mitogen-activated protein kinase pathway that underpin PARDS severity.

Airway immune mediator levels during asthma-like symptoms in young children and their possible role in response to azithromycin

BACKGROUND

Asthma-like symptoms in young children are orchestrated by the local airway immune response, but current knowledge largely relies on in vitro airway models. Azithromycin has been shown to reduce the duration of episodes with asthma-like symptoms, but efficacy may depend on the individual child's immune response.

OBJECTIVES

To investigate in vivo upper airway immune mediator levels during episodes with asthma-like symptoms in young children and their ability to predict the clinical response to azithromycin treatment.

METHODS

A total of 535 children aged 0-3 years from the Copenhagen Prospective Studies of Asthma in Childhood-2010 mother-child cohort were examined for immune mediator levels in samples of nasal epithelial lining fluid during episodes with asthma-like symptoms as well as in the asymptomatic state. In a sub-study, children with recurrent asthma-like symptoms were randomized to either a 3-day course of oral azithromycin (10 mg/kg; n = 32) or placebo (n = 38). In the current study, we compared the pretreatment immune mediator levels with the clinical response to treatment with azithromycin in an exploratory post hoc analysis.

RESULTS

The immune mediator concentrations during vs outside episodes were significantly upregulated for IFN-ɣ (ratio 1.73), TNF-α (ratio 2.05), IL-1β (ratio 1.45), IL-10 (ratio 1.97), while CCL22 (ratio 0.65) was downregulated. Low levels of TNF-α and IL-10 and high levels of CCL22 predicted better treatment response to azithromycin (P-values < .05).

CONCLUSION

Upper airway immune mediator levels were altered during episodes of asthma-like symptoms, and levels of TNF-α, CCL22, and IL-10 may predict the response to azithromycin treatment.

Measures of ventilation heterogeneity mapped with hyperpolarized helium-3 MRI demonstrate a T2-high phenotype in asthma

BACKGROUND

Hyperpolarized gas with helium (HHe-3) MR (magnetic resonance) is a noninvasive imaging method which maps and quantifies regions of ventilation heterogeneity (VH) in the lung. VH is an important feature of asthma, but little is known as to how VH informs patient phenotypes.

PURPOSE

To determine if VH indicators quantified by HHe-3 MR imaging (MRI) predict phenotypic characteristics and map to regions of inflammation in children with problematic wheeze or asthma.

METHODS

Sixty children with poorly-controlled wheeze or asthma underwent HHe-3 MRI, including 22 with bronchoalveolar lavage (BAL). The HHe-3 signal intensity defined four ventilation compartments. The non-ventilated and hypoventilated compartments divided by the total lung volume defined a VH index (VHI %).

RESULTS

Children with VHI % in the upper quartile had significantly greater airflow limitation, bronchodilator responsiveness, blood eosinophils, expired nitric oxide (FeNO), and BAL eosinophilic or neutrophilic granulocyte patterns compared to children with VHI % in the lower quartile. Lavage return from hypoventilated bronchial segments had greater eosinophil % than from ventilated segments.

CONCLUSION

In children with asthma, greater VHI % as measured by HHe-3 MRI identifies a severe phenotype with higher type 2 inflammatory markers, and maps to regions of lung eosinophilia. Listed on ClinicalTrials. gov (NCT02577497).

Sensitive mass spectrometric determination of kinin-kallikrein system peptides in light of COVID-19

The outbreak of COVID-19 has raised interest in the kinin-kallikrein system. Viral blockade of the angiotensin-converting enzyme 2 impedes degradation of the active kinin des-Arg(9)-bradykinin, which thus increasingly activates bradykinin receptors known to promote inflammation, cough, and edema-symptoms that are commonly observed in COVID-19. However, lean and reliable investigation of the postulated alterations is currently hindered by non-specific peptide adsorption, lacking sensitivity, and cross-reactivity of applicable assays. Here, an LC-MS/MS method was established to determine the following kinins in respiratory lavage fluids: kallidin, bradykinin, des-Arg(10)-kallidin, des-Arg(9)-bradykinin, bradykinin 1-7, bradykinin 2-9 and bradykinin 1-5. This method was fully validated according to regulatory bioanalytical guidelines of the European Medicine Agency and the US Food and Drug Administration and has a broad calibration curve range (up to a factor of 10³), encompassing low quantification limits of 4.4-22.8 pg/mL (depending on the individual kinin). The application of the developed LC-MS/MS method to nasal lavage fluid allowed for the rapid (~ 2 h), comprehensive and low-volume (100 µL) determination of kinins. Hence, this novel assay may support current efforts to investigate the pathophysiology of COVID-19, but can also be extended to other diseases.

