Differential cytology of bronchoalveolar lavage fluid in normal children

Development of innate and adaptive immunity to RSV in young children

Infection of the respiratory tract with respiratory syncytial virus (RSV) is common and occurs repeatedly throughout life with most severe disease occurring at the extremes of age: in young infants and the elderly. Effective anti-viral therapeutics are not available and therefore prevention has been the primary strategy for reducing the disease burden. Our current understanding of respiratory mucosal cell biology and the immune response within the respiratory tract is inadequate to prevent infection caused by a pathogen like RSV that does not disseminate outside of this environment. Gaps in our understanding of the activation of innate and adaptive immunity in response to RSV and the role of age upon infection also limit improvements in the design of therapeutics and vaccines for young infants. However, advancements in structural biology have improved our ability to characterize antibodies against viral proteins and in 2023 the first vaccines for those over 60 years and pregnant women became available, potentially reducing the burden of disease. This review will examine our current understanding of the critical facets of anti-RSV immune responses in infants and young children as well as highlight areas where more research is needed.

[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.

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.

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.

Emerging Human Coronavirus Infections (SARS, MERS, and COVID-19): Where They Are Leading Us

Coronavirus infections are responsible for mild, moderate, and severe infections in birds and mammals. These were first isolated in humans as causal microorganisms responsible for common cold. The 2002-2003 SARS epidemic caused by SARS-CoV and 2012 MERS epidemic (64 countries affected) caused by MERS-CoV showed their acute and fatal side. These two CoV infections killed thousands of patients infected worldwide. However, WHO has still reported the MERS case in December 2019 in middle-eastern country (Saudi Arabia), indicating the MERS epidemic has not ended completely yet. Although we have not yet understood completely these two CoV epidemics, a third most dangerous and severe CoV infection has been originated in the Wuhan city, Hubei district of China in December 2019. This CoV infection called COVID-19 or SARS-CoV2 infection has now spread to 210 countries and territories around the world. COVID-19 has now been declared a pandemic by the World Health Organization (WHO). It has infected more than 16.69 million people with more than 663,540 deaths across the world. Thus the current manuscript aims to describe all three (SARS, MERS, and COVID-19) in terms of their causal organisms (SARS-CoV, MERS-CoV, and SARS-CoV2), similarities and differences in their clinical symptoms, outcomes, immunology, and immunopathogenesis, and possible future therapeutic approaches.

Elastase Exocytosis by Airway Neutrophils Is Associated with Early Lung Damage in Children with Cystic Fibrosis

RATIONALE

Neutrophils are recruited to the airways of individuals with cystic fibrosis (CF). In adolescents and adults with CF, airway neutrophils actively exocytose the primary granule protease elastase (NE), whose extracellular activity correlates with lung damage. During childhood, free extracellular NE activity is measurable only in a subset of patients, and the exocytic function of airway neutrophils is unknown.

OBJECTIVES

To measure NE exocytosis by airway neutrophils in relation to free extracellular NE activity and lung damage in children with CF.

METHODS

We measured lung damage using chest computed tomography coupled with the Perth-Rotterdam Annotated Grid Morphometric Analysis for Cystic Fibrosis scoring system. Concomitantly, we phenotyped blood and BAL fluid leukocytes by flow and image cytometry, and measured free extracellular NE activity using spectrophotometric and Förster resonance energy transfer assays. Children with airway inflammation linked to aerodigestive disorder were enrolled as control subjects.

MEASUREMENTS AND MAIN RESULTS

Children with CF but not disease control children harbored BAL fluid neutrophils with high exocytosis of primary granules, before the detection of bronchiectasis. This measure of NE exocytosis correlated with lung damage (R = 0.55; P = 0.0008), whereas the molecular measure of free extracellular NE activity did not. This discrepancy may be caused by the inhibition of extracellular NE by BAL fluid antiproteases and its binding to leukocytes.

CONCLUSIONS

NE exocytosis by airway neutrophils occurs in all children with CF, and its cellular measure correlates with early lung damage. These findings implicate live airway neutrophils in early CF pathogenesis, which should instruct biomarker development and antiinflammatory therapy in children with CF.

Towards developing a valid scoring tool for bronchitis during flexible bronchoscopy

BACKGROUND

A valid bronchoscopic scoring tool for bronchitis would be useful for clinical and research purposes as currently there are none in children. From 100 digitally recorded flexible bronchoscopies (FB), we related the various macroscopic features to airway neutrophil % to develop a FB-derived bronchitis score (BScore_exp ). We aimed to develop a FB-derived bronchitis tool.

METHODS

FB recordings for six visualised features: secretions (amount and color) and mucosal appearance (erythema, pallor, ridging, oedema) based on pre-determined criteria on a pictorial chart were assessed by two physicians independently, blinded to the clinical history. These features were used to obtain various models of BScore_exp that were plotted against bronchoalveolar lavage (BAL) neutrophil % using a receiver operating characteristic (ROC) curve. Inter- and intra-rater agreement (weighted-kappa, K) were assessed from 30 FBs.

RESULTS

Using BAL neutrophilia of 20% to define inflammation, the highest area under ROC (aROC) of 0.71, 95%CI 0.61-0.82 was obtained by the giving three times weightage to secretion amount and color and adding it to erythema and oedema. Inter-rater K values for secretion amount (K = 0.87, 95%CI 0.73-1.0) and color (K = 0.86, 95%CI 0.69-1.0) were excellent. Respective intra-rater K were 0.95 (0.87-1.0) and 0.68 (0.47-0.89). Other inter-rater K ranged from 0.4 (erythema) to 0.64 (pallor).

CONCLUSION

A repeatable FB-defined bronchitis scoring tool can be derived. However, a prospective study needs to be performed with larger numbers to further evaluate and validate these results.

