Why, when and how to investigate primary ciliary dyskinesia in adult patients with bronchiectasis

A novel splicing mutation DNAH5 c.13,338 + 5G > C is involved in the pathogenesis of primary ciliary dyskinesia in a family with primary familial brain calcification

BACKGROUND

Primary ciliary dyskinesia (PCD) is an autosomal recessive hereditary disease characterized by recurrent respiratory infections. In clinical manifestations, DNAH5 (NM_001361.3) is one of the recessive pathogenic genes. Primary familial brain calcification (PFBC) is a neurodegenerative disease characterized by bilateral calcification in the basal ganglia and other brain regions. PFBC can be inherited in an autosomal dominant or recessive manner. A family with PCD caused by a DNAH5 compound heterozygous variant and PFBC caused by a MYORG homozygous variant was analyzed.

METHODS

In this study, we recruited three generations of Han families with primary ciliary dyskinesia combined with primary familial brain calcification. Their clinical phenotype data were collected, next-generation sequencing was performed to screen suspected pathogenic mutations in the proband and segregation analysis of families was carried out by Sanger sequencing. The mutant and wild-type plasmids were constructed and transfected into HEK293T cells instantaneously, and splicing patterns were detected by Minigene splicing assay. The structure and function of mutations were analyzed by bioinformatics analysis.

RESULTS

The clinical phenotypes of the proband (II10) and his sister (II8) were bronchiectasis, recurrent pulmonary infection, multiple symmetric calcifications of bilateral globus pallidus and cerebellar dentate nucleus, paranasal sinusitis in the whole group, and electron microscopy of bronchial mucosa showed that the ciliary axoneme was defective. There was also total visceral inversion in II10 but not in II8. A novel splice variant C.13,338 + 5G > C and a frameshift variant C.4314delT (p. Asn1438lysfs *10) were found in the DNAH5 gene in proband (II10) and II8. c.347_348dupCTGGCCTTCCGC homozygous insertion variation was found in the MYORG of the proband. The two pathogenic genes were co-segregated in the family. Minigene showed that DNAH5 c.13,338 + 5G > C has two abnormal splicing modes: One is that part of the intron bases where the mutation site located is translated, resulting in early translation termination of DNAH5; The other is the mutation resulting in the deletion of exon76.

CONCLUSIONS

The newly identified DNAH5 splicing mutation c.13,338 + 5G > C is involved in the pathogenesis of PCD in the family, and forms a compound heterozygote with the pathogenic variant DNAH5 c.4314delT lead to the pathogenesis of PCD.

Primary Ciliary Dyskinesia in Adult Bronchiectasis: Data from the German Bronchiectasis Registry PROGNOSIS

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare genetic disorder caused by the malfunction of motile cilia and a specific etiology of adult bronchiectasis of unknown prevalence. A better understanding of the clinical phenotype of adults with PCD is needed to identify individuals for referral to diagnostic testing.

RESEARCH QUESTION

What is the frequency of PCD among adults with bronchiectasis; how do people with PCD differ from those with other etiologies; and which clinical characteristics are independently associated with PCD?

STUDY DESIGN AND METHODS

We investigated the proportion of PCD among the participants of the German Bronchiectasis Registry PROGNOSIS, applied multiple imputation to account for missing data in 64 (FEV1), 58 (breathlessness), 26 (pulmonary exacerbations), and two patients (BMI), respectively, and identified predictive variables from baseline data using multivariate logistic regression analysis.

RESULTS

We consecutively recruited 1,000 patients from 38 centers across all levels of the German health care system. Overall, PCD was the fifth most common etiology of bronchiectasis in 87 patients (9%) after idiopathic, postinfective, COPD, and asthma. People with PCD showed a distinct clinical phenotype. In multivariate regression analysis, the chance of PCD being the etiology of bronchiectasis increased with the presence of upper airway disease (chronic rhinosinusitis and/or nasal polyps; adjusted OR [aOR], 6.3; 95% CI, 3.3-11.9; P < .001), age < 53 years (aOR, 5.3; 95% CI, 2.7-10.4; P < .001), radiologic involvement of any middle and lower lobe (aOR, 3.7; 95% CI, 1.3-10.8; P = .016), duration of bronchiectasis > 15 years (aOR, 3.6; 95% CI, 1.9-6.9; P < .001), and a history of Pseudomonas aeruginosa isolation from respiratory specimen (aOR, 2.4; 95% CI, 1.3-4.5; P = .007).

