ORMDL3/GSDMB genotype as a risk factor for early-onset adult asthma is linked to total serum IgE levels but not to allergic sensitization.

BACKGROUND: An orosomucoid-like 3 (ORMDL3)/gasdermin B (GSDMB) gene locus on chromosome 17q is consistently associated with childhood-onset asthma, which is highly atopic. As some evidence suggests the relationship between asthma and allergic sensitization reflects asthma patient susceptibility to augmented IgE responses driven by common environmental allergens rather than an increased asthma risk after allergen exposure, we aimed to determine any relationships between this locus region and childhood-onset adult asthma with regard to serum total IgE levels or allergic sensitization. METHODS: We conducted a case-control association study using three independent Japanese populations (3869 total adults) and analyzed the ORs for association of rs7216389, an expression quantitative trait locus for ORMDL3/GSDMB, with adult asthma according to onset age. Additionally, associations between the rs7216389 genotype and total serum IgE levels or allergic sensitization was examined. RESULTS: Rs7216389 was associated with both childhood-onset adult asthma (OR for asthmatic patients afflicted at the age of 10 years or younger = 1.61, p = 0.00021) and asthmatic patients with higher levels of total serum IgE (OR for asthmatic patients with IgE ≥1000IU/mL = 1.55, p = 0.0033). In both healthy controls and in the combined healthy and asthmatic individuals, rs7216389 was correlated with increased total serum IgE levels (p < 0.0005), but not allergic sensitization (p > 0.1). CONCLUSIONS: ORMDL3/GSDMB is an important susceptibility gene for childhood-onset adult asthma in Japanese populations and this association is linked to elevated total serum IgE levels but not to allergic sensitization.

Genetic impact of CDHR3 on the adult onset of asthma and COPD.

BACKGROUND: Adult-onset asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous diseases caused by complex gene-environment interactions. A functional single nucleotide polymorphism of cadherin-related family member 3 (CDHR3), known as a receptor of rhinovirus-C, is associated with childhood-onset asthma especially in atopic individuals. OBJECTIVE: Here, we identified risk factors for adult-onset asthma and COPD, focusing on the impact of the CDHR3 variant in atopic individuals. METHODS: We conducted a longitudinal, retrospective, observational cohort study of 1523 healthy adults with baseline examinations at Tsukuba Medical Center Hospital in 2008 and retrospectively identified new-onset, physician-diagnosed asthma or COPD from 2009 to 2018. We assessed risk factors by the Cox regression analysis. The impact of CDHR3 variant rs6967330 was also examined in individuals with pre-existing atopy. RESULTS: Over 10 study years, 103 people developed airway diseases (79 asthma and 24 COPD; 52 females, average onset-age 55 years old, range 38-80). Higher body mass index (BMI) and lower forced expiratory volume in one second/forced vital capacity (FEV1 /FVC) ratio were significant risk factors (BMI: HR 1.072 [95% CI 1.005-1.14], P = .034; FEV1 /FVC ratio: HR 1.091 [1.044-1.14], P = .00011). Restriction to atopic individuals saw the A allele at rs6967330 and lower FEV1 /FVC ratio to associate with adult-onset disease (A allele: HR 2.89 [1.57-5.20], P = .00062; FEV1 /FVC ratio: HR 1.10 [1.04-1.17], P = .0010). CONCLUSION AND CLINICAL RELEVANCE: Genetic susceptibility to rhinovirus-C infection in atopic individuals is a risk factor for chronic airway diseases even in later life.

A cis-eQTL allele regulating reduced expression of CHI3L1 is associated with late-onset adult asthma in Japanese cohorts.