Neutrophil-Lymphocyte Ratio in Children with Recurrent Wheezing

Pediatric recurrent wheezing is a common disorder with potential asthma risk; however, its diagnosis much relies on physician's subjective evaluation. Hence, efficient noninvasive biomarkers are in great need. In this retrospective study, blood routine test was analyzed in 143 wheezing children and 137 control individuals, and various cell types were discriminated and counted. Total IgE in plasma was detected using enzyme-linked immunosorbent assay. Receiver operating characteristic curve was plotted and area under curve (AUC) was calculated to evaluate the clinical potential of both indexes for diagnosing pediatric recurrent wheezing. The theoretical cutoff values for both indexes were also calculated using a Youden index. The results showed that neutrophil significantly increased in wheezing children, whereas lymphocyte decreased sharply. Total IgE, neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) were significantly elevated in wheezing patients. Besides, NLR and PLR were found unchanged in different genders. The results showed that NLR (AUC = 0.647) and PLR (AUC = 0.628) were able to discriminate recurrent wheezing. Cutoff for NLR was 0.98 (Youden index 24.8%) and cutoff for PLR was 116.4 (Youden index 19.4%). The mentioned evidence supported NLR and PLR as potential diagnostic indexes for pediatric recurrent wheezing.

Innate Immunity to Respiratory Infection in Early Life

Early life is a period of particular susceptibility to respiratory infections and symptoms are frequently more severe in infants than in adults. The neonatal immune system is generally held to be deficient in most compartments; responses to innate stimuli are weak, antigen-presenting cells have poor immunostimulatory activity and adaptive lymphocyte responses are limited, leading to poor immune memory and ineffective vaccine responses. For mucosal surfaces such as the lung, which is continuously exposed to airborne antigen and to potential pathogenic invasion, the ability to discriminate between harmless and potentially dangerous antigens is essential, to prevent inflammation that could lead to loss of gaseous exchange and damage to the developing lung tissue. We have only recently begun to define the differences in respiratory immunity in early life and its environmental and developmental influences. The innate immune system may be of relatively greater importance than the adaptive immune system in the neonatal and infant period than later in life, as it does not require specific antigenic experience. A better understanding of what constitutes protective innate immunity in the respiratory tract in this age group and the factors that influence its development should allow us to predict why certain infants are vulnerable to severe respiratory infections, design treatments to accelerate the development of protective immunity, and design age specific adjuvants to better boost immunity to infection in the lung.

Postnatal Innate Immune Development: From Birth to Adulthood

It is well established that adaptive immune responses are deficient in early life, contributing to increased mortality and morbidity. The developmental trajectories of different components of innate immunity are only recently being explored. Individual molecules, cells, or pathways of innate recognition and signaling, within different compartments/anatomical sites, demonstrate variable maturation patterns. Despite some discrepancies among published data, valuable information is emerging, showing that the developmental pattern of cytokine responses during early life is age and toll-like receptor specific, and may be modified by genetic and environmental factors. Interestingly, specific environmental exposures have been linked both to innate function modifications and the occurrence of chronic inflammatory disorders, such as respiratory allergies. As these conditions are on the rise, our knowledge on innate immune development and its modulating factors needs to be expanded. Improved understanding of the sequence of events associated with disease onset and persistence will lead toward meaningful interventions. This review describes the state-of-the-art on normal postnatal innate immune ontogeny and highlights research areas that are currently explored or should be further addressed.

Age-related variation in the cellular composition of equine bronchoalveolar lavage fluid

BACKGROUND

Previous reports reveal variation in the cellular composition of equine bronchoalveolar lavage fluid (BALF).

OBJECTIVES

The purpose of this study was to compare the profiles of BALF from horses to assess age-related differences. Serial BALF samples were collected from the same individuals over a one-year period to identify changes in individual animals as they aged.

METHODS

Collection of BALF was performed on horses aged one week and one, 2, 6, and 12 months. Total nucleated cell count (TNCC), protein concentration, and cytology were assessed. Longitudinal analysis was performed and compared to healthy adults.

RESULTS

Foals at one week and 6 months of age had significantly higher TNCC than adults (medians: 320/μL, 285/μL, and 90/μL, respectively); no differences in total protein were found. Foals at one month had the highest proportion of macrophages (median: 87.3%), differing significantly from both yearlings and adults (medians: 45.5% and 48.7%, respectively). Foals aged one week and one month had significantly lower proportions of lymphocytes than yearlings and adults (medians: 3.2% and 4.7% vs 43.2% and 45.8%, respectively). Eosinophil percentage was lowest in foals aged one week, one month, and 2 months (median: 0.0%) and highest in foals aged 6 months (median: 2.2%). Mast cell percentages were highest in yearlings and adults (medians: 2.2% and 3.3%, respectively) and neutrophil percentage was highest in foals aged one week (13.7%).

CONCLUSIONS

Cytologic profiles of BALF from foals and adult horses differed considerably. Significant changes in TNCC and percentages of lymphocytes, macrophages, and eosinophils occurred with age.

Clinical, cytological and microbiological evaluation of bronchoalveolar lavage in children: A referral hospital-based study

INTRODUCTION

Diffuse lung diseases (DLD) in children involve a group of heterogeneous, rare disorders. In spite of the low diagnostic yield in pediatric DLD, bronchoalveolar lavage (BAL) can be used to diagnose specific disorders. There are few studies about microbial and cellular profiles of BAL samples in these patients. This study was conducted to evaluate the clinical, cytological and microbiological evaluation of BAL in children with DLD.

METHODS

The clinical, cytological and microbiological profiles of BAL samples of all patients with DLD who underwent the fiberoptic bronchoscopy (FOB) at Children's Medical Center, an Iranian referral pediatrics Hospital during a year were evaluated.

