Single-cell RNA sequencing of cystic fibrosis liver disease explants reveals endothelial complement activation.

BACKGROUND & AIMS: Cystic fibrosis (CF) is considered a multisystemic disorder in which CF-associated liver disease (CFLD) is the third most common cause of mortality. Currently, no effective treatment is available for CFLD because its pathophysiology is still unclear. Interestingly, CFLD exhibits identical vascular characteristics as non-cirrhotic portal hypertension, recently classified as porto-sinusoidal vascular disorders (PSVD). METHODS: Since endothelial cells (ECs) are an important component in PSVD, we performed single-cell RNA sequencing (scRNA-seq) on four explant livers from CFLD patients to identify differential endothelial characteristics which could contribute to the disease. We comprehensively characterized the endothelial compartment and compared it with publicly available scRNA-seq datasets from cirrhotic and healthy livers. Key gene signatures were validated ex vivo on patient tissues. RESULTS: We found that ECs from CF liver explants are more closely related to healthy than cirrhotic patients. In CF patients we also discovered a distinct population of liver sinusoidal ECs-coined CF LSECs-upregulating genes involved in the complement cascade and coagulation. Finally, our immunostainings further validated the predominant periportal location of CF LSECs. CONCLUSIONS: Our work showed novel aspects of human liver ECs at the single-cell level thereby supporting endothelial involvement in CFLD, and reinforcing the hypothesis that ECs could be a driver of PSVD. Therefore, considering the vascular compartment in CF and CFLD may help developing new therapeutic approaches for these diseases.

Genetic Spectrum and Clinical Characteristics of Patients with Primary Ciliary Dyskinesia: a Belgian Single Center Study.

PURPOSE: We aimed to examine the correlation between clinical characteristics and the pathogenic gene variants in patients with Primary Ciliary Dyskinesia (PCD). METHODS: We conducted a retrospective single-center study in patients with PCD followed at the University Hospitals Leuven. We included patients with genetically confirmed PCD and described their genotype, data from ultrastructural ciliary evaluation and clinical characteristics. Genotype/phenotype correlations were studied in patients with the most frequently involved genes. RESULTS: We enrolled 74 patients with a median age of 25.58 years. The most frequently involved genes were DNAH11 (n = 23) and DNAH5 (n = 19). The most frequent types of pathogenic variants were missense (n = 42) and frameshift variants (n = 36) and most patients had compound heterozygous variants (n = 44). Ciliary ultrastructure (p < 0.001), situs (p = 0.015) and age at diagnosis (median 9.50 vs 4.71 years, p = 0.037) differed between DNAH11 and DNAH5. When correcting for situs this difference in age at diagnosis was no longer significant (p = 0.973). Patients with situs inversus were diagnosed earlier (p = 0.031). Respiratory tract microbiology (p = 0.161), lung function (cross-sectional, p = 0.829 and longitudinal, p = 0.329) and chest CT abnormalities (p = 0.202) were not significantly different between DNAH11 and DNAH5 variants. CONCLUSION: This study suggests a genotype-phenotype correlation for some of the evaluated clinical characteristics of the two most frequently involved genes in this study, namely DNAH11 and DNAH5.

Early SARS-CoV-2 Reinfections within 60 Days and Implications for Retesting Policies.

Illustrated by a clinical case supplemented by epidemiologic data, early reinfections with SARS-CoV-2 Omicron BA.1 after infection with Delta variant, and reinfection with Omicron BA.2 after Omicron BA.1 infection, can occur within 60 days, especially in young, unvaccinated persons. The case definition of reinfection, which influences retesting policies, should be reconsidered.

Elexacaftor-Tezacaftor-Ivacaftor for Cystic Fibrosis with a Single Phe508del Allele.

