Coexisting atopic conditions influence the likelihood of allergic bronchopulmonary aspergillosis in asthma

Prevalence of Aspergillus Sensitization and Allergic Bronchopulmonary Aspergillosis in Adults With Bronchial Asthma: A Systematic Review of Global Data

BACKGROUND

The prevalence of allergic bronchopulmonary aspergillosis (ABPA) in asthmatic patients remains unclear and is likely different across geographic locales.

OBJECTIVE

To systematically review the literature for estimating the prevalence of Aspergillus sensitization (AS) and ABPA in adults with bronchial asthma.

METHODS

We searched the PubMed and Embase databases for studies reporting the prevalence of AS or ABPA in at least 50 asthmatic subjects. The primary outcome was to assess the prevalence of ABPA. The secondary outcome was to evaluate the prevalence of AS in asthma and that of ABPA in asthma with AS. We pooled the prevalence estimates using a random-effects model and examined the factors influencing the prevalence using multivariate meta-regression.

RESULTS

Of the 11,801 records retrieved, 86 studies with 25,770 asthmatic subjects met the inclusion criteria. Most of the studies were from tertiary care centers. The pooled prevalence of ABPA in asthma (47 studies; 9822 asthmatic subjects) was 11.3% (95% CI, 8.7-14.2). The pooled prevalence of AS in asthma (73 studies; 23,003 asthmatic subjects) was 25.1% (95% CI, 20.5-30.0), whereas the prevalence of ABPA in AS (36 studies; 2954 asthmatic subjects) was 37.0% (95% CI, 27.9-46.6). Multivariate meta-regression identified studies published from India (odds ratio, 1.11; 95% CI, 1.01-1.23) as the only factor associated with higher ABPA prevalence. There was presence of significant statistical heterogeneity and publication bias.

CONCLUSIONS

We found a high prevalence of ABPA in adult asthmatic subjects, underscoring the need for screening for ABPA in all asthmatic subjects seeking tertiary care.

Proteomic Analysis of Serum Differentially Expressed Proteins Between Allergic Bronchopulmonary Aspergillosis and Asthma

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) constantly develops in asthmatics, which has not been fully investigated.

OBJECTIVES

This study aimed to investigate serum differentially expressed proteins (DEPs) between ABPA and asthma using the new approach isobaric tags by relative and absolute quantitation (iTRAQ).

METHODS

Each 16 serum samples from ABPA or asthmatic subjects were pooled and screened using iTRAQ. After bioinformatic analysis, five candidate DEPs were validated in the enlarged serum samples from additional 21 ABPA, 31 asthmatic and 20 healthy subjects using ELISA. A receiver operating characteristic (ROC) curve was used to estimate the diagnostic power of carnosine dipeptidase 1 (CNDP1).

RESULTS

A total of 29 DEPs were screened out between ABPA and asthmatic groups. Over half of them were enriched in proteolysis and regulation of protein metabolic process. Further verification showed serum levels of immunoglobulin heavy constant gamma 1, α-1-acid glycoprotein 1, corticosteroid-binding globulin and vitronectin were neither differentially altered between ABPA and asthma nor consistent with the proteomic analysis. Only serum CNDP1 was significantly decreased in ABPA patients, compared with asthmatics and healthy controls (P < 0.01 and P < 0.05). The ROC analysis determined 10.73 ng/mL as the cutoff value of CNDP1, which could distinguish ABPA among asthmatics (AUC 0.770, 95%CI 0.632-0.875, P < 0.001).

CONCLUSIONS

This study firstly identified serological DEPs between ABPA and asthma using the new technique iTRAQ. Serum CNDP1 might assist the differential diagnosis of ABPA from asthma and serve as a new pathogenetic factor in fungal colonization and sensitization.

Airway mycosis in allergic airway disease

The allergic airway diseases, including chronic rhinosinusitis (CRS), asthma, allergic bronchopulmonary mycosis (ABPM) and many others, comprise a heterogeneous collection of inflammatory disorders affecting the upper and lower airways and lung parenchyma that represent the most common chronic diseases of humanity. In addition to their shared tissue tropism, the allergic airway diseases are characterized by a distinct pattern of inflammation involving the accumulation of eosinophils, type 2 macrophages, innate lymphoid cells type 2 (ILC2), IgE-secreting B cells, and T helper type 2 (Th2) cells in airway tissues, and the prominent production of type 2 cytokines including interleukin (IL-) 33, IL-4, IL-5, IL-13, and many others. These factors and related inflammatory molecules induce characteristic remodeling and other changes of the airways that include goblet cell metaplasia, enhanced mucus secretion, smooth muscle hypertrophy, tissue swelling and polyp formation that account for the major clinical manifestations of nasal obstruction, headache, hyposmia, cough, shortness of breath, chest pain, wheezing, and, in the most severe cases of lower airway disease, death due to respiratory failure or disseminated, systemic disease. The syndromic nature of the allergic airway diseases that now include many physiological variants or endotypes suggests that distinct endogenous or environmental factors underlie their expression. However, findings from different perspectives now collectively link these disorders to a single infectious source, the fungi, and a molecular pathogenesis that involves the local production of airway proteinases by these organisms. In this review, we discuss the evidence linking fungi and their proteinases to the surprisingly wide variety of chronic airway and systemic disorders and the immune pathogenesis of these conditions as they relate to environmental fungi. We further discuss the important implications these new findings have for the diagnosis and future therapy of these common conditions.

