Assessing immune function in adult bronchiectasis

Pathophysiology of Chronic Bronchial Infection in Bronchiectasis

Bronchiectasis is a complex and heterogeneous disease. Its pathophysiology is poorly understood, but chronic bronchial infection plays an important role in its natural history, and is associated with poor quality of life, more exacerbations and increased mortality. Pseudomonas aeruginosa, Haemophilus influenzae and Staphylococcus aureus are the most common bacteria related to chronic bronchial infection. Non-tuberculous mycobacteria, fungi and respiratory viruses are also present during clinical stability, and may increase the risk of acute exacerbation. Chronic inflammation is present in bronchiectasis, especially neutrophilic inflammation. However, macrophages and eosinophils also play a key role in the disease. Finally, airway epithelium has innate mechanisms such as mucociliary clearance and antibacterial molecules like mucins and antimicrobial peptides that protect the airways from pathogens. This review addresses how the persistence of microorganisms in the airways and the imbalance of the immune system contribute to the development of chronic bronchial infection in bronchiectasis.

Peripheral Neutrophil-to-Lymphocyte Ratio in Bronchiectasis: A Marker of Disease Severity

Most patients with bronchiectasis have a predominantly neutrophilic inflammatory profile, although other cells such as lymphocytes (as controllers of bronchial inflammation) and eosinophils also play a significant pathophysiological role. Easy-to-interpret blood biomarkers with a discriminative capacity for severity or prognosis are needed. The objective of this study was to assess whether the peripheral neutrophil-to-lymphocyte ratio (NLR) is associated with different outcomes of severity in bronchiectasis. A total of 1369 patients with bronchiectasis from the Spanish Registry of Bronchiectasis were included. To compare groups, the sample was divided into increasing quartiles of NLR ratio. Correlations between quantitative variables were established using Pearson's P test. A simple linear regression (with the value of exacerbations as a quantitative variable) was used to determine the independent relationship between the number and severity of exacerbations and the NLR ratio. The area under the curve (AUC)-ROC was used to determine the predictive capacity of the NLR for severe bronchiectasis, according to the different multidimensional scores. Mean age: 69 (15) years (66.3% of women). The mean NLR was 2.92 (2.03). A higher NLR was associated with more severe bronchiectasis (with an especially significant discriminative power for severe forms) according to the commonly used scores (FACED, E-FACED and BSI), as well as with poorer quality of life (SGRQ), more comorbidities (Charlson index), infection by pathogenic microorganisms, and greater application of treatment. Furthermore, the NLR correlated better with severity scores than other parameters of systemic inflammation. Finally, it was an independent predictor of the incident number and severity of exacerbations. In conclusion, the NLR is an inexpensive and easy-to-measure marker of systemic inflammation for determining severity and predicting exacerbations (especially the most severe) in patients with bronchiectasis.

B Cell Subsets in Colombian Adults with Predominantly Antibody Deficiencies, Bronchiectasis or Recurrent Pneumonia

Aim: To evaluate and describe lymphocyte populations’ and B cell subsets’ frequencies in patients presenting with Predominantly antibody deficiencies (PAD) and diagnosed with bronchiectasis or recurrent pneumonia seen in Cali (Colombian Southwest region). Materials and Methods: 16 subjects with PAD, 20 subjects with pulmonary complications (bronchiectasis or recurrent pneumonia) and 20 healthy donors (HD). Controls and probands between 14 and 64 years old, regardless of gender were included. Lymphocyte populations (T, B and NK cells) and B cell subsets were evaluated in peripheral blood mononuclear cells using flow cytometry, T/B/NK reagent and the pre-germinal center antibody panel proposed by the EUROflow consortium were used. EUROclass and the classification proposed by Driessen et al. were implemented. Results: CVID patients exhibited increase absolute numbers of CD8+ T cells and reduce NK cells as compare with HD, other PAD cases or pulmonary complications. PAD B cell subsets were disturbed when compared to the age range-matched healthy donors. Among B cell subsets, the memory B cell compartment was the most affected, especially switched memory B cells. Four participants were classified as B- and two CVID as smB-Trnorm and smB-21low groups according to EUROclass classification. The most frequent patterns proposed by Driessen et al. were B cell production and germinal center defect. Conclusions: B cell subsets, especially memory B cells, are disturbed in PAD patients from Southwestern Colombia. To the best of our knowledge this is the most comprehensive study of B cell subsets in Colombian adults.