BACKGROUND: Cystic fibrosis is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein, and nearly 90% of patients have at least one copy of the Phe508del CFTR mutation. In a phase 2 trial involving patients who were heterozygous for the Phe508del CFTR mutation and a minimal-function mutation (Phe508del-minimal function genotype), the next-generation CFTR corrector elexacaftor, in combination with tezacaftor and ivacaftor, improved Phe508del CFTR function and clinical outcomes. METHODS: We conducted a phase 3, randomized, double-blind, placebo-controlled trial to confirm the efficacy and safety of elexacaftor-tezacaftor-ivacaftor in patients 12 years of age or older with cystic fibrosis with Phe508del-minimal function genotypes. Patients were randomly assigned to receive elexacaftor-tezacaftor-ivacaftor or placebo for 24 weeks. The primary end point was absolute change from baseline in percentage of predicted forced expiratory volume in 1 second (FEV1) at week 4. RESULTS: A total of 403 patients underwent randomization and received at least one dose of active treatment or placebo. Elexacaftor-tezacaftor-ivacaftor, relative to placebo, resulted in a percentage of predicted FEV1 that was 13.8 points higher at 4 weeks and 14.3 points higher through 24 weeks, a rate of pulmonary exacerbations that was 63% lower, a respiratory domain score on the Cystic Fibrosis Questionnaire-Revised (range, 0 to 100, with higher scores indicating a higher patient-reported quality of life with regard to respiratory symptoms; minimum clinically important difference, 4 points) that was 20.2 points higher, and a sweat chloride concentration that was 41.8 mmol per liter lower (P<0.001 for all comparisons). Elexacaftor-tezacaftor-ivacaftor was generally safe and had an acceptable side-effect profile. Most patients had adverse events that were mild or moderate. Adverse events leading to discontinuation of the trial regimen occurred in 1% of the patients in the elexacaftor-tezacaftor-ivacaftor group. CONCLUSIONS: Elexacaftor-tezacaftor-ivacaftor was efficacious in patients with cystic fibrosis with Phe508del-minimal function genotypes, in whom previous CFTR modulator regimens were ineffective. (Funded by Vertex Pharmaceuticals; VX17-445-102 ClinicalTrials.gov number, NCT03525444.).

Coronavirus disease 2019 in patients with inborn errors of immunity: An international study.

BACKGROUND: There is uncertainty about the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in individuals with rare inborn errors of immunity (IEI), a population at risk of developing severe coronavirus disease 2019. This is relevant not only for these patients but also for the general population, because studies of IEIs can unveil key requirements for host defense. OBJECTIVE: We sought to describe the presentation, manifestations, and outcome of SARS-CoV-2 infection in IEI to inform physicians and enhance understanding of host defense against SARS-CoV-2. METHODS: An invitation to participate in a retrospective study was distributed globally to scientific, medical, and patient societies involved in the care and advocacy for patients with IEI. RESULTS: We gathered information on 94 patients with IEI with SARS-CoV-2 infection. Their median age was 25 to 34 years. Fifty-three patients (56%) suffered from primary antibody deficiency, 9 (9.6%) had immune dysregulation syndrome, 6 (6.4%) a phagocyte defect, 7 (7.4%) an autoinflammatory disorder, 14 (15%) a combined immunodeficiency, 3 (3%) an innate immune defect, and 2 (2%) bone marrow failure. Ten were asymptomatic, 25 were treated as outpatients, 28 required admission without intensive care or ventilation, 13 required noninvasive ventilation or oxygen administration, 18 were admitted to intensive care units, 12 required invasive ventilation, and 3 required extracorporeal membrane oxygenation. Nine patients (7 adults and 2 children) died. CONCLUSIONS: This study demonstrates that (1) more than 30% of patients with IEI had mild coronavirus disease 2019 (COVID-19) and (2) risk factors predisposing to severe disease/mortality in the general population also seemed to affect patients with IEI, including more younger patients. Further studies will identify pathways that are associated with increased risk of severe disease and are nonredundant or redundant for protection against SARS-CoV-2.

Assays of CFTR Function In Vitro, Ex Vivo and In Vivo.

Cystic fibrosis, a multi-organ genetic disease, is characterized by abnormal function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, a chloride channel at the apical membrane of several epithelia. In recent years, therapeutic strategies have been developed to correct the CFTR defect. To evaluate CFTR function at baseline for diagnosis, or the efficacy of CFTR-restoring therapy, reliable tests are needed to measure CFTR function, in vitro, ex vivo and in vivo. In vitro techniques either directly or indirectly measure ion fluxes; direct measurement of ion fluxes and quenching of fluorescence in cell-based assays, change in transmembrane voltage or current in patch clamp or Ussing chamber, swelling of CFTR-containing organoids by secondary water influx upon CFTR activation. Several cell or tissue types can be used. Ex vivo and in vivo assays similarly evaluate current (intestinal current measurement) and membrane potential differences (nasal potential difference), on tissues from individual patients. In the sweat test, the most frequently used in vivo evaluation of CFTR function, chloride concentration or stimulated sweat rate can be directly measured. Here, we will describe the currently available bio-assays for quantitative evaluation of CFTR function, their indications, advantages and disadvantages, and correlation with clinical outcome measures.