INTERPRETATION

Within our nationally representative cohort, PCD was a common etiology of bronchiectasis. We identified few easy-to-assess phenotypic features, which may promote awareness for PCD among adults with bronchiectasis.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02574143; URL: www.

CLINICALTRIALS

gov.

Fertility care among people with primary ciliary dyskinesia

INTRODUCTION

Fertility care is important for people living with primary ciliary dyskinesia (PCD) who are at increased risk of fertility problems. We investigated fertility care in an international participatory study.

METHODS

Participants of the COVID-PCD study completed an online questionnaire addressing fertility issues. We used logistic regression to study factors associated with fertility specialist visits.

RESULTS

Among 384 respondents (response rate 53%), 266 were adults (median age 44 years, interquartile range [IQR]: 33-54, 68% female), 16 adolescents, and 102 parents of children with PCD. Only half of adult participants (128; 48%) received care from fertility specialists at a median age of 30 years (IQR: 27-33)-a median of 10 years after PCD diagnosis. Only 12% were referred to fertility specialists by their PCD physician. Fertility specialist visits were reported more often by adults with pregnancy attempts (odds ratio [OR]: 9.1, 95% confidence interval [CI]: 3.8-23.6) and among people who reported fertility as important for them (OR: 5.9, 95% CI: 2.6-14.6) and less often by females (OR: 0.4, 95% CI: 0.2-0.8). Only 56% of participants who talked with healthcare professionals about fertility were satisfied with information they received. They expressed needs for more comprehensive fertility information and reported dissatisfaction with physician knowledge about PCD and fertility.

CONCLUSION

People with PCD are inconsistently referred to fertility specialists. We recommend care from fertility specialists become standard in routine PCD care, and that PCD physicians provide initial fertility information either at diagnosis or no later than transition to adult care.

Ciliary Ultrastructure Assessed by Transmission Electron Microscopy in Adults with Bronchiectasis and Suspected Primary Ciliary Dyskinesia but Inconclusive Genotype

Whole-exome sequencing has expedited the diagnostic work-up of primary ciliary dyskinesia (PCD), when used in addition to clinical phenotype and nasal nitric oxide. However, it reveals variants of uncertain significance (VUS) in established PCD genes or (likely) pathogenic variants in genes of uncertain significance in approximately 30% of tested individuals. We aimed to assess genotype-phenotype correlations in adults with bronchiectasis, clinical suspicion of PCD, and inconclusive whole-exome sequencing results using transmission electron microscopy (TEM) and ciliary image averaging by the PCD Detect software. We recruited 16 patients with VUS in CCDC39, CCDC40, CCDC103, DNAH5, DNAH5/CCDC40, DNAH8/HYDIN, DNAH11, and DNAI1 as well as variants in the PCD candidate genes DNAH1, DNAH7, NEK10, and NME5. We found normal ciliary ultrastructure in eight patients with VUS in CCDC39, DNAH1, DNAH7, DNAH8/HYDIN, DNAH11, and DNAI1. In six patients with VUS in CCDC40, CCDC103, DNAH5, and DNAI1, we identified a corresponding ultrastructural hallmark defect. In one patient with homozygous variant in NME5, we detected a central complex defect supporting clinical relevance. Using TEM as a targeted approach, we established important genotype-phenotype correlations and definite PCD in a considerable proportion of patients. Overall, the PCD Detect software proved feasible in support of TEM.

Which side are they on? Diagnosing primary ciliary dyskinesias in low- or middle-income countries: A review and case series

Background

Primary ciliary dyskinesia (PCD) is a rare genetic condition with a variable clinical presentation, making its diagnosis a challenge. We describe two unrelated sibling pairs with PCD: adult siblings in the first and perinatal/neonatal in the second. Both families highlight the more common and rarer clinical manifestations of PCD. We use these cases to highlight: (i) current understanding of the underlying genetic and pathophysiological mechanisms of PCD; (ii) the diversity of cardiac and respiratory features of PCD across a wide age range; (iii) aspects of the history and clinical examination that should raise suspicion of PCD; and (iv) the role of next-generation sequencing gene panel testing in confirmation of the diagnosis. We note genomic evidence predicting that PCD is relatively common in black African populations.