Comparison of different sets of immunological tests to identify treatable immunodeficiencies in adult bronchiectasis patients

Background

The reported prevalence of immunodeficiencies in bronchiectasis patients is variable depending on the frequency and extent of immunological tests performed. European Respiratory Society guidelines recommend a minimum bundle of tests. Broadening the spectrum of immunological tests could increase the number of patients diagnosed with an immunodeficiency and those who could receive specific therapy. The primary objective of the present study was to assess the performance of different sets of immunological tests in diagnosing any, primary, secondary or treatable immunodeficiencies in adults with bronchiectasis.

Methods

An observational, cross-sectional study was conducted at the Bronchiectasis Program of the Policlinico University Hospital in Milan, Italy, from September 2016 to June 2019. Adult outpatients with a clinical and radiological diagnosis of bronchiectasis underwent the same immunological screening during the first visit when clinically stable consisting of: complete blood count; immunoglobulin (Ig) subclass tests for IgA, IgG, IgM and IgG; total IgE; lymphocyte subsets; and HIV antibodies. The primary endpoint was the prevalence of patients with any immunodeficiencies using five different sets of immunological tests.

Results

A total of 401 bronchiectasis patients underwent the immunological screening. A significantly different prevalence of bronchiectasis patients diagnosed with any, primary or secondary immunodeficiencies was found across different bundles. 44.6% of bronchiectasis patients had a diagnosis of immunodeficiency when IgG subclasses and lymphocyte subsets were added to the minimum bundle suggested by the guidelines.

Conclusion

A four-fold increase in the diagnosis of immunodeficiencies can be found in adults with bronchiectasis when IgG subclasses and lymphocyte subsets are added to the bundle of tests recommended by guidelines.

Systemic Inflammatory Biomarkers Define Specific Clusters in Patients with Bronchiectasis: A Large-Cohort Study

Differential phenotypic characteristics using data mining approaches were defined in a large cohort of patients from the Spanish Online Bronchiectasis Registry (RIBRON). Three differential phenotypic clusters (hierarchical clustering, scikit-learn library for Python, and agglomerative methods) according to systemic biomarkers: neutrophil, eosinophil, and lymphocyte counts, C reactive protein, and hemoglobin were obtained in a patient large-cohort (n = 1092). Clusters #1–3 were named as mild, moderate, and severe on the basis of disease severity scores. Patients in cluster #3 were significantly more severe (FEV1, age, colonization, extension, dyspnea (FACED), exacerbation (EFACED), and bronchiectasis severity index (BSI) scores) than patients in clusters #1 and #2. Exacerbation and hospitalization numbers, Charlson index, and blood inflammatory markers were significantly greater in cluster #3 than in clusters #1 and #2. Chronic colonization by Pseudomonas aeruginosa and COPD prevalence were higher in cluster # 3 than in cluster #1. Airflow limitation and diffusion capacity were reduced in cluster #3 compared to clusters #1 and #2. Multivariate ordinal logistic regression analysis further confirmed these results. Similar results were obtained after excluding COPD patients. Clustering analysis offers a powerful tool to better characterize patients with bronchiectasis. These results have clinical implications in the management of the complexity and heterogeneity of bronchiectasis patients.

The clinical impact of self-reported symptoms of chronic rhinosinusitis in people with bronchiectasis

BACKGROUND

Chronic rhinosinusitis affects 62% of adults with bronchiectasis and is linked to greater bronchiectasis severity. However, the impact of symptoms of chronic rhinosinusitis on disease-specific and cough-related quality of life is unknown.

METHODS

In this cross-sectional study, adults with stable bronchiectasis and chronic rhinosinusitis symptoms completed the sinonasal outcome test-22 (SNOT-22), quality of life-bronchiectasis questionnaire, and Leicester cough questionnaire. Bronchiectasis severity was assessed using the bronchiectasis severity index (BSI) and chest high-resolution computed tomography (HRCT).

RESULTS

Sixty participants with bronchiectasis (mean [SD] forced expiratory volume in 1 s of 73.2 [25.5] %predicted) were included. Greater severity of chronic rhinosinusitis symptoms (based on SNOT-22) was moderately associated with impaired cough-related quality of life (according to the Leicester cough questionnaire; all r > -.60) and impaired bronchiectasis-specific quality of life (based on the quality of life-bronchiectasis questionnaire), with impaired physical function (r = -.518), less vitality (r = -.631), reduced social function (r = -.546), greater treatment burden (r = -.411), and increased severity of respiratory symptoms (r = -.534). Chronic rhinosinusitis symptoms were unrelated to disease severity according to the BSI (r = .135) and HRCT scoring (all r < .200). The severity of chronic rhinosinusitis symptoms was not affected by sputum color (p = .417) or the presence of Pseudomonas aeruginosa colonization (p = .73).