Lung clearance index predicts pulmonary exacerbations in individuals with primary ciliary dyskinesia: a multicentre cohort study.

BACKGROUND: Lung clearance index (LCI) is a promising lung function outcome in individuals with primary ciliary dyskinesia (PCD). The impact of events clinically important for individuals with PCD, such as pulmonary exacerbations, on LCI is unknown. METHODS: We conducted an international, multicentre, observational cohort study to assess the association of LCI and risk of pulmonary exacerbation, specific changes in LCI during pulmonary exacerbation and global variability of LCI across four visits every 4 months. Ninety individuals with PCD, aged 3-41 years, underwent nitrogen multiple-breath washout (MBW) and spirometry measurements. The association of LCI and pulmonary exacerbations was assessed by Cox proportional hazards and random-effects regression models. RESULTS: We obtained 430 MBW and 427 spirometry measurements. In total, 379 person-years at risk contributed to the analysis. Per one unit increase (deterioration) in LCI, the risk of future pulmonary exacerbation increased by 13%: HR (95% CI), 1.13 (1.04 to 1.23). If LCI changed from a range of values considered normal to abnormal, the risk of future pulmonary exacerbations increased by 87%: 1.87 (1.08 to 3.23). During pulmonary exacerbations, LCI increased by 1.22 units (14.5%). After pulmonary exacerbations, LCI tended to decline. Estimates of variability in LCI suggested lower variation within individuals compared with variation between individuals. Findings were comparable for forced expiratory volume in 1 s. CONCLUSION: On a visit-to-visit basis, LCI measurement may add to the prediction of pulmonary exacerbations, the assessment of lung function decline and the potential lung function response to treatment of pulmonary exacerbations.

Rectal organoid morphology analysis (ROMA) as a promising diagnostic tool in cystic fibrosis.

Diagnosing cystic fibrosis (CF) when sweat chloride is not in the CF range and less than 2 disease-causing CFTR mutations are found requires physiological CFTR assays, which are not always feasible or available. We developed a new physiological CFTR assay based on the morphological differences between rectal organoids from subjects with and without CF. In organoids from 167 subjects with and 22 without CF, two parameters derived from a semi-automated image analysis protocol (rectal organoid morphology analysis, ROMA) fully discriminated CF subjects with two disease-causing mutations from non-CF subjects (p<0.001). ROMA, feasible at all ages, can be centralised to improve standardisation.

Correction of CFTR function in intestinal organoids to guide treatment of cystic fibrosis.

RATIONALE: Given the vast number of cystic fibrosis transmembrane conductance regulator (CFTR) mutations, biomarkers predicting benefit from CFTR modulator therapies are needed for subjects with cystic fibrosis (CF). OBJECTIVES: To study CFTR function in organoids of subjects with common and rare CFTR mutations and evaluate correlations between CFTR function and clinical data. METHODS: Intestinal organoids were grown from rectal biopsies in a cohort of 97 subjects with CF. Residual CFTR function was measured by quantifying organoid swelling induced by forskolin and response to modulators by quantifying organoid swelling induced by CFTR correctors, potentiator and their combination. Organoid data were correlated with clinical data from the literature. RESULTS: Across 28 genotypes, residual CFTR function correlated (r2=0.87) with sweat chloride values. When studying the same genotypes, CFTR function rescue by CFTR modulators in organoids correlated tightly with mean improvement in lung function (r2=0.90) and sweat chloride (r2=0.95) reported in clinical trials. We identified candidate genotypes for modulator therapy, such as E92K, Q237E, R334W and L159S. Based on organoid results, two subjects started modulator treatment: one homozygous for complex allele Q359K_T360K, and the second with mutation E60K. Both subjects had major clinical benefit. CONCLUSIONS: Measurements of residual CFTR function and rescue of function by CFTR modulators in intestinal organoids correlate closely with clinical data. Our results for reference genotypes concur with previous results. CFTR function measured in organoids can be used to guide precision medicine in patients with CF, positioning organoids as a potential in vitro model to bring treatment to patients carrying rare CFTR mutations.

