Primary ciliary dyskinesia: diagnostic and phenotypic features

Pulmonary nontuberculous mycobacterial disease: new insights into risk factors for susceptibility, epidemiology, and approaches to management in immunocompetent and immunocompromised patients

Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and cause a wide range of diseases in humans. Pulmonary involvement, the most common disease manifestation of NTM infection, is being increasingly encountered in clinical settings. In addition, specific phenotypic and genetic characteristics of persons predisposed to contract pulmonary NTM disease are now beginning to be recognized. Prior to treatment, patients should meet clinical and microbiologic criteria for NTM disease. Treatment involves prolonged courses of antibiotics in various combination regimens that are often discontinued because of serious side effects. In some cases, complete cure of pulmonary disease is difficult to achieve. Rather, clinical improvement may be a more feasible goal. Surgical treatment is warranted for select patients.

Primary ciliary dyskinesia: evaluation using cilia beat frequency assessment via spectral analysis of digital microscopy images

Ciliary beat frequency (CBF) measurements provide valuable information for diagnosing of primary ciliary dyskinesia (PCD). We developed a system for measuring CBF, used it in association with electron microscopy to diagnose PCD, and then analyzed characteristics of PCD patients. The CBF measurement system was based on power spectra measured through digital imaging. Twenty-four patients suspected of having PCD (age 1-19 yr) were selected from a group of 75 children and adolescents with pneumopathies of unknown causes. Ten healthy, nonsmoking volunteers (age ≥ 17 yr) served as a control group. Nasal brush samples were collected, and CBF and electron microscopy were performed. PCD was diagnosed in 12 patients: 5 had radial spoke defects, 3 showed absent central microtubule pairs with transposition, 2 had outer dynein arm defects, 1 had a shortened outer dynein arm, and 1 had a normal ultrastructure. Previous studies have reported that the most common cilia defects are in the dynein arm. As expected, the mean CBF was higher in the control group (P < 0.001) and patients with normal ultrastructure (P < 0.002), than in those diagnosed with cilia ultrastructural defects (i.e., PCD patients). An obstructive ventilatory pattern was observed in 70% of the PCD patients who underwent pulmonary function tests. All PCD patients presented bronchial wall thickening on chest computed tomography scans. The protocol and diagnostic techniques employed allowed us to diagnose PCD in 16% of patients in this study.

Diagnostic yield of nasal scrape biopsies in primary ciliary dyskinesia: a multicenter experience

Examination of ciliary ultrastructure remains the cornerstone diagnostic test for primary ciliary dyskinesia (PCD), a disease of abnormal ciliary structure and/or function. Obtaining a biopsy with sufficient interpretable cilia and producing quality transmission electron micrographs (TEM) is challenging. Methods for processing tissues for optimal preservation of axonemal structures are not standardized. This study describes our experience using a standard operating procedure (SOP) for collecting nasal scrape biopsies and processing TEMs in a centralized laboratory. We enrolled patients with suspected PCD at research sites of the Genetic Disorders of Mucociliary Clearance Consortium. Biopsies were performed according to a SOP whereby curettes were used to scrape the inferior surface of the inferior turbinate, with samples placed in fixative. Specimens were shipped to a central laboratory where TEMs were prepared and blindly reviewed. Four hundred forty-eight specimens were obtained from 107 young children (0-5 years), 189 older children (5-18 years), and 152 adults (> 18 years), and 88% were adequate for formal interpretation. The proportion of adequate specimens was higher in adults than in children. Fifty percent of the adequate TEMs showed normal ciliary ultrastructure, 39% showed hallmark ultrastructural changes of PCD, and 11% had indeterminate findings. Among specimens without clearly normal ultrastructure, 72% had defects of the outer and/or inner dynein arms (IDA), while 7% had central apparatus defects with or without IDA defects. In summary, nasal scrape biopsies can be performed in the outpatient setting and yield interpretable samples, when performed by individuals with adequate training and experience according to an SOP.

The airway epithelium: more than just a structural barrier

The mammalian airway is lined by a variety of specialized epithelial cells that not only serve as a physical barrier but also respond to environment-induced damage through the release of biologically active factors and constant cellular renewal. The lung epithelium responds to environmental insults such as pathogens, cigarette smoke and pollution by secreting inflammatory mediators and antimicrobial peptides, and by recruiting immune cells to the site of infection or damage. When the epithelium is severely damaged, basal cells and Clara cells that have stem-cell-like properties are capable of self-renewal and proliferation in the affected area, to repair the damage. In order to effectively fight off infections, the epithelium requires the assistance of neutrophils recruited from the peripheral circulation through transendothelial followed by transepithelial migration events. Activated neutrophils migrate across the epithelium through a series of ligand-receptor interactions to the site of injury, where they secrete proteolytic enzymes and oxidative radicals for pathogen destruction. However, chronic activation and recruitment of neutrophils in airway diseases such as chronic obstructive pulmonary disease and asthma has been associated with tissue damage and disease severity. In this paper, we review the current understanding of the airway epithelial response to injury and its interaction with inflammatory cells, in particular the neutrophil.

Next generation massively parallel sequencing of targeted exomes to identify genetic mutations in primary ciliary dyskinesia: implications for application to clinical testing

PURPOSE

Advances in genetic sequencing technology have the potential to enhance testing for genes associated with genetically heterogeneous clinical syndromes, such as primary ciliary dyskinesia. The objective of this study was to investigate the performance characteristics of exon-capture technology coupled with massively parallel sequencing for clinical diagnostic evaluation.

