Primary ciliary dyskinesia: diagnostic and phenotypic features

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 Prospective German Non-CF-Bronchiectasis Registry (PROGNOSIS) study; 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.

Primary Ciliary Dyskinesia Caused by Homozygous DNAAF1 Mutations Resulting from a Consanguineous Marriage: A Case Report from Japan

We present the case of a 58-year-old female patient with primary ciliary dyskinesia (PCD). She was born to parents with a consanguineous marriage. Chest computed tomography conducted at age 41 years indicated no situs inversus, and findings of bronchiectasis were limited to the middle and lingular lobes. Despite long-term macrolide therapy, bronchiectasis exacerbations frequently occurred. PCD was suspected because of the low nasal nitric oxide level (20.7 nL/min). Electron microscopy revealed outer and inner dynein arm defects, and a genetic analysis identified a homozygous single-nucleotide deletion in the DNAAF1 gene. Based on these results, the patient was diagnosed with PCD due to a biallelic DNAAF1 mutation.

Ciliary Function, Antigen Stasis and Asthma

The prevalence of asthma exceeds 3% of the population. Asthma is observed to be more common in children following severe viral lower respiratory illnesses that affect ciliary function, but mechanisms linking ciliary function to asthma pathogenesis have been obscure. Recent data regarding primary ciliary dyskinesia (PCD) may help us to understand the association. Here, I will review what is known about the relationship between ciliary function and asthma. PCD is caused by pathologic variants in over 50 different genes that affect the structure and function of motile cilia. At the cellular level, a characteristic feature shared by most PCD patients is that antigens and other particles are not cleared from the epithelial surface. Poor antigen clearance results in pro-oxidant pathway activation and airway epithelial damage and may predispose PCD patients to DUOX1- and IL33-mediated asthma. Secondary ciliary dysfunction, such as that caused by viruses or by smoking, can also contribute to asthma development. Moreover, variants in genes that affect the function of cilia can be associated with poor lung function, even in the absence of PCD, and with increased asthma severity. The role of antigen stasis on the surface of dysfunctional airway cilia in the pathophysiology of asthma is a novel area for research, because specific airway clearance techniques and other therapeutic interventions, such as antioxidants, could be of value in preventing the development of asthma.

Combined approaches, including long-read sequencing, address the diagnostic challenge of HYDIN in primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD), a disorder of the motile cilia, is now recognised as an underdiagnosed cause of bronchiectasis. Accurate PCD diagnosis comprises clinical assessment, analysis of cilia and the identification of biallelic variants in one of 50 known PCD-related genes, including HYDIN. HYDIN-related PCD is underdiagnosed due to the presence of a pseudogene, HYDIN2, with 98% sequence homology to HYDIN. This presents a significant challenge for Short-Read Next Generation Sequencing (SR-NGS) and analysis, and many diagnostic PCD gene panels do not include HYDIN. We have used a combined approach of SR-NGS with bioinformatic masking of HYDIN2, and state-of-the-art long-read Nanopore sequencing (LR_NGS), together with analysis of respiratory cilia including transmission electron microscopy and immunofluorescence to address the underdiagnosis of HYDIN as a cause of PCD. Bioinformatic masking of HYDIN2 after SR-NGS facilitated the detection of biallelic HYDIN variants in 15 of 437 families, but compromised the detection of copy number variants. Supplementing testing with LR-NGS detected HYDIN deletions in 2 families, where SR-NGS had detected a single heterozygous HYDIN variant. LR-NGS was also able to confirm true homozygosity in 2 families when parental testing was not possible. Utilising a combined genomic diagnostic approach, biallelic HYDIN variants were detected in 17 families from 242 genetically confirmed PCD cases, comprising 7% of our PCD cohort. This represents the largest reported HYDIN cohort to date and highlights previous underdiagnosis of HYDIN-associated PCD. Moreover this provides further evidence for the utility of LR-NGS in diagnostic testing, particularly for regions of high genomic complexity.

Respiratory Aspects of Primary Ciliary Dyskinesia

This review article explores the respiratory aspects of primary ciliary dyskinesia (PCD), a rare, heterogenous, genetic disorder characterized by impaired motile ciliary function. It discusses the clinical diagnosis and management strategies for PCD-related respiratory disease, including chronic sinusitis, otitis media with effusion, recurrent pneumonia, and bronchiectasis. The review emphasizes the need for a multidisciplinary approach to optimize care and clinical trials to improve outcomes in individuals with PCD, highlighting the importance of accurate diagnosis.

Characterization of pathogenic genetic variants in Russian patients with primary ciliary dyskinesia using gene panel sequencing and transcript analysis

BACKGROUND

Primary ciliary dyskinesia (PCD) is a group of rare genetically heterogeneous disorders caused by defective cilia and flagella motility. The clinical phenotype of PCD patients commonly includes chronic oto-sino-pulmonary disease, infertility, and, in about half of cases, laterality defects due to randomization of left-right body asymmetry. To date, pathogenic variants in more than 50 genes responsible for motile cilia structure and assembly have been reported in such patients. While multiple population-specific mutations have been described in PCD cohorts from different countries, the data on genetic spectrum of PCD in Russian population are still extremely limited.

RESULTS

The present study provides a comprehensive clinical and genetic characterization of 21 Russian families with PCD living in various country regions. Anomalies of ciliary beating in patients` respiratory epithelial cells were confirmed by high-speed video microscopy. In the most cases, custom-designed panel sequencing allowed to uncover causative variants in well-known or rarely mentioned PCD-related genes, including DNAH5, DNAH11, CFAP300, LRRC6, ZMYND10, CCDC103, HYDIN, ODAD4, DNAL1, and OFD1. The variations comprised common mutations, as well as novel genetic variants, some of which probably specific for Russian patients. Additional targeted analysis of mRNA transcripts from ciliated cells enabled us to specify functional effects of newly identified genetic variants in DNAH5 (c.2052+3G>T, c.3599-2A>G), HYDIN (c.10949-2A>G, c.1797C>G), and ZMYND10 (c.510+1G>C) on splicing process. In particular, the splice site variant c.2052+3G>T, detected in four unrelated families, resulted in skipping of exon 14 in DNAH5 transcripts and, according to haplotype analysis of affected probands, was proposed as an ancestral founder mutation in Udmurt population.

CONCLUSIONS

The reported data provide a vital insight into genetic background of primary ciliary dyskinesia in the Russian population. The findings clearly illustrate the utility of gene panel sequencing coupled with transcriptional analysis in identification and clinical interpretation of novel genetic variants.

Neonatal diagnosis of primary ciliary dyskinesia in a high consanguinity population: a single tertiary center experience

Though PCD usually presents after birth in term neonates, diagnosing PCD during the neonatal and infancy stages is uncommon, particularly in children who do not exhibit laterality defects. We report our recent experience with the diagnosis of PCD in the neonatal and early infantile period in a highly consanguine population. This was achieved by implementing a novel genetic-based diagnostic approach based on direct testing for recognized regional genetic variants. We conducted a retrospective analysis of children diagnosed with PCD at Soroka University Medical Center during the neonatal or early infantile period between 2020 and 2023. We included children under 3 months of age who had a genetic confirmation of PCD, as evidenced by the presence of two pathogenic variants in recognized genes. Genetic testing targeted regional genetic variants in previously identified PCD genes. Eight patients were included. The median age at diagnosis was 12.5 days. Three (38%) were born prematurely < 34 weeks gestational age. All patients were presented with respiratory distress and hypoxemia after birth. The median duration of oxygen support was 23 days, and upper lobe atelectasis was present in five patients (63%). Congenital cardiac malformation was present in four patients. Organ laterality defects were present in four patients. Genetic mutations identified were in the DNAAF5, DNAL1, DNAAF3, and DNAH1 genes.     Conclusion: Neonatal diagnosis of PCD is uncommon, especially in atypical presentations such as children without laterality defects or preterms. Focusing on a genetic diagnosis of the local tribal pathogenic variants promotes a potential cost-efficient test leading to earlier diagnosis. There is a need for a standardized protocol for earlier diagnosis of PCD in high-consanguinity areas. What is Known: • Primary ciliary dyskinesia (PCD) typically presents after birth in term neonates. • Diagnosing PCD during neonatal and infancy stages is challenging, particularly in children without laterality defects. What is New: • A novel genetic-based diagnostic approach was implemented on the neonatal population in a highly consanguine community, focusing on direct testing for regional genetic variants, leading to early and rapid diagnosis of PCD.

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.