RESULTS

In 18 patients (18.4%) of the 98 cases studied, 22 pathogens were obtained as etiologic agents. The mean total cells count of BAL was 23.9 × 104 ± 12.9 × 104/ml. The mean percentages of cellular components were macrophages (70.2%), neutrophils (16.3%), lymphocytes (11.8%) and eosinophils (1.4%), respectively. The type of lung disease was significantly associated with the mean percentage of lymphocytes (p = 0.005) and the percentage of neutrophils (p = 0.042).

CONCLUSION

FOB and BAL evaluation in combination with clinical and radiographic imaging data may be helpful for identifying of presumptive diagnosis of DLD in children.

Refractory wheezing in Chinese children under 3 years of age: bronchial inflammation and airway malformation

Background

Wheezing is a common symptom in early childhood. However, refractory wheezing is difficult to treat, and it may thus account for extensive use of medical resources. It is therefore important to improve our understanding of the pathophysiology of refractory childhood wheezing.

Methods

In this descriptive study, we studied 156 children with refractory wheezing using fiberoptic bronchoscopy and bronchoalveolar lavage (BAL), and compared the results with a control group of 46 children with various pulmonary diseases but no wheezing. Etiology and cell classification were analyzed for each BAL sample.

Results

Overall, 21.8 % of children with refractory wheezing had airway malformations including tracheomalacia, airway stenosis, and tracheal bronchus. The incidence of airway malformations increased to 31 % in infants under 12 months of age. A significant increase in neutrophil ratio and decrease in macrophage ratio were observed in BAL from children with refractory wheezing compared with controls. Pathogen infection led to a higher ratio of neutrophils in the wheezing group compared with controls. However, there were no significant differences in neutrophil ratios among children with various pathogen infections. Furthermore, children with refractory wheezing had a high rate of Mycoplasma pneumoniae infection.

Conclusions

Airway malformations might play an important role in children under 3 years of age with refractory wheezing, especially in infants under 12 months of age. Neutrophil-mediated airway inflammation was characteristic of refractory wheezing in children under 3 years of age. In addition, infections such as M. pneumoniae may aggravate airway inflammation and affect refractory wheezing.

The findings of a clinical surveillance bronchoalveolar lavage programme in pre-school patients with cystic fibrosis

BACKGROUND

Evidence suggests infection is present in the lower airways of young children with cystic fibrosis (CF), even when clinically stable. Oropharyngeal samples (OPS) are typically used for airway surveillance in these children but have been shown to have low positive predictive values and low sensitivity in detecting lower airway infection when compared with the reference standard, bronchoalveolar lavage (BAL).

METHODS

The aim of this study was to determine the prevalence of pathogens in lower airway samples detected as part of a pilot clinical BAL surveillance programme, in young children aged from one to six years old, and to ascertain if their detection resulted in a change in treatment.

RESULTS

During the study 78 bronchoscopies were performed on 38 patients. The average age at the time of bronchoscopy was 2.7 years (range 0.3-7.0 year). A significant organism was detected in 58 (74.5%) BALs. Haemophilus influenzae was detected in 27 (34.6%) samples, 16 (20.5%) samples had Staphylococcus aureus, and nine (11.5%) had Pseudomonas aeruginosa. Change in treatment occurred after 46 (58.9%) BALs.

CONCLUSIONS

This study suggests that, in young non-expectorating children with CF, routine surveillance bronchoscopy allows the detection of significant lower airway pathogens and provides the opportunity for targeted treatment of sub-clinical infection.

Translational research in pediatrics III: bronchoalveolar lavage

The role of flexible bronchoscopy and bronchoalveolar lavage (BAL) for the care of children with airway and pulmonary diseases is well established, with collected BAL fluid most often used clinically for microbiologic pathogen identification and cellular analyses. More recently, powerful analytic research methods have been used to investigate BAL samples to better understand the pathophysiological basis of pediatric respiratory disease. Investigations have focused on the cellular components contained in BAL fluid, such as macrophages, lymphocytes, neutrophils, eosinophils, and mast cells, as well as the noncellular components such as serum molecules, inflammatory proteins, and surfactant. Molecular techniques are frequently used to investigate BAL fluid for the presence of infectious pathologies and for cellular gene expression. Recent advances in proteomics allow identification of multiple protein expression patterns linked to specific respiratory diseases, whereas newer analytic techniques allow for investigations on surfactant quantification and function. These translational research studies on BAL fluid have aided our understanding of pulmonary inflammation and the injury/repair responses in children. We review the ethics and practices for the execution of BAL in children for translational research purposes, with an emphasis on the optimal handling and processing of BAL samples.

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.

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.

Airway and lung pathology due to mucosal surface dehydration in {beta}-epithelial Na+ channel-overexpressing mice: role of TNF-{alpha} and IL-4R{alpha} signaling, influence of neonatal development, and limited efficacy of glucocorticoid treatment

Overexpression of the epithelial Na(+) channel beta subunit (Scnn1b gene, betaENaC protein) in transgenic (Tg) mouse airways dehydrates mucosal surfaces, producing mucus obstruction, inflammation, and neonatal mortality. Airway inflammation includes macrophage activation, neutrophil and eosinophil recruitment, and elevated KC, TNF-alpha, and chitinase levels. These changes recapitulate aspects of complex human obstructive airway diseases, but their molecular mechanisms are poorly understood. We used genetic and pharmacologic approaches to identify pathways relevant to the development of Scnn1b-Tg mouse lung pathology. Genetic deletion of TNF-alpha or its receptor, TNFR1, had no measurable effect on the phenotype. Deletion of IL-4Ralpha abolished transient mucous secretory cell (MuSC) abundance and eosinophilia normally observed in neonatal wild-type mice. Similarly, IL-4Ralpha deficiency decreased MuSC and eosinophils in neonatal Scnn1b-Tg mice, which correlated with improved neonatal survival. However, chronic lung pathology in adult Scnn1b-Tg mice was not affected by IL-4Ralpha status. Prednisolone treatment ablated eosinophilia and MuSC in adult Scnn1b-Tg mice, but did not decrease mucus plugging or neutrophilia. These studies demonstrate that: 1) normal neonatal mouse airway development entails an IL-4Ralpha-dependent, transient abundance of MuSC and eosinophils; 2) absence of IL-4Ralpha improved neonatal survival of Scnn1b-Tg mice, likely reflecting decreased formation of asphyxiating mucus plugs; and 3) in Scnn1b-Tg mice, neutrophilia, mucus obstruction, and airspace enlargement are IL-4Ralpha- and TNF-alpha-independent, and only MuSC and eosinophilia are sensitive to glucocorticoids. Thus, manipulation of multiple pathways will likely be required to treat the complex pathogenesis caused by airway surface dehydration.