Transcriptomic analysis of CFTR-impaired endothelial cells reveals a pro-inflammatory phenotype.

Cystic fibrosis (CF) is a life-threatening disorder characterised by decreased pulmonary mucociliary and pathogen clearance, and an exaggerated inflammatory response leading to progressive lung damage. CF is caused by bi-allelic pathogenic variants of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encodes a chloride channel. CFTR is expressed in endothelial cells (ECs) and EC dysfunction has been reported in CF patients, but a role for this ion channel in ECs regarding CF disease progression is poorly described.We used an unbiased RNA sequencing approach in complementary models of CFTR silencing and blockade (by the CFTR inhibitor CFTRinh-172) in human ECs to characterise the changes upon CFTR impairment. Key findings were further validated in vitro and in vivo in CFTR-knockout mice and ex vivo in CF patient-derived ECs.Both models of CFTR impairment revealed that EC proliferation, migration and autophagy were downregulated. Remarkably though, defective CFTR function led to EC activation and a persisting pro-inflammatory state of the endothelium with increased leukocyte adhesion. Further validation in CFTR-knockout mice revealed enhanced leukocyte extravasation in lung and liver parenchyma associated with increased levels of EC activation markers. In addition, CF patient-derived ECs displayed increased EC activation markers and leukocyte adhesion, which was partially rescued by the CFTR modulators VX-770 and VX-809.Our integrated analysis thus suggests that ECs are no innocent bystanders in CF pathology, but rather may contribute to the exaggerated inflammatory phenotype, raising the question of whether normalisation of vascular inflammation might be a novel therapeutic strategy to ameliorate the disease severity of CF.

Defining Polysaccharide Antibody Deficiency: Measurement of Anti-Pneumococcal Antibodies and Anti-Salmonella typhi Antibodies in a Cohort of Patients with Recurrent Infections.

BACKGROUND: The correlation between different methods for the detection of pneumococcal polysaccharide vaccine (PPV) responses to diagnose specific polysaccharide antibody deficiency (SAD) is poor and the criteria for defining a normal response lack consensus. We previously proposed fifth percentile (p5) values of PPV responses as a new cutoff for SAD. OBJECTIVE: To analyze the association of SAD (determined by either World Health Organization (WHO)-standardized ELISA or multiplex bead-based assay) with abnormal response to Salmonella (S.) typhi Vi vaccination in a cohort of patients with recurrent infections. METHODS: Ninety-four patients with a clinical history suggestive of antibody deficiency received PPV and S. typhi Vi vaccines. Polysaccharide responses to either 3 or 18 pneumococcal serotypes were measured by either the WHO ELISA or a multiplex in-house bead-based assay. Anti-S. typhi Vi IgG were measured by a commercial ELISA kit. Allohemagglutinins (AHA) were measured by agglutination method. RESULTS: Based on the American Academy of Allergy, Asthma and Immunology (AAAAI) criteria for WHO ELISA, 18/94 patients were diagnosed with SAD and 22/93 based on serotype-specific p5 cutoffs for bead-based assay. The association between the two methods was significant, with 10 subjects showing abnormal response according to both techniques. Abnormal response to S. typhi Vi vaccination was found in 7 patients, 6 of which had SAD. No correlation was found between polysaccharide response and AHA, age, or clinical phenotype. CONCLUSION: The lack of evidence-based gold standards for the diagnosis of SAD represents a challenge in clinical practice. In our cohort, we confirmed the insufficient correlation between different methods of specific PPV response measurement, and showed that the S. typhi Vi response was not contributive. Caution in the interpretation of results is warranted until more reliable diagnostic methods can be validated.

Fast compressive lens-free tomography for 3D biological cell culture imaging.

