Differential cytology of bronchoalveolar lavage fluid in asthmatic children

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.

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

Comparison of bronchoalveolar lavage fluid bacteriology and cytology in calves classified based on combined clinical scoring and lung ultrasonography

Respiratory tract infections are the leading cause of antimicrobial use in calves. Combining clinical examination and lung ultrasonography allows on-farm classification of calves as healthy or suffering from an upper respiratory tract infection (URTI), subclinical or clinical pneumonia. This might help to improve targeted antimicrobial therapy, restricting treatment to pneumonic cases. However, to what extent these diagnostic categories coincide with expected bacteriological and cytological bronchoalveolar lavage fluid (BALf) characteristics is currently unknown. The objective of this study was therefore to compare BALf bacteriology and cytology between healthy calves and calves with URTI, subclinical and clinical pneumonia. The hypothesis was that calves with subclinical and clinical pneumonia would have higher quantitative bacterial counts, bacterial isolation rates and neutrophil counts than URTIs or healthy animals. A cross-sectional study was performed on 305 indoor group-housed dairy and beef calves, from 62 farms. Calves were classified by combining clinical examination and lung ultrasonography. Clinical respiratory disease was defined using the Wisconsin score card and the Healthy Criterion (HC). The HC classified calves as clinically ill if at least one clinical sign was present. Ultrasonographic lung consolidation with a depth of ≥1 cm was considered indicative for pneumonia. Cytology and bacteriology were performed on BALf sampled by non-endoscopic bronchoalveolar lavage. Calves with clinical pneumonia were further subdivided based on culture result and presence of neutrophils phagocytosing bacteria. Combined lung ultrasonography and clinical examination (HC) classified 25.9 % (79/305) of the calves as healthy, 33.1 % (101/305) as URTI, 10.2 % (31/305) as subclinical and 30.8 % (94/305) as clinical pneumonia. Bacterial isolation rates and quantitative BALf culture results did not differ between groups. Calves with clinical pneumonia and neutrophil phagocytosis showed a significantly higher BALf neutrophil percentage compared to healthy calves (59.0 % vs. 37.7 % in healthy calves, P =.03). Inversely, lymphocyte percentage was lower in these calves (1.8 % vs. 5.3 % in healthy calves, P = .003). Classification of calves using lung ultrasonography and clinical scoring did not correspond with BALf bacteriology and cytology findings, as extrapolated from human and companion animal medicine. Under the current housing conditions of this study high rates of non-infectious airway inflammation or airway colonization by opportunistic pathogens, rather than infection might explain this. Isolation of respiratory pathogens from calves with various signs of respiratory disease or ultrasonographic lesions should be interpreted carefully. Of all cytological features, phagocytosis by neutrophils in BALf might be a useful criterion supporting the diagnosis of bacterial respiratory tract infection.

Vitamin D for secondary prevention of acute wheeze attacks in preschool and school-age children

INTRODUCTION

Vitamin D is best known for its role in bone health; however, the discovery of the vitamin D receptor and the expression of the gene encoding the vitamin D 1α-hydroxylase (CYP27B1) enzyme in a wide variety of tissues including immune cells and respiratory epithelium has led to the discovery of potential roles for vitamin D in the prevention of acute wheeze.

METHODS

We review here the literature concerning the relationships between circulating 25-hydroxyvitamin D (25(OH)D) concentration and secondary prevention of acute wheeze attacks in preschool and school-age children.

RESULTS

Epidemiological data suggest that vitamin D insufficiency (25(OH)D <75 nmol/L) is highly prevalent in preschool and school-age children with wheeze. Preschool age children with a history of wheeze attacks and circulating 25(OH)D <75 nmol/L are at increased risk and frequency of future acute wheeze. However, no consistent association between low vitamin D status and risk of acute wheeze is reported in school-age children. Seven randomised controlled trials (RCTs) with relatively small sample sizes (30-430) and variable quality showed inconsistent results regarding the effect of oral vitamin D supplementation during childhood on the risk of asthma attacks, asthma symptom control, inhaled corticosteroid requirements, spirometry and unscheduled healthcare attendances for wheeze. A RCT showed that vitamin D supplementation had no effect on the frequency of unplanned healthcare attendances due to acute wheeze in 22 preschool children.

DISCUSSION

An evidence-based recommendation for the use of vitamin D as a preventive therapy for wheeze attacks cannot be made until results of further trials are available. The assessment of circulating 25(OH)D concentration and the optimisation of vitamin D status to prevent acute respiratory tract infections, and to maintain skeletal and general health in preschool and school-age children with acute wheeze is worthwhile in its own right, but whether this will reduce the risk of acute wheeze attacks is unclear.