CONCLUSIONS

In adults with bronchiectasis, chronic rhinosinusitis has a consistent and negative impact on both cough-related and bronchiectasis-specific quality of life.

A retrospective correlative profiling of lung functions, microbiological, radiological, periodontal, hematological parameters in noncystic fibrosis bronchiectasis patients of North India

Introduction:

Noncystic fibrosis bronchiectasis (NCFB) is a neglected debilitating condition with scarce epidemiological literature explaining its geographical heterogeneity, especially in lower and middle-income countries. This study aimed to assess and correlate the functional profile of NCFB patients and evaluate the correlation of body mass index (BMI) with several disease variables.

Methods:

This mixed-method retrospective research study was conducted on 124 radiologically confirmed NCFB patients in terms of various qualitative and quantitative variables.

Results:

Restrictive ventilatory defect was the most common type with the preponderance of male former smokers. Mean platelet lymphocyte ratio (PLR; 104.08 ± 73.59) revealed certain degree of systemic inflammatory burden with a slightly higher mean peripheral leukocyte count (10665.19 ± 4268.81 cell/mm³) and eosinophilia of >2%. Almost all patients had periodontal disease with a higher prevalence of chronic periodontitis (54.83%). Moderately severe and predominantly cystic radiological type was encountered with 61.2% patients positive for Pseudomonas aeruginosa. Bronchiectasis aetiology comorbidity index (BACI) i.e., 2.34 ± 2.37 represented an intermediate mortality risk in our patients. On basis of BMI, majority were young underweights with poor pulmonary functions while PLR skewed toward overweight patients (nonsignificant P > 0.05). Forced expiratory volume/forced vital capacity displayed a negative weak moderately significant correlation with BACI (r = −0.24; P = 0.008). Peripheral lymphocyte count demonstrated a weak negative but significant correlation with modified Reiff score (r = −0.20; P = 0.023) while serum neutrophil count had a weak negative moderately significant correlation with hemoglobin (r = −0.20; P = 0.023).

Conclusions:

NCFB bears great heterogeneity with distinct geographical phenotypes and should be correlated thoroughly in terms of peripheral leukocytes count, pulmonary functions, radiology, BMI, and coexisting comorbidities for adequate management.

Phenotypic Clustering in Non-Cystic Fibrosis Bronchiectasis Patients: The Role of Eosinophils in Disease Severity

Whether high blood eosinophil counts may define a better phenotype in bronchiectasis patients, as shown in chronic obstructive pulmonary disease (COPD), remains to be investigated. Differential phenotypic characteristics according to eosinophil counts were assessed using a biostatistical approach in a large cohort study from the Spanish Online Bronchiectasis Registry (RIBRON). The 906 patients who met the inclusion criteria were clustered into two groups on the basis of their eosinophil levels. The potential differences according to the bronchiectasis severity index (BSI) score between two groups (Mann–Whitney U test and eosinophil count threshold: 100 cells/µL) showed the most balanced cluster sizes: above-threshold and below-threshold groups. Patients above the threshold exhibited significantly better clinical outcomes, lung function, and nutritional status, while showing lower systemic inflammation levels. The proportion of patients with mild disease was higher in the above-threshold group, while the below-threshold patients were more severe. Two distinct clinical phenotypes of stable patients with non-cystic fibrosis (CF) bronchiectasis of a wide range of disease severity were established on the basis of blood eosinophil counts using a biostatistical approach. Patients classified within the above-threshold cluster were those exhibiting a mild disease, significantly better clinical outcomes, lung function, and nutritional status while showing lower systemic inflammatory levels. These results will contribute to better characterizing bronchiectasis patients into phenotypic profiles with their clinical implications.