Disease surveillance using bronchoalveolar lavage

The role of pulmonary infection and inflammation in the pathogenesis of destructive lung disease in cystic fibrosis (CF) is undisputed. The use of bronchoscopy and bronchoalveolar lavage (BAL) has demonstrated that these processes may begin early in life and be present in the absence of overt clinical symptoms. Some children diagnosed following newborn screening can be infected with Pseudomonas aeruginosa in infancy. Studies using BAL have demonstrated a relationship between lower airway inflammation and bacterial load in the lungs; however, inflammation may occur in the absence of obvious current infection. BAL has the potential to provide a greater understanding of the pathogenesis of CF lung disease and microbiological surveillance provides the opportunity for early detection and eradication of P. aeruginosa. Lack of standardization inhibits the ability to compare data from different centres and to optimize treatment strategies. This review discusses the recommendations from a workshop held in early 2007 aimed at achieving a standardized approach to BAL in infants and young children with CF.

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.

Bronchoalveolar cytology for diagnosing pulmonary GVHD after bone marrow transplant in children

BACKGROUND

Cytological composition of bronchoalveolar lavage (BAL) fluid in pediatric bone marrow transplant (BMT) recipients with pulmonary complications has not been comprehensively described and BAL specific markers of pulmonary GVHD are lacking. The aim of this retrospective study was to assess the role of BAL in the diagnosis of pulmonary GVHD by comparing BAL cytological findings between pediatric allogenic BMT patients with pulmonary complications and oncology children receiving chemotherapy alone.

METHODS

Retrospective analysis of BAL specimens for cytology, total and differential cell counts and presence of infections.

RESULTS

Seventeen BMT and 13 chemotherapy BAL were analyzed. BAL total cell count was increased but similar between groups (96.9 x 10(4) vs. 98.2 x 10(4), P = NS). BAL cellular composition differed considerably between groups with a significantly higher number of lymphocytes (18% vs. 6.25%, P = 0.03) and a significantly lower number of neutrophils (25.9% vs. 58%, P = 0.02) in BMT BAL specimens. Atypical epithelial cells were significantly more frequent (75% vs. 30.8%, P = 0.027), and significantly more severe (P = 0.01) in BMT patients. The presence and severity of atypia was not associated with infection or pneumotoxic drug exposure (P = NS).

CONCLUSION

BAL cytology differs significantly between BMT and chemotherapy patients. The presence BAL lymphocytosis and severe epithelial cell atypia concomitantly to respiratory symptoms and GVHD in other organs may suggest the diagnosis of pulmonary GHVD. Prospective studies assessing the reliability of this finding combined with markers such as epithelial cell apoptosis and increased cytokines are needed.

Effects of early cigarette smoke exposure on early immune development and respiratory disease

Exposure to tobacco constituents during early development remains a common but avoidable toxic exposure, which has been clearly linked with decreased lung growth and subsequent wheezing illness. There is also now emerging evidence that tobacco smoke can influence early immune function. This includes alterations in cytokine production by the fetoplacental unit, as detected ex vivo in cord blood, as well as in patterns of fetal mononuclear cell responses in vitro. Recent studies also suggest that the newborns of smoking mothers have altered signalling through Toll-like receptors (TLRs) that are essential for innate microbial responses. This may be implicated in the increased predisposition to infection in exposed infants. TLR-mediated innate response pathways are also believed to be important in promoting regulatory pathways that inhibit allergic immune responses. However, although a number of studies have documented associations between early cigarette smoke exposure and subsequent allergic disease, this remains controversial. This review explores the consequences of smoking on these important aspects of early development, including potential mechanisms, interactions with predisposing asthma genes and a potential role in epigenetic regulation. Although parental smoking may not be the primary factor in the changing prevalence of asthma and respiratory disease, we propose that it is an important contributor, with significant potential to interact with other genetic factors and environmental risk factors to influence disease propensity.

Incidence rate and factors related to post-bronchoalveolar lavage fever in children

BACKGROUND

Post-bronchoscopy and bronchoalveolar lavage (BAL) fever in children has been described by several authors.

OBJECTIVES

This study aimed at assessing the occurrence of fever after these examinations and associated risk factors.

METHODS

The study was performed in the Bronchoscopy Unit of Hôpital Necker-Enfants Malades, Paris, France, from June 2004 to July 2005. 148 children who underwent fiberoptic bronchoscopy and BAL, and remained in the Unit for 24 h, were included.

RESULTS

37.8% of the patients presented post-BAL fever. In the multivariate analysis of the selected factors (age, immunodeficiency, general or local anesthesia, mucosal biopsy, inflammation and suppuration at the moment of the examination, abnormal bronchoalveolar fluid cellularity and infection), only age <2 years and presence of infection remained associated with fever.

CONCLUSIONS

The occurrence of fever is a frequent event in children who underwent BAL. In order to reduce post-BAL fever, antibiotic strategies should be devised based on prospective studies assessing identification of predictive air-way infection criteria and/or rapid bacteriological result analysis.