We present a compressive lens-free technique that performs tomographic imaging across a cubic millimeter-scale volume from highly sparse data. Compared with existing lens-free 3D microscopy systems, our method requires an order of magnitude fewer multi-angle illuminations for tomographic reconstruction, leading to a compact, cost-effective and scanning-free setup with a reduced data acquisition time to enable high-throughput 3D imaging of dynamic biological processes. We apply a fast proximal gradient algorithm with composite regularization to address the ill-posed tomographic inverse problem. Using simulated data, we show that the proposed method can achieve a reconstruction speed ∼10× faster than the state-of-the-art inverse problem approach in 3D lens-free microscopy. We experimentally validate the effectiveness of our method by imaging a resolution test chart and polystyrene beads, demonstrating its capability to resolve micron-size features in both lateral and axial directions. Furthermore, tomographic reconstruction results of neuronspheres and intestinal organoids reveal the potential of this 3D imaging technique for high-resolution and high-throughput biological applications.

Human DOCK2 Deficiency: Report of a Novel Mutation and Evidence for Neutrophil Dysfunction.

DOCK2 is a guanine-nucleotide-exchange factor for Rac proteins. Activated Rac serves various cellular functions including the reorganization of the actin cytoskeleton in lymphocytes and neutrophils and production of reactive oxygen species in neutrophils. Since 2015, six unrelated patients with combined immunodeficiency and early-onset severe viral infections caused by bi-allelic loss-of-function mutations in DOCK2 have been described. Until now, the function of phagocytes, specifically neutrophils, has not been assessed in human DOCK2 deficiency. Here, we describe a new kindred with four affected siblings harboring a homozygous splice-site mutation (c.2704-2 A > C) in DOCK2. The mutation results in alternative splicing and a complete loss of DOCK2 protein expression. The patients presented with leaky severe combined immunodeficiency or Omenn syndrome. The novel mutation affects EBV-B cell migration and results in NK cell dysfunction similar to previous observations. Moreover, both cytoskeletal rearrangement and reactive oxygen species production are partially impaired in DOCK2-deficient neutrophils.

Lung function evolution in children with old and new type bronchopulmonary dysplasia: a retrospective cohort analysis.

Bronchopulmonary dysplasia (BPD) is one of the most important sequelae of premature birth. There is concern that in some patients, lung injuries early in life may have lifelong consequences. In this retrospective observational cohort study, lung function evolution in children with BPD was investigated from childhood to young adulthood. Data from 355 pulmonary function tests (PFT) in 24 patients were analyzed, with a median age at first PFT of 7.6 years and at last PFT 18.2 years. FEV1 and FEV1/FVC were below the 5th percentile in respectively 18 and 13/24 patients. Comparing first and last measurement, there was significant worsening in FEV1 from a mean of 71.3% pred (SD 18.3) to 66.7% pred (SD 21.7) (p < 0.05) and in FEV1/FVC from 85.4% pred (SD 15.2) to 79.8% pred (SD 17.3) (p = 0.01). Evaluation of the individual lung function changes with linear regression showed deterioration in FEV1, FVC, and FEV1/FVC in respectively 17, 13, and 17/24 patients. Total group analysis showed significant deterioration in FEV1 (- 0.7%/year, p = 0.002) and FEV1/FVC (- 0.5%/year, p = 0.01). None of the 11 patients born up to 1990 improved in FEV1 vs 7 of the 13 patients born after 1990 (p = 0.006).Conclusion: This points out to further deterioration of the lung function during childhood in this selected group of children with BPD.What is Known:• Data on longitudinal changes in lung function in children with BPD are scarce.What is New:• In children with BPD at the severe end of the disease spectrum, lung function does not improve over time. On the contrary, in two-thirds of the subjects studied FEV1and FEV1/FVC worsen over time.• Lung function evolution towards adulthood was somewhat more favorable in children born after 1990 compared with those born earlier, probably reflecting improvements in neonatal care in subjects with new type BPD.

Correction to: Chronic Aichi Virus Infection in a Patient with X-Linked Agammaglobulinemia.

The original version of this article unfortunately did not display the appropriate captions in the figure. The correct version is displayed below.

Impact of PEGylation on the mucolytic activity of recombinant human deoxyribonuclease I in cystic fibrosis sputum.

