Nasal Nitric Oxide in Atypical Primary Ciliary Dyskinesia

Feasibility of nasal NO screening in healthy newborns

BACKGROUND

Nasal nitric oxide (nNO) measurement is recommended as a first line screening test for primary ciliary dyskinesia (PCD). While reliable velum- and non-velum-closure techniques exist for preschool children and older individuals, no data are available for neonates.

AIMS

To determine feasibility of nNO screening and nNO concentration in healthy newborns in the first week of life.

METHODS

Nasal NO was analyzed in tidal breathing during natural sleep using a CLD-88 sp NO analyzer (chemoluminescence sensor) and a NIOX MINO (electrochemical sensor). Test success and nNO concentration were determined and compared between the two devices.

RESULTS

Nasal NO was measured in 62 healthy neonates within the first week of life. Feasibility of nNO measurement was 100% for at least one nostril and 85.5% for both nostrils using the chemoluminescence device, but significantly lower with the electrochemical device (85.5% and 53.2%; p < .001). Median nNO concentration was 38 ppb (interquartile range, 27-55; range, 9-100) with the ECOMEDICS device and 23 (15-33, 8-59) with the NIOX MINO (p < .001), with a trend towards higher values for older subjects. None of the subjects exceeded nNO levels of 100 ppb.

CONCLUSION

Measurement of nNO using a chemoluminescence device is highly feasible in newborns during natural sleep. However, nNO levels are considerably lower compared to the published data for older individuals and in the range of a PCD reference group of infants between 4 and 8 weeks of age, potentially resulting in a great overlap with subjects with PCD in this age group. Therefore, screening for PCD using nasal NO might not be useful in the first week of life. Upon clinical suspicion, other diagnostic tests such as high-speed video analysis of the cilia should be applied.

Additional role of bronchial mucosal biopsy for ciliary structural abnormality in diagnosis of primary ciliary dyskinesia

Background

Transmission electron microscopy (TEM) is one of diagnostic tests for primary ciliary dyskinesia (PCD). The mucosal samples obtained for cilia examination are generally procured from the nasal turbinate, but these specimens often yield inadequate results. The bronchial mucosa is recognized as an alternative sample, but no study has examined the additional utility of bronchial mucosa compared with nasal mucosa in the diagnosis of PCD.

Methods

The medical records of 96 patients who underwent TEM for suspected PCD between April 1997 and June 2017 were reviewed. Patients were divided into three groups based on the site of mucosal biopsy: nasal biopsy (NB) group with nasal mucosal biopsy only; bronchial biopsy (BB) group with bronchial mucosal biopsy only; and nasal and bronchial biopsy (NBB) group with a combination of nasal and bronchial mucosal biopsies.

Results

The rate of PCD diagnosis was 28.8% (17/59) in the NB group, 41.2% (7/17) in the BB group, and 60.0% (12/20) in the NBB group. The yield of PCD diagnosis significantly increased in the NBB group compared with the NB group (P=0.012). In the NBB group, 25.0% (5/20) of patients were diagnosed with PCD by nasal mucosal biopsy, and 35.0% (7/20) of patients were additionally diagnosed by bronchial mucosal biopsy. The presence of sinusitis or bronchiectasis was not associated with prediction of PCD diagnosis from nasal or bronchial mucosal biopsy.

Conclusions

The combination of nasal and bronchial mucosal biopsy for TEM showed higher yields of PCD diagnosis than nasal mucosal biopsy alone.

European Respiratory Society guidelines for the diagnosis of primary ciliary dyskinesia

The diagnosis of primary ciliary dyskinesia is often confirmed with standard, albeit complex and expensive, tests. In many cases, however, the diagnosis remains difficult despite the array of sophisticated diagnostic tests. There is no "gold standard" reference test. Hence, a Task Force supported by the European Respiratory Society has developed this guideline to provide evidence-based recommendations on diagnostic testing, especially in light of new developments in such tests, and the need for robust diagnoses of patients who might enter randomised controlled trials of treatments. The guideline is based on pre-defined questions relevant for clinical care, a systematic review of the literature, and assessment of the evidence using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach. It focuses on clinical presentation, nasal nitric oxide, analysis of ciliary beat frequency and pattern by high-speed video-microscopy analysis, transmission electron microscopy, genotyping and immunofluorescence. It then used a modified Delphi survey to develop an algorithm for the use of diagnostic tests to definitively confirm and exclude the diagnosis of primary ciliary dyskinesia; and to provide advice when the diagnosis was not conclusive. Finally, this guideline proposes a set of quality criteria for future research on the validity of diagnostic methods for primary ciliary dyskinesia.