Study synopsis

What the study adds. This review of two sibling pairs illustrates the variable histories, presentations, diagnostic processes and clinical courses of primary ciliary dyskinesia (PCD) in low- or middle-income countries (LMICs), highlighting the diagnostic challenges faced when encountering such patients in settings where there may not be access to specialised resources. Possible diagnostic tools that can be used are discussed, weighing up their pros and cons in an LMIC setting, and a potential diagnostic approach that can be adapted to the treating clinician's own context is provided.Implications of the findings. Confirmation of the diagnosis of primary ciliary dyskinesia is no longer limited to well-resourced institutions, but can be done in less specialised environments using novel, highly accurate next-generation sequencing gene panel testing, reducing the need to transport patients as well as the overall cost to the healthcare system. Well-resourced institutions that see high volumes of patients with PCD can invest in new highly sensitive diagnostic tools such as high-speed video microscopy. There is a need for research investigating the validity of tools such as ciliary immunofluorescence in the South African population.

Primary Ciliary Dyskinesia Patient-Specific hiPSC-Derived Airway Epithelium in Air-Liquid Interface Culture Recapitulates Disease Specific Phenotypes In Vitro

Primary ciliary dyskinesia (PCD) is a rare heterogenic genetic disorder associated with perturbed biogenesis or function of motile cilia. Motile cilia dysfunction results in diminished mucociliary clearance (MCC) of pathogens in the respiratory tract and chronic airway inflammation and infections successively causing progressive lung damage. Current approaches to treat PCD are symptomatic, only, indicating an urgent need for curative therapeutic options. Here, we developed an in vitro model for PCD based on human induced pluripotent stem cell (hiPSC)-derived airway epithelium in Air-Liquid-Interface cultures. Applying transmission electron microscopy, immunofluorescence staining, ciliary beat frequency, and mucociliary transport measurements, we could demonstrate that ciliated respiratory epithelia cells derived from two PCD patient-specific hiPSC lines carrying mutations in DNAH5 and NME5, respectively, recapitulate the respective diseased phenotype on a molecular, structural and functional level.

ERS International Congress 2022: highlights from the Airway Diseases Assembly

The European Respiratory Society (ERS) celebrated the return of an in-person meeting in Barcelona, Spain, after 2 years of virtual congresses. The ERS Congress 2022 programme was replete with symposia, skills workshops and abstract presentations from all 14 assemblies, encompassing over 3000 abstracts presented in the form of thematic poster discussion and oral presentations. In this article, highlights from the ERS Congress 2022 (including from thematic poster sessions, oral presentations and symposia from keynote speakers), presented by Assembly 5 (Airway diseases, asthma, COPD and chronic cough), are reviewed by Early Career Members and experts in the field, with the aim of presenting key recent findings in the field.

Genome sequencing reveals underdiagnosis of primary ciliary dyskinesia in bronchiectasis

BACKGROUND

Bronchiectasis can result from infectious, genetic, immunological and allergic causes. 60-80% of cases are idiopathic, but a well-recognised genetic cause is the motile ciliopathy, primary ciliary dyskinesia (PCD). Diagnosis of PCD has management implications including addressing comorbidities, implementing genetic and fertility counselling and future access to PCD-specific treatments. Diagnostic testing can be complex; however, PCD genetic testing is moving rapidly from research into clinical diagnostics and would confirm the cause of bronchiectasis.

METHODS

This observational study used genetic data from severe bronchiectasis patients recruited to the UK 100,000 Genomes Project and patients referred for gene panel testing within a tertiary respiratory hospital. Patients referred for genetic testing due to clinical suspicion of PCD were excluded from both analyses. Data were accessed from the British Thoracic Society audit, to investigate whether motile ciliopathies are underdiagnosed in people with bronchiectasis in the UK.