Diagnostic Yield of Bronchoalveolar Lavage in Immunocompromised Children

Results from early studies in the diagnostic yield of bronchoalveolar lavage (BAL) in immunocompromised adults and children were variable. This prospective study aimed to determine the diagnostic yield of BALs in immunocompromised children over the first 18 months of service at a newly established children's hospital. Relationship between BAL results and changes in antimicrobial management was also studied. Twenty-one bronchoscopic BALs were performed on 18 children; 14 BALs (66.7%) yielded at least 1 pathogen and 7 (33.3%) yielded no pathogen. Two pathogens were found in 2 samples, and 1 pathogen was identified in 12 samples. Bacteria (n = 7 patients), viruses (n = 8 patients) and fungus (Pneumocycstis jirovecii in one patient) were yielded. Of the 21 BALs, 8 (38.1%) were associated with changes in antimicrobial management (Fisher's exact test, p = 0.018). No significant side effects such as pneumothorax or pulmonary hemorrhages were observed in this series. In conclusion, BAL in immunocompromised children is rewarding and has potential to impact on antimicrobial management.

Comparative Analysis of Clinical Parameters and Sputum Biomarkers in Establishing the Relevance of Filamentous Fungi in Cystic Fibrosis

Background

The relationship between fungal culture (FC) positivity and airway inflammation in CF is largely unknown. Identifying the clinical significance of filamentous fungi in CF using both clinical parameters and biomarkers may change our antimicrobial therapeutic strategies.

Objectives

To investigate the clinical characteristics and airway biomarker profile in relation to the detection of filamentous fungi in respiratory samples obtained from CF patients.

Methods

A prospective cohort study over 24 months, including children and adults with CF. Participants provided sputum and/or bronchoalveolar lavage samples, which underwent processing for bacterial and fungal culture, leukocyte differential cell count and biomarker analysis for neutrophil elastase (NE), interleukin-8 (IL-8), galactomannan and tumor necrosis factor receptor type 2 (TNF-R2). We performed FC using neat sputum plugs, an approach shown to be more sensitive compared to routine laboratory testing.

Results

Sixty-one patients provided 76 respiratory samples (72 sputum and 4 BAL). Median age was 17 years (range 6 months-59 years). FC positivity was noted in 49% of the cohort. FC positivity was greater during pulmonary exacerbation compared to the stable state (67 versus 50%). Participants aged 5-30 years had a lower FEV1 within the FC positive group. A significant association between FC positivity and non-tuberculosis mycobacterial (NTM) culture was observed on non-parametric testing (p = 0.022) and regression analysis (p = 0.007). Exposure to indoor mold was a predictor for FC positivity (p = 0.047). There was a trend towards increased lung clearance index (LCI), bronchiectasis and intravenous antibiotic use in the FC positive group. There was no significant difference in biomarkers between FC positive and negative patients.

Conclusion

Aspergillus. fumigatus is the commonest filamentous fungi cultured from CF airways. We found no difference in the airway biomarker profile between FC positive and negative patients. The role of galactomannan and TNFR2 as fungal specific biomarkers in CF remains uncertain. FC positivity is associated with a lower FEV₁ in younger patients, a lower LCI, NTM positivity, bronchiectasis, and intravenous antibiotic exposure. Larger trials are needed to determine the role of galactomannan and TNF-R2 as potential fungal biomarkers in CF.

Oxidative and Proteolytic Inactivation of Alpha-1 Antitrypsin in Bronchopulmonary Dysplasia Pathogenesis: A Top-Down Proteomic Bronchoalveolar Lavage Fluid Analysis