Assessment of pulmonary antibodies with induced sputum and bronchoalveolar lavage induced by nasal vaccination against Pseudomonas aeruginosa: a clinical phase I/II study

Background

Vaccination against Pseudomonas aeruginosa is a desirable albeit challenging strategy for prevention of airway infection in patients with cystic fibrosis. We assessed the immunogenicity of a nasal vaccine based on the outer membrane proteins F and I from Pseudomonas aeruginosa in the lower airways in a phase I/II clinical trial.

Methods

N = 12 healthy volunteers received 2 nasal vaccinations with an OprF-OprI gel as a primary and a systemic (n = 6) or a nasal booster vaccination (n = 6). Antibodies were assessed in induced sputum (IS), bronchoalveolar lavage (BAL), and in serum.

Results

OprF-OprI-specific IgG and IgA antibodies were found in both BAL and IS at comparable rates, but differed in the predominant isotype. IgA antibodies in IS did not correlate to the respective serum levels. Pulmonary antibodies were detectable in all vaccinees even 1 year after the vaccination. The systemic booster group had higher IgG levels in serum. However, the nasal booster group had the better long-term response with bronchial antibodies of both isotypes.

Conclusion

The nasal OprF-OprI-vaccine induces a lasting antibody response at both, systemic and airway mucosal site. IS is a feasible method to non-invasively assess bronchial antibodies. A further optimization of the vaccination schedule is warranted.

Il lavaggio broncoalveolare (BAL) in età pediatrica

Il lavaggio broncoalveolare o BAL, permettendo di ottenere le cellule ed i soluti presenti sulla superficie epiteliale del tratto respiratorio distale, si è dimostrato una metodica di ricerca essenziale per lo studio dei meccanismi eziopatogenetici delle malattie del polmone profondo, come ad esempio lo studio delle interstiziopatie, su cui esiste una vastissima letteratura di dati ottenuti con il BAL. Oltre a questo aspetto di metodica di ricerca, il BAL rappresenta perè anche una procedura diagnostica insostituibile nella pratica clinica quotidiana.

Airway inflammation in asymptomatic children with episodic wheeze

Airway pathologies have been comprehensively researched in adult asthma, but in children, the extent of airway inflammation associated with episodic wheeze, often diagnosed as asthma, has not been fully characterized. It is not clear whether persistent airway inflammation is present in the absence of wheezing symptoms, and there is controversy regarding the role of age and atopy. This study assessed cellular and cytokine markers of airway inflammation in asymptomatic children with a history of episodic wheeze. Children with a history of episodic wheeze and cough (study group) and nonasthmatic patients requiring elective surgery (control group) were recruited. All subjects in the study group had a history of significant episodic wheezing (>2 episodes per year), and used only as-needed beta-agonist treatment. Bronchoalveolar lavage (BAL) was obtained using bronchoscopic lavage (study group) and nonbronchoscopic lavage (control group). Differential cell counts of BAL and flow cytometry were performed to identify T-lymphocyte phenotypes, and intracellular cytokine profiles were measured after phorbol-12-myristate 13-acetate (PMA) stimulation of BAL fluid T-cells. Twenty-one children with a history of 2-12 episodes of wheeze per year and 21 nonasthmatic subjects without respiratory symptoms were recruited. Study and control subjects were matched for age (median age, 5 years) and demographic characteristics. Study subjects had higher IgE levels, but their measurements were still within normal range. No significant differences in BAL differential cell counts were noted, and in both groups, the majority of T-cells were CD3+ CD8+, with a median CD4:CD8 ratio of 0.6. There was no significant difference in T-cell expression of the activation markers HLA-DR and CD25 (IL-2 receptor), or in PMA-induced production of the intracellular cytokines IFN-gamma, IL-2, IL-4, IL-5, and IL-10. The results of this study suggest that significant T-cell-driven airway inflammation is absent in mild or nonatopic, asymptomatic children of this age group who have episodic wheeze. Our findings support asthma management guidelines that do not recommend long-term treatment of this group of patients with anti-inflammatory medications.

Lower airway inflammation in infants with cystic fibrosis detected by newborn screening

Controversy exists over whether the lower airway inflammation that characterizes cystic fibrosis (CF) is initiated primarily by the genetic defect. To determine if inflammation precedes infection, we examined bronchoalveolar lavage (BAL) fluid cytology, cytokines (interleukin (IL)-1beta, IL-4, IL-5, IL-6, IL-8, IL-10, and tumor necrosis factor-alpha), and free neutrophil elastase activity from 70 CF (aged 1.5-71 months) children detected by newborn screening and 19 (aged 2.0-48 months) controls with chronic stridor. CF subjects were selected and categorized as pristine (13 aged </= 6 months, lacking prior respiratory symptoms and exposure to antibiotics, and without respiratory pathogens on BAL), infected (42 with viruses or >/= 10(5) colony-forming units/ml of pathogenic bacteria in BAL), and uninfected (15 aged > 6 months, asymptomatic, not taking antibiotics at bronchoscopy, and free of pathogens in their BAL). To further resolve if inflammation develops without infection, inflammatory mediators in paired annual BAL samples from 38 CF subjects were measured, and results were grouped according to whether BAL showed persistence (n = 6), acquisition (n = 8), clearance (n = 13), or absence (n = 11) of infection. While pristine, uninfected, and control subjects had similar BAL profiles, infected patients showed elevated inflammatory indices, including increased IL-10 (P < 0.001). Pristine subjects had the fewest signs of inflammation. Analysis of BAL pairs found differences between the four infection groups for changes in neutrophil percentages, IL-8 (P < 0.001), and free neutrophil elastase (P = 0.009). Infection was associated with elevated inflammatory mediators in BAL fluid. In contrast, minimal or reduced signs of inflammation accompanied absence of eradication of infection from BAL fluid. We conclude that in CF, infection initiates and sustains airway inflammation.

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.