Managing comorbid conditions in severe asthma

Asthma care has increasingly focused on personalised management for severe asthma, and recognition of the role and importance of comorbid conditions has increased. Severe asthma can be crippling; associated comorbid conditions often play a key role in the significant disease morbidity and frequently contribute to a severe and difficult-to-treat asthma phenotype. Comorbid conditions can be broadly grouped as being either airway-related or airway-unrelated. Airway-related comorbid conditions with the greatest impact are allergic rhinitis, chronic rhinosinusitis, vocal cord dysfunction, lung fungal sensitisation and underlying structural lung disease. The most important airway-unrelated comorbid conditions are obesity, obstructive sleep apnoea, gastro-oesophageal reflux disease and anxiety and depression. A diagnostic and management algorithm for comorbid conditions in severe asthma is outlined. It concentrates initially on the group with common comorbid conditions that can be managed in primary care. If asthma remains troublesome, emphasis can shift to identifying uncommon and more complex factors. The algorithm allows for personalised diagnostic and management pathways to be implemented. Personalised diagnosis and management of comorbid conditions are essential to achieving effective and improved outcomes for patients with severe asthma.

Bronchiectasis in severe asthma: Clinical features and outcomes

BACKGROUND

Bronchiectasis is increasingly being identified in patients with severe asthma and could contribute to disease severity.

OBJECTIVE

To determine the prevalence of bronchiectasis in a population of patients with severe asthma and to better characterize the clinical features of these patients and their outcomes.

METHODS

We retrospectively reviewed the medical files of 184 subjects with confirmed severe asthma who had undergone high-resolution thoracic computed tomography and compared the characteristics and outcomes of subjects with and without bronchiectasis.

RESULTS

Bronchiectasis was identified in 86 patients (47%). These patients had concomitant hypersensitivity to nonsteroidal anti-inflammatory drugs (odds ratio [OR] 2.24, 95% confidence interval [CI] 1.00-5.03) and gastroesophageal reflux disease (OR 1.89, 95% CI 1.05-3.41) more frequently than subjects without bronchiectasis, but had less atopic dermatitis (OR 0.188, 95% CI 0.04-0.88). Subjects with bronchiectasis were more frequently hospitalized for asthma exacerbations (OR 2.09, 95% CI 1.08-4.05) and had higher blood eosinophil levels (464 vs 338; P = .005) than subjects without bronchiectasis.

CONCLUSION

Our study suggests that in subjects with severe asthma, the presence of bronchiectasis is associated with more frequent hospitalizations, concomitant gastroesophageal reflux disease, hypersensitivity to nonsteroidal anti-inflammatory drugs, and higher blood eosinophil counts. Bronchiectasis could represent an additional phenotypic feature of severe eosinophilic asthma.

Allergic bronchopulmonary aspergillosis in Japan: A nationwide survey

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) is an allergic pulmonary disease characterized by a hypersensitivity reaction to Aspergillus species colonizing the airways. The clinical characteristics of ABPA may differ depending on genetic and environmental background. We performed a nationwide survey to determine the clinical characteristics of ABPA in Japan.

METHODS

In 2013, a questionnaire on physician-diagnosed ABPA/allergic bronchopulmonary mycosis was sent to 903 medical centers specializing in respiratory or allergic diseases. Cases fulfilling the following criteria were categorized as possible ABPA-central bronchiectasis (ABPA-CB): 1) presence of specific serum immunoglobulin E (IgE) antibodies or a positive skin reaction to Aspergillus, and 2) bronchiectasis or mucoid impaction in the central bronchi.

RESULTS

Of 499 physician-diagnosed cases reported by 132 clinical centers, 358 cases met the criteria for possible ABPA-CB. Median age of ABPA-CB onset was 57 (interquartile range, 44-68) years; later-onset disease, developing ≥50 years of age, accounted for 66% of the cases and was associated with female sex, delayed onset of asthma, and lower levels of serum IgE. A third of the patients (120 patients, 34%) exhibited low levels of serum total IgE (<1000 IU/mL). Aspergillus species were isolated from sputum in 126/213 cases (59%), and Schizophyllum commune was identified in 12 (6%) patients. During the course of the treatment, ABPA recurred in 169 (48%) cases.

CONCLUSIONS

This nationwide survey identified several unique clinical characteristics of ABPA in Japan, such as late-onset, relatively lower serum IgE levels, and frequent recurrences/flares.