The study investigates the role of the oxidative and proteolytic inactivation of alpha-1 antitrypsin (AAT) in the pathogenesis of bronchopulmonary dysplasia (BPD) in premature infants. Bronchoalveolar lavage fluid (BALF) samples were collected on the 3rd day of life from mechanically ventilated neonates with gestational age ≤ 30 weeks and analyzed without previous treatment (top-down proteomics) by reverse-phase high-performance liquid chromatography-electrospray ionization mass spectrometry. AAT fragments were identified by high-resolution LTQ Orbitrap XL experiments and the relative abundances determined by considering the extracted ion current (XIC) peak area. Forty preterm neonates were studied: 20 (50%) did not develop BPD (no-BPD group), 17 (42.5%) developed mild or moderate new-BPD (mild + moderate BPD group), and 3 (7.5%) developed severe new-BPD (severe BPD group). Eighteen fragments of AAT and a fragment of AAT oxidized at a methionine residue were identified: significantly higher values of AAT fragments 25-57, 375-418, 397-418, 144-171, and 397-418 with oxidized methionine were found in the severe BPD group. The significantly higher levels of several AAT fragments and of the fragment 397-418, oxidized in BALF of preterm infants developing BPD, underlie the central role of an imbalance between proteases and protease inhibitors in exacerbating lung injury and inducing most severe forms of BPD. The study has some limitations, and between them, the small sample size implies the need for further confirmation by larger studies.

[Interstitial lung disease in infancy and early childhood]

Diffuse interstitial lung disease of infancy (chILD) shows a spectrum of disease substantially different from that of adults. Established classification systems divide chILD into conditions that are more prevalent in infancy and conditions that occur at any age. The classification is based on a multidisciplinary approach including clinical, radiological, genetic, and histological findings. Lung biopsies become necessary if other diagnostic investigations have not identified a precise chILD or if severe or refractory respiratory distress of unknown cause is present. As the majority of pediatric lung biopsies will be received first by pathologists outside of specialist centers this review summarizes relevant clinical and histological findings of chILD.

Phenotypes and personalized medicine in the acute respiratory distress syndrome

Although the acute respiratory distress syndrome (ARDS) is well defined by the development of acute hypoxemia, bilateral infiltrates and non-cardiogenic pulmonary edema, ARDS is heterogeneous in terms of clinical risk factors, physiology of lung injury, microbiology, and biology, potentially explaining why pharmacologic therapies have been mostly unsuccessful in treating ARDS. Identifying phenotypes of ARDS and integrating this information into patient selection for clinical trials may increase the chance for efficacy with new treatments. In this review, we focus on classifying ARDS by the associated clinical disorders, physiological data, and radiographic imaging. We consider biologic phenotypes, including plasma protein biomarkers, gene expression, and common causative microbiologic pathogens. We will also discuss the issue of focusing clinical trials on the patient's phase of lung injury, including prevention, administration of therapy during early acute lung injury, and treatment of established ARDS. A more in depth understanding of the interplay of these variables in ARDS should provide more success in designing and conducting clinical trials and achieving the goal of personalized medicine.

Development of a Sensitive High-Resolution Mass Spectrometry Approach for Urea Nitrogen Quantitation in Small Volumes of Bronchoalveolar Lavage Fluid (BALF)

A sensitive, selective, and quantitative method incorporating high-resolution mass spectrometry was developed for the determination of blood urea nitrogen (BUN) in bronchoalveolar lavage fluid. The method requires no sample cleanup or derivatization prior to analysis. High-performance liquid chromatography (HPLC) on a Hypersil Gold PFP column (100 × 3 mm, 3 μm particle size) connected to a C18 guard column was employed for a 10 min chromatographic separation. The detection of urea was achieved using a Thermo Scientific Q-Exactive Plus instrument incorporating selected ion monitoring (SIM) modes for the protonated adduct of urea. The urea analytical measuring range for the method is 0.047-17.134 mg/dL, resulting in a BUN analytical measurement range of 0.022-8.007 mg/dL, which allows for quantitation over 3 orders of magnitude (R² = 0.999). In addition, the method is suitable for small sample volumes (15 μL) with a high level of accuracy, precision, and specificity.