Growing from common ground: nontuberculous mycobacteria and bronchiectasis

Bronchiectasis and nontuberculous mycobacteria (NTM) are intricately intertwined, with NTM capable of being both a cause and consequence of bronchiectatic disease. This narrative review focuses on the common ground of bronchiectasis and NTM pulmonary disease (NTM-PD) in terms of diagnostic approach, underlying risk factors and treatment strategies. NTM-PD diagnosis relies on a combination of clinical, radiological and microbiological criteria. Although their epidemiology is complicated by detection and reporting biases, the prevalence and pathogenicity of NTM species vary geographically, with Mycobacterium avium complex and Mycobacterium abscessus subspecies most frequently isolated in bronchiectasis-associated NTM-PD. Diagnosis of nodular bronchiectatic NTM-PD should prompt investigation of host factors, including disorders of mucociliary clearance, connective tissue diseases and immunodeficiencies, either genetic or acquired. Treatment of NTM-PD in bronchiectasis involves a multidisciplinary approach and considers the (sub)species involved, disease severity and comorbidities. Current guideline-based antimicrobial treatment of NTM-PD is considered long, cumbersome and unsatisfying in terms of outcomes. Novel treatment regimens and strategies are being explored, including rifampicin-free regimens and inclusion of clofazimine and inhaled antibiotics. Host-directed therapies, such as immunomodulators and cytokine-based therapies, might enhance antimycobacterial immune responses. Optimising supportive care, as well as pathogen- and host-directed strategies, is crucial, highlighting the need for personalised approaches tailored to individual patient needs. Further research is warranted to elucidate the complex interplay between host and mycobacterial factors, informing more effective management strategies.

A rare case report: Left middle lobectomy in recurrent hemoptysis and chest infections of Kartagener syndrome patient

INTRODUCTION

Kartagener syndrome is rare, with an incidence of 1 in 32,000 live births. It consists of a triad of bronchiectasis, situs inversus, and sinusitis. Normally, the middle lobe is part of the right lung, but due to situs inversus, the middle lobe is part of the left lung, making it prone to bronchiectasis and infections.

CASE REPORT

We present a unique case of a 16-year-old adolescent with a known history of Kartagener syndrome who presented with recurrent chest infections and hemoptysis refractory to conservative management. He was diagnosed with bronchiectasis of the left middle lobe through a computed tomography (CT) scan and subsequently underwent a posterolateral thoracotomy and left middle lobectomy. This is a rare finding with limited literature available on such cases, to the best of our knowledge.

DISCUSSION

Conservative treatment is usually the first line of approach. However, in cases of recurrent chest infections and hemoptysis, surgical management is considered to prevent the infection from spreading to the healthy lung and to avoid life-threatening complications when medical therapy fails. Surgical intervention, while more invasive, can provide a definitive solution and improve the patient's quality of life.

CONCLUSION

Early diagnosis of Kartagener syndrome is crucial for determining the appropriate management course. In patients presenting with recurrent hemoptysis and chest infections, surgical resection is an effective treatment approach to prevent complications and enhance long-term outcomes.

Primary Ciliary Dyskinesia: A Clinical Review

Primary ciliary dyskinesia (PCD) is a rare, genetically heterogeneous, motile ciliopathy, characterized by neonatal respiratory distress, recurrent upper and lower respiratory tract infections, subfertility, and laterality defects. Diagnosis relies on a combination of tests for confirmation, including nasal nitric oxide (nNO) measurements, high-speed videomicroscopy analysis (HSVMA), immunofluorescent staining, axonemal ultrastructure analysis via transmission electron microscopy (TEM), and genetic testing. Notably, there is no single gold standard confirmatory or exclusionary test. Currently, 54 causative genes involved in cilia assembly, structure, and function have been linked to PCD; this rare disease has a spectrum of clinical manifestations and emerging genotype-phenotype relationships. In this review, we provide an overview of the structure and function of motile cilia, the emerging genetics and pathophysiology of this rare disease, as well as clinical features associated with motile ciliopathies, novel diagnostic tools, and updates on genotype-phenotype relationships in PCD.

Kartagener's Syndrome: A Case Series

Kartagener's syndrome is an uncommon autosomal recessive ciliary dyskinesia. It combines a triad comprised of bronchiectasis, chronic sinusitis, and situs inversus. This work aims to describe the clinical and paraclinical aspects of primary ciliary dyskinesia using Kartagener's syndrome as a model and to highlight the difficulties of confirming the diagnosis in our context. We report four observations (three boys and one girl with an average age of 10 years) of Kartagener's syndrome collected in the department of pediatric pneumo-allergology. Chronic bronchorrhea and otorhinolaryngological manifestations were found in all cases. Signs of neonatal respiratory distress syndrome were found in only one case. One child had dysmorphic facial features suggestive of Noonan's syndrome and conductive hearing loss. Digital hippocratism was found in half of the cases, along with pulmonary crackles and heart sounds perceived on the right. A chest CT scan showed bronchiectasis in all patients and necrotic adenopathy suggestive of tuberculosis in one case. Sinus imaging showed an appearance of pansinusitis. All children had abdominal situs inversus with dextrocardia. They had received antibiotic therapy with amoxicillin-clavulanic acid associated with respiratory physiotherapy. The girl had benefited from a right lobectomy with a follow-up of 18 months and a good evolution. In light of these four observations, Kartagener's syndrome is a rare disease but can be compatible with normal life if the treatment is done early. However, in our context, the difficulty of confirming the diagnosis explains its delay with the risk of progression of pulmonary lesions.

Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a rare, genetic disease characterized by dysfunctional motile cilia and abnormal mucociliary clearance, resulting in chronic sino-oto-pulmonary disease, neonatal respiratory distress, subfertility, and organ laterality defects. Over the past 2 decades, research and international collaborations have led to an improved understanding of disease prevalence, classic and variable phenotypes, novel diagnostics, genotype-phenotype correlations, long term morbidity, and innovative therapeutics. However, PCD is often underrecognized in clinical settings and the recent analyses of genetic databases suggest that only a fraction of these patients are being accurately diagnosed. Knowledge of significant advancements, from pathophysiology to the expanded range of clinical manifestations, will have important clinical impacts. These may include increasing disease recognition, improving diagnostic testing and management, and establishing an adequate pool of affected patients to enroll in upcoming clinical therapeutic trials. The objective of this state-of-the-art review is for readers to gain a greater understanding of the clinical spectrum of motile ciliopathies, cutting-edge diagnostic practices, emerging genotype-phenotype associations, and currently accepted management of people with PCD.

[Primary ciliary dyskinesia]

Primary ciliary dyskinesia (PCD) is a rare genetic disorder with a variable clinical phenotype that is accompanied by reduced motility of the cilia in the respiratory tract and numerous other organs. This leads to various characteristic symptoms and disease manifestations, primarily affecting the lungs (chronic persistent productive cough, bronchiectasis), the nose and paranasal sinuses (chronic persistent rhinitis or rhinosinusitis) as well as the middle ear (chronic otitis media, middle ear effusion). Moreover, PCD is associated with impaired fertility or lateralization defects (situs anomalies, congenital heart defects). The diagnostics of PCD are complex and require a combination of several sophisticated instrument-based diagnostic procedures. Through thorough history taking and evaluation, suspected cases can be comparatively well identified based on typical clinical features and referred to further diagnostics. In recent years, molecular genetic analysis through panel diagnostics or whole exome and whole genome sequencing, has gained in importance as this enables affected individuals to participate in disease-specific and genotype-specific clinical trials. Although the current treatment is purely symptomatic, the earliest possible diagnosis is crucial for connecting patients to specialized PCD centers, which can have a significant impact on the clinical course of the affected individuals.

Mechanisms of cilia regeneration in Xenopus multiciliated epithelium in vivo

Cilia regeneration is a physiological event, and while studied extensively in unicellular organisms, it remains poorly understood in vertebrates. In this study, using Xenopus multiciliated cells (MCCs) as a model, we demonstrate that, unlike unicellular organisms, deciliation removes the transition zone (TZ) and the ciliary axoneme. While MCCs immediately begin the regeneration of the ciliary axoneme, surprisingly, the assembly of TZ is delayed. However, ciliary tip proteins, Sentan and Clamp, localize to regenerating cilia without delay. Using cycloheximide (CHX) to block new protein synthesis, we show that the TZ protein B9d1 is not a component of the cilia precursor pool and requires new transcription/translation, providing insights into the delayed repair of TZ. Moreover, MCCs in CHX treatment assemble fewer (∼ 10 vs. ∼150 in controls) but near wild-type length (ranging between 60 to 90%) cilia by gradually concentrating ciliogenesis proteins like IFTs at a select few basal bodies. Using mathematical modeling, we show that cilia length compared to cilia number influences the force generated by MCCs more. In summary, our results question the requirement of TZ in motile cilia assembly and provide insights into how cells determine organelle size and number.