Highly viscous mucus and its impaired clearance characterize the lungs of patients with cystic fibrosis (CF). Pulmonary secretions of patients with CF display increased concentrations of high molecular weight components such as DNA and actin. Recombinant human deoxyribonuclease I (rhDNase) delivered by inhalation cleaves DNA filaments contained in respiratory secretions and thins them. However, rapid clearance of rhDNase from the lungs implies a daily administration and thereby a high therapy burden and a reduced patient compliance. A PEGylated version of rhDNase could sustain the presence of the protein within the lungs and reduce its administration frequency. Here, we evaluated the enzymatic activity of rhDNase conjugated to a two-arm 40 kDa polyethylene glycol (PEG40) in CF sputa. Rheology data indicated that both rhDNase and PEG40-rhDNase presented similar mucolytic activity in CF sputa, independently of the purulence of the sputum samples as well as of their DNA, actin and ions contents. The macroscopic appearance of the samples correlated with the DNA content of the sputa: the more purulent the sample, the higher the DNA concentration. Finally, quantification of the enzymes in CF sputa following rheology measurement suggests that PEGylation largely increases the stability of rhDNase in CF respiratory secretions, since 24-fold more PEG40-rhDNase than rhDNase was recovered from the samples. The present results are considered positive and provide support to the continuation of the research on a long acting version of rhDNase to treat CF lung disease.

Reference Values for Central Airway Dimensions on CT Images of Children and Adolescents.

OBJECTIVE: The purpose of this study was to acquire normative data on central airway dimensions on chest CT scans in the pediatric population. MATERIALS AND METHODS: Chest CT findings reported as normal by a radiologist were collected retrospectively at 10 international centers. An experienced and independent thoracic radiologist reevaluated all CT scans for image quality and for normal findings. Semiautomated image analysis was performed to measure dimensions of the trachea and right and left main bronchi at inspiration. Intrathoracic tracheal length was measured from carina to thorax inlet. Cross-sectional area and short and long axes were measured perpendicular to the longitudinal airway axis starting from the carina every centimeter upward for the trachea and every 0.5 cm downward for the main bronchi. The effects on airway diameters of age, sex, intrathoracic tracheal length, and distance from the carina were investigated by use of mixed-effects models analysis. RESULTS: Among 1160 CT scans collected, 388 were evaluated as normal by the independent radiologist with sufficient image quality and adequate inspiratory volume level. Central airways were successfully semiautomatically analyzed in 294 of 388 CT studies. Age, sex, intrathoracic tracheal length, and distance from carina were all significant predictors in the models for tracheal and right and left main bronchial diameters (p < 0.001). The central airway dimensions increased with age up to 20 years, and dimensions were larger in male than in female adolescents. CONCLUSION: Normative data were determined for the central airways of children and adolescents. Central airway dimensions depended on distance from the carina and on intrathoracic tracheal length.

Enhanced chemosensory sensitivity in patients with idiopathic rhinitis and its reversal by nasal capsaicin treatment.

BACKGROUND: The therapeutic action of capsaicin treatment in patients with idiopathic rhinitis (IR) is based on ablation of the transient receptor potential cation channel subfamily V, receptor 1 (TRPV1)-substance P nociceptive signaling pathway. However, the functional consequences of capsaicin treatment on nasal nerve activation and the association between the reduction in nasal hyperreactivity (NHR) and response to capsaicin treatment remain unknown. OBJECTIVE: We sought to study the effects of capsaicin nasal spray on the afferent innervation of the nasal mucosa by monitoring trigeminal nerve activity in patients with IR and healthy control (HC) subjects. METHODS: A double-blind, placebo-controlled randomized trial with capsaicin nasal spray was performed involving 33 patients with IR and 12 HC subjects. Before and at 4, 12, and 26 weeks after treatment, nasal mucosal potentials (NMPs) were measured while exposing the nasal mucosa of patients with IR and HC subjects to aerosols with increasing doses of the chemical irritants allyl isothiocyanate (AITC; also known as mustard oil) or capsaicin. The threshold for each compound was determined for each subject. The results of the NMP measurements were evaluated in parallel with the therapeutic response, visual analog scale scores for nasal symptoms, self-reported NHR, and mRNA expression of PGP9.5; TRPV1; transient receptor potential cation channel subfamily A, receptor 1 (TRPA1); TRPV4; transient receptor potential cation channel subfamily M, member 8 (TRPM8); and nerve growth factor (NGF) in nasal biopsy specimens. RESULTS: AITC turned out to be the best stimulus because the coughing induced by capsaicin interfered with measurements. At baseline, the threshold for evoking changes in NMPs based on AITC was significantly lower for patients with IR compared with HC subjects (P = .0423). Capsaicin treatment of IR patients increased the threshold for the response to AITC at 4 and 12 weeks compared with placebo (P = .0406 and P = .0325, respectively), which returned to baseline by week 26 (P = .0611). This increase correlated with changes in visual analog scale major symptom (P = .0004) and total symptom (P = .0018) scores. IR patients with self-reported NHR at baseline showed a trend to being better responders to capsaicin treatment compared with patients with IR but without NHR (P = .10). CONCLUSION: The lower threshold for AITC based on NMPs in patients with IR compared with HC subjects and the increased threshold for AITC after capsaicin treatment in patients with IR demonstrate the crucial role of TRPA1 and TRPV1 in IR pathophysiology. The strong correlation between the increase in AITC threshold in patients with IR and symptom reduction after capsaicin treatment demonstrates the clinical relevance of these findings.