BACKGROUND: The chitinase-like protein YKL-40 plays a major role in inhibiting the inflammasome. Deregulation of inflammasome activation is emerging as a key modulator of pathologic airway inflammation in patients with asthma. We determined whether cis-expression quantitative trait loci (eQTLs) of the gene that encodes YKL-40, chitinase 3-like 1 (CHI3L1), are involved in the onset of asthma or in specific asthma phenotypes. METHODS: This case-control study, which was conducted at the University of Tsukuba, Japan, included a total of 2709 adults from the Tsukuba genome-wide association study (GWAS) cohort (734 healthy volunteers and 237 asthma patients), the Tsukuba replication cohort (375 healthy adult volunteers and 381 adult asthma patients), and the Hokkaido replication cohort (554 healthy adult volunteers and 428 adult asthma patients). Among 34 cis-eQTLs in CHI3L1 in the lung, rs946261 was associated with adult asthma in these Japanese cohorts. The genetic impact of rs946261 on asthma was also examined according to the age at onset and adult asthma clusters. RESULTS: In the Tsukuba GWAS cohort, the C allele at rs946261 was significantly associated with reduced expression of CHI3L1 mRNA in the lung and with development of asthma (odds ratio (OR) 1.27; P = 0.036). The association was also observed following analysis of the three Japanese cohorts (OR 1.16; P = 0.013). A stronger association was found with late-onset asthma that developed at 41 years of age or later (OR 1.24; 95% confidence interval (CI) 1.07-1.45; P = 0.0058) and with a specific asthma phenotype characterized by late onset, less atopy, and mild airflow obstruction (OR 1.29; 95% CI 1.03-1.61; P = 0.027). CONCLUSIONS: The genotype consisting of the cis-eQTL allele that reduces expression of CHI3L1 was specifically associated with late-onset adult asthma. Given the important role of YKL-40 in many pathophysiological processes, including cell growth, migration, chemotaxis, reorganization, and tissue remodeling, it may be involved in an important pathogenic role in the establishment of inflammation and remodeling in asthmatic airways. Our findings may indicate the presence of a specific endotype related to exaggerated activation of YKL-40 in the pathogenesis of late-onset adult asthma.

Association analyses of eQTLs of the TYRO3 gene and allergic diseases in Japanese populations.

BACKGROUND: TYRO3 is a member of the TAM (TYRO3, AXL, MERTK) receptor tyrosine kinase family and functions to limit type 2 immune responses implicated in allergic sensitization. Recent studies have shown that multiple intronic variants of TYRO3 were associated with asthma, implying that genetic variation could contribute to errant immune activation. We therefore hypothesized that expression quantitative trait loci (eQTLs) of the TYRO3 gene influence the development of allergic diseases (including asthma and allergic rhinitis) in Japanese populations. METHODS: We performed a candidate gene case-control association study of 8 eQTLs of TYRO3 on atopy, asthma, and allergic rhinitis using 1168 unrelated Japanese adults who had GWAS genotyping. We then examined the genetic impact of rs2297377 (TYRO3) on atopy and allergic rhinitis in 2 other independent Japanese populations. RESULTS: A meta-analysis of 3 Japanese populations (a total of 2403 Japanese adults) revealed that rs2297377 was associated with atopy and allergic rhinitis (OR = 1.29 and 1.31; P = 0.00041 and 0.0010, respectively). The risk allele at rs2297377 correlated with decreased expression of TYRO3 mRNA. The gene-gene interaction between HLA-DPB1 and TYRO3 was not significant with regard to sensitization. The estimated proportion of atopy and allergic rhinitis cases attributable to the risk genotype was 14% and 16%, respectively. CONCLUSIONS: Our study identified TYRO3 as an important susceptibility gene to atopy and allergic rhinitis in Japanese.

Genetic association of the functional CDHR3 genotype with early-onset adult asthma in Japanese populations.

BACKGROUND: Recent studies have demonstrated that a coding SNP (rs6967330, Cys529→Tyr) in cadherin-related family member 3 (CDHR3), which was previously associated with wheezing illness and hospitalizations in infancy, could support efficient human rhinovirus C (RV-C) entry and replication. Here, we sought to examine the genetic contribution of this variant to the development of adult asthma. METHODS: We performed a candidate gene case-control association study of 2 independent Japanese populations (a total of 3366 adults). The odds ratios (ORs) for association of the A allele at rs6967330 with adult asthma were calculated according to age at onset of asthma. In addition, the effect of the CDHR3 genotype on the development of specific asthma phenotypes was examined. RESULTS: The A allele was associated with asthma (OR = 1.56; Mantel-Haenszel p = 0.0040) when the analysis was limited to patients with early-onset adult asthma. In addition, when the analysis was limited to atopic individuals, a stronger association of the CDHR3 variant with early-onset asthma was found, and interaction of the CDHR3 genotype with atopy was demonstrated. Finally, a significant association of this variant was specifically found with a phenotype of asthma characterized by atopy, early-onset, and lower lung function. CONCLUSIONS: Our study supports the concept that the CDHR3 variant is an important susceptibility factor for severe adult asthma in individuals who develop the disease in early life. The interaction between the CDHR3 variant and atopy indicates that genetic predisposition to early respiratory viral infection is combined with atopy in promoting asthma.