The utility of nasal nitric oxide in the diagnostic evaluation of primary ciliary dyskinesia

BACKGROUND

There is no gold-standard test for primary ciliary dyskinesia (PCD), rather American Thoracic Society guidelines recommend starting with nasal nitric oxide (nNO) in children ≥5 years old and confirming the diagnosis with genetic testing or ciliary biopsy with transmission electron microscopy (TEM). These guidelines have not been studied in a clinical setting. We present a case series describing the PCD diagnostic process at our pediatric PCD center.

METHODS

Diagnostic data from 131 patients undergoing PCD consultation were reviewed.

RESULTS

In all participants ≥ 5 years old and who completed nNO using resistor methodology, the first diagnostic test performed was nNO in 77% (73/95), genetic testing in 14% (13/95), and TEM in <1% (9/95). nNO was the only diagnostic test performed in 75% (55/73) of participants who completed nNO first. Seventy-five percent (55/73) had a single above the cutoff nNO value and PCD was determined to be unlikely in 91% (50/55) without performing additional confirmatory testing. Eleven percent (8/73) had multiple below the cutoff nNO values, with 38% (3/8) being diagnosed with PCD by confirmatory testing and 50% (4/8) with negative confirmatory testing, but being managed as PCD. The genetic testing positivity rate was 50% in participants who completed nNO first and 8% when genetic testing was completed first.

CONCLUSION

nNO is useful in three situations: an initial above the cutoff nNO value makes PCD unlikely and prevents additional confirmatory testing, repetitively below the cutoff nNO values without positive confirmatory testing suggests a probable PCD diagnosis and the yield of genetic testing is higher when nNO is performed first.

Multi-institutional Assessment of Otitis Media Epidemiology Using Real-world Data

OBJECTIVES

To determine rates and risk factors of pediatric otitis media (OM) using real-world electronic health record (PEDSnet) data from January 2009 through May 2021.

STUDY DESIGN

Retrospective cohort study.

SETTING

Seven pediatric academic health systems that participate in PEDSnet.

METHODS

Children <6 months-old at time of first outpatient, Emergency Department, or inpatient visit were included and followed longitudinally. A time-to-event analysis was performed using a Cox proportional hazards model to estimate hazard ratios for OM incidence based on sociodemographic factors and specific health conditions.

RESULTS

The PEDSnet cohort included 910,265 children, 54.3% male, mean age (months) 1.3 [standard deviation (SD) 1.6] and mean follow up (years) 4.3 (SD 3.2). By age 3 years, 39.6% of children had evidence of one OM episode. OM rates decreased following pneumococcal-13 vaccination (PCV-13) and the COVID-19 pandemic. Along with young age, non-Hispanic Black/African American or Hispanic race/ethnicity, public insurance, higher family income, and male sex had higher incidence rates. Health conditions that increased OM risk included cleft palate [adjusted hazard ratio (aHR) 4.0 [95% confidence interval (CI) 3.9-4.2], primary ciliary dyskinesia [aHR 2.5 (95% CI 1.8-3.5)], trisomy 21 [aHR 2.0 (95% CI 1.9-2.1)], atopic dermatitis [aHR 1.4 (95% CI 1.4-1.4)], and gastroesophageal reflux [aHR1.5 (95% CI 1.5-1.5)].

CONCLUSIONS

Approximately 20% of children by age 1 and 40% of children by age 3 years will have experienced an OM episode. OM rates decreased after PCV-13 and COVID-19. Children with abnormal ciliary function or craniofacial conditions, specifically cleft palate, carry the highest risk of OM.

Antigen stasis and airway nitrosative stress in human primary ciliary dyskinesia

Nasal nitric oxide (nNO) is low in most patients with primary ciliary dyskinesia (PCD). Decreased ciliary motion could lead to antigen stasis, increasing oxidant production and NO oxidation in the airways. This could both decrease gas phase NO and increase nitrosative stress. We studied primary airway epithelial cells from healthy controls (HCs) and patients with PCD with several different genotypes. We measured antigen clearance in fenestrated membranes exposed apically to the fluorescently labeled antigen Dermatophagoides pteronyssinus (Derp1-f). We immunoblotted for 3-nitrotyrosine (3-NT) and for oxidative response enzymes. We measured headspace NO above primary airway cells without and with a PCD-causing genotype. We measured nNO and exhaled breath condensate (EBC) H2O2 in vivo. Apical Derp1-f was cleared from HC better than from PCD cells. DUOX1 expression was lower in HC than in PCD cells at baseline and after 24-h Derp1-f exposure. HC cells had less 3-NT and NO3- than PCD cells. However, NO consumption by HC cells was less than that by PCD cells; NO loss was prevented by superoxide dismutase (SOD) and by apocynin. nNO was higher in HCs than in patients with PCD. EBC H2O2 was lower in HC than in patients with PCD. The PCD airway epithelium does not optimally clear antigens and is subject to oxidative and nitrosative stress. Oxidation associated with antigen stasis could represent a therapeutic target in PCD, one with convenient monitoring biomarkers.NEW & NOTEWORTHY The PCD airway epithelium does not optimally clear antigens, and antigen exposure can lead to NO oxidation and nitrosative stress. Oxidation caused by antigen stasis could represent a therapeutic target in PCD, and there are convenient monitoring biomarkers.

Navigating Infertility in Kartagener's Syndrome: A Clinical Case Report

Kartagener's syndrome is a genetic condition that is caused by a triad of symptoms, which includes bronchiectasis, chronic sinusitis, and situs inversus, and is considered rare. It is caused by defective ciliary motility, leading to impaired mucociliary clearance. We report a case of a 24-year-old male who presented with primary infertility and a long-standing history of recurrent respiratory infections. Physical examination revealed dextrocardia and digital clubbing. Radiological investigations confirmed situs inversus totalis and bronchiectasis. Semen analysis revealed azoospermia. Genetic analysis was not done due to financial constraints. However, the constellation of clinical features was diagnostic of Kartagener's syndrome. The patient was managed with antibiotics and chest physiotherapy. In vitro fertilization (IVF) was advised for infertility. A successful pregnancy was achieved through IVF, indicating viable sperm despite immotility. The aforementioned case underscores the significance of maintaining a heightened sense of suspicion for Kartagener's syndrome in individuals exhibiting unexplained bronchiectasis and infertility. Early diagnosis can prevent chronic respiratory morbidity and enable parenthood through assisted reproduction.

Magnetic Resonance Imaging of Pulmonary and Paranasal Sinus Abnormalities in Children with Primary Ciliary Dyskinesia Compared to Children with Cystic Fibrosis

Rationale: Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) are characterized by inherited impaired mucociliary clearance leading to chronic progressive lung disease as well as chronic rhinosinusitis (CRS). The diseases share morphological and functional commonalities on magnetic resonance imaging (MRI) of the lungs and paranasal sinuses, but comparative MRI studies are lacking. Objectives: To determine whether PCD shows different associations of pulmonary and paranasal sinus abnormalities on MRI and lung function test results in children (infants to adolescents) compared with children with CF. Methods: Eighteen children with PCD (median age, 9.5 [IQR, 3.4-12.7] yr; range, 0-18 yr) and 36 age-matched CF transmembrane conductance regulator modulator-naive children with CF (median age, 9.4 [3.4-13.2] yr; range, 0-18 yr) underwent same-session chest and paranasal sinus MRI as well as spirometry (to determine forced expiratory volume in 1 s percent predicted) and multiple-breath washout (to determine lung clearance index z-score). Pulmonary and paranasal sinus abnormalities were assessed using previously validated chest MRI and CRS-MRI scoring systems. Results: Mean chest MRI global score was similar in children with PCD and CF (15.0 [13.5-20.8] vs. 15.0 [9.0-15.0]; P = 0.601). Consolidations were more prevalent and severe in children with PCD (56% vs. 25% and 1.0 [0.0-2.8] vs. 0.0 [0.0-0.3], respectively; P < 0.05). The chest MRI global score correlated moderately with forced expiratory volume in 1 second percent predicted in children with PCD and children with CF (r = -0.523 and -0.687; P < 0.01) and with lung clearance index in children with CF (r = 0.650; P < 0.001) but not in PCD (r = 0.353; P = 0.196). CRS-MRI sum score and mucopyocele subscore were lower in children with PCD than in children with CF (27.5 [26.3-32.0] vs. 37.0 [37.8-40.0] and 2.0 [0.0-2.0] vs. 7.5 [4.8-9.0], respectively; P < 0.01). CRS-MRI sum score did not correlate with chest MRI score in PCD (r = 0.075-0.157; P = 0.557-0.788) but correlated moderately with MRI morphology score in CF (r = 0.437; P < 0.01). Conclusions: MRI detects differences in lung and paranasal sinus abnormalities between children with PCD and those with CF. Lung disease does not correlate with CRS in PCD but correlates in CF.