High levels of inherent variability in microbiological assessment of bronchoalveolar lavage samples from children with persistent bacterial bronchitis and healthy controls

Bronchoalveolar lavage (BAL) is widely regarded as providing "gold standard" samples for infective lower respiratory tract disease. Current approaches have been adopted empirically without robust assessment and hence carry many assumptions that have not been tested. Many of these uncertainties were highlighted in the ATS pediatric bronchoscopy guidelines. This study was designed to explore some of these issues. BAL was undertaken via an endotracheal tube in 13 subjects aged less than 6 years with persistent bacterial bronchitis and five healthy controls. Aliquots of the same pooled BAL sample were sent to two accredited laboratories. one producing semiquantitative results and the other quantitative results. For five patients potentially pathogenic bacteria were grown by one laboratory but not the other, while in three more there were discrepancies in the organisms reported. Despite being symptomatic and off antibiotics, only 3 of 13 patients were reported to have a pathogen at a density of more than 1 × 10⁴ colony forming unit. There was at best a poor correlation between semiquantitative and quantitative data. Potential pathogens were cultured in two of five control samples. The results suggest that the results from conventional microbiological assessment of BAL samples can be highly variable and that the proposal that a discrete cut-off is of value in patients with chronic endobronchial infection is probably invalid.

Surfactant Injury in the Early Phase of Severe Meconium Aspiration Syndrome

No in vivo data are available regarding the effect of meconium on human surfactant in the early stages of severe meconium aspiration syndrome (MAS). In the present study, we sought to characterize the changes in surfactant composition, function, and structure during the early phase of meconium injury. We designed a translational prospective cohort study of nonbronchoscopic BAL of neonates with severe MAS (n = 14) or no lung disease (n = 18). Surfactant lipids were analyzed by liquid chromatography-high-resolution mass spectrometry. Secretory phospholipase A₂ subtypes IB, V, and X and SP-A (surfactant protein A) were assayed by ELISA. SP-B and SP-C were analyzed by Western blotting under both nonreducing and reducing conditions. Surfactant function was assessed by adsorption test and captive bubble surfactometry, and lung aeration was evaluated by semiquantitative lung ultrasound. Surfactant nanostructure was studied using cryo-EM and atomic force microscopy. Several changes in phospholipid subclasses were detected during MAS. Lysophosphatidylcholine species released by phospholipase A₂ hydrolysis were increased. SP-B and SP-C were significantly increased together with some shorter immature forms of SP-B. Surfactant function was impaired and correlated with poor lung aeration. Surfactant nanostructure was significantly damaged in terms of vesicle size, tridimensional complexity, and compactness. Various alterations of surfactant phospholipids and proteins were detected in the early phase of severe meconium aspiration and were due to hydrolysis and inflammation and a defensive response. This impairs both surfactant structure and function, finally resulting in reduced lung aeration. These findings support the development of new surfactant protection and antiinflammatory strategies for severe MAS.

Total alveolar lavage with oxygen fine bubble dispersion directly improves lipopolysaccharide-induced acute respiratory distress syndrome of rats

Severe respiratory disorder induced by pulmonary inflammation is one of the causes of acute respiratory distress syndrome, which still has high mortality. It is crucial to remove causative substances and inflammatory mediators early in order to inhibit the progression of pulmonary inflammation. Total alveolar lavage (TAL) may avert the inflammatory response by eliminating causative substances in certain inflammatory lung diseases. We developed an efficient TAL system and examined the efficacy of short-term TAL treatment performed for acute lung injury models of rats. In the first experiment with a severe lung injury model, 15 rats were divided into 3 groups: sham group, mechanical gas ventilation (MGV) treatment group, and TAL treatment group. The treatments were conducted for 5 min, 20 min after the provocation of inflammation. Two days after treatment, the TAL and MGV treatment groups exhibited significant differences in blood oxygen levels, mean arterial pressure, weight-loss ratio, and inflammatory cytokine levels in the lungs. In contrast, almost no differences were observed between the TAL treatment and sham groups. In the second experiment with a lethal lung injury model, the TAL treatment dramatically improved the survival rate of the rats compared to the MGV treatment groups (p = 0.0079). Histopathological analysis confirmed pronounced differences in neutrophil accumulation and thickening of the interstitial membrane between the TAL and MGV treatment groups in both experiments. These results indicate that as little as 5 min of TAL treatment can protect rats from acute lung injury by removing causative substances from the lungs.

Development and validation of a bronchoscopically defined bronchitis scoring tool in children

INTRODUCTION/AIM

A validated tool for scoring bronchitis during flexible bronchoscopy (FB) is potentially useful for clinical practice and research. We aimed to develop a bronchoscopically defined bronchitis scoring system in children (BScore) based on our pilot study.