GENETIC INTERACTIONS BETWEEN ADRB2 AND PTGER4 ON RESPONSES TO SALMETEROL OR MONTELUKAST IN JAPANESE PATIENTS WITH MILD PERSISTENT ASTHMA.

BACKGROUND: Long-acting ß2-agonists (LABA) and leukotriene receptor antagonists (LTRA) are two principal agents that can be added to inhaled corticosteroids (ICS) for patients with asthma that is not adequately controlled by ICS alone. In our previous study, the Gly16Arg genotype of the ß2-adrenergic receptor (ADRB2) gene did not influence the differential bronchodilator effect of salmeterol versus montelukast as an add-on therapy to ICS within 16 weeks of follow-up (the J-Blossom study). METHODS: We examined if genes encoding CYSLTR1, CYSLTR2, PTGER2 or PTGER4 could explain differential responses to salmeterol versus montelukast using the participants of the J-Blossom study. This study included 76 patients with mild-to-moderate asthma. The difference in peak expiratory flow (PEF) (ΔPEF, l/min) after 16 weeks of treatment with salmeterol (ΔPEFsal) versus montelukast (ΔPEFmon) was associated with the genotypes at each of 4 genes. In addition, multivariate analyses were used to identify a gene-gene interaction between ADRB2 gene and each of these 4 genes. RESULTS: Although none of 4 genes were associated with ΔPEFsal-ΔPEFmon in the univariate analyses, multivariate analysis showed that PTGER4 gene, interacting with ADRB2 Gly16Arg, was associated with ΔPEFsal-ΔPEFmon (p=0.0032). CONCLUSION: Our findings suggested that the interactions between two genetic loci at ADRB2 and PTGER4 is important in determining the differential response to salmeterol versus montelukast in patients with chronic adult asthma.

[FACTORS ASSOCIATED WITH THE PRESENCE OF ALLERGEN-SPECIFIC IgE RESPONSES IN ASTHMA PATIENTS WHO HAD NO IgE RESPONSES DETECTABLE BY MAST-26].

AIM: To elucidate the characteristics of patients with asthma who have specific IgE responses to inhaled allergens detected by ImmunoCAP, which is not detectable by MAST-26. METHODS: A total of 168 patients with adult asthma who reside in the Kanto region were recruited. Levels of total serum IgE and allergen specific IgE antibodies towards 14 common inhaled allergens (MAST-26) were measured. Among these samples, 48 patients with no detectable allergen-specific IgE (group A) and 44 patients with strong sensitization to Dermatophagoides farinae (group B) were selected for further assessment of their sensitization to inhaled allergens such as cockroach and moth using ImmunoCAP. RESULTS: In group A, ImmunoCAP detected specific IgE responses to some inhaled allergens in 27.1% of the patients. The strongest predictive factor for the presence of allergen-specific IgE responses detected by ImmunoCAP was elevated levels of total serum IgE (p=0.0007). In group B, the presence of IgE responses specific to cockroach or moth by ImmunoCAP were found in 27.8% or 52.3% of the patients, respectively. The predictive factor for the presence of these positive IgE responses was also elevated levels of total serum IgE (p=0.0003). CONCLUSION: Asthma patients with no detectable specific IgE responses to any inhaled allergens by MAST-26 may be still sensitized to common inhaled allergens, including cockroach and moth. Thus, the presence of allergen-specific IgE responses may be re-assessed by ImmunoCAP in patients with asthma, especially when patients have higher levels of total serum IgE.