RESULTS

Pathogenic or likely pathogenic variants were identified in motile ciliopathy genes in 17 (12%) out of 142 individuals by whole-genome sequencing. Similarly, in a single centre with access to pathological diagnostic facilities, 5-10% of patients received a PCD diagnosis by gene panel, often linked to normal/inconclusive nasal nitric oxide and cilia functional test results. In 4898 audited patients with bronchiectasis, <2% were tested for PCD and <1% received genetic testing.

CONCLUSIONS

PCD is underdiagnosed as a cause of bronchiectasis. Increased uptake of genetic testing may help to identify bronchiectasis due to motile ciliopathies and ensure appropriate management.

Precision medicine in bronchiectasis

Bronchiectasis, due to its highly heterogenous nature, requires an individualised approach to therapy. Patients experience symptoms and exacerbations driven by a combination of impaired mucociliary clearance, airway inflammation and airway infection. Treatment of bronchiectasis aims to enhance airway clearance and to address the underlying causes of inflammation and infection susceptibility. Bronchiectasis has multiple causes and so the pathophysiology leading to individual symptoms and exacerbations are different between individuals. Standardised investigations are recommended by international guidelines to identify the underlying causes of bronchiectasis. The process of identifying the underlying biology within an individual is called “endotyping” and is an emerging concept across chronic diseases. Endotypes that have a specific treatment are referred to as “treatable traits” and a treatable traits approach to managing patients with bronchiectasis in a holistic and evidence-based manner is the key to improved outcomes. Bronchiectasis is an area of intense research. Endotyping allows identification of subsets of patients to allow medicines to be tested differently in the future where trials, rather than trying to achieve a “one size fits all” solution, can test efficacy in subsets of patients where the treatment is most likely to be efficacious.

Bronchiectasis, due to its highly heterogenous nature, requires an individualised approach to therapy. Treatment targets symptoms and exacerbations by aiming to improve mucociliary clearance and to reduce airway inflammation and airway infection.https://bit.ly/3ite4B2

Diagnosis of primary ciliary dyskinesia: discrepancy according to different algorithms

Background

Diagnosis of primary ciliary dyskinesia (PCD) is challenging since there is no gold standard test. The European Respiratory (ERS) and American Thoracic (ATS) Societies developed evidence-based diagnostic guidelines with considerable differences.

Objective

We aimed to compare the algorithms published by the ERS and the ATS with each other and with our own PCD-UNIBE algorithm in a clinical setting. Our algorithm is similar to the ERS algorithm with additional immunofluorescence staining. Agreement (Cohen's κ) and concordance between the three algorithms were assessed in patients with suspicion of PCD referred to our diagnostic centre.

Results

In 46 out of 54 patients (85%) the final diagnosis was concordant between all three algorithms (30 PCD negative, 16 PCD positive). In eight patients (15%) PCD diagnosis differed between the algorithms. Five patients (9%) were diagnosed as PCD only by the ATS, one (2%) only by the ERS and PCD-UNIBE, one (2%) only by the ATS and PCD-UNIBE, and one (2%) only by the PCD-UNIBE algorithm. Agreement was substantial between the ERS and the ATS (κ=0.72, 95% CI 0.53–0.92) and the ATS and the PCD-UNIBE (κ=0.73, 95% CI 0.53–0.92) and almost perfect between the ERS and the PCD-UNIBE algorithms (κ=0.92, 95% CI 0.80–1.00).

Conclusion

The different diagnostic algorithms lead to a contradictory diagnosis in a considerable proportion of patients. Thus, an updated, internationally harmonised and standardised PCD diagnostic algorithm is needed to improve diagnostics for these discordant cases.

There is no gold standard test for diagnosing PCD. The use of existing diagnostic algorithms leads to contradicting results in many patients (15% in this study). Thus, an updated and internationally harmonised diagnostic guideline is needed.https://bit.ly/2U19Vvq

Whole genome sequencing in the diagnosis of primary ciliary dyskinesia

BACKGROUND

It is estimated that 1-13% of cases of bronchiectasis in adults globally are attributable to primary ciliary dyskinesia (PCD) but many adult patients with bronchiectasis have not been investigated for PCD. PCD is a disorder caused by mutations in genes required for motile cilium structure or function, resulting in impaired mucociliary clearance. Symptoms appear in infancy but diagnosis is often late or missed, often due to the lack of a "gold standard" diagnostic tool and non-specific symptoms. Mutations in > 50 genes account for around 70% of cases, with additional genes, and non-coding, synonymous, missense changes or structural variants (SVs) in known genes presumed to account for the missing heritability.