Diagnosis, monitoring, and treatment of primary ciliary dyskinesia: PCD foundation consensus recommendations based on state of the art review

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous, rare lung disease resulting in chronic oto-sino-pulmonary disease in both children and adults. Many physicians incorrectly diagnose PCD or eliminate PCD from their differential diagnosis due to inexperience with diagnostic testing methods. Thus far, all therapies used for PCD are unproven through large clinical trials. This review article outlines consensus recommendations from PCD physicians in North America who have been engaged in a PCD centered research consortium for the last 10 years. These recommendations have been adopted by the governing board of the PCD Foundation to provide guidance for PCD clinical centers for diagnostic testing, monitoring, and appropriate short and long-term therapeutics in PCD patients.

Clinical application of nasal nitric oxide measurement in pediatric airway diseases

Nitric oxide plays an important role in several physiological and pathophysiological processes in the respiratory tract. Different ways to measure nasal nitric oxide levels in children are currently available. The possibility of obtaining nasal nitric oxide measurement from relatively young children, combined with the availability of portable devices that can be used even in the office setting, opens new perspectives for nasal nitric oxide analysis in the pediatric daily practice. This review presents a synopsis about the current clinical applications of nasal nitric oxide measurement in the pediatric clinical practice. A total of 3,775 articles on the topic were identified, of which 883 duplicates were removed, and 2,803 were excluded based on review of titles and abstracts. Eighty-nine full text articles were assessed for eligibility and 32 additional articles were obtained from the reference lists of the retrieved studies. Since very low nasal nitric oxide levels are found in the majority of patients with primary ciliary dyskinesia, most publications support a central role for nasal nitric oxide to screen the disease, and indicate that it is a very helpful first-line tool in the real-life work-up in all age groups. Decreased nasal nitric oxide concentration is also typical of cystic fibrosis, even though nasal nitric oxide is not as low as in primary ciliary dyskinesia. In other upper airway disorders such as allergic rhinitis, rhinosinusitis, nasal polyposis, and adenoidal hypertrophy, clinical utility of nasal nitric oxide is still critically questioned and remains to be established. Since nNO determination is flow dependent, a general consensus from the major investigators in this area is highly desirable so that future studies will be performed with the same flow rate. A shared nNO methodology will enable to overcome the challenges that lie ahead in incorporating nNO measurement into the mainstream clinical setting of pediatric airway diseases.

Nasal nitric oxide screening for primary ciliary dyskinesia: systematic review and meta-analysis

Nasal nitric oxide (nNO) concentrations are low in patients with primary ciliary dyskinesia (PCD) providing a noninvasive screening test.

We conducted a systematic review of the literature to examine the utility of nNO in screening for PCD, in particular 1) different respiratory manoeuvres during sampling (velum closure, tidal breathing, etc.), 2) accuracy in screening young/uncooperative children, 3) stationary versus portable analysers, and 4) nNO in “atypical” PCD.

96 papers were assessed according to modified PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria and 22 were included in this review.

Meta-analysis of 11 studies comparing nNO during a velum closure breath hold gave a mean±sd nNO of 19.4±18.6 nL·min-1 in PCD (n = 478) and 265.0±118.9 nL·min-1 in healthy controls (n = 338). Weighted mean difference for PCD versus healthy controls was 231.1 nL·min-1 (95% CI 193.3–268.9; n = 338) and 114.1 nL·min-1 (95% CI 101.5–126.8; n = 415) for PCD versus cystic fibrosis. Five studies of nNO measurement during tidal breathing demonstrated that this is an acceptable manoeuvre in young children where velum closure is not possible, but the discriminatory value was reduced. Four small studies of portable NO analysers suggest these are reliable tools for screening for PCD. However, nNO must be interpreted alongside clinical suspicion. Future studies should focus on standardising sampling techniques and reporting.