[Effects of thymic stromal lymphopoietin (TSLP) genotypes on asthma phenotypes defined by the atopy cluster -influence of smoking habits-].

INTRODUCTION: We have previously reported that a distinct sensitization pattern was associated with thymic stromal lymphopoietin (TSLP) genotype. The aim of this study is to identify the characteristics of asthma phenotypes determined by a cluster analysis of IgE responsiveness and the relationship between these phenotypes and TSLP genotypes. PATIENTS AND METHODS: We studied 297 patients of adult asthma and 1571 non-asthmatic healthy adults from Ibaraki, a prefecture in central Japan and Kamishihoro, a cedar-free, birch-dominant town in northern Japan. Levels of total serum IgE and specific IgE antibodies towards 14 major inhaled allergens were measured. With the use of these measures, cluster analysis was applied to classify the phenotypes of adult asthma. We also examined the genetic effects of 2 TSLP functional single nucleotide polymorphism (SNPs) on the development of each asthma phenotype using multinomial logistic regression analysis. RESULTS: The cluster analysis identified four distinct clinical phenotypes of asthma, including "Dust mite dominant" (A, N=82), "Multiple pollen" (B, N=14), "Cedar dominant" (C, N=44), and "Low reactivity" (D, N=154). Asthma phenotype A consisted of younger patients with elevated IgE levels and decreased pulmonary function. Asthma phenotype B was characterized by sensitization by many pollen allergens. Asthma phenotype C was not formed in Kamishihoro. Asthma phenotype D was a group of older women who are less atopic. In current or past smokers, both TSLP SNPs (rs2289276 and rs3860933) were associated with the asthma phenotype D (odds ratio 2.11 [1.36-3.30] and 2.11 [1.34-3.33], respectively). CONCLUSION: In patients with adult asthma who are less atopic, the genetic polymorphisms of TSLP may have some important roles in the development of the disease in smokers.

The primary ciliary dyskinesia-related genetic risk score is associated with susceptibility to adult-onset asthma.

BACKGROUND: Disturbance of mucociliary clearance is an important factor in the pathogenesis of asthma. We hypothesized that common variants in genes responsible for ciliary function may contribute to the development of asthma with certain phenotypes. METHODS: Three independent adult Japanese populations (including a total of 1,158 patients with asthma and 2,203 non-asthmatic healthy participants) were studied. First, based on the ClinVar database (https://www.ncbi.nlm.nih.gov/clinvar/), we selected 12 common single-nucleotide polymorphisms (SNPs) with molecular consequences (missense, nonsense, and 3'-untranslated region mutation) in 5 primary ciliary dyskinesia (PCD)-related genes and calculated a PCD-genetic risk score (GRS) as a cumulative effect of these PCD-related genes. Second, we performed a two-step cluster analysis using 3 variables, including PCD-GRS, forced expiratory volume in 1 second (%predicted FEV1), and age of asthma onset. RESULTS: Compared to adult asthma clusters with an average PCD-GRS, clusters with high and low PCD-GRS had similar overall characteristics: adult-onset, female predominance, preserved lung function, and fewer features of type 2 immunity as determined by IgE reactivity and blood eosinophil counts. The allele frequency of rs1530496, a SNP representing an expression quantitative trait locus (eQTL) of DNAH5 in the lung, showed the largest statistically significant difference between the PCD-GRS-High and PCD-GRS-Low asthma clusters (p = 1.4 x 10-15). CONCLUSION: Genes associated with PCD, particularly the common SNPs associated with abnormal expression of DNAH5, may have a certain influence on the development of adult-onset asthma, perhaps through impaired mucociliary clearance.

Asthma Phenotypes in Japanese Adults - Their Associations with the CCL5 ADRB2 Genotypes.

