Lymphocyte subsets in bronchoalveolar lavage fluid of children without bronchopulmonary disease

Pediatric hypersensitivity pneumonitis: literature update and proposal of a diagnostic algorithm

Hypersensitivity pneumonitis (HP) is a rare disease in childhood with the prevalence of 4 cases per 1 million children and an incidence of 2 cases per year. The average age of diagnosis at pediatric age is approximately 10 years. The pathogenesis of HP is characterized by an immunological reaction caused by recurrent exposure to triggering environmental agents (mostly bird antigens in children). The clinical picture of HP is complex and variable in children, often presenting in subacute forms with cough and exertion dyspnea. A diagnosis of HP should be considered in patients with an identified exposure to a triggering antigen, respiratory symptoms, and radiologic signs of interstitial lung disease. Blood tests and pulmonary function tests (PFT) support the diagnosis. Bronchoscopy (with bronchoalveolar lavage and tissue biopsy) may be needed in unclear cases. Antigen provocation test is rarely required. Of note, the persistence of symptoms despite various treatment regimens may support HP diagnosis. The avoidance of single/multiple triggers is crucial for effective treatment. No evidence- based guidelines for treatment are available; in particular, the role of systemic glucocorticoids in children is unclear. With adequate antigen avoidance, the prognosis in children with HP is generally favorable.

Pediatrics and COVID-19

Viral respiratory tract infections are prevalent in children. They have substantial effects on childhood morbidity throughout the world, especially in developing countries. In this chapter, we describe the preliminary characteristics of pediatric COVID-19 and discover that severe and critical disease in children is rare. Many children remain asymptomatic. The reason why severity increases with progressing age and largely spares children is not yet known. In the search for possible explanations, we explore key differences between the pediatric and adult immune responses to new pathogens, and in host factors, such as ACE2 abundance.

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.

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.

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.

Immune cell profile in infants' lung tissue

Little is known about the normal immune cell profile in the lungs of infants without pulmonary disease. Normal lung samples obtained at autopsy of 10 infants that died either due to incidental or inflicted causes or non-pulmonary diseases were stained for antibodies against B and T lymphocytes, macrophages, NK cells, cytotoxic cells, dendritic cells and mast cells. Cells were quantified in the airway epithelial layer, inner layer (between the epithelium and the outer smooth muscle border), outer layer (between the outer smooth muscle border and the external limits of the airway) and alveolar septa. Basement membrane or alveolar septa lengths were assessed by image analysis. Results were expressed as cells/mm. The median age of patients was 6.8 months, ranging from 11 to 840 days. The inner layer of the airways was the region with the smallest density of cells. There was a predominance of cells related to the innate immunity such as CD56+, Granzyme B+ and CD68+ cells in the epithelial layer and alveolar parenchyma. The outer layer and the lung parenchyma presented the highest cellular density. There were very few CD4+ T cells or dendritic cells in most of the lung compartments. The numbers of CD3+ T and granzyme B+ cells correlated positively with age. There was a compartmentalization of immune cells along airways and parenchyma, which may be related to the development of innate and acquired lung defense mechanisms.

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.

Interstitial Lung Disease in Children Older Than 2 Years

The spectrum of childhood interstitial lung diseases (chILD) encompasses a group of heterogeneous, rare disorders in children characterized by diffuse pulmonary infiltrates and disordered gas exchange. Whereas the disorders that present in early life are unique to children, those that present in older children are also seen in adults. This review will concentrate on chILD presenting in children older than 2 years of age with a focus on the idiopathic interstitial pneumonias, connective tissue diseases, alveolar hemorrhage, and hypersensitivity pneumonitis. A systematic approach to diagnosis that includes a careful history and physical, computed tomography of the chest, bronchoalveolar lavage, and lung biopsy can be very helpful in establishing the correct diagnosis. Treatment approaches are described, including general supportive measures, indications for a trial of systemic corticosteroids, or other immunomodulating therapies, and when lung transplantation reserved for those with end-stage lung disease should be considered.

Flexible bronchoscopy and bronchoalveolar lavage in pediatric patients with lung disease

OBJECTIVE

The use of flexible bronchoscopy (FOB) and bronchoalveolar lavage (BAL) in investigating pediatric patient with airway abnormalities and pulmonary infiltrates are indispensable and are now a routine procedure in many centers. Immunocompromised and cancer patients, especially after bone marrow transplantation, and children who have undergone surgery for congenital heart disease (CHD) are at high risk for pulmonary disease. Our aim was to study the diagnostic rate, safety, and clinical yield of FOB in critically ill pediatric patients.