METHODS

Children undergoing FB were prospectively enrolled. Their FB was digitally recorded and assessed (two clinicians blinded to each other and clinical history) for six features: secretion amount (six-point scale), secretion color (BronkoTest, 0-8), mucosal oedema (0-3), ridging (0-3), erythema (0-3), and pallor (0-3) based on pre-determined criteria. We correlated (Spearman's rho) each feature with bronchoalveolar lavage (BAL) neutrophil percentage (neutrophil%). BScore was then derived using models with combinations of the six features that best related to airway BAL neutrophil%. The various models of BScore were plotted against BAL neutrophil% using receiver operating characteristic (ROC) curves.

RESULTS

We analyzed 142 out of 150 children enrolled. Eight children were excluded for unavailability of BAL cytology or FB recordings. Chronic/recurrent cough was the commonest indication for FB (75%). The median age was 3 years (IQR, 1.5-5.3 years). Secretion amount (r = 0.42) and color (r = 0.46), mucosal oedema (r = 0.42), and erythema (r = 0.30) significantly correlated with BAL neutrophil%, P < .0001. The highest area under ROC (aROC) was obtained by the addition of the scores of all features excluding pallor (aROC = 0.84; 95% CI, 0.76-0.90) with airway neutrophilia (defined as BAL neutrophil% of >10%).

CONCLUSION

This prospective study has developed the first validated bronchitis scoring tool in children based on bronchoscopic visual inspection of airways. Further validation in other cohorts is however required.

Pulmonary Metagenomic Sequencing Suggests Missed Infections in Immunocompromised Children

BACKGROUND

Despite improved diagnostics, pulmonary pathogens in immunocompromised children frequently evade detection, leading to significant mortality. Therefore, we aimed to develop a highly sensitive metagenomic next-generation sequencing (mNGS) assay capable of evaluating the pulmonary microbiome and identifying diverse pathogens in the lungs of immunocompromised children.

METHODS

We collected 41 lower respiratory specimens from 34 immunocompromised children undergoing evaluation for pulmonary disease at 3 children's hospitals from 2014-2016. Samples underwent mechanical homogenization, parallel RNA/DNA extraction, and metagenomic sequencing. Sequencing reads were aligned to the National Center for Biotechnology Information nucleotide reference database to determine taxonomic identities. Statistical outliers were determined based on abundance within each sample and relative to other samples in the cohort.

RESULTS

We identified a rich cross-domain pulmonary microbiome that contained bacteria, fungi, RNA viruses, and DNA viruses in each patient. Potentially pathogenic bacteria were ubiquitous among samples but could be distinguished as possible causes of disease by parsing for outlier organisms. Samples with bacterial outliers had significantly depressed alpha-diversity (median, 0.61; interquartile range [IQR], 0.33-0.72 vs median, 0.96; IQR, 0.94-0.96; P < .001). Potential pathogens were detected in half of samples previously negative by clinical diagnostics, demonstrating increased sensitivity for missed pulmonary pathogens (P < .001).

CONCLUSIONS

An optimized mNGS assay for pulmonary microbes demonstrates significant inoculation of the lower airways of immunocompromised children with diverse bacteria, fungi, and viruses. Potential pathogens can be identified based on absolute and relative abundance. Ongoing investigation is needed to determine the pathogenic significance of outlier microbes in the lungs of immunocompromised children with pulmonary disease.

Transplacental transmission of SARS-CoV-2 infection

SARS-CoV-2 outbreak is the first pandemic of the century. SARS-CoV-2 infection is transmitted through droplets; other transmission routes are hypothesized but not confirmed. So far, it is unclear whether and how SARS-CoV-2 can be transmitted from the mother to the fetus. We demonstrate the transplacental transmission of SARS-CoV-2 in a neonate born to a mother infected in the last trimester and presenting with neurological compromise. The transmission is confirmed by comprehensive virological and pathological investigations. In detail, SARS-CoV-2 causes: (1) maternal viremia, (2) placental infection demonstrated by immunohistochemistry and very high viral load; placental inflammation, as shown by histological examination and immunohistochemistry, and (3) neonatal viremia following placental infection. The neonate is studied clinically, through imaging, and followed up. The neonate presented with neurological manifestations, similar to those described in adult patients.

Congenital infection of SARS-CoV-2 has been described, but the transmission routes remain unclear. Here, the authors report evidence of transplacental transmission of SARS-CoV-2 in a neonate born to a mother infected in the last trimester and presenting with neurological compromise.