Bronchoalveolar lavage eosinophil cationic protein and interleukin-8 levels in acute asthma and acute bronchiolitis

OBJECTIVE

In this study, we measured the levels of eosinophil cationic protein (ECP) and interleukin (IL)-8 in bronchoalveolar lavage (BAL) fluid from patients with acute asthma and acute bronchiolitis, to determine any similarities or dissimilarities in the profiles of these biochemical markers in the two diseases.

METHODS

BAL fluids were obtained from children with acute asthma (n=16), infants with acute bronchiolitis caused by respiratory syncytial virus (n=18), and control subjects (n=14). Children with asthma were selected to be free of viral infection. BAL cell counts and differentials were determined, and ECP and IL-8 levels were measured by radioimmunoassay and ELISA, respectively.

RESULTS

ECP levels in BAL fluids were significantly higher in the asthma group than in the bronchiolitis (P<0.01) or control (P<0.0001) groups. However, IL-8 levels were significantly higher in the bronchiolitis group than in the asthma (P<0.01) or control (P<0.001) groups. IL-8 levels in the asthma group and ECP levels in the bronchiolitis group were similar to those of the control group.

CONCLUSION

This difference in profiles of ECP and IL-8 in acute asthma and acute bronchiolitis, together with a different inflammatory cell pattern, suggests that the nature of the inflammatory process within the lower respiratory tract may be distinctive in these two diseases.

DNA concentrations in BAL fluid of cystic fibrosis patients with early lung disease: influence of treatment with dornase alpha

Recombinant DNase (dornase alpha) was shown to improve lung function and reduce pulmonary exacerbations in cystic fibrosis (CF) patients, but its effects on DNA concentrations in the lower airways remain unclear at the present time. As part of the Bronchoalveolar Lavage in the Evaluation of Anti-Inflammatory Treatment (BEAT) Study, a multicenter open study to evaluate the evolution of inflammation in CF patients with early lung disease and its modulation by dornase alpha treatment, we studied DNA concentrations in the bronchoalveolar lavage (BAL) fluid of 48 CF patients with mild lung disease. After the initial BAL, 29 patients received daily treatment with 2.5 mg of dornase alpha; 19 patients served as controls. BAL was repeated after 18 months in all patients. Mean BAL fluid DNA concentrations were not different between groups at baseline (mean +/- SD, 14.1 +/- 6.9 microg/ml for controls, and 17.6 +/- 11.2 microg/ml for the dornase alpha group), but higher than previously reported for infants with CF. A weak but positive correlation (P <0.01) was observed between the percentage of neutrophils in BAL fluid and DNA levels. On reassessment after 18 months, the percentage of neutrophils was not different between the two groups, but DNA had increased in controls, whereas decreased levels were observed in treated patients (P <0.03, t-test). DNA concentrations increased by more than 10 microg/ml in 7 of 19 controls compared to 2 of 29 CF patients treated with rhDNase (P=0.01, Fisher's test). Therefore, treatment with dornase alpha over 18 months reduces DNA load in BAL fluid, which may have a positive effect on the clearance of lower airway secretions.

Pediatric interstitial lung disease revisited

The spectrum of pediatric interstitial lung disease (PILD) includes a diverse group of rare disorders characterized by diffuse infiltrates and disordered gas exchange. Children with these conditions typically present with tachypnea, crackles, and hypoxemia. Recent advances have been made in the identification of different types of PILD that are unique to infancy. More exciting has been the discovery of genetic abnormalities of surfactant function, now described in both children and adults. A systematic evaluation of the child presenting with diffuse infiltrates of unknown etiology is essential to the diagnosis. Most often, lung biopsy is required. Current treatment options remain less than satisfactory, and morbidity and mortality remain considerable.

Microaspiration in Infants with Laryngomalacia

OBJECTIVES/HYPOTHESIS

Laryngomalacia is the most common congenital laryngeal anomaly and the most frequent cause of stridor in infants. Infants with laryngomalacia may have associated respiratory symptoms other than stridor. In this study, we evaluated whether infants with laryngomalacia have episodes of microaspiration by calculating the amount of lipids present in the alveolar macrophages.

STUDY DESIGN

We reviewed bronchoalveolar lavage (BAL) findings obtained in 14 infants with laryngomalacia and in 11 control children.

METHODS

BAL was performed during flexible fiberoptic bronchoscopy (FFB) to diagnose persistent stridor. The presence of microaspiration was determined by evaluating the amount of lipid per single macrophage, assigning each cell a score from 0 to 4 according to the amount of lipid in the cytoplasm.

RESULTS

The lipid-laden macrophage index was similar in patients and controls (31.5, range 12-177 vs. 45, range 35-106). In 5 of the 14 (36%) patients the index exceeded 100, and more than 25% of the cells were graded 3 and 4, indicating the presence of microaspiration. The lipid-laden macrophage index correlated significantly with the number and percentage of BAL neutrophils (Pearson correlation test, r = 0.83, P < .001 and r = 0.925, P < .001) as a marker of lung inflammation.

CONCLUSIONS

Infants with laryngomalacia may have episodes of microaspiration. BAL performed during FFB to evaluate stridor may add helpful therapeutic information without increasing the risks of the procedure.

Effect of Treatment with Dornase Alpha on Airway Inflammation in Patients with Cystic Fibrosis

Recombinant human deoxyribonuclease (rhDNase) has been shown to improve lung function and reduce the number of pulmonary exacerbations in patients with cystic fibrosis (CF), but its long-term effect on airway inflammation remains unknown. In this study, we used bronchoalveolar lavage (BAL) to investigate the long-term effect of rhDNase on inflammation in patients with CF having mild lung disease. A total of 105 patients with CF (> or =5 years of age) having normal lung function were randomized to receive rhDNase (2.5 mg/day) or no rhDNase. Patients with a normal percentage of neutrophils in BAL fluid at baseline were not randomized and served as the control group. The percentage of neutrophils in the pooled BAL sample was similar in both randomized groups at baseline. A significant increase in neutrophils was observed over the 3-year study period in both untreated patients and control subjects, whereas neutrophils remained unchanged in patients treated with rhDNase. Elastase activities and interleukin-8 concentrations also increased in untreated patients and remained stable in patients on rhDNase. We conclude that in patients with CF, an increase in neutrophilic airway inflammation is found that is positively influenced by rhDNase treatment.