DESIGN

: Retrospective chart review.

SETTING

Pediatric intensive care unit in a tertiary university hospital.

PATIENTS

Three hundred nineteen children who underwent 335 FOB procedures. The indications for bronchoscopy included infectious agent identification in immune-competent patients with new pulmonary infiltrates seen on chest radiograph (46%) and in patients with fever and neutropenia with respiratory symptoms (18%), airway anatomy evaluation in patients with upper airway obstruction (16%), CHD (15%), and airway trauma (5%). Data were obtained by reviewing the patients' charts, bronchoscopy reports, and laboratory results.

MEASUREMENTS AND MAIN RESULTS

The diagnostic rate of FOB procedures was 79%. FOB and BAL resulted in alteration of management (positive clinical yield) in 70 patients (23.9%). A definite infectious organism was identified in 56 patients (17.6%). The clinical yield in patients with cancer or primary immune deficiency (38.7%) was significantly higher compared with patients with CHD (20.4%, p < 0.01) and pneumonia (17%, p < 0.01). Major complications were observed in two procedures (prolonged apnea), and minor complications (transient desaturation, stridor, and minor bleeding) were observed in 45 patients (14%).

CONCLUSIONS

FOB and BAL have an important role in the evaluation of airway abnormality and pulmonary infiltrate in pediatric patients, in whom rapid and accurate diagnosis is crucial for survival. We suggest that FOB should be considered as an initial diagnostic tool in those critically ill patients.

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.

Airway inflammation and lung function decline in childhood post-infectious bronchiolitis obliterans

Post-infectious bronchiolitis obliterans (PBO) is a rare form of chronic obstructive lung disease in children with few data on the pulmonary function outcome and underlying inflammatory process. The aim of this study was to determine the change in lung function over time and to investigate by bronchoalveolar lavage (BAL) the inflammatory characteristics of pulmonary involvement. Eleven Caucasian children with PBO were evaluated to estimate the average rate of change in lung function indices using a mixed model. The differential cytology and lymphocyte subsets of BAL fluid were analyzed. The median follow-up was 10.2 (IQR 3.2-12) years. The estimated forced expiratory volume in 1 sec (FEV1) had a baseline intercept of 57% predicted (62% predicted after bronchodilator) at 10 years of age which fell at a rate of 1.01% per year whereas the estimated forced expiratory flow 25-75 (FEF25-75) had a baseline intercept of 36% predicted (42% predicted after bronchodilator) at 10 years of age which fell at a rate of 1.04% per year. The estimated FEV1/FVC ratio had a baseline intercept of 70% (74% after bronchodilator) at 10 years of age which declined with an average slope of 1.02% per year (-1.10% per year after bronchodilator). Although the baseline and post-bronchodilator level of estimated FVC was abnormal (68% and 69% predicted, respectively) it did not change significantly with time. The median disease duration at BAL evaluation was 3.7 (IQR 0.7-8) years. The percentage differential cell counts were characterized by a significant increase in neutrophils (median 50%, IQR 1-66%), and a slight increase of lymphocytes (median 14%, IQR 7.5-15%). In conclusion, pulmonary function in childhood PBO is characterized by significant airway obstruction which deteriorates over time. The presence of an ongoing inflammatory process could explain the decline in lung function over time.

CD8+ T cell responses in bronchoalveolar lavage fluid and peripheral blood mononuclear cells of infants with severe primary respiratory syncytial virus infections

A protective role for CD8+ T cells during viral infections is generally accepted, but little is known about how CD8+ T cell responses develop during primary infections in infants, their efficacy, and how memory is established after viral clearance. We studied CD8+ T cell responses in bronchoalveolar lavage (BAL) samples and blood of infants with a severe primary respiratory syncytial virus (RSV) infection. RSV-specific CD8+ T cells with an activated effector cell phenotype: CD27+CD28+CD45RO+CCR7-CD38+HLA-DR+Granzyme B+CD127- could be identified in BAL and blood. A high proportion of these CD8+ T cells proliferated and functionally responded upon in vitro stimulation with RSV Ag. Thus, despite the very young age of the patients, a robust systemic virus-specific CD8+ T cell response was elicited against a localized respiratory infection. RSV-specific T cell numbers as well as the total number of activated effector type CD8+ T cells peaked in blood around day 9-12 after the onset of primary symptoms, i.e., at the time of recovery. The lack of a correlation between RSV-specific T cell numbers and parameters of disease severity make a prominent role in immune pathology unlikely, in contrast the T cells might be involved in the recovery process.