Pathophysiology of Bronchiectasis

Bronchiectasis is a complex, heterogeneous disorder defined by both a radiological abnormality of permanent bronchial dilatation and a clinical syndrome. There are multiple underlying causes including severe infections, mycobacterial disease, autoimmune conditions, hypersensitivity disorders, and genetic conditions. The pathophysiology of disease is understood in terms of interdependent concepts of chronic infection, inflammation, impaired mucociliary clearance, and structural lung damage. Neutrophilic inflammation is characteristic of the disease, with elevated levels of harmful proteases such as neutrophil elastase associated with worse outcomes. Recent data show that neutrophil extracellular trap formation may be the key mechanism leading to protease release and severe bronchiectasis. Despite the dominant of neutrophilic disease, eosinophilic subtypes are recognized and may require specific treatments. Neutrophilic inflammation is associated with elevated bacterial loads and chronic infection with organisms such as Pseudomonas aeruginosa. Loss of diversity of the normal lung microbiota and dominance of proteobacteria such as Pseudomonas and Haemophilus are features of severe bronchiectasis and link to poor outcomes. Ciliary dysfunction is also a key feature, exemplified by the rare genetic syndrome of primary ciliary dyskinesia. Mucus symptoms arise through goblet cell hyperplasia and metaplasia and reduced ciliary function through dyskinesia and loss of ciliated cells. The contribution of chronic inflammation, infection, and mucus obstruction leads to progressive structural lung damage. The heterogeneity of the disease is the most challenging aspect of management. An understanding of the pathophysiology of disease and their biomarkers can help to guide personalized medicine approaches utilizing the concept of "treatable traits."

Neutrophil dysfunction in bronchiectasis: an emerging role for immunometabolism

Bronchiectasis is a heterogenous disease with multiple underlying causes. The pathophysiology is poorly understood but neutrophilic inflammation and dysfunctional killing of pathogens is believed to be key. There are, however, no licensed therapies for bronchiectasis that directly target neutrophilic inflammation. In this review, we discuss our current understanding of neutrophil dysfunction and therapeutic targeting in bronchiectasis. Immunometabolic reprogramming, a process through which inflammation changes inflammatory cell behaviour by altering intracellular metabolic pathways, is increasingly recognised across multiple inflammatory and autoimmune diseases. Here, we show evidence that much of the neutrophil dysfunction observed in bronchiectasis is consistent with immunometabolic reprogramming. Previous attempts at developing therapies targeting neutrophils have focused on reducing neutrophil numbers, resulting in increased frequency of infections. New approaches are needed and we propose that targeting metabolism could theoretically reverse neutrophil dysfunction and dysregulated inflammation. As an exemplar, 5' adenosine monophosphate (AMP)-activated protein kinase (AMPK) activation has already been shown to reverse phagocytic dysfunction and neutrophil extracellular trap (NET) formation in models of pulmonary disease. AMPK modulates multiple metabolic pathways, including glycolysis which is critical for energy generation in neutrophils. AMPK activators can reverse metabolic reprogramming and are already in clinical use and/or development. We propose the need for a new immunomodulatory approach, rather than an anti-inflammatory approach, to enhance bacterial clearance and reduce bronchiectasis disease severity.

Primary Immun Deficiency in Patients with Non-Cystic Fibrosis Bronchiectasis and Its Relationship with Clinical Parameters

OBJECTIVE

Bronchiectasis is characterized by chronic respiratory infection. The role of immunodeficiency in this disease is poorly studied in relation to clinical indices. The primary aim of this study was to determine the frequency of these neglected altered immune status by evaluating immunoglobulins, lymphocyte subsets, complement levels, and neutrophil function, and to assess its relationship with clinical parameters in adult patients with non-cystic fibrosis bronchiectasis (NCFB).

MATERIAL AND METHODS

A total of 74 (30 men and 44 women with a mean age of 47±17 years) adult patients with stable NCFB were enrolled in this study. The bronchiectasis severity index (BSI) and FACED (F:FEV1, A: Age, C: Chronic colonization, E: Extension, D: Dyspnea) scores were assessed. Peripheral blood samples were collected for the detection of total IgG, IgA, IgM, IgE, and IgG subclasses and C3 and C4 levels. The counts of CD3, CD4, CD8, CD19, CD16/56 expressing peripheral blood lymphocytes and neutrophil oxidative function were evaluated.

RESULTS

In the study population, BSI and FACED severity index scores increased with longer duration of the disease (p=0.01 and p=0.040, respectively). Of the 74 patients, 27 (37%) showed humoral aberrations. The number of male patients were higher in this group (p=0.03). High serum total IgE levels were associated with high scores in BSI (moderate-severe group versus mild group, p=0.030). Patients with bronchiectasis demonstrated lower CD3+ T cell count, lower CD4+ T helper cell percentage, and lower CD4+ T cell count (p=0.031, p=0.030, p=0.029, respectively) than healthy subjects. A significant negative correlation was found between the percentage and count of CD16/56+ natural killer (NK) cells and the number of exacerbations within the past year (r=-0.230, p=0.049 and r=-0.264, p=0.023, respectively).