METHODS

We performed a pilot study of four individuals with a variety of previously identified primary ciliary dyskinesia mutations. We designed a custom array (NimbleGen) to capture 2089 exons from 79 genes associated with primary ciliary dyskinesia or ciliary function and sequenced the enriched material using the GS FLX Titanium (Roche 454) platform. Bioinformatics analysis was performed in a blinded fashion in an attempt to detect the previously identified mutations and validate the process.

RESULTS

Three of three substitution mutations and one of three small insertion/deletion mutations were readily identified using this methodology. One small insertion mutation was clearly observed after adjusting the bioinformatics handling of previously described SNPs. This process failed to detect two known mutations: one single-nucleotide insertion and a whole-exon deletion. Additional retrospective bioinformatics analysis revealed strong sequence-based evidence for the insertion but failed to detect the whole-exon deletion. Numerous other variants were also detected, which may represent potential genetic modifiers of the primary ciliary dyskinesia phenotype.

CONCLUSIONS

We conclude that massively parallel sequencing has considerable potential for both research and clinical diagnostics, but further development is required before widespread adoption in a clinical setting.

Kartagener syndrome

Kartagener syndrome is a rare, ciliopathic, autosomal recessive genetic disorder that causes a defect in the action of the cilia lining the respiratory tract and fallopian tube. Patients usually present with chronic recurrent rhinosinusitis, otitis media, pneumonia, and bronchiectasis caused by pseudomonal infection. Situs inversus can be seen in about 50% of cases. Diagnosis can be made by tests to prove impaired cilia function, biopsy, and genetic studies. Treatment is supportive. In severe cases, the prognosis can be fatal if bilateral lung transplantation is delayed. We present a case of a 66-year-old woman with chronic recurrent upper respiratory infections, pseudomonal pneumonia, and chronic bronchiectasis who presented with acute respiratory failure. She was diagnosed with Kartagener syndrome based on her clinical presentation and genetic studies. She expired on ventilator with refractory respiratory and multiorgan failure.

Skeletal muscle metabolism in cystic fibrosis and primary ciliary dyskinesia

Previous studies have reported differences in muscle function and metabolism between patients with cystic fibrosis (CF) and healthy controls (HC), but it is currently unknown whether these abnormalities are specific to CF or also seen in other airway diseases. In this study, we used magnetic resonance spectroscopy (MRS) during exercise to assess muscle metabolism in CF patients. Twenty patients with CF and 20 age, gender, and habitual activity-matched HCs and a respiratory disease comparison group with primary ciliary dyskinesia (PCD; n = 10) were studied. Phosphorus MRS (P-MRS) was used to characterize muscle bioenergetic metabolism at rest and after high-, moderate-, and low-intensity exercise. CF patients exhibited lower resting ATP/phosphocreatine (PCr) ratio and significantly higher end-exercise pH values compared with both HC and PCD patients. Both CF and PCD patients demonstrated significantly slower PCr recovery time constants after high-intensity exercise. Our results suggest that not only there are specific abnormalities of muscle metabolism in CF patients but also there is a nonspecific impact of respiratory disease on muscle function.

Clinical significance of microbial infection and adaptation in cystic fibrosis

A select group of microorganisms inhabit the airways of individuals with cystic fibrosis. Once established within the pulmonary environment in these patients, many of these microbes adapt by altering aspects of their structure and physiology. Some of these microbes and adaptations are associated with more rapid deterioration in lung function and overall clinical status, whereas others appear to have little effect. Here we review current evidence supporting or refuting a role for the different microbes and their adaptations in contributing to poor clinical outcomes in cystic fibrosis.

Otologic features in children with primary ciliary dyskinesia

OBJECTIVES

To analyze otologic features in patients with primary ciliary dyskinesia (PCD) aged 0 to 18 years and to evaluate the correlation between ultrastructural defects and severity of otologic features.

DESIGN

Retrospective study.

SETTING

Pediatric referral center.

PATIENTS

Fifty-eight patients with PCD were evaluated in the following 4 age intervals: group 1, preschool (≤ 5 years [n = 47]); group 2, school (6-11 years [n = 50]); group 3, teenagers (12-17 years [n = 34]); and group 4, young adults (≥ 18 years; 27 years for the oldest [n = 10]). Follow-up was 2 to 6 years in each age group; 26 patients had total follow-up of more than 12 years. Ultrastructural defects occurred in the outer dynein arm (n = 33), the inner dynein arm (n = 13), and the central complex (n = 11). One patient had typical Kartagener syndrome with typical PCD features but normal ciliary ultrastructure.

MAIN OUTCOME MEASURES

Frequency of acute otitis media, otitis media with effusion, otorrhea, chronic otitis media, hearing loss, and middle ear surgery and type of antibiotic regimen according to age and type of defect.

RESULTS

Recurrent acute otitis media decreased from group 1 (32 of 47 [68%]) to group 4 (0 of 10 [0%]) (P < .001). Otitis media with effusion was more severe in groups 1 through 3 than in group 4 (P = .02). Otorrhea decreased in group 4: 30% vs 80% (3 of 10 vs 36 of 41) in the other groups (P < .001). Half of the patients with tympanostomy tubes eventually had tympanic perforation. Hearing loss was moderate in groups 1 through 3 and mild in group 4. Continuous antibiotic therapy could be slightly reduced only in group 4. Central complex defect was a significant marker of severity for all these criteria.