Lung cancer in situs inversus totalis (SIT)--literature review

We present 21 studies of cases of lung cancer in patients with situs inversus totalis (SIT) published worldwide. The first case was described in 1952. Thirteen patients were from Japan, 4 from Eastern Europe, including 2 Polish cases from the authors` center (Department of Thoracic Surgery, Pomeranian Medical University in Szczecin, Poland), 2 from Western Asia, 1 from the U.S. and 1 from Australia. Male patients (20/21) as well as left-sided lung cancer cases (14/21) and squamous cell carcinoma cases (8/21) dominated in the entire group. Thirteen patients underwent surgical treatment. There were 10 left-sided and 3 right-sided surgical interventions with uneventful intra- and postoperative course. Explorative thoracotomy was performed in one case only on the right side. Upper lobectomy was performed in 5 cases, pneumonectomy in 3 cases, lower bilobectomy and middle lobectomy in one case and lower lobectomy in two cases. Surgery was performed through thoracotomy in 10 cases, VATS-assisted approach in two cases and sternotomy in one case. Descriptions of the surgical anatomy confirmed mirror image of the anatomy in all cases and were consistent with the preoperative CT images. Preoperative diagnosis was discussed including the role of 3-D reconstruction of CT for improving perioperative safety in this group of patients. In conclusion, lung cancer/SIT cases despite inversed but regular anatomy can be operated on radically as cases with normal anatomy with preservation of intraoperative security level.

Up to date on primary ciliary dyskinesia in children

Primary ciliary dyskinesia (PCD) is a congenital, clinically and ultrastructurally heterogeneous disease due to abnormal structure and/or function of cilia, with impaired mucociliary transport leading to several respiratory disorders. PCD can be diagnosed by the combination of thorough clinical examination with functional and ultrastructural analysis of the cilia. This paper shows progresses in PCD diagnosis obtained by ciliogenesis in culture evaluation of ciliated respiratory cells and by genetic analysis of mutations in candidate genes. Moreover, since to date no specific treatments are available to correct the ciliary dysfunction, the paper shows the proper therapeutical approach by the use of respiratory physiotherapy and regular exercise to favour airways clearance, by antibiotics administration to control acute airway infections. Macrolides administration as antiinflammatory option is suggested.

Arginine and nitric oxide pathways in obesity-associated asthma

Obesity is a comorbidity that adversely affects asthma severity and control by mechanisms that are not fully understood. This review will discuss evidence supporting a role for nitric oxide (NO) as a potential mechanistic link between obesity and late-onset asthma (>12 years). Several studies have shown that there is an inverse association between increasing body mass index (BMI) and reduced exhaled NO. Newer evidence suggests that a potential explanation for this paradoxical relationship is related to nitric oxide synthase (NOS) uncoupling, which occurs due to an imbalance between L-arginine (NOS substrate) and its endogenous inhibitor, asymmetric di-methyl arginine (ADMA). The review will propose a theoretical framework to understand the relevance of this pathway and how it may differ between early and late-onset obese asthmatics. Finally, the paper will discuss potential new therapeutic approaches, based on these paradigms, for improving the respiratory health of obese subjects with asthma.

Primary ciliary dyskinesia, an orphan disease

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disease, caused by specific primary structural and/or functional abnormalities of the motile cilia, in contrast with the transitory abnormalities seen in secondary ciliary dyskinesia. Disease-causing mutations in at least 16 genes have already been identified. The true incidence of PCD may be higher than currently reported, because the diagnosis is challenging and often missed. For the confirmation of PCD, both ciliary motility as well as ciliary ultrastructure must be evaluated. An early and adequate diagnosis and therapy can theoretically prevent bronchiectasis. Measurement of nasal nitric oxide has some value as a screening test but cannot be performed in young children. In the respiratory tract epithelium, impaired mucociliary clearance leads to chronic and/or recurrent upper and lower respiratory tract infections. In up to 75 % of the patients, respiratory manifestations start in the newborn period, although the diagnosis is often missed at that time. During embryogenesis, nodal cilia, which are motile cilia, determine the correct lateralization of the organs. Dysfunction of these cilia leads to random lateralization and thus situs inversus in approximately 50 % of the patients with PCD. The tail of a spermatozoon has a structure similar to that of a motile cilium. Consequently, male infertility due to immotile spermatozoa is often part of the characteristics of PCD. Given the heterogeneity and the rarity of the disorder, therapy is not evidence-based. Many treatment schedules are proposed in analogy with the treatment for cystic fibrosis.

CONCLUSION

Respiratory infections, situs inversus and male infertility are typical manifestations of PCD, a rare autosomal recessive disorder.

Primary ciliary dyskinesia: clinical criteria indicating ultrastructural studies

INTRODUCTION

Primary ciliary dyskinesia (PCD) is a congenital disease characterized by impaired ciliary function, which involves a wide range of symptoms that are mainly respiratory. Recent articles that base diagnosis on ciliary ultrastructural studies have estimated its prevalence to be 1/10,000 newborns, which is higher than previously thought. Our objective is to define criteria for clinical suspicion of DCP that would indicate ultrastructural studies, while optimizing these and providing early diagnoses.

