Associations between respiratory pathogens and lung function in primary ciliary dyskinesia: cross-sectional analysis from the PROVALF-PCD cohort.

Introduction: Respiratory pathogens are frequently isolated from airway samples in primary ciliary dyskinesia (PCD) patients. Few studies have investigated associations between these pathogens and lung function, with current management based on evidence from cystic fibrosis. We investigated the association between commonly isolated respiratory pathogens and lung function in PCD patients. Methods: Using a cross-sectional design, we prospectively collected clinical and concurrent microbiology data from 408 participants with probable or confirmed PCD, aged ≥5 years, from 12 countries. We used Global Lung Function Initiative 2012 references to calculate forced expiratory volume in 1 s (FEV1) z-scores. For 351 patients (86%) with complete data, we assessed the association of the four most frequently isolated pathogens with lung function by fitting multilevel linear models with country as random intercept, adjusted for age at diagnosis, age at lung function, use of antibiotic prophylaxis and body mass index z-scores. Results: Individuals with Pseudomonas aeruginosa growth in culture had significantly lower FEV1 z-scores (ß= -0.87, 95% CI -1.40- -0.34), adjusted for presence of Haemophilus influenzae, methicillin-sensitive Staphylococcus aureus and Streptococcus pneumoniae, and for covariates. When stratified by age, associations remained strong for adults but not for children. Results were similar when ciliary defects by transmission electron microscopy were included in the models and when restricting analysis to only confirmed PCD cases. Conclusions: We found that P. aeruginosa was associated with worse lung function in individuals with PCD, particularly adults. These findings suggest that it is prudent to aim for P. aeruginosa eradication in the first instance, and to treat exacerbations promptly in colonised patients.

Do we neglect nutrition in childhood interstitial lung disease?

Growth failure and inadequate weight gain are common problems in childhood interstitial lung diseases (chILD) and these children usually need high calories. It is important to manage both pulmonary functions and nutrition as part of their overall treatment plan and early interventions will help children to improve their quality of life and slow the progression of chronic lung disease. Nutritional evaluation on routine clinical follow-up is important, although there are not any specific guidelines for chILD. Nutritional education, high balanced energy, protein, and fat diet will assist to improve weight gain and maintenance of adequate nutrition status in children with ILD.

The Coronavirus Disease 2019 Pandemic and Time to Diagnosis for Childhood Pulmonary Diseases: Outcomes of a Tertiary Care Center.

Coronavirus disease 2019 pandemic caused many changes in the social behaviors of individuals and the provision of health systems. Many studies revealed reductions in the number of diagnoses and delays in diagnosis time during the pandemic. This study aimed to evaluate the effect of the pandemic on the time to diagnosis of major diseases of pediatric pulmonology. Newly diagnosed patients with cystic fibrosis (CF), childhood interstitial lung disease (chILD), tuberculosis (TB), and primary ciliary dyskinesia (PCD) were grouped into pandemic (group 1) and 2 consecutive pre-pandemic periods divided into equal intervals (groups 2 and 3). For each disease group, the time to diagnosis was compared between the specified periods. A total number of patients were 171 in this study. In the CF group, there was no statistically difference in time to diagnosis between periods. In the chILD group, there was a statistically significant difference in time to diagnosis (P = .036) between groups (group 1: 2 months, group 2: 4 months and group 3: 10.5 months) that was not originated from pandemic period. In TB group there was no statistically significant difference between groups. In the PCD group, the impact of the pandemic on the time to diagnosis could not be clarified because the time interval to diagnosis (minimum: 2 years, maximum: 16 years) exceeded the studied periods (21 months). In our study, no effect found between the pandemic and age at diagnosis or time to diagnosis in patients with PCD, chILD, CF, and TB at our center.

Factors associated with pulmonary function decline of patients in the cystic fibrosis registry of Turkey: A retrospective cohort study.