CONCLUSIONS

Despite continuous antibiotic therapy, the middle ear condition in PCD remained severe throughout childhood, with improvement only after age 18 years. Armstrong grommet placement did not improve the middle ear condition. Central complex defect is a marker of severity.

Population specificity of the DNAI1 gene mutation spectrum in primary ciliary dyskinesia (PCD)

Background

Mutations in the DNAI1 gene, encoding a component of outer dynein arms of the ciliary apparatus, are the second most important genetic cause of primary ciliary dyskinesia (PCD), the genetically heterogeneous recessive disorder with the prevalence of ~1/20,000. The estimates of the DNAI1 involvement in PCD pathogenesis differ among the reported studies, ranging from 4% to 10%.

Methods

The coding sequence of DNAI1 was screened (SSCP analysis and direct sequencing) in a group of PCD patients (157 families, 185 affected individuals), the first ever studied large cohort of PCD patients of Slavic origin (mostly Polish); multiplex ligation-dependent probe amplification (MLPA) analysis was performed in a subset of ~80 families.

Results

Three previously reported mutations (IVS1+2-3insT, L513P and A538T) and two novel missense substitutions (C388Y and G515S) were identified in 12 families (i.e. ~8% of non-related Polish PCD patients). The structure of background SNP haplotypes indicated common origin of each of the two most frequent mutations, IVS1+2-3insT and A538T. MLPA analysis did not reveal any significant differences between patients and control samples. The Polish cohort was compared with all the previously studied PCD groups (a total of 487 families): IVS1+2-3insT remained the most prevalent pathogenetic change in DNAI1 (54% of the mutations identified worldwide), and the increased global prevalence of A538T (14%) was due to the contribution of the Polish cohort.

Conclusions

The worldwide involvement of DNAI1 mutations in PCD pathogenesis in families not preselected for ODA defects ranges from 7 to 10%; this global estimate as well as the mutation profile differs in specific populations. Analysis of the background SNP haplotypes suggests that the increased frequency of chromosomes carrying A538T mutations in Polish patients may reflects local (Polish or Slavic) founder effect. Results of the MLPA analysis indicate that no large exonic deletions are involved in PCD pathogenesis.

In vitro culturing of ciliary respiratory cells--a model for studies of genetic diseases

Primary ciliary dyskinesia (PCD) is a rare genetic disorder caused by the impaired functioning of ciliated cells. Its diagnosis is based on the analysis of the structure and functioning of cilia present in the respiratory epithelium (RE) of the patient. Abnormalities of cilia caused by hereditary mutations closely resemble and often overlap with defects induced by the environmental factors. As a result, proper diagnosis of PCD is difficult and may require repeated sampling of patients' tissue, which is not always possible. The culturing of differentiated cells and tissues derived from the human RE seems to be the best way to diagnose PCD, to study genotype-phenotype relations of genes involved in ciliary dysfunction, as well as other aspects related to the functioning of the RE. In this review, different methods of culturing differentiated cells and tissues derived from the human RE, along with their potential and limitations, are summarized. Several considerations with respect to the factors influencing the process of in vitro differentiation (cell-to-cell interactions, medium composition, cell-support substrate) are also discussed.

Hypertonic Saline Therapy in Cystic Fibrosis: Do Population Shifts Caused by the Osmotic Sensitivity of Infecting Bacteria Explain the Effectiveness of this Treatment?

Cystic fibrosis (CF) is caused by a defect in the CF transmembrane regulator that leads to depletion and dehydration of the airway surface liquid (ASL) of the lung epithelium, providing an environment that can be infected by bacteria leading to increased morbidity and mortality. Pseudomonas aeruginosa chronically infects more than 80% of CF patients and one hallmark of infection is the emergence of a mucoid phenotype associated with a worsening prognosis and more rapid decline in lung function. Hypertonic saline (HS) is a clinically proven treatment that improves mucociliary clearance through partial rehydration of the ASL of the lung. Strikingly, while HS therapy does not alter the prevalence of P. aeruginosa in the CF lung it does decrease the frequency of episodes of acute, severe illness known as infective exacerbations among CF patients. In this article, we propose a hypothesis whereby the positive clinical effects of HS treatment are explained by the osmotic sensitivity of the mucoid sub-population of P. aeruginosa in the CF lung leading to selection against this group in favor of the osmotically resistant non-mucoid variants.

Cilia dysfunction

Cilia are complex and powerful cellular structures that serve a multitude of functions across many types of organisms. In humans, one of the most critical roles of cilia is defense of the airway. The respiratory epithelium is lined with cilia that normally carry out an integrated and coordinated mechanism called mucociliary clearance. Mucociliary clearance, the process by which cilia transport the viscous mucus blanket of the upper airway to the gastrointestinal tract, is the primary means by which the upper airway clears itself of pathogens, allergens, debris, and toxins. The complex structure and regulatory mechanisms that dictate the form and function of normal cilia are not entirely understood, but it is clear that ciliary dysfunction results in impaired respiratory defense. Ciliary dysfunction may be primary, the result of genetic mutations resulting in abnormal cilia structure, or secondary, the result of environmental, infectious or inflammatory stimuli that disrupt normal motility or coordination.