Flexible Bronchoscopy in Evaluation of Persistent Wheezing in Children-Experiences from National Pediatric Center

Background and objectives: Persistent wheezing (PW) is defined as prolonged or recurrent episodes of wheezing despite regular treatment. Flexible bronchoscopy (FB) is recommended to determine the etiology of PW in children. This study aimed to determine the etiology of PW based on FB findings in a national pediatric center. Materials and Methods: Children presenting with PW that underwent flexible bronchoscopy from April 2016 to August 2019 at the Mother and Child Health Institute of Serbia were included in this observational study. After endoscopic evaluation, bronchoalveolar lavage fluid (BALF) samples were taken and further analyzed. Quantitative microbiology, cytological analysis and oil-red staining of specimens were performed to determine cellular constituents and presence of lipid laden macrophages (LLM). Upper gastrointestinal series were performed to exclude gastroesophageal reflux disease, swallowing dysfunction and vascular ring. Results: Pathological findings were revealed in 151 of 172 study participants, with bacterial lower airway infection (BLAI) (48.3%) and primary bronchomalacia (20.4%) as the most common. Younger participants were hospitalized for significantly longer periods (ρ = −0.366, p < 0.001). Study participants with BLAI and associated mucus plugging were notably younger (p < 0.001). Presence of LLM in BALF was not associated with findings of upper gastrointestinal series. All patients with confirmed BLAI were treated with oral antibiotics. Although FB is considered to be invasive, there were no complications associated with the procedure. Conclusions: Flexible bronchoscopy has an exceptional diagnostic value in evaluation of PW. In younger patients with BLAI, presence of mucus plugs may complicate the clinical course, so significant benefits can be achieved with therapeutic lavage during bronchoscopy.

Surfactant-secreted phospholipase A2interplay and respiratory outcome in preterm neonates

Secreted phospholipase A2hydrolyzes surfactant phospholipids and is crucial for the inflammatory cascade; preterm neonates are treated with exogenous surfactant, but the interaction between surfactant and phospholipase is unknown. We hypothesize that this interplay is complex and the enzyme plays a relevant role in neonates needing surfactant replacement. We aimed to: 1) identify phospholipases A2isoforms expressed in preterm lung; 2) study the enzyme role on surfactant retreatment and function and the effect of exogenous surfactant on the enzyme system; and 3) verify whether phospholipase A2is linked to respiratory outcomes. In bronchoalveolar lavages of preterm neonates, we measured enzyme activity (alone or with inhibitors), enzyme subtypes, surfactant protein-A, and inflammatory mediators. Surfactant function and phospholipid profile were also tested. Urea ratio was used to obtain epithelial lining fluid concentrations. Follow-up data were prospectively collected. Subtype-IIA is the main phospholipase isoform in preterm lung, although subtype-IB may be significantly expressed. Neonates needing surfactant retreatment have higher enzyme activity ( P = 0.021) and inflammatory mediators ( P always ≤ 0.001) and lower amounts of phospholipids ( P always < 0.05). Enzyme activity was inversely correlated to surfactant adsorption (ρ = −0.6; P = 0.008; adjusted P = 0.009), total phospholipids (ρ = −0.475; P = 0.05), and phosphatidylcholine (ρ = −0.622; P = 0.017). Exogenous surfactant significantly reduced global phospholipase activity ( P < 0.001) and subtype-IIA ( P = 0.005) and increased dioleoylphosphatidylglycerol ( P < 0.001) and surfactant adsorption ( P < 0.001). Enzyme activity correlated with duration of ventilation (ρ = 0.679, P = 0.005; adjusted P = 0.04) and respiratory morbidity score at 12 mo postnatal age (τ-b = 0.349, P = 0.037; adjusted P = 0.043) but was not associated with mortality, bronchopulmonary dysplasia, or other long-term respiratory outcomes.

An omic approach to congenital diaphragmatic hernia: a pilot study of genomic, microRNA, and metabolomic profiling

INTRODUCTION

The omic approach can help identify a signature that can be potentially used as biomarkers in babies with congenital diaphragmatic hernia (CDH).

OBJECTIVES

To find a specific microRNA (miR) and metabolic fingerprint of the tracheal aspirates (TA) of CDH patients. We conducted a genetic analysis from blood samples.

METHODS

TA samples collected in the first 48 h of life in patients with CDH, compared with age-matched controls. Metabolomics done by a mass spectroscopy-based assay. Genomics done using chromosomal microarray analysis.