Immunology

The concept of forbidden foods that should not be eaten goes back to the Garden of Eden and apart from its religious meanings it may also have foreshadowed the concept of foods that can provoke adverse reactions. Thus we could say that allergic diseases have plagued mankind since the beginning of life on earth. The prophet Job was affected by a condition that following the rare symptoms described by the Holy Bible might be identified as a severe form of atopic dermatitis (AD). The earliest record of an apparently allergic reaction is 2621 B.C., when death from stinging insects was first described by hieroglyphics carved into the walls of the tomb of Pharaoh Menes depicting his death following the sting of a wasp. In 79 A.D., the death of the Roman admiral Pliny the Elder was ascribed to the SO₂-rich gases emanating from the eruption of Mount Vesuvius. Hippocrates (460–377 B.C.) was probably the first to describe how cow’s milk (CM) could cause gastric upset and hives, proposing dietetic measures including both treatment and prevention for CM allergy.

Comparison of atopic and nonatopic children with chronic cough: bronchoalveolar lavage cell profile

Chronic cough is a common complaint in children and its relationship with asthma is controversial. The aim of the present study was to determine the pattern of airway inflammation in atopic and nonatopic children with chronic cough, and to investigate whether atopy is a predictive factor for eosinophilic inflammation in cough. Bronchoalveolar lavage (BAL; three aliquots of 1 ml/kg saline) was performed in the right middle lobe of 24 (11 atopic and 13 nonatopic) children with persistent cough (8 females, 16 males), mean age 4.7 years (range: 1-11). Atopy was defined as an elevated total serum IgE or a positive RAST test. Both atopic and nonatopic children with persistent cough had an increase in total cells/ml in BAL (atopic: median 39 x 10(4), range: 20-123; nonatopic: median 22 x 10(4), range: 17-132) compared to nonatopic controls (median 11 x 10(4), range 9-30). The increases were mainly in neutrophils (atopic: median 17%, range 2.5-88.5%; nonatopic: median 6%, range 1.0-55.0%) compared to controls (median 1.55%, range 0.5-7.0%; atopics vs. controls, P < 0.005). There were no significant increases in eosinophils, lymphocytes, epithelial cells, or mast cells. Eosinophils were elevated in only 5/11 atopic and none of the nonatopic children. The increased percentage of neutrophils in the BAL fluid of atopic and nonatopic children with persistent cough could be due to an underlying inflammatory process driving the cough, or even conceivably, due to the effect of coughing itself. In this highly selected series, the absence of eosinophilic inflammation in the majority suggests that most would be predicted not to respond to inhaled corticosteroid therapy. This study underscores the need to be cautious about treating coughing children with inhaled corticosteroids, even in the context of a tertiary referral practice.

Fiberoptic bronchoscopy and bronchoalveolar lavage for the evaluation of pulmonary disease in children with primary immunodeficiency and cancer

BACKGROUND

Patients with childhood cancer or primary immunodeficiencies (PID) are at high risk for developing pulmonary infections and non-infectious complications. The broad differential diagnoses and the critical condition of these patients often drive physicians to start broad-spectrum antibiotic therapy before a definite diagnostic procedure is performed. A definite diagnosis may be achieved in these situations by fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL).

PATIENTS AND METHODS

The records of 58 PIDs and cancer (immunocompromised group) pediatric patients who underwent 62 fiberoptic bronchoscopies between 2000 and 2004 were retrospectively reviewed and compared to 158 non-cancer patients who underwent 182 fiberoptic bronchoscopies during the same period.

RESULTS

The overall diagnostic rate achieved by macroscopic inspection of purulent secretions or hemorrhage, abnormal cell count, and infectious agent isolation in the immunocompromised patients was 84%. A definite organism was recovered in 53.2% of the patients. Probable infection defined as purulent secretions or abnormal cell count without infectious agent isolation was diagnosed in another 21% of the patients. The rate of complications was 30.6%. In the control group, the overall diagnostic rate was 76.9% (n.s) and an infectious agent was demonstrated in 12.1% (P < 0.001). Probable infection was diagnosed in 24.2% (n.s) while the rate of complications was lower (15%) (P < 0.01).

CONCLUSIONS

Rapid and accurate diagnoses were achieved in most procedures performed on immunocompromised patients. Although the rate of complications was higher in the immunocompromised group, they were usually very mild with no mortality. Based on these results, broncoalveolar lavage should be considered as an initial diagnostic tool in pediatric immunocompromised patients with pulmonary complications.

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.

Pulmonary chemokines and their receptors differentiate children with asthma and chronic cough

BACKGROUND

Cough is a frequent symptom in children, but the differentiation of asthmatic cough from cough of other origins can be difficult. Chemokines recruit T lymphocytes to inflamed tissues, and the corresponding chemokine receptors are differentially expressed on T H 1 and T H 2 cells.