Preschool Wheezing Phenotypes

Wheezing in preschool children is very common, with a wide differential diagnosis. It is essential to be sure of the exact sound that parents are describing; the term ‘wheeze‘ is often applied to non-specific sounds. Structural airway disease such as vascular ring should be considered. Thereafter we propose that umbrella terms for preschool wheeze should be abandoned in favour of ‘Hargreave phenotyping’, in which the presence and extent of the components of infection, inflammation, variable airflow obstruction, and fixed airflow obstruction are determined as far as is possible, rather than using a general umbrella term such as ‘asthma’. The justification for this approach is that it leads to a logical approach to treatment in the disparate airway diseases presenting in the preschool years, and should hopefully prevent over-treatment with inhaled corticosteroids. If, despite this approach, doubt remains as to the nature of the airway disease, then a therapeutic trial of treatment is permissible, but it should be for a short defined period only. In any event, such children should be reviewed regularly to see if treatments need to be changed.

Airway epithelial cytokine responses in childhood wheeze are independent of atopic status

BACKGROUND

Airway epithelial cells (AEC) are key contributors to immune function in the lungs but little is known about their role and function in children.

OBJECTIVES

Having previously established that nasal AEC mediator release correlates with that of bronchial AEC, we assessed AEC responses in children with and without a history of wheeze.

METHODS

Nasal AEC cultures were established from children (0.6-14.9 years) undergoing elective surgical procedures under general anaesthetic categorised as atopic asthmatic (n = 12), virus-induced wheeze (n = 8) or children without wheeze (n = 32). Mediator release by AEC monolayers at passage 2 was determined by cytometric bead array assay or ELISA.

RESULTS

Unstimulated AEC from children with a history of wheeze produced significantly less IL-8, IL-6, MCP-1 and G-CSF than AEC from healthy controls. There were no group differences in AEC release of VEGF, RANTES, MMP-9 or TIMP-1. After stimulation with the pro-inflammatory cytokines IL-1β and TNFα, AEC from children with current wheeze produced significantly less IL-8, IL-6 and MCP-1 than children without wheeze. Release of G-CSF, VEGF, MMP-9 and TIMP-1 did not differ between the wheeze and control group. There were no differences in mediator release between subjects with atopic asthma and those with virus-induced wheeze or between atopic and non-atopic controls. On multivariate analysis, wheeze was the only significant predictor of AEC mediator release.

CONCLUSION & CLINICAL RELEVANCE

Intrinsic differences in AEC from children with a history of wheeze may reflect a defect in cytokine production in vivo or an altered state of differentiation in vitro, independent of atopic status.

Wheeze in preschool age is associated with pulmonary bacterial infection and resolves after antibiotic therapy

Background

Neonates with airways colonized by Haemophilus influenzae, Streptococcus pneumoniae or Moraxella catarrhalis are at increased risk for recurrent wheeze which may resemble asthma early in life. It is not clear whether chronic colonization by these pathogens is causative for severe persistent wheeze in some preschool children and whether these children might benefit from antibiotic treatment. We assessed the relevance of bacterial colonization and chronic airway infection in preschool children with severe persistent wheezing and evaluated the outcome of long-time antibiotic treatment on the clinical course in such children.

Methodology/Principal Findings

Preschool children (n = 42) with severe persistent wheeze but no symptoms of acute pulmonary infection were investigated by bronchoscopy and bronchoalveolar lavage (BAL). Differential cell counts and microbiological and virological analyses were performed on BAL samples. Patients diagnosed with bacterial infection were treated with antibiotics for 2–16 weeks (n = 29). A modified ISAAC questionnaire was used for follow-up assessment of children at least 6 months after bronchoscopy. Of the 42 children with severe wheezing, 34 (81%) showed a neutrophilic inflammation and 20 (59%) of this subgroup had elevated bacterial counts (≥10⁴ colony forming units per milliliter) suggesting infection. Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis were the most frequently isolated species. After treatment with appropriate antibiotics 92% of patients showed a marked improvement of symptoms upon follow-up examination.

Conclusions/Significance

Chronic bacterial infections are relevant in a subgroup of preschool children with persistent wheezing and such children benefit significantly from antibiotic therapy.