BACKGROUND: Cluster analyses were previously performed to identify asthma phenotypes underlying asthma syndrome. Although a large number of patients with asthma develop the disease later in life, these previous cluster analyses focused mainly patients with younger-onset asthma. METHODS: Cluster analysis examined the existence of distinct phenotypes of late-onset asthma in Japanese patients with adult asthma. We then associated genotypes at the CCL5, TSLP, IL4, and ADRB2 genes with the clusters of asthma identified. RESULTS: Using the 8 variables of age, sex, age at onset of the disease, smoking status, total serum IgE, %FEV1, FEV1/FVC, and specific IgE responsiveness to common inhaled allergens, two-step cluster analysis of 880 Japanese adult asthma patients identified 6 phenotypes: cluster A (n = 155): older age at onset, no airflow obstruction; cluster B (n = 170): childhood onset, normal-to-mild airflow obstruction; cluster C (n = 119): childhood onset, the longest disease duration, and moderate-to-severe airflow obstruction; cluster D (n = 108): older age at onset, severe airflow obstruction; cluster E (n = 130): middle-age at onset, no airflow obstruction; and cluster F (n = 198): older age at onset, mild-to-moderate airflow obstruction. The CCL5-28C>G genotype was significantly associated with clusters A, B and D (OR 1.65, p = 0.0021; 1.67, 0.018; and 1.74, 0.011, respectively). The ADRB2 Arg16Gly genotype was also associated with clusters B and D (OR 0.47, p = 0.0004; and 0.63, 0.034, respectively). CONCLUSIONS: The current cluster analysis identified meaningful adult asthma phenotypes linked to the functional CCL5 and ADRB2 genotypes. Genetic and phenotypic data have the potential to elucidate the pheno- typic heterogeneity and pathophysiology of asthma.

Asthma phenotypes in Japanese adults - their associations with the CCL5 and ADRB2 genotypes.

BACKGROUND: Cluster analyses were previously performed to identify asthma phenotypes underlying asthma syndrome. Although a large number of patients with asthma develop the disease later in life, these previous cluster analyses focused mainly patients with younger-onset asthma. METHODS: Cluster analysis examined the existence of distinct phenotypes of late-onset asthma in Japanese patients with adult asthma. We then associated genotypes at the CCL5, TSLP, IL4, and ADRB2 genes with the clusters of asthma identified. RESULTS: Using the 8 variables of age, sex, age at onset of the disease, smoking status, total serum IgE, %FEV(1), FEV(1)/FVC, and specific IgE responsiveness to common inhaled allergens, two-step cluster analysis of 880 Japanese adult asthma patients identified 6 phenotypes: cluster A (n = 155): older age at onset, no airflow obstruction; cluster B (n = 170): childhood onset, normal-to-mild airflow obstruction; cluster C (n = 119): childhood onset, the longest disease duration, and moderate-to-severe airflow obstruction; cluster D (n = 108): older age at onset, severe airflow obstruction; cluster E (n = 130): middle-age at onset, no airflow obstruction; and cluster F (n = 198): older age at onset, mild-to-moderate airflow obstruction. The CCL5-28C>G genotype was significantly associated with clusters A, B and D (OR 1.65, p = 0.0021; 1.67, 0.018; and 1.74, 0.011, respectively). The ADRB2 Arg16Gly genotype was also associated with clusters B and D (OR 0.47, p = 0.0004; and 0.63, 0.034, respectively). CONCLUSIONS: The current cluster analysis identified meaningful adult asthma phenotypes linked to the functional CCL5 and ADRB2 genotypes. Genetic and phenotypic data have the potential to elucidate the phenotypic heterogeneity and pathophysiology of asthma.

A distinct sensitization pattern associated with asthma and the thymic stromal lymphopoietin (TSLP) genotype.