Immune and airway effects of house dust mite aeroallergen exposures during postnatal development of the infant rhesus monkey

BACKGROUND

The effect of chronic environmental aeroallergen exposure on the immune system and airways has not been experimentally defined in very young children.

OBJECTIVE

The purpose of this study was to determine the immunophenotype of peripheral blood and airway leucocytes in the newborn rhesus macaque monkey, following recurrent aerosol exposure to house dust mite (HDM) (Dermatophagoides farinae).

METHODS

A regimen of HDM aerosolization was initiated for 2 h per day, three times per week, starting when rhesus macaque monkeys were 1 week of age. All monkeys were inoculated with diptheria, tetanus, and acellular pertussis vaccine at 5 weeks of age to simulate human infant vaccination schedules.

RESULTS

Following 8 weeks of HDM aeroallergen exposure, infant monkeys exhibited a significant reduction in the total peripheral blood lymphocyte numbers and a decreased frequency of peripheral blood CD4+ T lymphocytes with a CD45RA-'memory' immunophenotype. Lavage CD4+ T lymphocytes from HDM-exposed monkeys showed elevated expression of CD25, as well as an increase in CD45RA-/CD62L-/CD11ahigh immunophenotype. Eosinophils were more abundant within airways of HDM-exposed monkeys, accumulating maximally within the trachea.

CONCLUSION

These data demonstrate the development of immunological responses following chronic inhalation of a common environmental allergen during postnatal maturation in the non-human primate.

Bronchoalveolar lavage cytokine profiles in acute asthma and acute bronchiolitis

BACKGROUND

The pathogenetic basis for the relationship between acute bronchiolitis and asthma has not yet been completely elucidated.

OBJECTIVE

The aim of this study was to compare these 2 diseases in terms of their patterns of airway cytokine response (T(H)1 or T(H)2).

METHODS

By using a bronchoalveolar lavage (BAL) technique, this study investigated the cytokine levels of BAL fluid in children with acute asthma who had no identifiable respiratory syncytial virus (RSV) infection (n = 18) and in infants with acute bronchiolitis caused by RSV (n = 22). Comparisons were made with normal control subjects (n = 14). IFN-gamma (T(H)1) and IL-4 and IL-5 (T(H)2) levels were measured in concentrated BAL fluids by means of ELISA.

RESULTS

The IL-5 level (P <.001) and IL-5/IFN-gamma ratio (P <.001) were significantly increased in the asthmatic group with no identifiable RSV infection and in the RSV-induced bronchiolitis group compared with values in the control group. When infants in the bronchiolitis group were divided into eosinophil-positive and eosinophil-negative subgroups, the eosinophil-positive subgroup had significantly increased IL-5 levels (P <.001) and IL-5/IFN-gamma ratios (P <.01) compared with those in the control group, but similar cytokine responses were not induced in the eosinophil-negative subgroup. The percentage of BAL eosinophils correlated significantly with levels of BAL IL-5 in both the asthma group (r = 0.80, P =.000) and the bronchiolitis group (r = 0.82, P =.000).

CONCLUSIONS

These findings suggest that a subgroup of the RSV-induced bronchiolitis group results in a T(H)2-type response, and this could provide a valuable framework to explain the link between RSV-induced bronchiolitis and asthma.

Differential cytology of bronchoalveolar lavage fluid in asthmatic children

Although asthma usually begins in childhood, limited information is available as to the inflammatory reaction of asthmatic children compared to adults and the influence of age. We investigated the cytology of bronchoalveolar lavage fluid (BALF) in 39 newly diagnosed wheezy children (minimum of 3 wheezing episodes during last 6 months): 21 allergic and 18 nonallergic subjects. None had received antiinflammatory treatment. Bronchoalveolar lavage (BAL) was performed, instilling 0.5 ml.kg(-1) body weight of warmed saline in 4 successive fractions. The first 2 aliquots (BALF 1) were pooled for microbiology and cytology, and the last 2 (BALF 2) for cytology only. Recovery correlated inversely with age, the most significant being for BALF 2 (r = -0.52, P = 0.001). Children under 2 years of age had larger amounts of ciliated columnar and goblet cells (P = 0.0074). Other cell types did not show age dependency. Differential cytology was characterized by a high number of creola bodies, bronchial epithelial cells (M = 68 x 10(3).ml(-1), R = 5-349), and neutrophils (M = 92 x 10(3).ml(-1), R = 0-1,257). Eosinophils were the only cells distinguishing allergic from nonallergic subjects (P = 0.003). The 16 children with positive microbiology had more neutrophils than the noninfected (P = 0.008), the latter still having more neutrophils than found in adults. These data suggest a limited age dependency in BALF cytology. Differential cytology in BALF might be helpful in differentiating asthma in children. Neutrophil inflammation might be more important than in adults.

Neutrophils in asthma pathophysiology

Although the role of eosinophils, mast cells, and T cells in asthma has long been recognized, several reports suggest that neutrophils may also be involved. In most studies of people with mild asthma, neutrophil numbers in the airways are not different from controls. However, in severe asthma, including asthma deaths, neutrophils are usually raised. Furthermore, most pediatric studies suggest that neutrophils are raised in some children, in particular in the young or infantile wheeze group. Measurements of inflammatory mediators in the airways of asthmatic subjects suggest that neutrophils are activated.