Evaluation and management of pulmonary disease in ataxia-telangiectasia

Ataxia-telangiectasia (A-T) is a rare autosomal recessive disorder caused by mutations in the ATM gene, resulting in faulty repair of breakages in double-stranded DNA. The clinical phenotype is complex and is characterized by neurologic abnormalities, immunodeficiencies, susceptibility to malignancies, recurrent sinopulmonary infections, and cutaneous abnormalities. Lung disease is common in patients with A-T and often progresses with age and neurological decline. Diseases of the respiratory system cause significant morbidity and are a frequent cause of death in the A-T population. Lung disease in this population is thought to exhibit features of one or more of the following phenotypes: recurrent sinopulmonary infections with bronchiectasis, interstitial lung disease, and lung disease associated with neurological abnormalities. Here, we review available evidence and present expert opinion on the diagnosis, evaluation, and management of lung disease in A-T, as discussed in a recent multidisciplinary workshop. Although more data are emerging on this unique population, many recommendations are made based on similarities to other more well-studied diseases. Gaps in current knowledge and areas for future research in the field of pulmonary disease in A-T are also outlined.

Characteristics of chloride transport in nasal mucosa from patients with primary ciliary dyskinesia

OBJECTIVES/HYPOTHESIS

Primary ciliary dyskinesia (PCD) is an inherited disorder that produces lifelong difficulties with chronic airway inflammation. Little is known about the role of chronic airway inflammation on chloride ion transport properties in PCD. This study assessed the cyclic adenosine monophosphate (cAMP)-regulated chloride (Cl) ion transport properties of freshly excised nasal mucosa from PCD compared with normal and chronic rhinosinusitis (CRS).

STUDY DESIGN

Electrophysiology study utilizing Ussing type hemi-chamber technique with three different types of nasal tissue (normal, CRS, PCD) obtained from patients during endoscopic surgery at a tertiary referral center.

METHODS

Nasal tissues were examined under short-circuit conditions, and gradient-driven Cl currents were continuously recorded. The cAMP elevating agonist (forskolin) was added to stimulate cystic fibrosis transmembrane conductance regulator-mediated Cl secretion. To prevent misinterpretation of flux measurement, Cl transport inhibitors were used at the end of all experiments. Basal Cl currents (I(Cl)) and changes in I(Cl) to forskolin (DeltaI(Cl)) were compared between normal, CRS, and PCD nasal tissues.

RESULTS

Forskolin stimulated Cl currents across all different types of nasal epithelia. The Cl secretory response was effectively blocked by the Cl ion transport inhibitors. I(Cl) were significantly higher in normals (155.0 +/- 9.3 microA/cm(2)) compared to CRS (79.1 +/- 15.0 microA/cm(2)) and PCD (70.9 +/- 20.4 microA/cm(2)) (P = .005). DeltaI(Cl) in CRS (14.8 +/- 2.3 microA/cm(2)) and PCD (12.2 +/- 2.4 microA/cm(2)) were markedly diminished compared to normals (28.3 +/- 4.7 microA/cm(2)) (P = .024).

CONCLUSIONS

PCD tissues were characterized by impaired I(Cl) and DeltaI(Cl). Both parameters were reduced by 54.3% and 56.9% in PCD when compared to normals.

ENT manifestations in patients with primary ciliary dyskinesia: prevalence and significance of otorhinolaryngologic co-morbidities

Primary ciliary dyskinesia (PCD) is a rare inherited disease with a prevalence of about 1:20,000. The underlying pathogenesis is disrupted ciliary function, which results in delayed mucus transportation leading to chronic inflammation, mainly in the upper and lower respiratory tract. Although the pathogenesis of the disease and its clinical presentation is somewhat understood, data regarding the prevalence of accompanying symptoms is limited, especially in the field of otorhinolaryngology. A total of 44 patients diagnosed with PCD answered a questionnaire regarding the diagnosis and clinical presentation of the disease, their medical history and clinical manifestations, and medical treatment in the field of otorhinolaryngology. The majority of participants (70%) had seen a physician more than 50 times before the diagnosis was made at an average age of 10.9 ± 14.4 years. As much as 59% of all patients had recurring problems at the paranasal sinuses and 69% of these patients needed corresponding surgical intervention. Even more patients (81%) suffered from recurring otitis media and, as a result, 78% of these patients underwent paracentesis with temporary tympanostomy tubes at least once at an average age of 9.5 ± 13.0 years. Otorhinolaryngologic symptoms, especially chronic otitis media and chronic rhinosinusitis, are frequently associated with PCD. Surgical intervention to treat these symptoms is common. The awareness of this disease should be raised, especially among ENT physicians, and surgical intervention should be indicated carefully.

Isolation and characterization of microparticles in sputum from cystic fibrosis patients

Background

Microparticles (MPs) are membrane vesicles released during cell activation and apoptosis. MPs have different biological effects depending on the cell from they originate. Cystic fibrosis (CF) lung disease is characterized by massive neutrophil granulocyte influx in the airways, their activation and eventually apoptosis. We investigated on the presence and phenotype of MPs in the sputum, a rich non-invasive source of inflammation biomarkers, of acute and stable CF adult patients.

Methods

Spontaneous sputum, obtained from 21 CF patients (10 acute and 11 stable) and 7 patients with primary ciliary dyskinesia (PCD), was liquefied with Sputasol. MPs were counted, visualized by electron microscopy, and identified in the supernatants of treated sputum by cytofluorimetry and immunolabelling for leukocyte (CD11a), granulocyte (CD66b), and monocyte-macrophage (CD11b) antigens.