RESULTS

CDH (n = 17) and 16 control neonates enrolled. miR-16, miR-17, miR-18, miR-19b, and miR-20a had an increased expression, while miR-19a had a twofold decreased expression in CDH patients, compared with age-matched control patients. Specific metabolites separated neonates with CDH from controls. A genetic mutation found in a small subset of patients.

CONCLUSIONS

Specific patterns of metabolites and miR expression can be discerned in TA samples in infants with CDH.

Dissimilarity of the gut-lung axis and dysbiosis of the lower airways in ventilated preterm infants

BACKGROUND

Chronic lung disease of prematurity (CLD), also called bronchopulmonary dysplasia, is a major consequence of preterm birth, but the role of the microbiome in its development remains unclear. Therefore, we assessed the progression of the bacterial community in ventilated preterm infants over time in the upper and lower airways, and assessed the gut-lung axis by comparing bacterial communities in the upper and lower airways with stool findings. Finally, we assessed whether the bacterial communities were associated with lung inflammation to suggest dysbiosis.

METHODS

We serially sampled multiple anatomical sites including the upper airway (nasopharyngeal aspirates), lower airways (tracheal aspirate fluid and bronchoalveolar lavage fluid) and the gut (stool) of ventilated preterm-born infants. Bacterial DNA load was measured in all samples and sequenced using the V3-V4 region of the 16S rRNA gene.

RESULTS

From 1102 (539 nasopharyngeal aspirates, 276 tracheal aspirate fluid, 89 bronchoalveolar lavage, 198 stool) samples from 55 preterm infants, 352 (32%) amplified suitably for 16S RNA gene sequencing. Bacterial load was low at birth and quickly increased with time, but was associated with predominant operational taxonomic units (OTUs) in all sample types. There was dissimilarity in bacterial communities between the upper and lower airways and the gut, with a separate dysbiotic inflammatory process occurring in the lower airways of infants. Individual OTUs were associated with increased inflammatory markers.

CONCLUSIONS

Taken together, these findings suggest that targeted treatment of the predominant organisms, including those not routinely treated, such as Ureaplasma spp., may decrease the development of CLD in preterm-born infants.

Etiologic spectrum of interstitial lung diseases in Chinese children older than 2 years of age

Background

Childhood interstitial lung diseases (ILD) (chILD) refer to a rare heterogeneous group of disorders. Global collaborations have been working on the etiologies and classification scheme of chILD. With the development of medical technologies, some new diseases were identified to be associated with chILD and its etiologic spectrum is expanding. The aim of this study is to describe the etiologic spectrum of chILD in children older than 2 years of age and summarize the approaches to diagnosis of chILD.

Methods

We made a retrospective analysis of children older than 2 years of age with chILD who referred to Beijing Children’s Hospital from 21 provinces all over China from 2013 to 2018. After excluding pulmonary infection, congenital heart disease, bronchopulmonary dysplasia, bronchiolitis obliterans and bronchiectasis, 133 patients were included and categorized by etiology. Clinical manifestations, high-resolution computed tomography, laboratory data, genetic data and pathologic findings were all collected and reviewed.

Results

Systemic disease associated ILD were the most common causes, accounting for 49.6% of the patients, followed by alveolar structure disorder-associated ILD (27%), exposure related ILD (13.5%), and disorders masquerading as ILD (3.8%). In systemic disease associated ILD, in addition to common etiologies such as vasculitis (10.5%) and connective tissue diseases (9.0%), primary immunodeficiency diseases (PID) associated ILD (9.8%), interstitial pneumonia with autoimmune features (6.8%), and metabolic diseases (6.8%) were not rarely found. Some newly reported etiologies such as STING–associated vasculopathy with onset in infancy, COPA syndrome and STAT3 mutation were included in PID associated ILD. Genetic tests contributed to 15% of the diagnoses which mainly distributed in PID associated ILD, metabolic diseases and surfactant dysfunction disorders, and contributed to the final diagnoses more than lung biopsies (13.5%) and biopsies of rashes or other tissues (12%).

Conclusions

This study first demonstrated an etiologic spectrum of chILD in Chinese children older than 2 years of age and summarized the approaches to diagnosis. The etiologic spectrum of chILD is expanding with more genetic etiologies being recognized.