Matrix metalloproteases in BAL fluid of patients with cystic fibrosis and their modulation by treatment with dornase alpha

BACKGROUND

Matrix metalloproteinases (MMPs) are involved in the remodelling and degradation of extracellular matrix and may play a role in pulmonary tissue destruction in cystic fibrosis (CF).

METHODS

Bronchoalveolar lavage (BAL) fluid levels of MMP-8, MMP-9, and their natural inhibitor TIMP-1 were measured on two occasions within 18 months in 23 children with mild CF, 13 of whom were treated with DNase.

RESULTS

MMP-8 (39.3 (6.8) v 0.12 (0.01) ng/ml), MMP-9 (58.0 (11.4) v 0.5 (0.02) ng/ml), and the molar ratio of MMP-9/TIMP-1 (0.36 (0.05) v 0.048 (0.01)) were significantly higher in patients with CF than in control children without lung disease. Gelatine zymography showed the typical banding pattern of neutrophil derived MMP-9, including 130 kDa NGAL-MMP-9 complex and 92 kDa latent MMP-9 bands; 85 kDa bands (corresponding to active MMP-9) were seen in all patients. There was a close correlation between BAL fluid concentrations of MMPs and alpha(2)-macroglobulin, a marker of alveolocapillary leakage. After 18 months MMP levels were increased in untreated patients and decreased in patients treated with DNase.

CONCLUSIONS

Uninhibited MMPs may contribute to pulmonary tissue destruction even in CF patients with mild lung disease that may be positively affected by treatment with DNase.

Bronchoalveolar cells in children < 3 years old with severe recurrent wheezing

STUDY OBJECTIVE

To determine the cell profile of BAL from infants with severe recurrent wheezing who were not acutely ill at the time of investigation, suggesting an ongoing inflammation.

DESIGN AND PATIENTS

In a retrospective study, we determined BAL cell profiles for 83 children with wheezing aged 4 to 32 months (mean +/- SD, 11.3 +/- 5.5 months). Fiberoptic bronchoscopy was performed in children with severe recurrent wheezy bronchitis unresponsive to inhaled steroids. These children were compared with 17 children aged 6 to 36 months (mean, 15.1 +/- 7.5 months) with various nonwheezing pulmonary diseases. Children were included as control subjects if they had no endobronchial inflammation and no atopy.

RESULTS

The BAL cell profile of young children with wheezing typically includes a significantly higher cell count (mean, 644.4 +/- 956.8 x 10(3)/mL vs 313 +/- 203.2 x 10(3)/mL, p = 0.008), a significantly higher percentage of neutrophils (mean, 9 +/- 12.1% vs 2.1 +/- 2.2%, p = 0.003), and a higher neutrophil count (mean, 43.2 +/- 81.6 x 10(3)/mL vs 7.9 +/- 11.8 x 10(3)/mL, p = 0.003), as compared with control subjects. The larger number of neutrophils in children with wheezing was not correlated with bacterial or viral infection, or with age, sex, or atopic status. In contrast to the situation in asthmatic adults, eosinophil levels were not higher in children with wheezing than in control subjects (mean, 0.09 +/- 0.27% vs 0.08 +/- 0.25%).

CONCLUSION

Neutrophil-mediated inflammation in the airways appears to better characterize severe recurrent wheezing in children < 3 years old.

Levels of interleukin-2, interferon-gamma, and interleukin-4 in bronchoalveolar lavage fluid from patients with Mycoplasma pneumonia: implication of tendency toward increased immunoglobulin E production

OBJECTIVE

In connection with the possible relationship between Mycoplasma infection and the onset of asthma, several studies have shown not only a high level of serum total immunoglobulin E (IgE) but also the production of IgE specific to Mycoplasma or common allergens during the course of Mycoplasma infection. It has been suggested that the balance of T helper type 1 (TH1)/T helper type 2 (TH2) immune response may regulate the synthesis of IgE. The objective of this study was to investigate the pattern of cytokine response (TH1 or TH2) during an episode of acute lower respiratory tract infection caused by Mycoplasma pneumoniae.

STUDY DESIGN

Using a bronchoalveolar lavage (BAL) with flexible bronchoscopy procedure, this study determined the levels of interleukin (IL)-2, interferon (IFN)-gamma (TH1), and IL-4 (TH2) in the supernatant of BAL fluid as well as the BAL cellular profiles of patients with Mycoplasma pneumonia (n = 14). These results were compared with those of patients with pneumococcal pneumonia (n = 12) or those of children with no identifiable airway infections (control group: n = 8).

RESULTS

The BAL cellular profile in the Mycoplasma pneumonia group was characterized by a high percentage of neutrophils and lymphocytes. A significantly increased level of IL-2 was found in both pneumonia groups, compared with the control group. In contrast, the IFN-gamma level was not different for the 3 groups. The level of IL-4 and ratio of IL-4/IFN-gamma were significantly elevated in the Mycoplasma pneumonia group, but not in the pneumococcal pneumonia group, compared with the controls.

CONCLUSIONS

IL-4 levels and IL-4/IFN-gamma ratios in BAL fluid are significantly higher in patients with Mycoplasma pneumonia than in patients with pneumococcal pneumonia or control participants. The BAL cytokine data suggest a predominant TH2-like cytokine response in Mycoplasma pneumonia, thus representing a favorable condition for IgE production.

Quantitation of lipid-laden macrophages in evaluation of lower airway cytology specimens from pediatric patients

Quantitation of lipid-laden macrophages has been used as a tool in the diagnosis of aspiration-related respiratory disorders. Fifty-six respiratory specimens from pediatric patients with lung diseases were retrospectively reviewed, and lipid-laden macrophage indices were evaluated according to modified published grading methods. The indices from patients at high risk for aspiration were significantly different from those at low risk. A simpler and more reproducible grading method was introduced. An important issue regarding sample adequacy was also addressed.