OBJECTIVE

We sought to determine whether levels of T H 1/T H 2-related chemokines and their receptors differ in bronchoalveolar lavage fluid (BALF) from 12 children with allergic asthma, 15 nonatopic children with chronic cough, and 10 children without airway disease.

METHODS

The T H 1-related (IFN-gamma-inducible protein of 10 kd [IP-10], IFN-gamma-inducible T cell alpha chemoattractant [ITAC], monokine induced by IFN-gamma [Mig], and IFN-gamma) and T H 2-related (thymus- and activation-regulated chemokine [TARC], macrophage-derived chemokine [MDC], IL-5, and IL-4) chemokines and cytokines were quantified in BALF by ELISA and a particle-based multiplex array. Percentages of pulmonary lymphocytes expressing CXCR3 + and CCR5 + (T H 1) and CCR4 + and CCR3 + (T H 2) chemokine receptors were determined in BALF by flow cytometry.

RESULTS

Pulmonary CCR4 + CD4 + cells and levels of TARC and MDC were significantly increased in asthmatic children versus children with chronic cough or without airway disease. In asthmatic children CCR4 + CD4 + cells correlated positively with levels of TARC, MDC, and serum IgE levels and negatively with FEV 1 . In contrast, CXCR3 + CD8 + cells and levels of ITAC were significantly increased in children with non-atopic chronic cough compared with the other groups. In children with chronic cough, CXCR3 + CD8 + cells correlated with levels of ITAC and IFN-gamma.

CONCLUSION

Pulmonary CCR4 + CD4 + and CXCR3 + CD8 + cells and their ligands TARC, MDC, and ITAC clearly differentiate asthmatic children from nonatopic children with chronic cough. The analysis of these markers could facilitate the diagnostic discrimination of asthma versus other reasons for chronic cough in children.

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.

Celiac disease and pulmonary hemosiderosis in a patient with chronic granulomatous disease

We report on a patient with the hitherto undescribed combination of chronic granulomatous disease, pulmonary hemosiderosis, and celiac disease. The hemosiderosis resolved with a gluten-free diet and glucocorticosteroid pulse therapy, but the restrictive lung function pattern remained unchanged. Lung function improved markedly by immunosuppression with daily glucocorticosteroid and azathioprine treatment.

Lymphocytic inflammation in childhood bronchiolitis obliterans

Childhood bronchiolitis obliterans (CBO) is an infrequent, severe disorder characterized by persistent obstructive respiratory symptoms after an acute episode of bronchiolitis. The viral etiology is most common, and adenovirus is the most frequently identified causative agent. Pathologically, the disease is characterized as constrictive type BO, with variable degrees of chronic inflammation and fibrosis in the bronchioles. The nature of the cellular infiltrate is largely unknown, and its characterization may provide better understanding of the disease and offer clues for therapy. Therefore, the aim of the present study was to characterize the inflammatory infiltrate in the bronchioles of 23 open lung biopsies of children with CBO and to compare this to the infiltrate in histologically normal airways. Our results show that CD3+ T cells were the most frequent cell type observed in CBO, with a predominance of the CD8+ T-cell subtype. When compared to the control group, there was a larger number of CD8+, CD4+, CD20+, granzyme B+, and perforin+ lymphocytes in the CBO group. Further studies are needed to address the role of different cell types in the development of CBO.

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.

Paediatric flexible bronchoscopy

Flexible bronchoscopy is an emerging diagnostic, therapeutic and supportive procedure used in paediatric respiratory medicine. Despite the improvements in instruments and anaesthetic support for this procedure, supervised training, strict quality-control measures and ongoing research are essential to ensure standards of safe practice and judicial use of the procedure.

Increased bronchoalveolar lavage CD8 lymphocyte subset population in wheezy infants