BACKGROUND: The decline in pulmonary function is a predictor of disease progression in patients with cystic fibrosis (CF). This study aimed to determine the decline rate of percent predicted forced expiratory volume in 1 s (ppFEV1) based on the data of the CF Registry of Turkey. The secondary aim was to investigate the risk factors related to the decline in ppFEV1. METHODS: A retrospective cohort study of CF patients over 6 years old, with pulmonary function data over at least 2 years of follow-up was extracted from the national CF registry for years 2017-2019. Patients were classified according to disease severity and age groups. Multivariate analysis was used to predict the decline in ppFEV1 and to investigate the associated risk factors. RESULTS: A total of 1722 pulmonary function test results were available from 574 patients over the study period. Mean diagnostic age was older and weight for age, height for age, and body mass index z scores were significantly lower in the group of ppFEV1 < 40, while chronic Pseudomonas aeruginosa (p < .001) and mucoid P. aeruginosa colonization (p < .001) were significantly higher in this group (p < .001). Overall mean annual ppFEV1 decline was -0.97% (95% confidence interval [CI] = -0.02 to -1.92%). The mean change of ppFEV1 was significantly higher in the group with ppFEV1 ≥ 70 compared with the other (ppFEV1 < 40 and ppFEV1: 40-69) two groups (p = .004). Chronic P. aeruginosa colonization (odds ratio [OR] = 1.79 95% CI = 1.26-2.54; p = .01) and initial ppFEV1 ≥ 70 (OR = 2.98 95% CI = 1.06-8.36), p = .038) were associated with significant ppFEV1 decline in the whole cohort. CONCLUSIONS: This data analysis recommends close follow-up of patients with normal initial ppFEV1 levels at baseline; advocates for early interventions for P. aeruginosa; and underlines the importance of nutritional interventions to slow down lung disease progression.

Exercise intolerance, oxidative stress, and irisin in pediatric cystic fibrosis: Can telehealth-based exercise training make a difference?

BACKGROUND: Patients with cystic fibrosis (CF) experience increased oxidative stress. Tele-exercise can be a new method to improve exercise in CF. OBJECTIVE: This study aimed to investigate the effect of telehealth-based exercise training using different modalities (combined exercise training group, CombG, core stabilization exercise group, SG), in comparison with control group (CG), on exercise capacity, oxidative stress, and irisin in children with CF. METHODS: Thirty-nine children with CF (mean age=11.41±2.18 years, mean FEV1(z-score)=-0.66±1.96) were included in the study. The children were randomly allocated to groups. The CombG and SG performed core stabilization exercises (CS) 3 days per week for 8 weeks. The CombG also performed aerobic exercises 3 days per week in addition to CS. Physical activity (PA) recommendations were provided to the CG. Exercise capacity was evaluated using the Modified Shuttle Test (MST). Oxidative stress was assessed using total antioxidant status (TAS), total oxidant status (TOS), Oxidative Stress Index (OSI), malondialdehyde (MDA), and superoxide dismutase (SOD). The irisin level was also measured. RESULTS: Children's baseline sex, age, BMI, and FEV1 z-scores were similar (p > 0.05). The MST distance (p = 0.047,np2=0.157) and%MST distance (p = 0.045, np2=0.159) significantly improved in the CombG compared with the SG and CG. Although TAS and SOD decreased over time (p < 0.05), no significant changes were observed for TAS, TOS, OSI, MDA, SOD, and irisin parameters between the groups after training (p > 0.05). CONCLUSIONS: Combining aerobic exercise training with core stabilization applied using telehealth improved exercise capacity more than core stabilitation training only or PA recommendations in children with CF.

The predictive role of lung clearance index on FEV1 decline in cystic fibrosis.