METHODS

UK patients with no identified genetic confirmation for the cause of their PCD or bronchiectasis were eligible for whole genome sequencing (WGS) in the Genomics England Ltd 100,000 Genomes Project. 21 PCD probands and 52 non-cystic fibrosis (CF) bronchiectasis probands were recruited in Wessex Genome Medicine Centre (GMC). We carried out analysis of single nucleotide variants (SNVs) and SVs in all families recruited in Wessex GMC.

RESULTS

16/21 probands in the PCD cohort received confirmed (n = 9), probable (n = 4) or possible (n = 3) diagnosis from WGS, although 13/16 of these could have been picked up by current standard of care gene panel testing. In the other cases, SVs were identified which were missed by panel testing. We identified variants in novel PCD candidate genes (IFT140 and PLK4) in 2 probands in the PCD cohort. 3/52 probands in the non-CF bronchiectasis cohort received a confirmed (n = 2) or possible (n = 1) diagnosis of PCD. We identified variants in novel PCD candidate genes (CFAP53 and CEP164) in 2 further probands in the non-CF bronchiectasis cohort.

CONCLUSIONS

Genetic testing is an important component of diagnosing PCD, especially in cases of atypical disease history. WGS is effective in cases where prior gene panel testing has found no variants or only heterozygous variants. In these cases it may detect SVs and is a powerful tool for novel gene discovery.

Evaluation of age at diagnosis and clinical findings of children with primary ciliary dyskinesia

OBJECTIVE

Patients with primary ciliary dyskinesia (PCD) may present with different clinical findings at different ages, and age at diagnosis may differ. We aimed to review clinical factors that affected age at diagnosis of patients with PCD.

STUDY DESIGN

All 70 patients with PCD who were followed in our pediatric pulmonology department were included. Demographic features, clinical findings, PrImary CiliAry DyskinesiA Rule (PICADAR) scores and pulmonary function tests of patients were recorded and clinical factors that affected age at diagnosis were evaluated.

RESULTS

The mean age at diagnosis was 8.3 ± 4.6 years. Most of patients (95.7%) had a persistent wet cough. The mean PICADAR score was 6.5 ± 3.2, and there was a negative correlation between PICADAR and age at diagnosis (r = -0.271, p = .023). The mean ages at diagnosis of patients with situs abnormality and recurrent wheezing were earlier than in patients without situs abnormality and recurrent wheezing (6.7 ± 4.3 and 6.8 ± 4.3, p = .002 vs. 9.8 ± 4.3 and 9.0 ± 4.6 years, p = .040, respectively). The mean age at diagnosis of patients with bronchiectasis was later than in patients without bronchiectasis (10.8 ± 3.9 and 6.9 ± 4.4 years, p = .001). Other clinical features were not statistically significant according to age at diagnosis (p > .05). There was no statistically significant relation between age at diagnosis and sex, sibling or relative with PCD and parental consanguinity (p > .05).

CONCLUSION

Although most patients diagnosed with PCD had symptoms, the diagnosis may be delayed. High PICADAR score is a useful guide to evaluate PCD. Situs abnormality and recurrent wheezing could be clues for early diagnosis of PCD. Early diagnosis of PCD may prevent bronchiectasis.

Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is an inherited cause of bronchiectasis. The estimated PCD prevalence in children with bronchiectasis is up to 26% and in adults with bronchiectasis is 1 to 13%. Due to dysfunction of the multiple motile cilia of the respiratory tract patients suffer from poor mucociliary clearance. Clinical manifestations are heterogeneous; however, a typical patient presents with chronic productive cough and rhinosinusitis from early life. Other symptoms reflect the multiple roles of motile cilia in other organs and can include otitis media and hearing loss, infertility, situs inversus, complex congenital heart disease, and more rarely other syndromic features such as hydrocephalus and retinitis pigmentosa. Awareness, identification, and diagnosis of a patient with PCD are important for multidisciplinary care and genetic counseling. Diagnosis can be pursued through a multitest pathway which includes the measurement of nasal nitric oxide, sampling the nasal epithelium to assess ciliary function and structure, and genotyping. Diagnosis is confirmed by the identification of a hallmark ultrastructural defect or pathogenic mutations in one of > 45 PCD causing genes. When a diagnosis is established management is centered around improving mucociliary clearance through physiotherapy and treatment of infection with antibiotics. The first international randomized controlled trial in PCD has recently been conducted showing azithromycin is effective in reducing exacerbations. It is likely that evidence-based PCD-specific management guidelines and therapies will be developed in the near future. This article examines prevalence, clinical features, diagnosis, and management of PCD highlighting recent advances in basic science and clinical care.

Diagnosis and Initial Investigation of Bronchiectasis

Bronchiectasis refers to both the name of a disease and a single radiological appearance that may, or may not, be associated with disease. As chronic respiratory disease, bronchiectasis is characterized by a variable range of signs and symptoms that may overlap with other chronic respiratory conditions. The proper identification of bronchiectasis as a disease in both primary and secondary care is of paramount importance. However, a standardized definition of radiologically and clinically significant bronchiectasis is still missing. Disease heterogeneity is a hallmark of bronchiectasis and applies not only to radiological features and clinical manifestations but also to other aspects of the disease, including the etiological and microbiological diagnosis as well as the evaluation of pulmonary function. Although the guidelines suggest a "minimum bundle" of tests, the diagnostic approach to bronchiectasis is challenging and may be driven by the "treatable traits" approach based on endotypes and biological characteristics. A broad spectrum of diagnostic tests could be used to investigate the etiology of bronchiectasis as well as other pulmonary, extrapulmonary, and environmental traits. Individualizing bronchiectasis workup according to the site of care (e.g., primary, secondary, and tertiary care) could help optimize patients' management and reduce healthcare costs.

Exploring factors associated with acquisition and chronicity of infection in bronchiectasis: A population-based study

INTRODUCTION

Chronic infection is associated with adverse outcomes among people with bronchiectasis. However, it is not known which factors are associated with a bacterial infection, and with persistence of an infection after the first episode. We aimed to determine factors associated with a new infection and with chronicity of Pseudomonas aeruginosa (PA) and H. influenzae (HI), the most common organisms in bronchiectasis infection.

METHODS

Using an Israeli population database, we identified individuals diagnosed with bronchiectasis. Cox proportional hazard models were used to assess risk factors for first isolation and Logistic regression for chronicity of infection after a first isolation of PA and HI.

RESULTS

We included 1305 people with a median of 5 respiratory samples per individual. PA was initially isolated in 297 people, of whom 97 (33%) developed chronic PA infection. HI was newly identified in 169 people, of whom 39 (23%) developed chronic infection (p = 0.029). Factors associated with increased risk of a new infection with PA were COPD (HR 1.87 [1.52-2.28], previous isolation of HI (HR 1.38 [1.07-1.78]), and alcohol abuse (HR 2.22 [1.13-4.3]). Younger age was associated with increased risk of HI infection, while COPD was associated with a lower risk of HI infection. Prescription of an anti- PA antibiotic was associated with chronic PA after a new infection (OR = 1.8 [1.09-2.9], p = 0.02). A landmark analysis showed that survival was worse in people with chronic PA infection vs. single or intermittent infection (Log rank: p = 0.034) CONCLUSIONS: Younger age and presence of PCD are associated with a new isolation of HI. A new infection with PA is associated with previous HI infection, PCD, COPD, and alcohol abuse. Unexpectedly, treatment with appropriate anti-PA antimicrobials was not associated with a reduced risk of chronicity.

The Primary Ciliary Dyskinesia Computed Tomography Score in Adults with Bronchiectasis: A Derivation und Validation Study

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare genetic disorder which requires a complex diagnostic workup. Thus, an easy and widely available screening method would be helpful to identify patients who need a further diagnostic workup for PCD.