The airway microbiota in siblings with primary ciliary dyskinesia: Related factors and correlation with clinical characteristics

OBJECTIVES-AIM

We aimed to show the composition and structure of and explore affecting factors on airway microbiota in primary ciliary dyskinesia (PCD) patients using culture-independent techniques.

METHOD

A cross-sectional observational study was performed. We recruited 14 PCD patients (seven pairs of siblings) and nine parents. Bacterial rDNA was extracted from sputum and nasal samples. Sputum samples were also inoculated on suitable bacteriological media.

RESULTS

Thirty-three separate genera were detected in sputum samples of PCD patients, and 41 were in nasal samples of parents. The detected genera were dominated by phyla Proteobacteria in PCD patients and their parents. Culture-dependent analyses could not detect many of the bacterial species detected with culture-independent analyses. There were no significant differences in alpha diversity between the siblings' pairs, and siblings' samples did not cluster together nearly as strongly as nonsiblings' samples. Patients who had no new complaints and no bacterial growth with the culture-dependent method at the time of study and patients who had no Haemophilus influenzae growth in the previous year had a significantly greater diversity (p < .05). Microbiota communities tended to cluster together by age, pulmonary exacerbation status, the existence of at least one H. influenzae growth with culture-dependent analyses in the previous year, and forced expiratory volume in 1 sec z and FEF25-75 z-scores.

CONCLUSION

The airway microbiota of patients with PCD have presented more diverse bacterial communities than had been indicated with culture-dependent methods. The study identifies relationships between bacterial airway microbiota composition and the clinical measures of patients. Sibling pairs have no more community similarities than nonsibling PCD patients. Our results may indicate that the patients' clinical characteristics, which determine the disease severity, might affect the PCD microbiome.

Redox Imbalance in Nasal Epithelial Cells of Primary Ciliary Dyskinesia Patients

Background: Primary Ciliary Dyskinesia (PCD) represents a rare condition marked by an abnormal mobility pattern of cilia and flagella, resulting in impaired mucociliary clearance. This deficiency leads to recurrent infections and persistent inflammation of the airways. While previous studies have indicated heightened oxidative stress levels in the exhaled breath condensate of pediatric PCD patients, the assessment of oxidative stress within the affected respiratory tissue remains unexplored. Aims: To assess the oxidative status of human nasal epithelial cells (NECs) in PCD patients. Methods: Thirty-five PCD patients and thirty-five healthy control subjects were prospectively included in the study. Levels of reactive oxygen species (ROS), reactive nitrogen species (RNS), glutathione (GSH), intracellular Ca2+, plasma membrane potential, and oxidative damage in lipids and proteins were measured. In addition, apoptosis and mitochondrial function were analyzed by flow cytometry in NECs. Results: NECs from PCD patients showed reduced levels of apoptosis (p = 0.004), superoxide anion (O2-, p = 0.018), peroxynitrite (ONOO-, p = 0.007), nitric oxide (NO, p = 0.007), mitochondrial hydrogen peroxide (mtH2O2, p < 0.0001), and mitochondrial superoxide anion (mtO2-, p = 0.0004) and increased mitochondrial mass (p = 0.009) compared to those from healthy individuals. No significant differences were observed in oxidized proteins (p = 0.137) and the oxidized/reduced lipid ratio (p = 0.7973). The oxidative profile of NEC cells in PCD patients, according to their ciliary motility, recurrent otitis, recurrent pneumonia, atelectasis, bronchiectasis, and situs inversus, showed no statistically significant differences in the parameters studied. Conversely, patients with chronic rhinosinusitis exhibited lower levels of ONOO- than PCD patients without this condition, with no significant differences related to other symptoms. Conclusions: Our findings strongly suggest the presence of a redox imbalance, specifically leaning toward a reductive state, in PCD patients.

Safety and efficacy of the epithelial sodium channel blocker idrevloride in people with primary ciliary dyskinesia (CLEAN-PCD): a multinational, phase 2, randomised, double-blind, placebo-controlled crossover trial

BACKGROUND

Mucociliary clearance is dysfunctional in people with primary ciliary dyskinesia, resulting in the accumulation of dehydrated mucus in the airways that is difficult to clear. We undertook a study to assess the benefit on lung function of treatment with a nebulised epithelial sodium channel (ENaC) blocker, idrevloride, with or without hypertonic saline, in people with primary ciliary dyskinesia.

METHODS

The CLEAN-PCD trial was a phase 2, randomised, double-blind, placebo-controlled crossover trial conducted at 32 tertiary adult and paediatric care centres and university hospitals in Canada, Denmark, Germany, Italy, the Netherlands, Poland, the UK, and the USA. People with a confirmed diagnosis of primary ciliary dyskinesia, aged 12 years or older, with a percentage of predicted FEV1 (ppFEV1) in the range of 40% to <90%, were randomly assigned in a 2:2:1:1 ratio (block size=6), stratified by ppFEV1 at screening, to one of four sequences: (1) idrevloride in hypertonic saline in treatment period 1 then hypertonic saline in treatment period 2; (2) hypertonic saline in treatment period 1 then idrevloride in hypertonic saline in treatment period 2; (3) idrevloride in treatment period 1 then placebo in treatment period 2; and (4) placebo in treatment period 1 then idrevloride in treatment period 2. The idrevloride dose was 85 μg and hypertonic saline was 4·2% NaCl. 3 mL of each study treatment was nebulised twice daily for 28 days in treatment periods 1 and 2; the two 28-day treatment periods were separated by a 28-day washout period. The primary endpoint was absolute change from baseline in ppFEV1 after 28 days. Safety assessments and reports of adverse events were made at clinic visits during each treatment period and by a follow-up telephone call 28 days after the last dose of study drug. Additionally, adverse events could be reported at a follow-up telephone call 3 days after the start of dosing and as they arose. Participants who received at least one dose of study drug were included in the safety analyses (safety set), and those who also had spirometry data were included in the efficacy analyses (full analysis set). The completed study is registered (EudraCT 2015-004917-26; ClinicalTrials.govNCT02871778).

FINDINGS

Between Sep 14, 2016, and May 31, 2018, 216 patients were screened and 123 were randomly assigned to one of four crossover sequences. Across the two treatment periods, treatment with idrevloride in hypertonic saline was initiated in 80 patients and completed in 78 patients (all 78 had data available and were included in the analysis); hypertonic saline initiated in 81 patients and completed in 76 patients (75 had data available and were included in the analysis); idrevloride initiated in 37 patients and completed in 35 patients (34 had data available and were included in the analysis); and placebo initiated in 36 patients and completed in 34 patients (all 34 had data available and were included in the analysis). Greater absolute increases in ppFEV1 from baseline to 28 days of treatment were seen with idrevloride in hypertonic saline (least-squares mean absolute change from baseline 1·0 percentage points, 95% CI -0·4 to 2·4) than with hypertonic saline alone (least-squares mean absolute change from baseline of -0·5 percentage points, -2·0 to 0·9; difference 1·5 percentage points, 95% CI <0·1 to 3·0; p=0·044). There was no significant difference in ppFEV1 for the parallel comparison of idrevloride in hypertonic saline compared with placebo or the crossover comparison of idrevloride with placebo. Adverse events were similar across treatments (57 to 65% of patients). Cough occurred in a greater proportion of participants during treatments that contained idrevloride or hypertonic saline compared with placebo, and oropharyngeal pain occurred in a greater proportion of participants during idrevloride treatments than during treatment with hypertonic saline alone or placebo, whereas chest discomfort was more common during treatments that included hypertonic saline.

INTERPRETATION

In this phase 2 crossover study, idrevloride in hypertonic saline was safe and associated with improved lung function over a 28-day period in people with primary ciliary dyskinesia compared with hypertonic saline alone. Larger, longer clinical studies are warranted to explore the potential benefits of idrevloride in combination with hypertonic saline in people with primary ciliary dyskinesia.

FUNDING

Parion Sciences, under agreement with Vertex Pharmaceuticals.