Episodes of wheezing are very common in infancy but, despite their high prevalence, their mechanism is still poorly understood. To better understand the airway inflammation of wheezing infants, we examined cells of the bronchoalveolar lavage (BAL), focusing on the phenotype of lymphocytes and macrophages by using cytofluorimetry. Twenty-one wheezers (mean age 15.4 months) and seven non-wheezers (mean age 24.1 months) were studied. BAL was collected at fiberoptic bronchoscopy. Total and differential cell counts were similar in both populations. Eosinophils were not detected in the BAL fluid. The cell-surface markers CD2, CD3, CD4, CD7, CD8, CD19, and CD45 were studied for the lymphocyte sub-population analysis. The cell-surface markers CD14, CD54, CD62L, and human leucocyte antigen (HLA)-DR were studied for the macrophage sub-population analysis. A significant increase in the CD8(+) lymphocyte population (p = 0.03) was observed in wheezers (median 43.1%, 25-75% percentile: 30.1-54.9%), as compared to non-wheezers (median 29.3%, 25-75% percentile: 13.5-34.7%). A significantly (p = 0.04) decreased expression of HLA-DR (mean fluorescence intensity [MFI]) was detected in the macrophage population of the wheezers (median MFI, 7,016; range 2135-7986), as compared to non-wheezers (median MFI, 8,369; range: 6478-8860). The results of the present study suggest that viral infection may have induced a CD8(+) response in BAL cells.

Usefulness of bronchoalveolar lavage for the diagnosis and treatment of refractory pneumonia in a patient with Kostmann syndrome, a severe congenital neutropenia

An 11-year-old girl with Kostmann syndrome developed refractory pneumonia. Culture of oral discharge, throat-swab specimens, and blood could not identity the causative organism, and systemic antimicrobial therapy failed to achieve improvement. We then performed diagnostic bronchoalveolar lavage (BAL) and culture of BAL fluid (BALF) yielded Pseudomonas aeruginosa. Therapeutic BAL using gentamicin produced a striking improvement of her pneumonia.

CONCLUSION

In immunocompromised children with pneumonia, BAL helps to identify the causative organism. If the patient is unresponsive to systemic antimicrobial therapy, BAL using antimicrobial agents is also worth trying.

Sex dependent differences in physiological ageing in the immune system of lower airways in healthy non-smoking volunteers: study of lymphocyte subsets in bronchoalveolar lavage fluid and blood

BACKGROUND

Age related changes in the immune system have been studied frequently but a possible relation to sex has not, to our knowledge, previously been examined. The effect of age and sex on the composition of lymphocyte subsets in bronchoalveolar lavage (BAL) fluid and peripheral blood was therefore examined.

METHODS

Bronchoscopy with lavage was performed in 32 healthy non-atopic, non-smoking volunteers (16 women aged 26-63 years (mean 44) and 16 men aged 23-63 years (mean 39)). Cytospin preparations for differential counts of BAL fluid cells and surface antigen expression of lymphocytes from BAL fluid and blood were analysed by flow cytometry.

RESULTS

Most parameters in the BAL fluid changed with age in women. The percentage of CD4+ lymphocytes increased with age from a mean of 48 (SD10)% in women aged < or =40 years to 69 (11)% in women aged >43 years (p=0.001). The percentage of CD8+ lymphocytes tended to decrease with age and the CD4/CD8 ratio was 5.8 (1.2) in women aged >43 years compared with 2.1 (0.7) in those aged < or =40 years (p<0.0001). Women aged >43 years differed from men aged >43 years as well as from younger subjects of both sexes with respect to CD4+ cells and CD4/CD8 ratio, and from younger women with respect to CD8+ cells. There was no age related change in the CD4/CD8 ratio in blood. No sex related differences were seen in the blood or BAL fluid of adults below the age of 40 years.

CONCLUSIONS

The composition of lymphocytes with different phenotypes in the lower respiratory tract changes with age in women but not in men. This may have implications for some clinical conditions such as chronic dry cough which are observed predominantly in women.

Sex dependent differences in physiological ageing in the immune system of lower airways in healthy non-smoking volunteers: study of lymphocyte subsets in bronchoalveolar lavage fluid and blood

BACKGROUND

Age related changes in the immune system have been studied frequently but a possible relation to sex has not, to our knowledge, previously been examined. The effect of age and sex on the composition of lymphocyte subsets in bronchoalveolar lavage (BAL) fluid and peripheral blood was therefore examined.

METHODS

Bronchoscopy with lavage was performed in 32 healthy non-atopic, non-smoking volunteers (16 women aged 26–63 years (mean 44) and 16 men aged 23–63 years (mean 39)). Cytospin preparations for differential counts of BAL fluid cells and surface antigen expression of lymphocytes from BAL fluid and blood were analysed by flow cytometry.

RESULTS

Most parameters in the BAL fluid changed with age in women. The percentage of CD4+ lymphocytes increased with age from a mean of 48 (SD10)% in women aged ⩽40 years to 69 (11)% in women aged >43 years (p=0.001). The percentage of CD8+ lymphocytes tended to decrease with age and the CD4/CD8 ratio was 5.8 (1.2) in women aged >43 years compared with 2.1 (0.7) in those aged ⩽40 years (p<0.0001). Women aged >43 years differed from men aged >43 years as well as from younger subjects of both sexes with respect to CD4+ cells and CD4/CD8 ratio, and from younger women with respect to CD8+ cells. There was no age related change in the CD4/CD8 ratio in blood. No sex related differences were seen in the blood or BAL fluid of adults below the age of 40 years.