OBJECTIVES

The aim of the study was to develop and validate a computed tomography (CT) score for PCD to facilitate etiological diagnosis in adults with bronchiectasis.

METHOD

Chest CTs from 121 adults with bronchiectasis were scored for bronchiectasis morphology, distribution, and associated findings. Patients with and without the etiological diagnosis of PCD (46 and 75, respectively) were compared. Significantly, different imaging findings (p < 0.05) in univariate analysis were considered for multivariate analysis. Distinct findings were used to build the score. Based on this score, receiver operating characteristic (ROC) curve analysis was performed. The score was validated with 2 independent cohorts, another cohort from the same institution with 56 patients (28 with PCD) and an external cohort from another referral center with 172 patients (86 with PCD).

RESULTS

The following parameters predicted PCD in adults with bronchiectasis and were included in the score with weighting according to their regression coefficients: 2 points were given for predominance in the middle/lower lobe, 2 points for tree-in-bud pattern, 2 points for atelectasis or prior resection of a middle/lower lobe, and 3 points for absence of emphysema and fibrosis. Situs inversus was only observed in subjects with PCD (Kartagener syndrome) and, thus, was not used in the primary ciliary dyskinesia computed tomography (PCD-CT) score as group comparisons could not be performed. ROC curve analysis revealed an area under the curve (AUC) of 0.90 (95% CI 0.85-0.96). Youden index was the highest at a threshold of >6 with a sensitivity of 83% and a specificity of 83%. In the validation cohorts, ROC curve analysis confirmed the performance of the score with an AUC of 0.83 (95% CI 0.72-0.94) in the first validation cohort and 0.79 (95% CI 0.73-0.86) in the external validation cohort.

CONCLUSIONS

The PCD-CT score provides the first validated CT score for PCD and helps physicians in identifying adult bronchiectasis patients who require further diagnostic workup. Key message: The PCD-CT score provides the first validated CT score to assist physicians in identifying adult bronchiectasis patients who require a further diagnostic workup for PCD. It potentially improves earlier recognition of this rare and underdiagnosed disease.

Protease-Antiprotease Imbalance in Bronchiectasis

Airway inflammation plays a central role in bronchiectasis. Protease-antiprotease balance is crucial in bronchiectasis pathophysiology and increased presence of unopposed proteases activity may contribute to bronchiectasis onset and progression. Proteases' over-reactivity and antiprotease deficiency may have a role in increasing inflammation in bronchiectasis airways and may lead to extracellular matrix degradation and tissue damage. Imbalances in serine proteases and matrix-metallo proteinases (MMPs) have been associated to bronchiectasis. Active neutrophil elastase has been associated with disease severity and poor long-term outcomes in this disease. Moreover, high levels of MMPs have been associated with radiological and disease severity. Finally, severe deficiency of α1-antitrypsin (AAT), as PiSZ and PiZZ (proteinase inhibitor SZ and ZZ) phenotype, have been associated with bronchiectasis development. Several treatments are under study to reduce protease activity in lungs. Molecules to inhibit neutrophil elastase activity have been developed in both oral or inhaled form, along with compounds inhibiting dipeptydil-peptidase 1, enzyme responsible for the activation of serine proteases. Finally, supplementation with AAT is in use for patients with severe deficiency. The identification of different targets of therapy within the protease-antiprotease balance contributes to a precision medicine approach in bronchiectasis and eventually interrupts and disrupts the vicious vortex which characterizes the disease.

Generation of two hiPSC lines (MHHi016-A, MHHi016-B) from a primary ciliary dyskinesia patient carrying a homozygous 5 bp duplication (c.248_252dup (p.Gly85Cysfs*11)) in exon 1 of the CCNO gene

Cyclin O (CCNO) is involved in cell cycle regulation and mutations of CCNO are linked to the rare genetic disease primary ciliary dyskinesia (PCD). Mutations in CCNO are associated with reduced cilia number and cilia agenesis on epithelia of the respiratory tract. This article deals with the description of two hiPSC lines generated from a PCD patient carrying a mutation in exon 1 of the CCNO gene. The lines offer a valuable tool for in vitro modeling PCD pathophysiology.