Results

Electron microscopy revealed that sputum MPs were in the 100-500 nm range and did not contain bacteria, confirming microbiological tests. CF sputa contained higher number of MPs in comparison with PCD sputa. Levels of CD11a⁺-and CD66b⁺-, but not CD11b⁺-MPs were significantly higher in CF than in PCD, without differences between acute and stable patients.

Conclusions

In summary, MPs are detectable in sputa obtained from CF patients and are predominantly of granulocyte origin. This novel isolation method for MPs from sputum opens a new opportunity for the study of lung pathology in CF.

Primary ciliary dyskinesia in Amish communities

Primary ciliary dyskinesia is an autosomal recessive multigenic disease that results in impaired mucociliary clearance. We have diagnosed 9 subjects with primary ciliary dyskinesia from geographically dispersed Amish communities, on the basis of clinical characteristics and ciliary ultrastructural defects. Despite consanguinity, affected individuals had evidence of genetic heterogeneity.

Epithelium, cilia, and mucus: their importance in chronic rhinosinusitis

Chronic rhinosinusitis is a common disease resulting from inflammation of the sinonasal mucosa. It has long been recognized that patients with chronic rhinosinusitis have impaired capacity to clear sinonasal secretions. However, the cause of this pathologic process is not well understood. In this article the components of mucociliary clearance, including cilia, mucus production, and cilia beat frequency, are reviewed and alterations of the system discussed regarding contribution to the disease process.

[Primary ciliary dyskinesia (Pcd) in Austria]

INTRODUCTION

Primary ciliary dyskinesia (PCD) is a rare hereditary recessive disease with symptoms of recurrent pneumonia, chronic bronchitis, bronchiectasis, and chronic sinusitis. Chronic rhinitis is often the presenting symptom in newborns and infants. Approximately half of the patients show visceral mirror image arrangements (situs inversus). In this study, we aimed 1) to determine the number of paediatric PCD patients in Austria, 2) to show the diagnostic and therapeutic modalities used in the clinical centres and 3) to describe symptoms of children with PCD.

PATIENTS, MATERIAL AND METHODS

For the first two aims, we analysed data from a questionnaire survey of the European Respiratory Society (ERS) task force on Primary Ciliary Dyskinesia in children. All paediatric respiratory units in Austria received a questionnaire. Symptoms of PCD patients from Vienna Children's University Hospital (aim 3) were extracted from case histories.

RESULTS

In 13 Austrian clinics 48 patients with PCD (36 aged from 0-19 years) were identified. The prevalence of reported cases (aged 0-19 yrs) in Austria was 1:48000. Median age at diagnosis was 4.8 years (IQR 0.3-8.2), lower in children with situs inversus compared to those without (3.1 vs. 8.1 yrs, p = 0.067). In 2005-2006, the saccharine test was still the most commonly used screening test for PCD in Austria (45%). Confirmation of the diagnosis was usually by electron microscopy (73%). All clinics treated exacerbations immediately with antibiotics, 73% prescribed airway clearance therapy routinely to all patients. Other therapies and diagnostic tests were applied very inconsistently across Austrian hospitals. All PCD patients from Vienna (n = 13) had increased upper and lower respiratory secretions, most had recurring airway infections (n = 12), bronchiectasis (n = 7) and bronchitis (n = 7).

CONCLUSION

Diagnosis and therapy of PCD in Austria are inhomogeneous. Prospective studies are needed to learn more about the course of the disease and to evaluate benefits and harms of different treatment strategies.

Temporal relationship between primary and motile ciliogenesis in airway epithelial cells

Cilia are traditionally classified as motile or primary. Motile cilia are restricted to specific populations of well-differentiated epithelial cells, including those in the airway, brain ventricles, and oviducts. Primary cilia are nonmotile, solitary structures that are present in many cell types, and often have sensory functions such as in the retina and renal tubules. Primary cilia were also implicated in the regulation of fundamental processes in development. Rare depictions of primary cilia in embryonic airways led us to hypothesize that primary cilia in airway cells are temporally related to motile ciliogenesis. We identified primary cilia in undifferentiated, cultured airway epithelial cells from mice and humans and in developing lungs. The solitary cilia in the airways express proteins considered unique to primary cilia, including polycystin-1 and polycystin-2. A temporal analysis of airway epithelial cell differentiation showed that cells with primary cilia acquire markers of motile ciliogenesis, suggesting that motile ciliated cells originate from primary ciliated cells. Whereas motile ciliogenesis requires Foxj1, primary ciliogenesis does not, and the expression of Foxj1 was associated with a loss of primary cilia, just before the appearance of motile cilia. Primary cilia were not found in well-differentiated airway epithelial cells. However, after injury, they appear in the luminal layer of epithelium and in basal cells. The transient nature of primary cilia, together with the temporal and spatial patterns of expression in the development and repair of airway epithelium, suggests a critical role of primary cilia in determining outcomes during airway epithelial cell differentiation.