CONCLUSIONS

The composition of lymphocytes with different phenotypes in the lower respiratory tract changes with age in women but not in men. This may have implications for some clinical conditions such as chronic dry cough which are observed predominantly in women.

B-lymphocyte aggregates in alveoli from a child with hypersensitivity pneumonitis (bird breeders lung)

BACKGROUND

Hypersensitivity pneumonitis is an interstitial lung disease mediated through a patient's immunologic response to a variety of inhaled organic dusts. Studies of the cellular components of lavage fluid from patients with this disease show marked increases of CD8+ suppressor/cytotoxic T-lymphocytes.

OBJECTIVE

In this study, we identified, in addition to the expected suppressor T-cells and natural killer cells, follicle-like aggregates of B-cells in the lung interstitium of an affected patient.

METHODS

The patient was an 11-year-old non-asthmatic, Caucasian male who presented with a 4-month history of progressive dyspnea, cough, and fever. The home contained nine cockatiel and two doves. Admission pulmonary functions revealed a restrictive pattern with diminished diffusion capacity. Prior to a diagnosis, the patient underwent bronchoalveolar lavage and transbronchial biopsy. Serum precipitins were eventually positive to pigeon (which cross-reacts with dove) droppings. The symptoms resolved after a prolonged course of prednisone.

RESULTS

Analysis of bronchoalveolar lavage lymphocyte population revealed a predominance of CD8+ cells (50%) with 85% expressing the activation marker HLA-DR. The percentage of CD4+ and CD56+ were 32% and 16%, respectively. The transbronchial biopsy revealed CD20+ follicle-like aggregates within the lung interstitium.

CONCLUSIONS

The histopathologic findings confirm that in hypersensitivity pneumonitis, the predominant immune response is an infiltrate of CD8+ T cells. The presence of B cell aggregates, however, may indicate that the local synthesis of antibody may be involved in an antibody-dependent cellular cytotoxic mechanism.

High fever after flexible bronchoscopy and bronchoalveolar lavage in noncritically ill immunocompetent children

Flexible bronchoscopy (FB) and bronchoalveolar lavage (BAL) have been applied increasingly to the evaluation of pulmonary disease in children. Although several complications have been reported following FB and BAL, high fever after BAL in immunocompetent children has not previously been reported. To determine the frequency, clinical characteristics, and outcome of these complications in children who developed high fever post-BAL, we retrospectively reviewed all bronchoscopic procedures done on an outpatient basis between August 1995 and July 1997. We identified 78 immunocompetent noncritically ill children who had undergone FB and BAL as an outpatient procedure for evaluation of underlying pulmonary disease, of whom 13 (17%) developed temperature (T) higher than or equal to 39 degrees C (fever group). The 13 patients in the fever group had a median age of 10 (range, 4-48) months and a reported T of 39.4 degrees C (39.1-40.6 degrees C) occurring 7.5 (4-12) hr after BAL. To determine if there were differences in clinical or BAL fluid (BALF) characteristics, we compared each child in the fever group to two children in the nonfever group, based upon primary indications and age. There were no differences in demographic or clinical characteristics between the two groups. Lymphocyte concentrations in BALF were significantly reduced in the fever group (P = 0.03). An abnormal BALF cell differential (defined as one or more of the following: neutrophils >10%, lymphocytes >30%, or eosinophils >1%) was significantly more common in the fever group (P = 0.008, odds ratio 3.6). We conclude that high fever is a frequent adverse event following BAL in noncritically ill immunocompetent children with underlying pulmonary disease. Pre-BAL clinical characteristics are not associated with development of high fever. However, the finding of an abnormal BALF cell differential is strongly associated with development of high fever post-BAL.