CONCLUSION

Humoral aberrations in adult patients with NCFB were found to be frequent. IgE levels were related to high scores for disease severity indices. Furthermore, patients with low percentage and counts of NK cells had higher rates of exacerbations. These results emphasize the importance of immune function assessment in adult patients with NCFB.

Understanding the role of neutrophils in chronic inflammatory airway disease

Airway neutrophilia is a common feature of many chronic inflammatory lung diseases and is associated with disease progression, often regardless of the initiating cause. Neutrophils and their products are thought to be key mediators of the inflammatory changes in the airways of patients with chronic obstructive pulmonary disease (COPD) and have been shown to cause many of the pathological features associated with disease, including emphysema and mucus hypersecretion. Patients with COPD also have high rates of bacterial colonisation and recurrent infective exacerbations, suggesting that neutrophil host defence mechanisms are impaired, a concept supported by studies showing alterations to neutrophil migration, degranulation and reactive oxygen species production in cells isolated from patients with COPD. Although the role of neutrophils is best described in COPD, many of the pathological features of this disease are not unique to COPD and also feature in other chronic inflammatory airway diseases, including asthma, cystic fibrosis, alpha-1 anti-trypsin deficiency, and bronchiectasis. There is increasing evidence for immune cell dysfunction contributing to inflammation in many of these diseases, focusing interest on the neutrophil as a key driver of pulmonary inflammation and a potential therapeutic target than spans diseases. This review discusses the evidence for neutrophilic involvement in COPD and also considers their roles in alpha-1 anti-trypsin deficiency, bronchiectasis, asthma, and cystic fibrosis. We provide an in-depth assessment of the role of the neutrophil in each of these conditions, exploring recent advances in understanding, and finally discussing the possibility of common mechanisms across diseases.

The Role of the Immune Response in the Pathogenesis of Bronchiectasis

Bronchiectasis is a prevalent respiratory condition characterised by permanent and abnormal dilation of the lung airways (bronchi). There are a large variety of causative factors that have been identified for bronchiectasis; all of these compromise the function of the immune response to fight infection. A triggering factor may lead to the establishment of chronic infection in the lower respiratory tract. The bacteria responsible for the lower respiratory tract infection are usually found as commensals in the upper respiratory tract microbiome. The consequent inflammatory response to infection is largely responsible for the pathology of this condition. Both innate and adaptive immune responses are activated. The literature has highlighted the central role of neutrophils in the pathogenesis of bronchiectasis. Proteases produced in the lung by the inflammatory response damage the airways and lead to the pathological dilation that is the pathognomonic feature of bronchiectasis. The small airways demonstrate infiltration with lymphoid follicles that may contribute to localised small airway obstruction. Despite aggressive treatment, most patients will have persistent disease. Manipulating the immune response in bronchiectasis may potentially have therapeutic potential.

Antibody deficiency in patients with frequent exacerbations of Chronic Obstructive Pulmonary Disease (COPD)

Chronic Obstructive Pulmonary Disease is the third leading cause of death in the US, and is associated with periodic exacerbations, which account for the largest proportion of health care utilization, and lead to significant morbidity, mortality, and worsening lung function. A subset of patients with COPD have frequent exacerbations, occurring 2 or more times per year. Despite many interventions to reduce COPD exacerbations, there is a significant lack of knowledge in regards to their mechanisms and predisposing factors. We describe here an important observation that defines antibody deficiency as a potential risk factor for frequent COPD exacerbations. We report a case series of patients who have frequent COPD exacerbations, and who were found to have an underlying primary antibody deficiency syndrome. We also report on the outcome of COPD exacerbations following treatment in a subset with of these patients with antibody deficiency. We identified patients with COPD who had 2 or more moderate to severe exacerbations per year; immune evaluation including serum immunoglobulin levels and pneumococcal IgG titers was performed. Patients diagnosed with an antibody deficiency syndrome were treated with either immunoglobulin replacement therapy or prophylactic antibiotics, and their COPD exacerbations were monitored over time. A total of 42 patients were identified who had 2 or more moderate to severe COPD exacerbations per year. Twenty-nine patients had an underlying antibody deficiency syndrome: common variable immunodeficiency (8), specific antibody deficiency (20), and selective IgA deficiency (1). Twenty-two patients had a follow-up for at least 1 year after treatment of their antibody deficiency, which resulted in a significant reduction of COPD exacerbations, courses of oral corticosteroid use and cumulative annual dose of oral corticosteroid use, rescue antibiotic use, and hospitalizations for COPD exacerbations. This case series identifies antibody deficiency as a potentially treatable risk factor for frequent COPD exacerbations; testing for antibody deficiency should be considered in difficult to manage frequently exacerbating COPD patients. Further prospective studies are warranted to further test this hypothesis.