Founder mutation(s) in the RSPH9 gene leading to primary ciliary dyskinesia in two inbred Bedouin families

A rare mutation in the RSPH9 gene leading to primary ciliary dyskinesia was previously identified in two Bedouin families, one from Israel and one from the United Arab Emirates (UAE). Herein we analyse mutation segregation in the Israeli family, present the clinical disease spectrum, and estimate mutation age in the two families. Mutation segregation was studied by restriction fragment length analysis. Mutation ages were estimated using a model of the decrease in the length of ancestral haplotypes. The mutations in each of the two families had a common ancestor less than 95 and less than 17 generations in the past. If the mutations in the two families are descended from a common ancestor, that mutation would have to have arisen at least 150 generations ago. If the Bedouin population has been roughly constant in size for at least 6000 years, it is possible that the mutations in the two families are identical by descent. If there were substantial fluctuations in the size of the Bedouin population, it is more likely that there were two independent mutations. Based on the available data, the population genetic analysis does not strongly favour one conclusion over the other.

Diagnosis and management of chronic rhinosinusitis in adults

Chronic rhinosinusitis (CRS) is characterized by mucosal inflammation affecting both the nasal cavity and paranasal sinuses; its causes are potentially numerous, disparate, and frequently overlapping. The more common conditions that are associated with CRS are perennial allergic and nonallergic rhinitis, nasal polyps, and anatomical mechanical obstruction (septum/turbinate issues). Other less common etiologies include inflammation (eg, from superantigens), fungal sinusitis or bacterial sinusitis with or without associated biofilm formation, gastroesophageal reflux, smoke and other environmental exposures, immune deficiencies, genetics, and aspirin-exacerbated respiratory disease. A diagnosis of CRS is strongly suggested by a history of symptoms (eg, congestion and/or fullness; nasal obstruction, blockage, discharge, and/or purulence; discolored postnasal discharge; hyposmia/anosmia; facial pain and/or pressure) and their duration for > 3 months. A definitive diagnosis requires physical evidence of mucosal swelling or discharge appreciated during physical examination coupled with CT imaging if inflammation does not involve the middle meatus or ethmoid bulla. Multivariant causation makes the diagnosis of CRS and selection of treatment complex. Furthermore, various types of health care providers including ear, nose, and throat (ENT) specialists, allergists, primary care physicians, and pulmonologists treat CRS, and each is likely to have a different approach. A structured approach to the diagnosis and management of CRS can help streamline and standardize care no matter where patients present for evaluation and treatment. A 2008 Working Group on CRS in Adults, supported by the American Academy of Otolaryngic Allergy (AAOA), developed a series of algorithms for the differential diagnosis and treatment of CRS in adults, based on the evolving understanding of CRS as an inflammatory disease. The algorithms presented in this paper address an approach for all CRS patients as well as approaches for those with nasal polyps, edema observed on nasal endoscopy, purulence observed on nasal endoscopy, an abnormal history and physical examination, and an abnormal history and normal physical examination.

Primary ciliary dyskinesia that responded to long-term, low-dose clarithromycin

A 46-year-old man was referred to our hospital with hemoptysis. He had been diagnosed with chronic sinusitis since childhood, but had received no treatment. Chest CT showed a diffuse centrilobular granular shadow and thickened bronchial walls. Otitis media and decreased spermatic motor ability were identified. In addition, electron microscopy of a biopsy specimen of the nasal mucosa showed a deficiency of inner dynein. Based on these clinical findings, primary ciliary dyskinesia (PCD) was diagnosed and successfully treated with long-term, low-dose clarithromycin. Although the effects of macrolide therapy remain controversial, long-term treatment with low-dose clarithromycin might confer clinical benefits upon patients with PCD.

Noninvasive real-time measurement of nasal mucociliary clearance in mice by pinhole gamma scintigraphy

Mucociliary clearance (MCC) is the key defense mechanism in the upper airways, as the removal of debris-laden mucus in the sinuses completely depends on MCC. So far, how the nasal MCC is regulated remains unknown. Recently, mice deficient in genes encoding the components of MCC apparatus have been generated, which will allow investigators to conduct more in-depth nasal MCC studies. However, the methodology necessary to comprehensively evaluate the nasal MCC in this species is not well established. We therefore developed a novel method to measure nasal MCC in live mice using pinhole gamma camera. Insoluble radiolabeled particles were delivered into the noses of lightly anesthetized mice. The nasal clearance of these particles was measured continuously in a real-time manner. The effect of three different anesthetics-avertin, pentobarbital, and isoflurane-on nasal MCC was also determined. In mice anesthetized by 1.1% isoflurane, radiolabeled particles were immediately moved into the oropharynx, which was significantly accelerated by the treatment of hypertonic but not isotonic saline. According to the clearance rate, the mouse nasal MCC presented two distinct phases: a rapid phase and a slow phase. In addition, we found that isoflurane had a very small inhibitory effect on nasal MCC vs. both avertin and pentobarbital. This was further supported by its dose response. Collectively, we have developed a noninvasive method to monitor the real-time nasal MCC in live mice under physiological conditions. It provides more comprehensive evaluation on nasal MCC rather than assessing a single component of the MCC apparatus in isolation.

Management of otitis media with effusion in children with primary ciliary dyskinesia: a literature review

OBJECTIVE

Primary ciliary dyskinesia is an autosomal recessively inherited group of disorders of ciliary ultrastructure. Otolaryngologists are frequently involved in the management of some of the most common symptoms of primary ciliary dyskinesia including chronic rhinitis, sinusitis and otitis media with effusion. A dilemma for otorhinolaryngologists is whether ventilation tubes are of benefit in children with primary ciliary dyskinesia and otitis media with effusion and what effective alternatives exist. This paper aims to address this issue via a literature review and case presentation.