Bronchoalveolar cell profiles in children with asthma, infantile wheeze, chronic cough, or cystic fibrosis

Differential cell counts of bronchoalveolar lavage (BAL) have been reported in normal children but few data on cellular profiles in bronchial diseases in childhood are available. We determined the BAL cell profiles of 72 children divided into 5 groups: asthma (n = 14), chronic cough (n = 12), infantile wheeze (n = 26), cystic fibrosis (n = 10), and control (n = 10). The highest total cell, eosinophil, and neutrophil counts were found in children with cystic fibrosis. The cell profile of children with chronic cough was similar to that of control children. Asthma and infantile wheeze were characterized by a high median ratio of eosinophils (3%) and neutrophils (12%), respectively. In both diseases, epithelial shedding was suggested by an elevated epithelial cell count, 13.5 and 12%, respectively. Lymphocyte subset analysis showed a higher proportion of CD8 cells (58 versus 40%) and therefore a lower CD4/CD8 ratio (0.266 versus 0. 455) in children with asthma compared with infantile wheezers (p = 0. 02). Irrespective of the presence or absence of radiological abnormalities, a proportion of neutrophils > 10%, was found in one-third of the children with asthma and in half of the infantile wheezers, and was related to symptom severity. We suggest that neutrophil-mediated inflammation, with or without bacterial infection, may contribute to symptoms of asthma in childhood. Chronic cough, however, is not associated with the cell profiles suggestive of asthma and in isolation should not be treated with prophylactic antiasthma drugs.

Clinical utility of flexible bronchoscopy and bronchoalveolar lavage in young children with recurrent wheezing

OBJECTIVE

The objective of this study was to determine in young children with recurrent wheezing poorly responsive to bronchodilator therapy whether flexible bronchoscopy (FB) and bronchoalveolar lavage (BAL) provide clinically useful information, whether age-specific differences are present in bronchoscopic and BAL fluid (BALF) findings, and whether differential cellular analysis of BALF is useful in suggesting an infectious or inflammatory process.

DESIGN

This was a retrospective case series with descriptive and analytical components. The study population included children referred to a large tertiary care children's hospital subspecialty service for further evaluation of recurrent wheezing. Clinical and demographic data and findings of FB and BALF studies were collected from chart review. For purposes of data analysis patients were divided into 0- to 6-, 7- to 12-, and 13- to 18-month age groups.

RESULTS

Thirty otherwise healthy children, 0 to 18 months of age with recurrent wheezing, who had undergone FB were identified; and 28 were found to have positive diagnostic findings. Airway abnormalities were found in 17 (57%) and tended to be more common in the 0- to 6-month age group. In the 27 who also had BAL performed, 3 (11%) had a positive bacterial culture, 9 (33%) a positive viral culture, and 5 (19%) an elevated lipid-laden macrophage index suggesting aspiration. Differential cellular analysis was abnormal in 11 (41%), a finding that was significantly associated with a positive bacterial culture, a positive viral culture, or an elevated lipid-laden macrophage index.

CONCLUSIONS

In this population of young children with recurrent wheezing poorly responsive to bronchodilator therapy, FB and BAL yielded useful diagnostic findings in most children studied. In addition, in the presence of an infectious or inflammatory process, differential cellular analysis of BALF revealed an increased percentage of neutrophils.

Yield from flexible bronchoscopy in children

Flexible fiberoptic (FO) bronchoscopy can now be undertaken readily in children using topical anesthesia and light sedation and has largely supplanted rigid open tube (OT) bronchoscopy for diagnostic purposes. The present study examined the contribution of the FO bronchoscope to clinical management in children presenting with specific types of problems. We examined the first 200 consecutive flexible bronchoscopies performed in 1995 in children under 18 years of age (median age, 2.27 years). Indications for bronchoscopy were noisy breathing (26.5%), recurrent pneumonia (21.0%), suspected pneumonia in an immunocompromised patient (10.5%), atelectasis or bronchial toilet (12.5%), possible foreign body aspiration (13.0%), and miscellaneous other reasons (16.5%). Inspection of the airway was abnormal in 67.0% of all investigations and made a clinically meaningful contribution to management in 67.5%, especially in those with noisy breathing (98.1%), possible foreign body aspiration (100%), and atelectasis (76.0%). Bronchoalveolar lavage (BAL) cytology was abnormal in 80.4% of the 107 lavages, but contributed little to management except in those with recurrent pneumonia (73.8%). Bacteria were isolated in 26.6% of the 109 specimens cultured, but this finding rarely affected management. Fungi were isolated in 47.4% of the 19 lavages in the immunocomprised group. Together, inspection, BAL and microbiology contributed to management in a mean of 90.5% (range, 76.2-100%) of patients in the various groups. We concluded that a high yield of clinically meaningful information can be expected from FO bronchoscopy in children when coupled with BAL and microbiological studies of lavage fluid.