Bronchiectasis in Children: Current Concepts in Immunology and Microbiology

Bronchiectasis is a complex chronic respiratory condition traditionally characterized by chronic infection, airway inflammation, and progressive decline in lung function. Early diagnosis and intensive treatment protocols can stabilize or even improve the clinical prognosis of children with bronchiectasis. However, understanding the host immunologic mechanisms that contribute to recurrent infection and prolonged inflammation has been identified as an important area of research that would contribute substantially to effective prevention strategies for children at risk of bronchiectasis. This review will focus on the current understanding of the role of the host immune response and important pathogens in the pathogenesis of bronchiectasis (not associated with cystic fibrosis) in children.

Bronchiectasis: Current Concepts in Pathogenesis, Immunology, and Microbiology

Bronchiectasis is a disorder of persistent lung inflammation and recurrent infection, defined by a common pathological end point: irreversible bronchial dilatation arrived at through diverse etiologies. This suggests an interplay between immunogenetic susceptibility, immune dysregulation, bacterial infection, and lung damage. The damaged epithelium impairs mucus removal and facilitates bacterial infection with increased cough, sputum production, and airflow obstruction. Lung infection is caused by respiratory bacterial and fungal pathogens, including Pseudomonas aeruginosa, Haemophilus, Aspergillus fumigatus, and nontuberculous mycobacteria. Recent studies have highlighted the relationship between the lung microbiota and microbial-pathogen niches. Disease may result from environments favoring interleukin-17-driven neutrophilia. Bronchiectasis may present in autoimmune disease, as well as conditions of immune dysregulation, such as combined variable immune deficiency, transporter associated with antigen processing-deficiency syndrome, and hyperimmunoglobulin E syndrome. Differences in prevalence across geography and ethnicity implicate an etiological mix of genetics and environment underpinning susceptibility.

Management of bronchiectasis in adults

Formerly regarded as a rare disease, bronchiectasis is now increasingly recognised and a renewed interest in the condition is stimulating drug development and clinical research. Bronchiectasis represents the final common pathway of a number of infectious, genetic, autoimmune, developmental and allergic disorders and is highly heterogeneous in its aetiology, impact and prognosis. The goals of therapy should be: to improve airway mucus clearance through physiotherapy with or without adjunctive therapies; to suppress, eradicate and prevent airway bacterial colonisation; to reduce airway inflammation; and to improve physical functioning and quality of life. Fortunately, an increasing body of evidence supports interventions in bronchiectasis. The field has benefited greatly from the introduction of evidence-based guidelines in some European countries and randomised controlled trials have now demonstrated the benefit of long-term macrolide therapy, with accumulating evidence for inhaled therapies, physiotherapy and pulmonary rehabilitation. This review provides a critical update on the management of bronchiectasis focussing on emerging evidence and recent randomised controlled trials.

Changes in B cell immunophenotype in common variable immunodeficiency: cause or effect - is bronchiectasis indicative of undiagnosed immunodeficiency?

Common variable immunodeficiency (CVID) is the most common severe primary immunodeficiency, but the pathology of this condition is poorly understood. CVID involves a defect in the production of immunoglobulin from B cells, with a subsequent predisposition to infections. Approximately 10-20% of cases are inherited, but even in families with a genetic defect the penetrance is far from complete. A classification system for CVID has been suggested (EUROclass) based on B cell immunophenotyping, but it has not been shown that altered B cell immunophenotype is not a consequence of the complications and treatment of CVID. This study compares the EUROclass B cell immunophenotype of CVID patients (n = 30) with suitable disease controls with bronchiectasis (n = 11), granulomatous disease (Crohn's disease) (n = 9) and neurological patients on immunoglobulin treatment (n = 6). The results of this study correlate with previous literature, that alterations in B cell immunophenotype are associated strongly with CVID. Interestingly, three of the 11 bronchiectasis patients without known immunodeficiency had an altered B cell immunophenotype, suggesting the possibility of undiagnosed immunodeficiency, or that bronchiectasis may cause a secondary alteration in B cell immunophenotype. This study showed a significant difference in B cell immunophenotype between CVID patients compared to disease control groups of granulomatous disease and immunoglobulin treatment. This suggests that granulomatous disease (in Crohn's disease) and immunoglobulin treatment (for chronic neurological conditions) are not causal of an altered B cell immunophenotype in these control populations.