Impact of primary ciliary dyskinesia: Beyond sinobronchial syndrome in Japan

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterized by impaired motile cilia function, particularly in the upper and lower airways. To date, more than 50 causative genes related to the movement, development, and maintenance of cilia have been identified. PCD mostly follows an autosomal recessive inheritance pattern, in which PCD symptoms manifest only in the presence of pathogenic variants in both alleles. Several genes causing PCD have been recently identified that neither lead to situs inversus nor cause definitive abnormalities in ciliary ultrastructure. Importantly, the distribution of disease-causing genes and pathogenic variants varies depending on ethnicity. In Japan, homozygosity for a ∼27.7-kb deletion of DRC1 is estimated to be the most common cause of PCD, presumably as a founder mutation. The clinical picture of PCD is similar to that of sinobronchial syndrome, thus making its differentiation from diffuse panbronchiolitis and other related disorders difficult. Given the diagnostic challenges, many cases remain undiagnosed or misdiagnosed, particularly in adults. While no fundamental cure is currently available, lifelong medical subsidies are provided in Japan, and proper respiratory management, along with continued prevention and treatment of infections, is believed to mitigate the decline in respiratory function. Timely action will be necessary when specific treatments for PCD become available in the future. This narrative review focuses on variations in the disease status of PCD in a non-Western country.

Bronchodilator responsiveness in children with primary ciliary dyskinesia

Background

Reversible airway obstruction is common in children with primary ciliary dyskinesia. However, the diagnostic value of adding bronchodilator (BD) response testing to routine spirometry is unclear.

Methods

This is a retrospective analysis of pulmonary function test results obtained from children with primary ciliary dyskinesia seen as outpatients at the Hospital for Sick Children, Toronto. Spirometry results were collected for every appointment with BD response testing ("Visit", with pre-BD and post-BD measurements) as well as for the previous ("Baseline") and following ("Follow-up") encounters.

Results

A positive BD response was seen in 86 out of 474 (18.1%) of the pulmonary function tests from 82 children with primary ciliary dyskinesia. BD responsiveness was associated with a significant absolute change (±sd) in % predicted forced expiratory volume in 1 s (FEV1) from Baseline to Visit pre-BD (-6.5±10.3%, p<0.001), but not from Baseline to Follow-up (0.4±10.8, p=0.757). Antimicrobial therapy was initiated more commonly following a Visit with a positive BD response (OR 3.8, 95% CI 2.2-6.6) compared to no BD response. Children with a positive BD response had a greater annual decline in FEV1 % predicted compared to those with no BD response (-0.9% per year versus -0.5% per year, p<0.001). The annual decline in FEV1 % predicted was greater in children with multiple compared to one measured positive BD responses (-1.3% per year versus -0.6% per year, p<0.001) and in those not treated with antibiotic therapy following a positive BD response compared to those treated with antibiotics (-1.1% versus -0.6%, p<0.001).

Conclusion

A positive BD response in children with primary ciliary dyskinesia may help identify those at risk for accelerated lung disease progression.

Functions of cilia in cardiac development and disease

Errors in embryonic cardiac development are a leading cause of congenital heart defects (CHDs), including morphological abnormalities of the heart that are often detected after birth. In the past few decades, an emerging role for cilia in the pathogenesis of CHD has been identified, but this topic still largely remains an unexplored area. Mouse forward genetic screens and whole exome sequencing analysis of CHD patients have identified enrichment for de novo mutations in ciliary genes or non-ciliary genes, which regulate cilia-related pathways, linking cilia function to aberrant cardiac development. Key events in cardiac morphogenesis, including left-right asymmetric development of the heart, are dependent upon cilia function. Cilia dysfunction during left-right axis formation contributes to CHD as evidenced by the substantial proportion of heterotaxy patients displaying complex CHD. Cilia-transduced signaling also regulates later events during heart development such as cardiac valve formation, outflow tract septation, ventricle development, and atrioventricular septa formation. In this review, we summarize the role of motile and non-motile (primary cilia) in cardiac asymmetry establishment and later events during heart development.

Dual-allele heterozygous mutation of DNAH5 gene in a boy with primary ciliary dyskinesia: A case report

RATIONALE

To analyze clinical and imaging features, ciliary structure and family gene mutation loci of a primary ciliary dyskinesia (PCD) boy with a dual-allele heterozygous mutation of DNAH5.

PATIENT CONCERNS

Clinical data of the proband and relatives. Electronic bronchoscopy, transmission electron microscope (TEM) of the cilia and next-generation sequencing (NGS) were performed. PCD-related DNAH5 exon mutation sites were searched.

DIAGNOSES

A 10-year and 10-month-old boy was hospitalized due to "recurrent cough, expectoration, sputum and shortness of breathing after activity for over 7 years, and aggravated for 1 week." Moderate and fine wet rales were detected in bilateral lungs. Clubbing fingers and toes were observed. In local hospitals, he was diagnosed with Mycoplasma pneumoniae infection and Streptococcus pneumoniae was cultured.

INTERVENTIONS

Pulmonary function testing showed mixed ventilation dysfunction and positive for bronchial dilation test. Imaging examination and fiberoptic bronchoscopy revealed transposition of all viscera, bilateral pneumonia, and bronchiectasis. TEM detected no loss of the outer dynein arms. NGS identified 2 mutations (c.4360C>T, c.9346C>T) in the DNAH5 gene inherited from healthy parents.

OUTCOMES

According to literature review until 2022, among 144 exon gene mutations causing amino acid changes, C>T mutation is the most common in 44 cases, followed by deletion mutations in 30 cases. Among the amino acid changes induced by gene mutation, terminated mutations were identified in 89 cases.

LESSONS

For suspected PCD patients, TEM and NGS should be performed. Prompt diagnosis and treatment may delay the incidence of bronchiectasis and improve clinical prognosis.

Clinical and Imaging Features of Cystic Fibrosis in Korean Children

Cystic fibrosis (CF) is a fatal hereditary disorder that primarily affects Caucasians and is rare in Asian populations, including Koreans. Diagnosing CF is often challenging and delayed owing to its rarity and its overlapping features with non-CF diseases, ultimately affecting the patient prognosis. Radiologists can provide initial clues for clinically unsuspected cases and play a crucial role in establishing an early childhood diagnosis. This pictorial essay reviews the clinical and imaging features of genetically confirmed CF in Korean children and increases awareness of this rare disease, thereby facilitating early diagnosis.

Nasal Nitric Oxide in Children: A Review of Current Outreach in Pediatric Respiratory Medicine

Nasal nitric oxide (nNO) is a gas synthesized by the inducible and constitutive NO synthase (NOS) enzyme in the airway cells of the nasal mucosa. Like lung nitric oxide, it is thought to be associated with airway inflammation in various respiratory diseases in children. The aim of our review was to investigate the current state of use of nNO measurement in children. A comprehensive search was conducted using the Web of Science and PubMed databases specifically targeting publications in the English language, with the following keywords: nasal NO, children, allergic rhinitis, chronic rhinosinusitis, acute rhinosinusitis, primary ciliary dyskinesia (PCD), and cystic fibrosis (CF). We describe the use of nNO in pediatric allergic rhinitis, chronic rhinosinusitis, acute rhinosinusitis, PCD, and CF based on the latest literature. nNO is a noninvasive, clinically applicable test for use in pediatric allergic rhinitis, chronic rhinosinusitis, acute rhinosinusitis, PCD, and CF. It can be used as a complementary method in the diagnosis of these respiratory diseases and as a monitoring method for the treatment of allergic rhinitis and acute and chronic rhinosinusitis.

Otolaryngological burden of disease in children with primary ciliary dyskinesia in Victoria, Australia

OBJECTIVES

The aim of this study was to summarize the otolaryngological manifestations amongst children with primary ciliary dyskinesia (cwPCD) to improve diagnosis, investigations and management amongst otolaryngologists.

METHODS

A retrospective review of primary ciliary dyskinesia (PCD) diagnoses at our institution over an 8-year period between January 2014 and October 2022 was conducted. Patient characteristics, diagnosis, otolaryngological symptomatology, treatment and outcomes were recorded.

RESULTS

24 patients were identified. Thirteen patients (54%) had documented conductive hearing loss on audiological evaluation; with 11 (85%) requiring hearing aids. Six patients (25%) underwent middle ear ventilation tube (MEVT) insertion with 67% experiencing post-MEVT otorrhoea. Twenty children (83%) reported chronic nasal discharge however only 3 (13%) reported nasal obstruction. Nine patients (38%) had symptoms consistent with sleep disordered breathing with 79% of them requiring operative management with adenotonsillectomy.

CONCLUSION

Middle ear effusion is common amongst cwPCD and should be managed with conservative measures due to the significant burden of post-MEVT otorrhoea. Sinonasal symptoms rarely need surgical intervention. Many otolaryngological symptoms of PCD are often underreported, particularly sleep-disordered breathing. Paediatric PCD patients should be managed in a multidisciplinary team with routine and tailored therapies to manage all aspects of the condition.