The diagnostic value of bronchoalveolar lavage in immunocompetent children with chronic diffuse pulmonary infiltrates

We have investigated the diagnostic value of (BAL) in 29 immunocompetent children (ages 1 month to 18 years) with chronic diffuse pulmonary infiltrates on chest radiograph who presented for evaluation over a 3-year period. The median age at the time of the BAL was 20 months with a range of 1-210 months. Positive results (1) diagnostic of a primary disorder; (2) consistent with a diagnosis; or (3) diagnostic of a secondary disorder, were obtained in 20/29 patients (13 with a single positive BAL finding and 7 with more than one finding). BAL was diagnostic of a primary disorder in only 5 patients (17%) with aspiration detected in 3 and infection in 2. The differential diagnosis was narrowed in 15 patients by the presence of lymphocytosis, neutrophilia, or eosinophilia. A secondary disorder was uncovered in 8 patients. Negative results were obtained in 9 additional patients. We conclude that BAL provided useful information in children with chronic diffuse infiltrates, but its ability to determine the primary cause was limited.

Immunoglobulin and beta 2-microglobulin concentrations in bronchoalveolar lavage of children and adults

Immunoglobulins play an important role in the pulmonary host defense, but little information is available about immunoglobulin and beta 2-microglobulin concentrations in the lung of normal children. Using bronchoalveolar lavage (BAL) we have studied immunoglobulin and beta 2-microglobulin levels in 30 children 3-15 years old undergoing elective surgery for nonpulmonary illnesses and in 15 healthy adult volunteers. BAL was performed with 3 x 1 ml/kg of body weight normal saline through an endotracheal tube after induction of anesthesia in children and under local anesthesia in adults. Similar concentrations of IgA and IgG were found in BAL fluid of children and adults even though serum levels were lower in children. As comparable results were obtained for albumin, a serum-derived protein, these data suggest that the permeability of the alveolar membrane is higher in children. IgE and IgM were detected in BAL fluid in only a fraction of children. beta 2-microglobulin levels were higher in both blood and BAL fluid of children. These data provide the first reference data for immunoglobulin and beta 2-microglobulin in children and can serve as a basis for future studies of children with pulmonary diseases.

Differential cytology of bronchoalveolar lavage fluid in immunosuppressed children with pulmonary infiltrates

OBJECTIVE

Bronchoalveolar lavage (BAL) is a well established technique for the detection of pathogens in immunosuppressed children, but its diagnostic yield is variable. The aim of this study was to investigate whether BAL differential cell counts are helpful in the evaluation of pulmonary infiltrates in immunocompromised children.

STUDY DESIGN

BAL was performed 28 times in 27 febrile immunocompromised children with pulmonary infiltrates. All patients were pretreated with broad spectrum antibiotics; 11 children also received amphotericin B. BAL was conducted with a flexible bronchoscope wedged in the area of maximal pathology as suggested by the chest radiograph or in the middle lobe in patients with diffuse interstitial radiographic changes. Differential cell counts were performed from cell smears obtained after centrifugation of BAL fluid.

RESULTS

Bacterial or fungal organisms were detected in BAL fluid of 12 patients. Patients with bacterial or fungal infections (group 1) had a significantly higher percentage of granulocytes in BAL fluid both compared with patients with sterile BAL cultures (group 2) and with a control group of children without pulmonary disease (p < 0.001, Wilcoxon test). The proportion of lymphocytes was not different from the control group in group 1 but significantly increased in group 2 (p < 0.001, Wilcoxon test). Blood differential cell counts were not different in the two patient groups. Lymphocyte subsets of BAL fluid obtained in a subgroup of patients were not significantly different from controls.

CONCLUSION

These data suggest that BAL differential cell counts may be a useful adjunct in the differential diagnosis of pulmonary infection in immunocompromised children.

Adjustment of bronchoalveolar lavage volume to body weight in children

To define the amount of epithelial lining fluid (ELF) that is recovered during bronchoalveolar lavage (BAL) in the pediatric age group, we measured albumin and urea concentrations in serum and BAL fluid (BALF) of 37 children aged 3-15 years without bronchopulmonary disease. The children were studied while undergoing elective surgery for non-pulmonary illnesses using a BAL protocol adjusted to body weight. ELF increased with age in proportion to increases in lavage volume. When corrected for the child's weight, approximately 20 mu l ELF/kg body weight were recovered throughout the age range. ELF derived by determining albumin or urea concentrations in BALF were significantly correlated; however, considerable variability was observed in older children when the urea method was used. This was likely due to the increase in dwell time that is known to affect urea concentrations in BALF. In children ELF/100 ml BALF was higher than in adults, suggesting a greater permeability of the alveolar membrane in children. These data show that a BAL protocol adjusted to body weight will yield constant fractions of ELF in children aged 3-15 years. These results should facilitate the comparison of BALF constituents in children of different age groups.