Cell profile of BAL fluid in children and adolescents with and without lung disease

The objective of this study was to review the literature on bronchoalveolar lavage fluid cell profiles in healthy children and adolescents, as well as on the use of BAL as a diagnostic and follow-up tool for lung disease patients in this age bracket. To that end, we used the Medline database, compiling studies published between 1989 and 2009 employing the following MeSH descriptors (with Boolean operators) as search terms: bronchoalveolar lavage AND cytology OR cell AND child. In healthy children, the cell profile includes alveolar macrophages (> 80%), lymphocytes (approximately 10%), neutrophils (approximately 2%) and eosinophils (< 1%). The profile varies depending on the disease under study. The number of neutrophils is greater in wheezing children, especially in non-atopic children, as well as in those with pulmonary infectious and inflammatory profiles, including cystic fibrosis and interstitial lung disease. Eosinophil counts are elevated in children/adolescents with asthma and can reach high levels in those with allergic bronchopulmonary aspergillosis or eosinophilic syndromes. In a heterogeneous group of diseases, the number of lymphocytes can increase. Evaluation of the BAL fluid cell profile, when used in conjunction with clinical and imaging findings, has proven to be an essential tool in the investigation of various lung diseases. Less invasive than transbronchial and open lung biopsies, BAL has great clinical value. Further studies adopting standard international protocols should be carried out. Such studies should involve various age groups and settings in order to obtain reference values for BAL fluid cell profiles, which are necessary for a more accurate interpretation of findings in children and adolescents with lung diseases.

Markers of eosinophilic and neutrophilic inflammation in bronchoalveolar lavage of asthmatic and atopic children

BACKGROUND

Recent studies performing fiberoptic bronchoscopy in children have improved our understanding of asthma pathophysiology. Eosinophilic, but also neutrophilic, inflammation has been described in asthma, but the relationship with atopy was incompletely investigated. The aim of this study is to examine inflammatory cells and mediators in children with asthma compared to the appropriate controls, i.e. atopic children without asthma and children with no atopy or asthma. Moreover, asthmatic children were analysed separately based on the presence of atopy and stratified by age.

METHODS

We recruited 191 children undergoing fiberoptic bronchoscopy for appropriate indications: 91 asthmatics (aged 1.4-17 years), 44 atopics without asthma (1.6-17.8 years) and 56 nonasthmatic nonatopic controls (1.4-14 years). In bronchoalveolar lavage, total and differential cell counts and inflammatory mediators, including ECP, eotaxin, IL-8 and TNFalpha, were analysed.

RESULTS

Eosinophils and ECP levels were increased in asthmatic children when compared to controls (P = 0.002 and P = 0.01, respectively), but also atopic children without asthma had increased ECP levels compared to controls (P = 0.0001). Among asthmatic children, eosinophils and ECP levels were not different between atopic and nonatopic individuals. Neither neutrophils nor the related mediators (IL-8 and TNFalpha) differed significantly in the three groups. This pattern of inflammation was observed in both preschool and school-aged asthmatic children.

CONCLUSIONS

This study suggests that markers of eosinophilic, but not neutrophilic inflammation, are increased in asthmatic children and also in atopic children without asthma. Of interest, in asthmatic children, the activation of the eosinophilic response is not solely because of the presence of atopy.

Pediatric bronchoalveolar lavage: practical considerations and future prospects

Despite the utilization of bronchoalveolar lavage (BAL) in children since the early 1970s, several challenges remain once the procedure is complete. These include little documentation on normal controls, the limitations due to the size of the patient, and uniform processes for assessment. It was not until 1995 that a taskforce on pediatric BAL was formed by the European Respiratory Society, and to our knowledge, they remain the only committee evaluating the process [1]. We examined our procedures and reviewed the literature in an attempt to document the most fruitful practices that would allow improved data comparison and introduce possible investigations.

Bronchoalveolar lavage MMP-9 and TIMP-1 in preschool wheezers and their relationship to persistent wheeze

Atopic preschool children are more likely to develop persistent wheezing, which could be a consequence of early airway remodeling. Protease-antiprotease balance between MMP-9 and its cognate inhibitor TIMP-1 may be involved in this process. Our hypothesis was that atopic wheezing preschool children would have an imbalance of MMP-9 to TIMP-1 in bronchoalveolar lavage (BAL). BAL from 52 preschool wheezers was compared with 14 controls without wheeze. A subgroup completed an International Study of Asthma and Allergy in Childhood symptom questionnaire 2 y later. Molar ratios of MMP-9/TIMP-1 were higher in wheezy children (p < 0.001; median 4.0%, range 0-8.7) than controls (0.6%, 0-1.8), and showed an excess of TIMP-1 in the airway. BAL TIMP-1 was raised in children with persistent wheezing (p = 0.028; 34.4 ng/mL, 9.1-93.1 compared with 10.6 ng/mL 6.1-18.6), as was serum levels of intercellular adhesion molecule-1 (p = 0.027). The absolute concentration of TIMP-1 in the airway, rather than its molar ratio with MMP-9, was associated with persistent wheezing. The processes involved with airway remodeling are complex but excess TIMP-1 may impede matrix protein turnover and thereby contribute to persistent changes in airway structure and wheezing.