Bronchiectasis

The frequency of diagnosing bronchiectasis is increasing around the world. Cystic fibrosis is the most common inherited cause of bronchiectasis, but there is increasing recognition of significant numbers of patients with bronchiectasis from various causes. With increasing awareness of bronchiectasis, a significant number of research, concerning the causes and treatments, were published over the past few years. Investigation of the underlying cause of bronchiectasis is the most important key to effective management. The purpose of this report is to review the immunological abnormalities that cause bronchiectasis in those that the cystic fibrosis has been excluded, identify the available evidences of current management, and discuss several controversies in the treatment of this disorder.

Mechanisms of immune dysfunction and bacterial persistence in non-cystic fibrosis bronchiectasis

Bronchiectasis is a chronic inflammatory lung disease. The underlying cause is not identified in the majority of patients, but bronchiectasis is associated with a number of severe infections, immunodeficiencies and autoimmune disorders. Regardless of the underlying cause, the disease is characterised by a vicious cycle of bacterial colonisation, airway inflammation and airway structural damage. Inflammation in bronchiectasis is predominantly neutrophil driven. Neutrophils migrate to the airway under the action of pro-inflammatory cytokines such as interleukin-8, tumour necrosis factor-α and interleukin-1β, all of which are increased in the airway of patients with bronchiectasis. Bacterial infection persists in the airway despite large numbers of neutrophils that would be expected to phagocytose and kill pathogens under normal circumstances. Evidence suggests that neutrophils are disabled by multiple mechanisms including cleavage of phagocytic receptors by neutrophil elastase and inhibition of phagocytosis by neutrophil peptides. Complement activation is impaired and neutrophil elastase may cleave activated complement from pathogens preventing effective opsonisation. Organisms also evade clearance by adapting to chronic infection. The formation of biofilms, reduced motility and the down-regulation of virulence factors are among the strategies used to subvert innate immune mechanisms. Greater understanding of the mechanisms underlying chronic colonisation in bronchiectasis will assist in the development of new treatments for this important disease.

Airway microbiology and host defences in paediatric non-CF bronchiectasis

Bronchiectasis in children without cystic fibrosis is most common in socioeconomically disadvantaged communities. Recurrent pneumonia in early childhood and defective pulmonary defences are important risk factors. These help establish a 'vicious cycle' of impaired mucociliary clearance, infection, airway inflammation and progressive lung injury. Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis and Pseudomonas aeruginosa are the main infecting pathogens. H. influenzae predominates across all ages, while P. aeruginosa is found in older children with advanced disease. It is uncertain whether viruses and upper airway commensal bacteria play an important aetiological role. Overall, the microbiological data are limited however and there are difficulties obtaining reliable respiratory specimens from young children. Bronchiectasis is a complex disorder resulting from susceptibility to pulmonary infection and poorly regulated respiratory innate and adaptive immunity. Airway inflammatory responses are excessive and persist, even once infection is cleared. Improved specimen collection, molecular techniques and biomarkers are needed to enhance management.

[Inflammation markers in the exhaled air of patients with bronchiectasis unassociated with cystic fibrosis]

INTRODUCTION

The aim of the study was to analyse the relationship between the intensity of the respiratory tract inflammation, expressed by oxidative stress markers, and the severity of the disease in patients with bronchiectasis unassociated with cystic fibrosis.

PATIENTS AND METHODS

The study included 25 patients with stable bronchiectasis (15 females and 10 males). As determining factors of severity, the following parameters were collected: degree of dyspnoea, number of exacerbations/admissions in the last year, mean daily sputum volume, sputum colour (graduated colour scale), bacterial colonisation, respiratory function tests, quality of life (St. George questionnaire) and radiological extension of the lesions (Bhalla scale). Inflammation was analysed using the measurement of nitric oxide, pH and concentration of nitrites, nitrates and isoprostane in the exhaled air condensate. The C reactive protein and erythrocyte sedimentation rate were also determined in peripheral blood.

RESULTS

There were no significant relationships between the markers in the exhaled air condensate and the clinical, radiological and functional involvement or the quality of life of the patients. Only bacterial colonisation (16 cases) was associated with higher values of nitrates in exhaled air (mean+/-standard deviation: 18+/-4 compared to 7+/-2microM; r(2)=0.6) and a higher number of exacerbations (3.1+/-1.9 compared to 1.7+/-1.9; r(2)=0.3).