BACKGROUND: Atopy is a phenotypically heterogeneous condition, and the extent to which atopy accounts for asthma is controversial. In this study, we aimed to identify the presence of distinct sensitization patterns to common inhaled allergens and their association with asthma, allergic rhinitis and TSLP genotypes. METHODS: We studied 1683 adults from Tsukuba, a city in central Japan and 297 adults from Kamishihoro, a cedar-free, birch-dominant town in northern Japan. Levels of total serum IgE and specific IgE antibodies towards 14 major inhaled allergens were measured. With the use of these measures, cluster analysis was applied to classify the subjects' sensitization patterns. We also examined the genetic effects of 2 TSLP functional SNPs on the development of each sensitization pattern. RESULTS: In the Tsukuba study, cluster analysis identified four clusters, including "Dust mite dominant", "Multiple pollen", "Cedar dominant", and "Low reactivity". In the Kamishihoro study, "Dust mite dominant", "Multiple pollen" and "Low reactivity" clusters were also identified, but a "Cedar dominant" cluster was not formed. The association with asthma was strongest for the "Dust mite dominant" cluster in both the Tsukuba and the Kamishihoro studies. In never smokers, both SNPs were associated with the "Dust mite dominant" cluster (OR > 1.2). In contrast, in current or past smokers, these alleles were inversely associated with the "Multiple pollen" cluster (OR < 0.5). CONCLUSIONS: Cluster analysis identified the presence of distinct sensitization patterns to common inhaled allergens. TSLP may cause asthma by promoting innate allergic responses to indoor allergens and this contribution is significantly modified by smoking.

Identification of distinct phenotypes related to benralizumab responsiveness in patients with severe eosinophilic asthma.

PURPOSE: To characterize the clinical phenotypes of severe eosinophilic asthma based on early responsiveness to benralizumab in terms of forced expiratory volume in 1 second (FEV1) improvement. PATIENTS AND METHODS: Sixty-four participants diagnosed with severe eosinophilic asthma and who had completed 4 months of benralizumab treatment were included in this analysis. Pre-treatment clinical factors were compared between responders and non-responders according to improvements in ACT or FEV1. Correlations between the sums of increased Type 2-related inflammatory parameters and changes of ACT or FEV1 were also evaluated before and after the 4-month treatment. A two-step cluster analysis was performed to identify distinct phenotypes related to benralizumab responsiveness in terms of FEV1. RESULTS: At the 4-month timepoint, all parameters, except for FeNO, were significantly improved after benralizumab treatment. FEV1 responders were associated with higher levels of Type 2-related inflammatory parameters. An improvement in FEV1 but not in ACT was clearly associated with increases in the sums of increased type 2-related inflammation parameters (p = 0.0001). The cluster analysis identified 5 distinct phenotypes of severe eosinophilic asthma according to the variable FEV1 responsiveness to benralizumab. The greatest response was found in the distinct phenotype of severe eosinophilic asthma, which was characterized by modest increase in total IgE and FeNO relative to blood eosinophils with least exposure to smoking. CONCLUSION: This study, to the best of our knowledge, is the first cluster analysis to report distinct phenotypes related to clinical benralizumab response in a real-world population with severe eosinophilic asthma. These results may help to predict responsiveness to benralizumab in patients with severe eosinophilic asthma.

Expression quantitative trait loci for ETV4 and MEOX1 are associated with adult asthma in Japanese populations.

ETS variant transcription factor 4 (ETV4) is a recently identified transcription factor that regulates gene expression-based biomarkers of asthma and IL6 production in an airway epithelial cell line. Given that ETV4 has not yet been implicated in asthma genetics, we performed genetic association studies of adult asthma in the ETV4 region using two independent Japanese cohorts (a total of 1532 controls and 783 cases). SNPs located between ETV4 and mesenchyme homeobox 1 (MEOX1) were significantly associated with adult asthma, including rs4792901 and rs2880540 (P = 5.63E-5 and 2.77E-5, respectively). The CC haplotype of these two SNPs was also significantly associated with adult asthma (P = 8.43E-7). Even when both SNPs were included in a logistic regression model, the association of either rs4792901 or rs2880540 remained significant (P = 0.013 or 0.007, respectively), suggesting that the two SNPs may have independent effects on the development of asthma. Both SNPs were expression quantitative trait loci, and the asthma risk alleles at both SNPs were correlated with increased levels of ETV4 mRNA expression. In addition, the asthma risk allele at rs4792901 was associated with increased serum IL6 levels (P = 0.041) in 651 healthy adults. Our findings imply that ETV4 is involved in the pathogenesis of asthma, possibly through the heightened production of IL6.

The Concavity of the Maximal Expiratory Flow-Volume Curve Reflects the Extent of Emphysema in Obstructive Lung Diseases.