BACKGROUND: The lung clearance index (LCI) is a sensitive lung function index that is used to detect early lung disease changes in children with cystic fibrosis (CF). This study aimed to define the predictive role of baseline LCI, along with other potential factors on the change in forced expiratory volume in one second (FEV1) during one-year follow-up in CF patients who had a percent predicted (pp) FEV1≥80. METHODS: LCI was concurrently performed on 57 CF patients who had ppFEV1 ≥80 at month zero. The ppFEV1 decline was evaluated prospectively during the one year follow up. The primary outcome of ppFEV1 decline in the study group in one year was dichotomized according to the median value for the decline in ppFEV1, which was 3.7. The LCI value predicting ppFEV1 decline at the end of one year was calculated with receiver operating characteristic curve analysis. Regression analysis was performed. Furthermore, a decision tree was constructed using classification and regression tree methods to better define the potential effect of confounders on the ppFEV1 decline. RESULTS: The LCI value for predicting ppFEV1 decline >3.7% at the end of one year was 8.2 (area under the curve: 0.80) Multivariable regression analysis showed that the absence of the F508del mutation in at least one allele, LCI >8.2 and initial FEV1 z-score were predictors of a ppFEV1 decline >3.7 (p<0.001). Factors altering ppFEV1 decline>3.7% at the end of one-year evaluated by decision trees were as follows: initial FEV1 z-score, type of CFTR mutation, LCI value and initial weight-for-age z-score. CONCLUSIONS: LCI is sensitive for predicting ppFEV1 decline in patients with ppFEV1 ≥80 along with the initial FEV1-z-score and type of CFTR mutation.

Evaluation of otorhinolaryngologic, audiologic, and genetic findings in children with cystic fibrosis: A tertiary care experience.

OBJECTIVES: To evaluate otorhinolaryngologic findings and the relationship between aminoglycoside (AG) exposure and hearing loss in paediatric patients with cystic fibrosis (cwCF). We also aimed to investigate the genetic predisposition to AG ototoxicity by screening for m.1555A>G mutations. METHODS: CwCF who underwent otorhinolaryngologic and audiologic examinations were retrospectively included. Clinical characteristics, ear-nose-throat related symptoms, and a history of ototoxic drug exposure were recorded. m.1555A>G mutations were retrospectively screened among patients with audiologic evaluations. RESULTS: Two hundred thirty-four cwCF were included in this study with a median age of 10.7 (range, 6.8-14.2) years. Nasal obstruction (14.1%) was the most common symptom. Fifty-two (22.2%) patients had chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP). There was a positive correlation between CRSwNP and the symptom of nasal obstruction (r:.234, p < .001), snoring (r:.179, p = .006), and sleeping with mouth open (r:.138, p = .034). One hundred forty-nine (63.6%) patients had audiologic evaluations; 14 (9.4%) had hearing impairment. No statistical significance existed between ototoxicity and IV AG exposure (p = .90). Six (42.8%) of 14 patients did not receive ototoxic drugs. One hundred nineteen (50.8%) patients were screened for m.1555A>G mutations, and none were detected. CONCLUSIONS: Almost a quarter of the study population had CRSwNP. Neither the relationship between AGs exposure and hearing loss nor the genetic predisposition to AG ototoxicity could be shown in cwCF.

Health-related quality scores in childhood interstitial lung disease: Good agreement between patient and caregiver reports.

INTRODUCTION: Childhood interstitial lung disease (chILD) is a heterogeneous group of mostly chronic respiratory disorders. Assessment of health-related quality of life (HrQoL) in chILD has become increasingly important in clinical care and research. The aim of this study was to assess differences between patient-reported (self) and caregiver-reported (proxy) HrQoL scores. METHODS: This study used data obtained from the chILD-EU Register. After inclusion (baseline), the patient's health status was followed up at predefined study visits. At each study visit, caregivers and patients were handed validated, age-specific HrQoL questionnaires. HrQoL data entered at baseline were used to compare self- and proxy-reported HrQoL scores. For the longitudinal analysis, we compared HrQoL scores between the baseline and the next follow-up visit. RESULTS: No differences between patient- and caregiver-reported HrQoL scores were found for school functioning, chILD-specific questionnaire score, and physical health summary score. Self-reported HrQoL scores were higher for the subscales emotional functioning (77.4 vs. 70.7; p < .001), social functioning (81.9 vs. 76.2; p < .001), as well as psycho-social summary score (76.5 vs. 71.8; p < .001) and total score (74.7 vs. 70.8; <.001). The longitudinal analysis showed that a significant change in a patient-reported HrQoL score resulted in a significant change in a caregiver-reported HrQoL score after a mean time of 11.0 months (SD 9.4). CONCLUSIONS: We found a good agreement between children- and caregiver-related HrQoL scores. In chILD, caregivers are able to sense changes in children's HrQoL scores over time and may be used as a proxy for children unable to complete HrQoL questionnaires.