Is bronchiectasis really a disease?

The definition of a disease requires that distinguishing signs and symptoms are present that are common, and that the constellation of signs and symptoms differentiate the condition from other causes. In bronchiectasis, anatomical changes, airways inflammation and airway infection are the distinguishing features that are common to this disease. However, bronchiectasis is a heterogenous disease: signs and symptoms are shared with other airway diseases, there are multiple aetiologies and certain phenotypes of bronchiectasis have distinct clinical and laboratory features that are not common to all people with bronchiectasis. Furthermore, response to therapeutic interventions in clinical trials is not uniform. The concept of bronchiectasis as a treatable trait has been suggested, but this may be too restrictive in view of the heterogeneity of bronchiectasis. It is our opinion that bronchiectasis should be defined as a disease in its own right, but one that shares several pathophysiological features and "treatable traits" with other airway diseases. These traits define the large heterogeneity in the pathogenesis and clinical features and suggest a more targeted approach to therapy.

Understanding Primary Ciliary Dyskinesia: Experience From a Mediterranean Diagnostic Reference Centre

Background: Due to the lack of a gold standard diagnostic test, reference centres with experienced personnel and costly procedures are needed for primary ciliary dyskinesia (PCD) diagnostics. Diagnostic flowcharts always start with clinical symptoms. Therefore, the aim of this work is to define differential clinical criteria so that only patients clinically compatible with PCD are referred to reference centres. Materials and methods: 18 variables from 476 Mediterranean patients with clinically suspicious PCD were collected. After analysing cilia function and ultrastructure, 89 individuals were diagnosed with PCD and 387 had a negative diagnosis. Simple logistic regression analysis, considering PCD as a dependent variable and the others as independent variables, was done. In order to define the variables that best explain PCD, a step-wise logistic regression model was defined. Aiming to classify individuals as PCD or PCD-like patients, based on variables included in the study, a classification and regression tree (CART) was designed. Results and conclusions: Simple logistic regression analysis shows statistically significant association between age at the beginning of their symptomatology, periodicity, fertility, situs inversus, recurrent otitis, atelectasis, bronchiectasis, chronic productive cough, rhinorrea, rhinusinusitis and recurrent pneumonias, and PCD. The step-wise logistic regression model selected situs inversus, atelectasis, rhinorrea, chronic productive cough, bronchiectasis, recurrent pneumonias, and otitis as PCD predictive variables (82% sensitivity, 88% specificity, and 0.92 Area Under the Curve (AUC)). A decision tree was designed in order to classify new individuals based on pansinusitis, situs inversus, periodicity, rhinorrea, bronchiectasis, and chronic wet cough.

Severe pulmonary disease in an adult primary ciliary dyskinesia population in Brazil

Primary Ciliary Dyskinesia (PCD) is underdiagnosed in Brazil. We enrolled patients from an adult service of Bronchiectasis over a two-year period in a cross-sectional study. The inclusion criteria were laterality disorders (LD), cough with recurrent infections and the exclusion of other causes of bronchiectasis. Patients underwent at least two of the following tests: nasal nitric oxide, ciliary movement and analysis of ciliary immunofluorescence, and genetic tests (31 PCD genes + CFTR gene). The clinical characterization included the PICADAR and bronchiectasis scores, pulmonary function, chronic Pseudomonas aeruginosa (cPA) colonization, exhaled breath condensate (EBC) and mucus rheology (MR). Forty-nine of the 500 patients were diagnosed with definite (42/49), probable (5/49), and clinical (2/49) PCD. Twenty-four patients (24/47) presented bi-allelic pathogenic variants in a total of 31 screened PCD genes. A PICADAR score > 5 was found in 37/49 patients, consanguinity in 27/49, LD in 28/49, and eight PCD sibling groups. FACED diagnosed 23/49 patients with moderate or severe bronchiectasis; FEV1 ≤ 50% in 25/49 patients, eight patients had undergone lung transplantation, four had been lobectomized and cPA+ was determined in 20/49. The EBC and MR were altered in all patients. This adult PCD population was characterized by consanguinity, severe lung impairment, genetic variability, altered EBC and MR.