A novel mutation in PCD-associated gene DNAAF3 causes male infertility due to asthenozoospermia

Primary ciliary dyskinesia (PCD) is a rare autosomal-recessive disease manifested with recurrent infections of respiratory tract and infertility. DNAAF3 is identified as a novel gene associated with PCD and different mutations in DNAAF3 results in different clinical features of PCD patients, such as situs inversus, sinusitis and bronchiectasis. However, the sperm phenotypic characteristics of PCD males are generally poorly investigated. Our reproductive medicine centre received a case of PCD patient with infertility, who presented with sinusitis, recurrent infections of the lower airway and severe asthenozoospermia; However, no situs inversus was found in the patient. A novel homozygous mutation in DNAAF3(c.551T>A; p.V184E) was identified in the PCD patient by whole-exome sequencing. Subsequent Sanger sequencing further confirmed that the DNAAF3 had a homozygous missense variant in the fifth exon. Transmission electron microscopy and immunostaining analysis of the sperms from the patient showed a complete absence of outer dynein arms and partial absence of inner dynein arms, which resulted in the reduction in sperm motility. However, this infertility was overcome by intracytoplasmic sperm injections, as his wife achieved successful pregnancy. These findings showed that the PCD-associated pathogenic mutation within DNAAF3 also causes severe asthenozoospermia and male infertility ultimately due to sperm flagella axoneme defect in humans. Our study not only contributes to understand the sperm phenotypic characteristics of patients with DNAAF3 mutations but also expands the spectrum of DNAAF3 mutations and may contribute to the genetic diagnosis and therapy for infertile patient with PCD.

Pediatric Pulmonology 2022 year in review: Rare and diffuse lung disease

The field of rare and diffuse pediatric lung disease continues to evolve and expand rapidly as clinicians and researchers make advancements in the diagnosis and treatment of children's interstitial and diffuse lung disease, non-cystic fibrosis bronchiectasis, and primary ciliary dyskinesia. Papers published on these topics in Pediatric Pulmonology and other journals in 2022 describe newly recognized disorders, elucidate disease mechanisms and courses, explore potential biomarkers, and assess novel treatments. In this review, we will discuss these important advancements and place them in the context of existing literature.

Ear and upper airway clinical outcome measures for use in primary ciliary dyskinesia research: a scoping review

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterised by pulmonary, otological and sino-nasal manifestations. Well-defined clinical outcome measures are needed in such rare diseases research to improve follow-up and treatments. Pulmonary outcome measures have recently been described. The aim of this study was to identify ear and upper airway outcome measures that could be used for longitudinal follow-up of individuals with PCD.

METHODS

A scoping review was performed by systematically searching MEDLINE, Embase and Cochrane Database of Systematic Reviews online databases for studies published from January 1996 to March 2022 that included at least 10 adult or paediatric PCD patients and reported ear and upper airway outcomes.

RESULTS

33 studies (1794 patients) were included. 10 ear and upper airway outcomes were reported. 17 studies reported audiometry, 16 reported otoscopic findings, and 13 reported rhinoscopic findings and sinus imaging. Health-related quality of life questionnaires were performed in seven studies. There was a high variability in definitions and measurement of outcomes between studies.

CONCLUSIONS

This scoping review highlights the lack of data regarding ear and upper airway outcomes in PCD. It also reports a high heterogeneity in outcome definitions or measures. We provide well-founded specific suggestions to standardise ear and upper airway outcome definitions and reporting for future PCD research studies.

DNALI1 interacts with the MEIG1/PACRG complex within the manchette and is required for proper sperm flagellum assembly in mice

The manchette is a transient and unique structure present in elongating spermatids and required for proper differentiation of the germ cells during spermatogenesis. Previous work indicated that the MEIG1/PACRG complex locates in the manchette and is involved in the transport of cargos, such as SPAG16L, to build the sperm flagellum. Here, using co-immunoprecipitation and pull-down approaches in various cell systems, we established that DNALI1, an axonemal component originally cloned from Chlamydomonas reinhardtii, recruits and stabilizes PACRG and we confirm in vivo, the co-localization of DNALI1 and PACRG in the manchette by immunofluorescence of elongating murine spermatids. We next generated mice with a specific deficiency of DNALI1 in male germ cells, and observed a dramatic reduction of the sperm cells, which results in male infertility. In addition, we observed that the majority of the sperm cells exhibited abnormal morphology including misshapen heads, bent tails, enlarged midpiece, discontinuous accessory structure, emphasizing the importance of DNALI1 in sperm differentiation. Examination of testis histology confirmed impaired spermiogenesis in the mutant mice. Importantly, while testicular levels of MEIG1, PACRG, and SPAG16L proteins were unchanged in the Dnali1 mutant mice, their localization within the manchette was greatly affected, indicating that DNALI1 is required for the formation of the MEIG1/PACRG complex within the manchette. Interestingly, in contrast to MEIG1 and PACRG-deficient mice, the DNALI1-deficient mice also showed impaired sperm spermiation/individualization, suggesting additional functions beyond its involvement in the manchette structure. Overall, our work identifies DNALI1 as a protein required for sperm development.

Inborn errors of human transcription factors governing IFN-γ antimycobacterial immunity

Inborn errors of immunity (IEI) delineate redundant and essential defense mechanisms in humans. We review 15 autosomal-dominant (AD) or -recessive (AR) IEI involving 11 transcription factors (TFs) and impairing interferon-gamma (IFN-γ) immunity, conferring a predisposition to mycobacterial diseases. We consider three mechanism-based categories: 1) IEI mainly affecting myeloid compartment development (AD GATA2 and AR and AD IRF8 deficiencies), 2) IEI mainly affecting lymphoid compartment development (AR FOXN1, AR PAX1, AR RORγ/RORγT, AR T-bet, AR c-Rel, AD STAT3 gain-of-function (GOF), and loss-of-function (LOF) deficiencies), and 3) IEI mainly affecting myeloid and/or lymphoid function (AR and AD STAT1 LOF, AD STAT1 GOF, AR IRF1, and AD NFKB1 deficiencies). We discuss the contribution of the discovery and study of inborn errors of TFs essential for host defense against mycobacteria to molecular and cellular analyses of human IFN-γ immunity.

Care for Patients with Type-2 Chronic Rhinosinusitis

In the last 20 years, growing interest in chronic rhinosinusitis (CRS) has become evident in medical literature; nevertheless, it is still difficult to identify the real prevalence of the disease. Epidemiological studies are few and focused on heterogeneous populations and diagnostic methods. Recent research has contributed to identifying CRS as a disease characterized by heterogeneous clinical scenarios, high impact on quality of life, and elevated social costs. Patient stratification with phenotypes and identification of the pathobiological mechanism at the origin of the disease (endotype) and its comorbidities are pivotal in the diagnostic process, and they should be addressed in order to properly tailor treatment. A multidisciplinary approach, shared diagnostic and therapeutic data, and follow-up processes are therefore necessary. Oncological multidisciplinary boards offer models to imitate in accordance with the principles of precision medicine: tracing a diagnostic pathway with the purpose of identifying the patient’s immunological profile, monitoring therapeutical processes, abstaining from having only a single specialist involved in treatment, and placing the patient at the center of the therapeutic plan. Awareness and participation from the patient’s perspective are fundamental steps to optimize the clinical course, improve quality of life, and reduce the socioeconomic burden.

Pathophysiology of pulmonary nontuberculous mycobacterial (NTM) disease

In recent years, the incidence and prevalence of pulmonary nontuberculous mycobacterial (NTM) disease have increased worldwide. Although the reasons for this increase are unclear, dealing with this disease is essential. Pulmonary NTM disease is a chronic pulmonary infection caused by NTM bacteria, which are ubiquitous in various environments. In Japan, Mycobacterium avium-intracellulare complex (MAC) accounts for approximately 90% of the causative organisms of pulmonary NTM disease, which is also called pulmonary MAC disease or pulmonary MAI disease. It is important to elucidate the pathophysiology of this disease, which occurs frequently in postmenopausal women despite the absence of obvious immunodeficiency. The pathophysiology of this disease has not been fully elucidated; however, it can largely be divided into bacterial (environmental) and host-side problems. The host factors can be further divided into immune and airway problems. The authors suggest that the triangular relationship between bacteria, immunity, and the airway is important in the pathophysiology of this disease. The latest findings on the pathophysiology of pulmonary NTM disease are reviewed.