A concave-shaped maximal expiratory flow-volume (MEFV) curve is a spirometric feature in chronic obstructive pulmonary disease (COPD). The MEFV curve is characterized by an increase in the Obstructive Index, which is defined as a ratio of forced vital capacity to the volume-difference between two points of half of the peak expiratory flow on the MEFV curve. We hypothesized that the Obstructive Index would reflect the severity of emphysema in patients with COPD and asthma-COPD overlap (ACO). Thus, the aim of this retrospective study was to evaluate whether the Obstructive Index on spirometry is associated with the extent of emphysema on computed tomography (CT) in patients with COPD, ACO, and asthma (N = 65, 15, and 53, respectively). The percentage of low-attenuation volume (LAV%) and wall area (WA%) were measured on CT. The Obstructive Index was higher in patients with COPD and ACO than in those with asthma. Spearman correlation showed that a greater Obstructive Index was associated with a higher LAV%, but not WA%. Multivariate analysis showed that Obstructive Index was associated with LAV% (standardized ß = 0.43, P < 0.0001) independent of other spirometric indices. The Obstructive Index is a useful spirometric index that reflects the extent of emphysema.

Reduced incidence of lung cancer in patients with idiopathic pulmonary fibrosis treated with pirfenidone.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a disease with a worse prognosis than some types of cancer. In patients with IPF, lung cancer is critical because of the associated high mortality rate from its progression and fatal complications from anticancer treatments. Therefore, preventing lung cancer in patients with IPF is primordial. Pirfenidone is an anti-fibrotic agent that reduces the decline in forced vital capacity. This study aimed to assess the effect of pirfenidone in the development of lung cancer in patients with IPF. METHODS: Data from 261 patients with IPF with and without pirfenidone were retrospectively reviewed, and the incidence of lung cancer was analyzed. RESULTS: In the pirfenidone group, the incidence of lung cancer was significantly lower than in the non-pirfenidone group (2.4% vs. 22.0%, P < 0.0001). Multivariate Cox proportional hazards regression analysis demonstrated that pirfenidone decreased the risk of lung cancer (hazard ratio, 0.11; 95% confidence interval, 0.03 to 0.46; P = 0.003), whereas coexisting emphysema increased the incidence of lung cancer (hazard ratio, 3.22; 95% confidence interval, 1.35 to 7.70; P = 0.009). CONCLUSIONS: Pirfenidone might correlate with a decreased risk of lung cancer in patients with IPF. However, no definite conclusion can be drawn from this retrospective study, and a multicenter, prospective cohort study is still warranted to confirm the effect of pirfenidone on lung cancer in patients with IPF.

Limited value of transbronchial lung biopsy for diagnosing Mycobacterium avium complex lung disease.

BACKGROUND AND AIMS: It remains unclear whether transbronchial lung biopsy (TBLB) is useful for diagnosing Mycobacterium avium complex (MAC) lung disease. METHODS: Thirty-eight consecutive patients with MAC lung disease, who were evaluated with TBLB tissue culture between June 2006 and May 2010, were included. Bronchial washing (BW) and histopathological evaluation were performed in all patients. The positivity rates of BW and TBLB tissue culture, and typical histopathological findings for MAC disease were investigated. Furthermore, all patients were divided into two groups according to the presence of intrabronchial purulent or mucopurulent secretion and the clinical, bacteriological and pathological characteristics were compared between the two groups. RESULTS: The positive culture rates of BW and TBLB specimens for MAC were 100% (38 patients) and 28.9% (11 patients). BW materials were much more sensitive for culture positivity than TBLB specimens (P < 0.0001). Typical pathological findings for MAC disease were present in the TBLB specimens of only 11 patients (28.9%). Intrabronchial secretion was identified in 15 patients (39.5%, secretion-positive group) and absent in 23 patients (60.5%, secretion-negative group). Typical histopathological findings for MAC disease were more common in the secretion-positive group than in the secretion-negative group (53.3% vs 13.0%, P = 0.01), although the radiological classification and smear positivity of BW were not different between the two groups. CONCLUSION: TBLB for pathological and bacterial investigations would provide only a limited value for MAC diagnosis. Moreover, the presence of intrabronchial secretion may be an important manifestation of ongoing airway damage, which would require early treatment.