METHODS

An extensive review of the literature was undertaken and a discussion of the advantages and disadvantages of ventilation tubes in the management of otitis media with effusion in these children is presented and compared with that of the general population. We present a case of a 9 months old boy with Kartagener's Syndrome and chronic bilateral otitis media with effusion to illustrate our findings.

RESULTS

Eight papers were identified, all with small study numbers. The main outcome measures were hearing, otorrhoea and tympanic membrane structural changes. The natural history of otitis media with effusion and hearing loss in primary ciliary dyskinesia appears to be fluctuant into adulthood. Therefore, otitis media with effusion in primary ciliary dyskinesia does not resolve by the age of 9 years, regardless of treatment, as previously assumed. Ventilation tube insertion improves hearing in primary ciliary dyskinesia, but may lead to a higher rate of otorrhoea when compared to the general population. Tympanic membrane changes were clinically insignificant. Our patient eventually underwent successful insertion of bilateral ventilation tubes with a marked improvement in hearing and language with minimal otorrhoea.

CONCLUSION/DISCUSSION

The highest level of evidence found for the management of otitis media with effusion in children with primary ciliary dyskinesia was level IV. Currently, the evidence is inconclusive and conflicting. Whilst our results are promising, clearly higher quality research on a larger number of patients is required to definitively evaluate the management options for otitis media with effusion in these children.

Loss-of-function mutations in the human ortholog of Chlamydomonas reinhardtii ODA7 disrupt dynein arm assembly and cause primary ciliary dyskinesia

Cilia and flagella are evolutionarily conserved structures that play various physiological roles in diverse cell types. Defects in motile cilia result in primary ciliary dyskinesia (PCD), the most prominent ciliopathy, characterized by the association of respiratory symptoms, male infertility, and, in nearly 50% of cases, situs inversus. So far, most identified disease-causing mutations involve genes encoding various ciliary components, such those belonging to the dynein arms that are essential for ciliary motion. Following a candidate-gene approach based on data from a mutant strain of the biflagellated alga Chlamydomonas reinhardtii carrying an ODA7 defect, we identified four families with a PCD phenotype characterized by the absence of both dynein arms and loss-of-function mutations in the human orthologous gene called LRRC50. Functional analyses performed in Chlamydomonas reinhardtii and in another flagellated protist, Trypanosoma brucei, support a key role for LRRC50, a member of the leucine-rich-repeat superfamily, in cytoplasmic preassembly of dynein arms.

Diagnostic testing of patients suspected of primary ciliary dyskinesia

RATIONALE

Electron microscopy (EM) of ciliated epithelium is widely used to diagnose primary ciliary dyskinesia (PCD). Ciliary beat frequency (CBF) has been used to screen samples to determine whether EM is indicated. Beat pattern analysis has been advocated as an additional diagnostic test. Neither has been subject to formal review.

OBJECTIVES

To determine the ability of CBF and beat pattern analysis to predict EM-diagnosed PCD.

METHODS

CBF calculation and beat pattern analysis, using high-speed video microscopy, and EM were performed on nasal tissue from 371 patients consecutively referred to the Leicester Royal Infirmary for diagnostic assessment for PCD. With EM as the "gold standard," receiver operating characteristic (ROC) curves were constructed and sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values were calculated for CBF less than 11 Hz, ciliary dyskinesia score equal to or exceeding 2, at least 90% of ciliated edges beating dyskinetically, and an immotility index equal to or exceeding 10%.

MEASUREMENTS AND MAIN RESULTS

PCD was excluded in 270 patients and confirmed in 70 by EM. The sensitivity, specificity, PPV, and NPV for CBF less than 11 Hz were 87.1, 77.2, 50.0, and 95.8%, respectively. These values were higher for ciliary dyskinesia scores equal to or exceeding 2 (92.5, 97.6, 91.2, and 98.0%) and when at least 90% of ciliated edges were dyskinetic (97.1, 95.3, 84.6, and 99.2%). ROCs confirmed that the ciliary dyskinesia score and percentage of dyskinetic edges were superior screening indices compared with CBF and the immotility index.

CONCLUSIONS

The use of CBF alone to screen which biopsies should have EM will result in a significant number of missed diagnoses. Ciliary beat pattern analysis is a more sensitive and specific test for PCD with higher PPV and NPV.

Conditional deletion of dnaic1 in a murine model of primary ciliary dyskinesia causes chronic rhinosinusitis

Studies of primary ciliary dyskinesia (PCD) have been hampered by the lack of a suitable animal model because disruption of essential ciliary genes in mice results in a high incidence of lethal hydrocephalus. To develop a viable mouse model for long-term studies of PCD, we have generated a transgenic mouse line in which two conserved exons of the mouse intermediate dynein chain gene, Dnaic1, are flanked by loxP sites (Dnaic1(flox/flox)). Dnaic1 is the murine homolog of human DNAI1, which is mutated in approximately 10% of human PCD cases. These mice have been crossed with mice expressing a tamoxifen-inducible Cre recombinase (CreER). Treatment of adult Dnaic1(flox/flox)/CreER(+/-) mice with tamoxifen results in an almost complete deletion of Dnaic1 with no evidence of hydrocephalus. Treated animals have reduced levels of full-length Dnaic1 mRNA, and electron micrographs of cilia demonstrate a loss of outer dynein arm structures. In treated Dnaic1(flox/flox)/CreER(+/-) animals, mucociliary clearance (MCC) was reduced over time. After approximately 3 months, no MCC was observed in the nasopharynx, whereas in the trachea, MCC was observed for up to 6 months, likely reflecting a difference in the turnover of ciliated cells in these tissues. All treated animals developed severe rhinosinusitis, demonstrating the importance of MCC to the health of the upper airways. However, no evidence of lung disease was observed up to 11 months after Dnaic1 deletion, suggesting that other mechanisms are able to compensate for the lack of MCC in the lower airways of mice. This model will be useful for the study of the pathogenesis and treatment of PCD.