Laterality Defects in Primary Ciliary Dyskinesia: Relationship to Ultrastructural Defect or Genotype

Rationale: The association between organ laterality abnormalities and ciliary ultrastructural defect or genotype in primary ciliary dyskinesia is poorly understood. Objectives: To determine if there is an association between presence and/or type of laterality abnormality and ciliary ultrastructural defect or genotype. Methods: Participants with primary ciliary dyskinesia in a multicenter, prospective study were grouped based on ciliary ultrastructural defect or genotype. In a retrospective analysis of these data, the association of ciliary ultrastructural defect or genotype and likelihood of a laterality abnormality was evaluated by logistic regression adjusted for presence of two loss-of-function versus one or more not-loss-of-function variants. Results: Of 559 participants, 286 (51.2%), 215 (38.5%), and 58 (10.4%) were identified as having situs solitus, situs inversustotalis, and situs ambiguus, respectively; heterotaxy, defined as situs ambiguus with complex cardiovascular defects, was present in 14 (2.5%). Compared with the group with inner dynein arm defects with microtubular disorganization, laterality defects were more likely in the outer dynein arm defects group (odds ratio [OR], 2.07; 95% confidence interval [CI], 1.21-3.54; P < 0.01) and less likely in the normal/near normal ultrastructure group (OR, 0.04; 95% CI, 0.013-0.151; P < 0.01). Heterotaxy was present in 11 of 242 (4.5%) in the outer dynein arm defects group but 0 of 96 in the inner dynein arm defects with microtubular disorganization group (P = 0.038). Conclusion: In primary ciliary dyskinesia, risk of a laterality abnormality differs by ciliary ultrastructural defect. Pathophysiologic mechanisms underlying these differences require further exploration.

Role of a novel mouse mutant of the Galnt2 tm1Lat/tm1Lat gene in otitis media

Genetic susceptibility is one of the most important causes of otitis media (OM). Mutant Galnt2 homozygote (Galnt2 tm1Lat/tm1Lat) mimics human otitis media in comparable pathology and causes hearing loss. Otitis media is characterized by effusion and dysregulated mucosa proliferation and capillary expansion in the middle ear cavity, which is associated with hearing loss. The mucociliary dysfunction could be seen in the middle ear cavity (MEC) in a patient harboring the disease that develops in severity with age by a scanning electron microscope. Tumor necrosis factor alpha (TNF-α), transforming growth factor-beta 1 (TGF-β1), Muc5ac, and Muc5b upregulate the expression in the middle ear, which correlates with inflammation, craniofacial development, and mucin secretion. The mouse model with a mutation in the Galnt2 (Galnt2 tm1Lat/tm1Lat) was explored in this study as a novel model of human otitis media.

Lung Function in Children with Primary Ciliary Dyskinesia

BACKGROUND

Primary ciliary dyskinesia (PCD) is characterized by impaired mucociliary clearance that results in accumulation of mucus and bacteria in the airways. Lower respiratory tract infections lead to airway remodeling and lung function impairment. The aim of our narrative review is to discuss available data on lung function in PCD children, focusing on risk factors for lung function impairment.

METHODS

Relevant published studies searching MEDLINE/Pubmed are included in this narrative review, using these terms: "primary ciliary dyskinesia" and "pulmonary function test" or "spirometry" or "lung function". Filters were language (English) and age of study subjects (0-18 years).

RESULTS AND CONCLUSIONS

The majority of recent published studies showed normal spirometric values in PCD children, even if some authors described a pulmonary impairment. Together with spirometry, Lung Clearance Index has been applied for detecting peripheral airway disease, and it might have a role in early mild lung disease assessment. Studies on lung function trajectories after PCD diagnosis showed a significant heterogeneity, with some patients maintaining reasonably good lung function, whereas others showing a decline. Further studies are needed to analyze lung function prospectively from childhood into adulthood, and to evaluate whether lung function trajectories are affected by PCD clinical phenotype, ultrastructural ciliary defect or genetic background.

Chronic Rhinosinusitis: T2r38 Genotyping and Nasal Cytology in Primary Ciliary Dyskinesia

OBJECTIVES

Chronic rhinosinusitis (CRS) is a major hallmark of primary ciliary dyskinesia (PCD). We investigated the possible correlation between some severity markers of CRS and several clinical features of the disease. We further studied the bitter taste receptor TAS2R38 polymorphisms to identify the genotypes associated with more severe disease.

METHODS

We included 39 adult PCD patients with (CRSwNP) and without nasal polyposis (CRSsNP); a sample for nasal cytology was obtained and clinical cytological grading (CCG) was determined. The SNOT-22 and Lund-Mackay scores were recorded. A sample of DNA was extracted from peripheral blood to investigate TAS2R38 polymorphisms.

RESULTS

CRSwNP patients had features of more severe disease: indeed, they had statistically significantly higher frequency of previous sinus surgery, higher SNOT-22, LM scores, and CCG than CRSsNP patients. Upon genotyping of TAS2R38 polymorphisms, we observed that the AVI-AVI genotype, associated to homozygous nonfunctional bitter TAS2R38 receptor, was more prevalent among CRSwNP (100%) than in CRSsNP patients (0%); furthermore, AVI-AVI subjects showed statistically significantly worse SNOT-22 and CCG scores than PAV-PAV and PAV-AVI subjects. The group of AVI-AVI patients also had more frequent respiratory exacerbations, Gram-negative infections, and Pseudomonas aeruginosa colonization than PAV-PAV and PAV-AVI patients.

CONCLUSION

Our findings indicate for the first time that PCD patients with CRSwNP display a more severe disease than those with CRSsNP. Genotyping of TAS2R38 polymorphisms demonstrated that in PCD patients, the AVI-AVI genotype is strikingly more prevalent among CRSwNP than in CRSsNP, while the PAV-PAV genotype might be protective against Gram-negative infections and respiratory exacerbations.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:248-254, 2023.

Novel SPEF2 Variant in a Japanese Patient with Primary Ciliary Dyskinesia: A Case Report and Literature Review

Primary ciliary dyskinesia (PCD) is a genetic and congenital disease associated with an abnormal ciliary ultrastructure and function and is estimated to affect 1 in 15,000-20,000 individuals. A PCD diagnosis can be achieved by genotyping. Here, we performed whole-exome analysis for the diagnosis of PCD and described the detailed clinical characteristics of the case. A 39-year-old Japanese woman with sinusitis and bronchiectasis without situs inversus had had upper and lower respiratory symptoms since childhood and had received long-term macrolide therapy without an accurate diagnosis. A moderate deterioration of cilia function was observed by high-speed video microscopy analysis; additionally, the number of cells with moving cilia was fewer than that in patients without PCD. Electron microscopy revealed no apparent structural abnormalities. We performed whole-exome analysis and identified novel biallelic variants of SPEF2 in the homozygous state (c.1860_1861insCT). We confirmed the absence of SPEF2 protein expression in the cilia of the nasal mucosa using fluorescent immunostaining. Accordingly, she was diagnosed as having PCD with the SPEF2 variant. The present case suggests that the deterioration of cilia function is moderate, the number of respiratory cells with moving cilia might be reduced, and the respiratory condition could be severe in patients with PCD with the SPEF2 variant.

Mice with lung airway ciliopathy develop persistent Mycobacterium abscessus lung infection and have a proinflammatory lung phenotype associated with decreased T regulatory cells

Introduction

Human pulmonary infection with non-tuberculous mycobacteria (NTM) such as Mycobacterium abscessus (Mabs) occurs in seemingly immunocompetent patients with underlying structural lung disease such as bronchiectasis in which normal ciliary function is perturbed. In addition to alterations in mucociliary clearance, the local immunologic milieu may be altered in patients with structural lung disease, but the nature of these changes and how they relate to NTM persistence remain unclear.

Methods

We used a mouse strain containing a conditional floxed allele of the gene IFT88, which encodes for the protein Polaris. Deletion of this gene in adult mice reportedly leads to loss of cilia on lung airway epithelium and to the development of bronchiectasis. In a series of experiments, IFT88 control mice and IFT88 KO mice received different preparations of Mabs lung inocula with lung CFU assessed out to approximately 8 weeks post-infection. In addition, cytokine levels in bronchoalveolar lavage (BAL) fluid, lung T cell subset analysis, and lung histopathology and morphometry were performed at various time points.

Results

Mabs embedded in agarose beads persisted in the lungs of IFT88 KO mice out to approximately 8 weeks (54 days), while Mabs agarose beads in the lungs of IFT88 control mice was cleared from the lungs of all mice at this time point. T cells subset analysis showed a decrease in the percentage of CD4⁺FoxP3⁺ T cells in the total lymphocyte population in the lungs of IFT88 KO mice relative to IFT88 control mice. Proinflammatory cytokines were elevated in the BAL fluid from infected IFT88 KO mice compared to infected IFT88 control mice, and histopathology showed an increased inflammatory response and greater numbers of granulomas in the lungs of infected IFT88 KO mice compared to the lungs of infected IFT88 control mice. Scanning lung morphometry did not show a significant difference comparing lung airway area and lung airway perimeter between IFT88 KO mice and IFT88 control mice.