METHODS

Ours is a descriptive, retrospective review of patients diagnosed with DCP in the Pediatric Pulmonology Unit at our hospital, from 1994 to 2010. The inclusion of cases was based on clinical suspicion criteria. Diagnosis was confirmed by characteristic ultrastructural changes observed in the electron microscopic study of the cilia.

RESULTS

Sixty-three samples were analyzed, and 34 cases of DCP and one case of acilia were confirmed. Mean age at diagnosis was 3.6 (range: 1 month to 19 years of age). The most frequent initial symptom was prolonged neonatal tachypnea in the newborns (20%) and lower respiratory tract episodes in the school-aged patients: recurrent pneumonia (46%), difficult-to-control asthma (26%), bronchiectasis (8.6%) and massive atelectasis (2.9%). Associated symptoms were present in 46% of the cases.

CONCLUSION

Our publication proposes the implementation of several clinical criteria depending on the age of presentation that would indicate the active search for alterations in the ciliary epithelium at reference centers.

Effectiveness of sequencing selected exons of DNAH5 and DNAI1 in diagnosis of primary ciliary dyskinesia

INTRODUCTION

Primary ciliary dyskinesia (PCD) is a rare genetically heterogenous condition. Mutations in DNAH5 or DNAI1 genes can be found in about a third of the patients with PCD. Increased occurrence of mutations was described in several exons of these long genes. The objective of the study was to test the sensitivity of sequencing of selected 13 exons (as compared to costly sequencing of all 100 exons of the two genes), and to determine the prevalence of the DNAH5 or DNAI1 mutations in the Czech PCD database.

METHODS

The Czech national PCD database has identified 31 pediatric patients, diagnosed based on clinical findings and tests on the ciliated epithelium. Twenty-seven patients from 24 families agreed on genetic testing. In the first step, direct sequencing of selected 13 exons (9 of DNAH5 and 4 of DNAI1) was performed, and then we compared its effectiveness in detecting at least one mutation with results of sequencing all 100 exons of the two genes.

RESULTS

The sequencing of all exons identified compound heterozygosity for PCD mutations in nine patients from eight families (DNAH5 in eight and DNAI1 in one patient), and heterozygozity for a DNAH5 mutation of uncertain functional significance in one additional patient. The first step of selected exon sequencing detected a mutation in five out of these eight families, its actual sensitivity being 62.5%, with a high predictive value. The phenotypic and clinical characteristics of all the paediatric patients with PCD are shown.

CONCLUSIONS

Selected exon sequencing detects at least one mutated allele in over a half of our patients who have PCD due to DNAH5 or DNAI1 mutations. To lower the costs of the genetic testing, targeted step-wise genetic testing may be a reasonable approach to detect mutations in PCD patients, especially if their phenotype is taken into account.

Expression of nitric oxide synthases in primary ciliary dyskinesia

Nitric oxide is believed to play a central role in nonspecific defense of upper airways. Patients with primary ciliary dyskinesia have very low concentration of nasal nitric oxide, which may contribute to the chronic upper airway diseases encountered by these patients. The mechanisms underlying this drop of nasal nitric oxide in primary ciliary dyskinesia are still unknown. The goal of the present work was to study nitric oxide synthases expression in upper airway tissues from patients with primary ciliary dyskinesia. For this purpose, 5 patients with primary ciliary dyskinesia and 10 nonallergic age-matched patients without primary ciliary dyskinesia undergoing nasal polypectomy were included. Nasal nitric oxide concentration was measured before polypectomy, and nitric oxide synthase expression and function were studied in nasal polyps. The nasal nitric oxide in patients with primary ciliary dyskinesia was lower than that in patients without primary ciliary dyskinesia (13 [9-16] ppb versus 210 [167-254] ppb, P < .0001). Nitric oxide synthase 2 immunostaining was prominent at the apical part of the ciliated epithelial cells and was similar in both groups. Nitric oxide synthase 3 staining was restricted to endothelial cells in both groups. In addition, reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase activity was superimposable to nitric oxide synthases 2 and 3 immunostaining, suggesting a preserved NADPH-activity of nitric oxide synthase. We therefore conclude that the drop in nasal nitric oxide in patients with primary ciliary dyskinesia is not secondary to the loss of nitric oxide synthase expression.

[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.

Nasal nitric oxide concentration in suspected chronic rhinosinusitis

BACKGROUND

The role that nasal nitric oxide (nNO) plays in sinonasal diseases is increasingly appreciated.