Relationship between the sensation of activity limitation and the results of functional assessment in asthma patients.

OBJECTIVE: In asthma patients, the assessment of activity limitation is based on questions evaluating how limited the patient feels in their activities. However, the lack of functional data complicates the interpretation of the answers. We aimed to evaluate the intensity of relationships between the patient's perception of activity limitation and the results of several functional tests. METHODS: Twenty patients complaining of asthma exacerbation were invited to complete three scores (Chronic Respiratory Disease questionnaire, Asthma Control Questionnaire, Hospital Anxiety and Depression scale). They also underwent lung function measurements, a 6-minute walk test and a cardio-pulmonary exercise test. In addition, physical activity was studied by actigraphy. Spearman's rank correlation coefficients between the patient's perception of activity limitation and each of the other parameters were analysed. RESULTS: Five parameters were significantly correlated with the perception of activity limitation: ACQ question 4, related to dyspnea (rs 0.74, p < 0.001); Emotion domain of the Chronic Respiratory Disease questionnaire (rs -0.57, p = 0.02); HAD anxiety (rs 0.48, p = 0.032); HAD depression (rs 0.46, p = 0.041); ACQ question 6, related to reliever use (rs 0.46, p = 0.046). No parameters from the lung function test, 6MWT, CPET or actigraphy, were significantly correlated with the perception of activity limitation. CONCLUSIONS: In response to questions about limitation of activity, patients do not specifically answer mentioning physical limitation but rather the psychological burden associated with this constraint.

Morphometric Analysis of Explant Lungs in Cystic Fibrosis.

RATIONALE: After repeated cycles of lung infection and inflammation, patients with cystic fibrosis (CF) evolve to respiratory insufficiency. Although histology and imaging have provided descriptive information, a thorough morphometric analysis of end-stage CF lung disease is lacking. OBJECTIVES: To quantify the involvement of small and large airways in end-stage CF. METHODS: Multidetector computed tomography (MDCT) and micro-CT were applied to 11 air-inflated CF explanted lungs and 7 control lungs to measure, count, and describe the airway and parenchymal abnormalities in end-stage CF lungs. Selected abnormalities were further investigated with thin section histology. MEASUREMENTS AND MAIN RESULTS: On MDCT, CF explanted lungs showed an increased median (interquartile range) number (631 [511-710] vs. 344 [277-349]; P = 0.003) and size of visible airways (cumulative airway diameter 217 cm [209-250] vs. 91 cm [80-105]; P < 0.001) compared with controls. Airway obstruction was seen, starting from generation 6 and increasing to 40 to 50% of airways from generation 9 onward. Micro-CT showed that the total number of terminal bronchioles was decreased (2.9/ml [2.6-4.4] vs. 5.3/ml [4.8-5.7]; P < 0.001); 49% were obstructed, and the cross-sectional area of the open terminal bronchioles was reduced (0.093 mm(2) [0.084-0.123] vs. 0.179 mm(2) [0.140-0.196]; P < 0.001). On micro-CT, 41% of the obstructed airways reopened more distally. This remodeling was confirmed on histological analysis. Parenchymal changes were also seen, mostly in a patchy and peribronchiolar distribution. CONCLUSIONS: Extensive changes of dilatation and obstruction in nearly all airway generations were observed in end-stage CF lung disease.