Discussion

Persistent lung infection in our model was established using Mabs embedded in agarose beads. The utility of using IFT88 mice is that a significant difference in Mabs lung CFU is observed comparing IFT88 KO mice to IFT88 control mice thus allowing for studies assessing the mechanism(s) of Mabs lung persistence. Our finding of minimal differences in lung airway area and lung airway diameter comparing IFT88 KO mice to IFT88 control mice suggests that the development of a proinflammatory lung phenotype in IFT88 KO mice contributes to Mabs lung persistence independent of bronchiectasis. The contribution of cilia to immune regulation is increasingly recognized, and our results suggest that ciliopathy associated with structural lung disease may play a role in NTM pulmonary infection via alteration of the local immunologic lung milieu.

Mycobacterium abscessus: It's Complex

Mycobacterium abscessus (M. abscessus) is an opportunistic pathogen usually colonizing abnormal lung airways and is often seen in patients with cystic fibrosis. Currently, there is no vaccine available for M. abscessus in clinical development. The treatment of M. abscessus-related pulmonary diseases is peculiar due to intrinsic resistance to several commonly used antibiotics. The development of either prophylactic or therapeutic interventions for M. abscessus pulmonary infections is hindered by the absence of an adequate experimental animal model. In this review, we outline the critical elements related to M. abscessus virulence mechanisms, host-pathogen interactions, and treatment challenges associated with M. abscessus pulmonary infections. The challenges of effectively combating this pathogen include developing appropriate preclinical animal models of infection, developing proper diagnostics, and designing novel strategies for treating drug-resistant M. abscessus.

High Nasal Nitric Oxide, Cilia Analyses and Genotypes in a Retrospective Cohort of Children with Primary Ciliary Dyskinesia

RATIONALE

While children with primary ciliary dyskinesia (PCD) typically have low nasal nitric oxide (nNO), some children with indisputable PCD may have unexplained high nNO levels.

OBJECTIVES

To look for relationships between nNO measures and genetic findings (and cilia motility or ultrastructure when available) in PCD children with a known genotype.

METHODS

We studied retrospectively 73 PCD children (median (range) age 9.5 (2.1 to 18.2) years). nNO was the mean value of a plateau reached while velum was closed (nNO-VC, threshold 77 nL.min-1), or calculated as the average of 5 peaks obtained during tidal breathing (nNO-TB, threshold 40 nL.min-1). Cilia beat was classified either as motile (including dyskinetic pattern) or immotile depending on whether motility was present or absent in all cilia, or as a mixture of motile and immotile cilia. Genotypes were classified as: pathogenic mutations in a gene known to be associated with high nNO (mild genotype); bi-allelic truncating mutations in other genes (severe mutations); putative hypomorphic pathogenic mutation (missense, single amino-acid deletion or moderate splicing mutations) in at least one allele thought to be possibly associated with a residual production of a functional protein.

RESULTS

nNO was above the discriminant threshold in 16/73 (21.9%) children (11 nNO-VC and 5 nNO-TB). High nNO was less frequent in children with severe mutations (2/42) than in those with mild genotypes (7/10) or at least one hypomorphic mutation (7/21)(P < 0.0001). Median [IQR] nNO-VC values (n=60) were significantly different in the three genotypic groups: severe mutations 18 [10;26] nL.min-1 (n=36), possible residual functional protein production (putative hypomorphic mutations) 23 [16;68] nL.min-1 (n=17), and mild genotypes 139 [57;216] nL.min-1 (n=7); P=0.0002. The higher the cilia motility the higher the nNO-VC (16 [10;23], 23 [17;56], and 78 [45;93] nL.min-1 in patients with respectively immotile, dyskinetic motile/immotile, and dyskinetic motile cilia; P<0.0001), while nNO values were scattered across different ultrastructure defects (P = 0.07).

CONCLUSIONS

In PCD children, high nNO values were linked not only to specific genes and but also to potentially hypomorphic mutations in other genes (with possible functional protein production). nNO values increased with the proportion of motile cilia.

Coexistence of pan-hypogammaglobulinaemia and primary ciliary dyskinesia

A patient, an adolescent male, presented to us with complaints of recurrent respiratory tract infections since childhood. Differentials considered were cystic fibrosis (CF), bronchial asthma with allergic bronchopulmonary aspergillosis (ABPA), primary ciliary dyskinesia (PCD) and primary immunodeficiency disorders. Sweat chloride test, total IgE and Aspergillus fumigatus specific serum IgE and IgG levels were normal ruling out CF and ABPA. Nasal nitric oxide (NO) screening test showed reduced NO levels, and high-speed video microscopy of nasal scrapings showed stiff beating cilia with reduced ciliary beat frequency confirming the diagnosis of PCD. Immunodeficiency workup showed reduced serum IgG, IgA and IgM, when repeated on two separate occasions when the patient was not harbouring any active infection, suggestive of pan-hypogammaglobulinaemia. Thus, a diagnosis of coexistent PCD and pan-hypogammaglobulinaemia was made. Detection of immunodeficiency disorders is important in patients with PCD as they may benefit from immunoglobulin replacement.

Translation of the quality of life questionnaire for primary ciliary dyskinesia (QOL-PCD) into Hebrew: The Israeli experience

BACKGROUND

Patients with primary ciliary dyskinesia (PCD) have chronic morbidities affecting their quality of life (QOL). Health-related QOL (HRQOL) has been recognized as an important tool for assessing the burden of PCD on patients and their families. A PCD-specific HRQOL questionnaire (QOL-PCD) was developed and validated for the English-speaking populations. Still, it has not yet been translated into Hebrew or adapted for Israeli PCD patients.

METHODS

This describes our translation of the original English version of QOL-PCD into a Hebrew version. The process involved forward translation by independent translators, construction of a consensus version, back-translation into the original English version, analysis by the expert committee, and a pretest. The pretest was administered to 20 participants with PCD (the patients and the parents of minor patients) to assess the feasibility and practicality of the tool. Scale and item indices (scale-level content validity index [S-CVI] and item-level content validity index [I-CVI]) were calculated for content validity.

RESULTS

All study participants understood the final Hebrew version that the expert committee had approved with no difficulty. The instrument had satisfactory (>0.80) content validity, with S-CVI indexes of 0.99 for the adult version, 0.86 for the parental version, 0.95 for the adolescent version, and 1.00 for the child version.

CONCLUSION

The English version of a QOL-PCD was translated into Hebrew and adapted in Israel. This translation is a valid instrument to assess HRQOL in Hebrew-speaking patients with PCD and their family members. It may be helpful for PCD patient management and research in Israel.

HSP90 Modulates T2R Bitter Taste Receptor Nitric Oxide Production and Innate Immune Responses in Human Airway Epithelial Cells and Macrophages

Bitter taste receptors (T2Rs) are G protein-coupled receptors (GPCRs) expressed in various cell types including ciliated airway epithelial cells and macrophages. T2Rs in these two innate immune cell types are activated by bitter products, including those secreted by Pseudomonas aeruginosa, leading to Ca2+-dependent activation of endothelial nitric oxide (NO) synthase (eNOS). NO enhances mucociliary clearance and has direct antibacterial effects in ciliated epithelial cells. NO also increases phagocytosis by macrophages. Using biochemistry and live-cell imaging, we explored the role of heat shock protein 90 (HSP90) in regulating T2R-dependent NO pathways in primary sinonasal epithelial cells, primary monocyte-derived macrophages, and a human bronchiolar cell line (H441). Immunofluorescence showed that H441 cells express eNOS and T2Rs and that the bitter agonist denatonium benzoate activates NO production in a Ca2+- and HSP90-dependent manner in cells grown either as submerged cultures or at the air-liquid interface. In primary sinonasal epithelial cells, we determined that HSP90 inhibition reduces T2R-stimulated NO production and ciliary beating, which likely limits pathogen clearance. In primary monocyte-derived macrophages, we found that HSP-90 is integral to T2R-stimulated NO production and phagocytosis of FITC-labeled Escherichia coli and pHrodo-Staphylococcus aureus. Our study demonstrates that HSP90 serves as an innate immune modulator by regulating NO production downstream of T2R signaling by augmenting eNOS activation without impairing upstream Ca2+ signaling. These findings suggest that HSP90 plays an important role in airway antibacterial innate immunity and may be an important target in airway diseases such as chronic rhinosinusitis, asthma, or cystic fibrosis.