CONCLUSIONS

In our study, the measurement of inflammation markers in exhaled air is only associated with some parameters of severity in patients with bacterial bronchiectasis.

Malnutrition on the menu: nutritional status of institutionalised elderly Australians in low-level care

BACKGROUND

Most studies reporting malnutrition in the elderly relate to high-level care. However, one third of Australians in aged care reside in low-level care facilities. Data is limited on their nutritional status.

OBJECTIVE

To investigate the nutritional status of elderly in low-level care facilities.

DESIGN

A cross sectional study design.

SETTING

14 low-level aged care facilities in metropolitan Melbourne.

PARTICIPANTS

Convenience sample of 103 ambulatory elderly (86 +/- 6.6 years (mean +/- SD), 76% female, comprising 15% of the hostel population) able to perform daily functions of living.

MEASUREMENTS

Nutritional intake assessed by three-day weighed food records, and nutritional status by haematological and biochemical markers and body composition (dual energy X-ray absorptiometry).

RESULTS

FOOD served did not supply the estimated average requirements (EAR) for 5 of the 14 nutrients analysed. Compared with EAR, 34% of participants were protein malnourished and 62% had energy intake deficits. Micronutrient intake was low for calcium, magnesium, folate, zinc (for men) and dietary fibre. Vitamin D deficiency (serum 25OH Vitamin D < 50 nmol/L) was present in 58% of residents. More men than women had low haemoglobin (P < 0.000), low red blood cells (P < 0.000), and a raised white blood cell count (P = 0.004). Forty three percent of men and 21% women had sarcopenia, 28% of men and 44% women had excess body fat (> 28% and >40%, respectively) and 14% of men and 12 % of women were sarcopenic-obese. Only 12% showed no sign of undernutrition using seven different nutritional indicators. Around 65% had two or more indicators of undernutrition.

CONCLUSION

These findings highlight the need for the supply of more, better quality, nutrient dense food to residents and better detection of undernutrition in aged care facilities. Maintenance of nutritional status has the potential to reduce morbidity and delay the transition to high-level care.

Bactericidal activity of neutrophils with reduced oxidative burst from adults with bronchiectasis

Recent work has shown that the most common abnormality on screening of immune function in cohort of adult subjects with bronchiectasis was a low neutrophil oxidative burst. To assess the functional significance of a low oxidative burst in subjects with idiopathic bronchiectasis. Neutrophils with a low oxidative burst were obtained from six bronchiectasis patients and assessed for their ability to kill Staphylococcus aureus. The results were compared with those obtained using neutrophils from 12 healthy controls subjects and control neutrophils treated with dimethylthiourea (DMTU), an inhibitor of the oxidative burst. The results showed that the bronchiectasis subjects had significantly reduced killing of bacteria compared with controls (p<0.001). The addition of DMTU to neutrophils of control subjects significantly impaired both the oxidative burst and bactericidal activity. The addition of interferon-gamma enhanced oxidative burst in both groups. Abnormal neutrophil function in some subjects with bronchiectasis may account for their high rate of infection.

Influenza vaccine for children and adults with bronchiectasis

BACKGROUND

Bronchiectasis is a major cause of respiratory morbidity especially in developing countries. In affluent countries, bronchiectasis is increasingly recognised in certain subsections of communities (e.g. Aboriginal communities) as well as a coexistent disease/comorbidity and disease modifier in respiratory diseases such as COPD (reported rates of 29-50% in adults). Respiratory exacerbations in people with bronchiectasis are associated with reduced quality of life, accelerated pulmonary decline, hospitalisation and even death. Current recommendations for inactivated influenza vaccination includes adults aged 65 years and over, those in residential care and health care workers and also all adults and children with chronic illness, particularly cardiac and pulmonary diseases.

OBJECTIVES

To evaluate the effectiveness of influenza vaccine as routine management in children and adults with bronchiectasis in (a) reducing the severity and frequency of respiratory exacerbations and (b) pulmonary decline

SEARCH STRATEGY

The Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register, MEDLINE and EMBASE databases were searched by the Cochrane Airways Group. Pharmaceutical manufacturers of influenza were also contacted. The latest searches were performed in July 2006.

SELECTION CRITERIA

All randomised controlled trials with at least one annual influenza vaccine involving children or adults with bronchiectasis.

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion. It was planned that two independent reviewers selected, extracted and assessed data for inclusion.

MAIN RESULTS

No eligible trials were identified and thus no data were available for analysis.

AUTHORS' CONCLUSIONS

There is neither evidence for, nor against, routine annual influenza vaccination for children and adults with bronchiectasis.