Lung disease assessment in primary ciliary dyskinesia: a comparison between chest high-field magnetic resonance imaging and high-resolution computed tomography findings

Background

Primary ciliary dyskinesia (PCD) is associated with pulmonary involvement that requires periodical assessment. Chest high-resolution computed tomography (HRCT) has become the method of choice to evaluate chronic lung disease, but entails exposure to ionizing radiation. Magnetic resonance imaging (MRI) has been proposed as a potential radiation-free technique in several chest disorders. Aim of our study is to evaluate whether high-field MRI is as effective as HRCT in identifying PCD pulmonary abnormalities. We also analyzed the relationships between the severity and extension of lung disease, and functional data.

Methods

Thirteen PCD patients (8 children/5 adults; median age, 15.2 yrs) underwent chest HRCT and high-field 3T MRI, spirometry, and deep throat or sputum culture. Images were scored using a modified version of the Helbich system.

Results

HRCT and MRI total scores were 12 (range, 6–20) and 12 (range, 5–17), respectively. Agreement between HRCT and MRI scores was good or excellent (r > 0.8). HRCT and MRI total scores were significantly related to forced vital capacity (r = -0.5, p = 0.05; and r = -0.7, p = 0.009, respectively) and forced expiratory volume at 1 second (r = -0.6, p = 0.03; and r = -0.7, p = 0.009, respectively).

Conclusion

Chest high-field 3T MRI appears to be as effective as HRCT in assessing the extent and severity of lung abnormalities in PCD. MRI scores might be used for longitudinal assessment and be an outcome surrogate in future studies.

Clinical and genetic aspects of primary ciliary dyskinesia/Kartagener syndrome

Primary ciliary dyskinesia is a genetically heterogeneous disorder of motile cilia. Most of the disease-causing mutations identified to date involve the heavy (dynein axonemal heavy chain 5) or intermediate(dynein axonemal intermediate chain 1) chain dynein genes in ciliary outer dynein arms, although a few mutations have been noted in other genes. Clinical molecular genetic testing for primary ciliary dyskinesia is available for the most common mutations. The respiratory manifestations of primary ciliary dyskinesia (chronic bronchitis leading to bronchiectasis, chronic rhino-sinusitis, and chronic otitis media)reflect impaired mucociliary clearance owing to defective axonemal structure. Ciliary ultrastructural analysis in most patients (>80%) reveals defective dynein arms, although defects in other axonemal components have also been observed. Approximately 50% of patients with primary ciliary dyskinesia have laterality defects (including situs inversus totalis and, less commonly, heterotaxy, and congenital heart disease),reflecting dysfunction of embryological nodal cilia. Male infertility is common and reflects defects in sperm tail axonemes. Most patients with primary ciliary dyskinesia have a history of neonatal respiratory distress, suggesting that motile cilia play a role in fluid clearance during the transition from a fetal to neonatal lung. Ciliopathies involving sensory cilia, including autosomal dominant or recessive polycystic kidney disease, Bardet-Biedl syndrome, and Alstrom syndrome, may have chronic respiratory symptoms and even bronchiectasis suggesting clinical overlap with primary ciliary dyskinesia.

Primary ciliary dyskinesia: when to suspect the diagnosis and how to confirm it

Primary ciliary dyskinesia (PCD) is a rare, autosomal recessive condition. The signs and symptoms are due to congenital abnormalities of ciliary structure and function, resulting in impaired mucociliary clearance. This affects the ciliated epithelium lining the nose, sinuses, Eustachian tube and airways. As a consequence, the patient typically presents with a range of features, including recurrent upper and lower respiratory tract infections, persistent glue ear and possible hearing deficit. Around half of all patients will have situs anomalies, most typically situs inversus totalis. The most significant morbidity results from the development of bronchiectasis. Access to early diagnosis and effective treatment is essential to reduce disease progression and to alleviate the burden of symptoms. This review aims to provide a clinical guide to what to look for and when to suspect the diagnosis. Recent advances in the screening and diagnostic tests available will be outlined, as well as some future directions that aim to enhance the current diagnostic techniques.

Management of primary ciliary dyskinesia: the lower airways

Primary ciliary dyskinesia (PCD) is a genetic disease associated with defective ciliary structure and function. Chronic oto-sino-pulmonary infection is the most common clinical presentation. Patients should be monitored in centres with expertise in PCD. Regular respiratory monitoring consists of lung function tests, adapted to the patient's age, and cough swab or sputum cultures. Chest X-rays are insensitive but the use of high-resolution computed tomography should be considered carefully to avoid excessive radiation. Treatment of the chronic suppuration of the lower airways relies on antibiotics to which the isolated bacteria are sensitive, together with respiratory physiotherapy and exercise to clear excessive bronchial secretions. Bronchodilators and anti-inflammatory agents have no proven benefit and should be prescribed, if at all, on an individual basis. Treatment of the lower airways should always be in conjunction with that of the upper airways. Importantly in PCD, respiratory disease may be controlled with the use of early, adequate and aggressive management.