Pharmacotherapy of impaired mucociliary clearance in non-CF pediatric lung disease. A review of the literature

Mucoactive agents are used to treat a variety of lung diseases involving impaired mucociliary clearance or mucus hypersecretion. The mucoactive agents studied most frequently are N-acetylcysteine (NAC), recombinant human DNase (rhDNase), and hypertonic saline. Studies on the efficacy of these have been mainly conducted in adults, and in patients with cystic fibrosis (CF). The exact role of mucoactive agents in children with non-CF lung disease is not well established. We present an overview of the current literature reporting clinical outcome measures of treatment with NAC, rhDNase, and hypertonic saline in children.

The Role of Timely Intervention in Middle Lobe Syndrome in Children

STUDY OBJECTIVES

Middle lobe syndrome (MLS) in children is characterized by a spectrum of clinical and radiographic presentations, from persistent or recurrent atelectasis to pneumonitis and bronchiectasis of the right middle lobe (RML) and/or lingula. This study was undertaken to evaluate the effect of early intervention, including fiberoptic bronchoscopy (FOB), in the development of bronchiectasis in MLS.

DESIGN

Children with atelectasis of the RML and/or lingula persisting for > 1 month or recurring two or more times despite conventional treatment underwent high-resolution CT (HRCT) scanning and FOB. Appropriate treatment and follow-up were provided, and the effect of the duration of symptoms on clinical outcome and the development of bronchiectasis was investigated. The patient cohort was retrospectively reviewed.

PATIENTS

We evaluated 55 children with MLS. The median age at diagnosis, duration of symptoms, and duration of clinical deterioration before diagnosis were 5.5 years (range, 3 months to 12 years), 14.5 months (range, 3 to 48 months), and 8 months (range, 3 to 36 months), respectively.

MEASUREMENTS AND RESULTS

FOB revealed marked obstruction in two children (ie, a foreign body and an endobronchial tumor) and positive findings for a culture of BAL fluid in 49.1% of patients. The remaining 53 patients were followed up for a median duration of 24 months (range, 5 to 96 months). The clinical outcome was "cure" in 60.4% of patients, "improvement" in 32.1% of patients, and "no change" in the remaining patients. Bronchiectasis was documented prior to FOB by HRCT scan in 15 patients (27.3%). The duration of the deterioration of symptoms prior to presentation positively correlated with the development of bronchiectasis (p = 0.03) and an unfavorable clinical outcome (ie, improvement or no change) [p = 0.02]; a positive correlation was also found between the duration of symptoms and the development of bronchiectasis (p = 0.04).

CONCLUSIONS

Timely medical intervention in patients with MLS that includes FOB with BAL prevents bronchiectasis that may be responsible for an ultimately unfavorable outcome.

Production of granulomatous inflammation in lungs of rat pups and adults by Sephadex beads

Granulomatous inflammation is a process that involves mononuclear leukocytes as well as other inflammatory cells. The heterogeneity of its appearance may be due to the variety of cytokines and chemokines that are involved. In this study, we compared granuloma formation and bronchoalveolar leukocyte differential in the lungs of rats (2- and 8-wk-old) that were treated intravenously with Sephadex beads. In addition, the kinetics of cytokine and chemokine production was determined in these groups. In adults, the beads caused lung granulomas associated with infiltration of eosinophils and neutrophils and increased eosinophil and neutrophil counts in the bronchoalveolar lavage fluid within 16 h. In pups, the granulomas were formed slowly and did not reach the size achieved in adults. Eosinophils and neutrophils were sparsely found in the periphery of the granulomas, even at 32 h. Pups were also unable to respond rapidly to Sephadex bead treatment with eosinophil and neutrophil infiltration in the bronchoalveolar lavage fluid. Tumor necrosis factor-alpha was significantly increased in both groups, but the cytokine was lower in pups than in adults. Interferon-gamma and eotaxin were increased only in adults, and IL-4 and regulated on activation, normal T cell expressed, and secreted was increased only in pups. In conclusion, the i.v. administration of Sephadex beads produced granulomatous inflammation in the lungs of adult rats, but pups were unable to respond as rapidly to the treatment. In addition, the difference in response between the two age groups was associated with the kinetics of cytokine and chemokine production.