OBJECTIVE

To test the diagnostic value of measuring nNO levels in a symptomatic population undergoing evaluation for potential chronic rhinosinusitis (CRS).

METHODS

Of the patients referred to an outpatient allergy clinic for persistent nasal symptoms, those reporting nasal blockage plus 1 or more additional symptoms (discolored discharge, anterior or postnasal drip, facial pain or pressure, and reduction or loss of smell) were categorized as having CRS according to sinus computed tomography scores, with (CRSwNP) and without (CRSsNP) nasal polyps on the basis of endoscopic signs. All the included patients underwent nNO measurement and skin prick tests for common inhalant allergens. Healthy individuals served as controls for nNO measurement.

RESULTS

Levels of nNO were significantly lower in patients with CRSwNP (median, 340 ppb; 25th-75th percentile, 145-390 ppb) compared with patients with CRSsNP (762 ppb; 620-1,013 ppb), patients without CRS (917 ppb; 647-1,159 ppb), and controls (843 ppb; 762-962 ppb) (P < .001). Low values of nNO separated very well patients with CRSwNP, and the nNO cutoff value of less than 442 ppb was associated with the best combination of specificity (91%) and sensitivity (87%), resulting in a negative predictive value of 91% and a positive predictive value of 87%. A significant inverse relationship was observed between nNO level and sinus computed tomography score (r2 = -0.39, P < .001).

CONCLUSION

Testing for nNO is highly predictive of CRSwNP in a selected population of patients with symptoms suggestive of CRS.

Torquetenovirus infection and ciliary dysmotility in children with recurrent pneumonia

BACKGROUND

The aim of the study was to assess Torquetenovirus (TTV) loads within respiratory ciliated cells and to verify the existence of a correlation between TTV loads and functional or structural ciliary abnormalities, in a group of children with recurrent or persistent pneumonia.

METHODS

Nasal brushing samples of 55 children (28 male) were evaluated for ciliary motion and ultrastructural assessment, as well as for detection and quantification of TTV. Moreover, presence and load of TTV within ciliated cells, obtained from 5 patients by laser capture microdissection, were determined.

RESULTS

The nasal samples of 47 (85%) children with persistent or recurrent pneumonia resulted positive for TTV (loads = 2.1-7.3 log10 copies/microg total DNA). TTV were demonstrated also within microdissected ciliated cells. No significant difference between primary (11 subjects) and secondary ciliary dyskinesia (44 subjects) for TTV prevalence and mean loads were found. A significant correlation was observed between nasal TTV loads and ciliary beat frequency score (r = 0.305; P < 0.05), but not between TTV loads and presence of abnormal motion patterns, in patients with secondary ciliary abnormalities. As expected no correlations were found between nasal TTV loads and ciliary motion analysis in primary ciliary dyskinesia.

CONCLUSIONS

The presence of TTV in nasal samples demonstrates TTV ability to infect respiratory ciliated cells and suggests that these cells are potentially able to support virus replication. Moreover, TTV may behave in respiratory cells in a similar way to other viruses, that is, they disrupt the mucociliary escalator.

Bronchiectasis in Children with Recurrent Pneumonia: An Immunopathological Damage Associated with Secondary Ciliary Dysmotility

The aim of this study is to assess ciliary motion patterns in children with bronchiectasis unrelated to cystic fibrosis or primary ciliary dyskinesia. In 51 children with recurrent pneumonia, high resolution computed tomography (HRCT) was carried out to detect and score bronchiectasis. Moreover, ciliary ultrastructure, beat frequency and motion pattern were evaluated and compared to those observed in 30 healthy children. Bronchiectasis at HRCT was found in 31/51 children. Ciliary dysmotility was found in 20/31 children with bronchiectasis (64.5%). Overall, ciliary dysmotility was found in 39/51 patients (76.5%). Ciliary dysmotility showed a significant correlation with the HRCT score (p=0.02). Absent motion in some fields was found in 44/51 patients (86.3%) and this also showed significant correlation with the HRCT score (p=0.005). The specificity and sensitivity of ciliary dysmotility as an indicator of bronchiectasis was 74.3% and 83.3% respectively. The positive predictive value was 93.5%, and negative predictive value was 50%. Ciliary dysmotility, in children with recurrent airways infections, correlates with the presence and severity of bronchiectasis. Whether ciliary dysmotility is a cause or a consequence of anatomical lesion is a matter of speculation. Very likely there is an amplification and self-maintaining mechanism between the two events which may lead to more serious disease.