Analyses of 1236 genotyped primary ciliary dyskinesia individuals identify regional clusters of distinct DNA variants and significant genotype-phenotype correlations.

BACKGROUND: Primary ciliary dyskinesia (PCD) represents a group of rare hereditary disorders characterised by deficient ciliary airway clearance that can be associated with laterality defects. We aimed to describe the underlying gene defects, geographical differences in genotypes and their relationship to diagnostic findings and clinical phenotypes. METHODS: Genetic variants and clinical findings (age, sex, body mass index, laterality defects, forced expiratory volume in 1 s (FEV1)) were collected from 19 countries using the European Reference Network's ERN-LUNG international PCD Registry. Genetic data were evaluated according to American College of Medical Genetics and Genomics guidelines. We assessed regional distribution of implicated genes and genetic variants as well as genotype correlations with laterality defects and FEV1. RESULTS: The study included 1236 individuals carrying 908 distinct pathogenic DNA variants in 46 PCD genes. We found considerable variation in the distribution of PCD genotypes across countries due to the presence of distinct founder variants. The prevalence of PCD genotypes associated with pathognomonic ultrastructural defects (mean 72%, range 47-100%) and laterality defects (mean 42%, range 28-69%) varied widely among countries. The prevalence of laterality defects was significantly lower in PCD individuals without pathognomonic ciliary ultrastructure defects (18%). The PCD cohort had a reduced median FEV1 z-score (-1.66). Median FEV1 z-scores were significantly lower in CCNO (-3.26), CCDC39 (-2.49) and CCDC40 (-2.96) variant groups, while the FEV1 z-score reductions were significantly milder in DNAH11 (-0.83) and ODAD1 (-0.85) variant groups compared to the whole PCD cohort. CONCLUSION: This unprecedented multinational dataset of DNA variants and information on their distribution across countries facilitates interpretation of the genetic epidemiology of PCD and indicates that the genetic variant can predict diagnostic and phenotypic features such as the course of lung function.

Comparison of clinical features of cystic fibrosis patients eligible but not on CFTR modulators to ineligible for CFTR modulators.

INTRODUCTION: Cystic fibrosis transmembrane conductance regulator (CFTR) modulator drugs target the underlying defect and improve CFTR function. They are a part of standard care in many countries, but not all patients are eligible for these drugs due to age and genotype. Here, we aimed to determine the characteristics of non-eligible patients for CFTR modulators in the CF registry of Turkey (CFRT) to highlight their clinical needs. METHODS: This retrospective cohort study included CF patient data from the CFRT in 2021. The decision of eligibility for the CFTR modulator was determined according to the 'Vertex treatment-Finder' on the Vertex® website. Demographic and clinical characteristics of patients were compared between eligible (group 1) and ineligible (group 2) groups for CFTR modulators. RESULTS: Among the study population (N = 1527), 873 (57.2%) were in group 1 and 654 (42.8%) were in group 2. There was no statistical difference between groups regarding sex, meconium ileus history, diagnoses via newborn screening, FEV1 z-score, CF-associated complications, organ transplant history, and death. Patients in group 2 had a higher incidence of pancreatic insufficiency (87.7% vs. 83.2%, p = .010), lower median height z-scores (-0.87 vs. -0.55, p < .001), lower median body mass index z-scores (-0.65 vs. -0.50, p < .001), longer days receiving antibiotics due to pulmonary exacerbation (0 [interquartile range, IQR: 0-2] vs. 0 [IQR: 0-7], p = 0.001), and more non-invasive ventilation support (2.6% vs. 0.9%, p = 0.008) than patients in group 1. CONCLUSION: The ineligible group had worse clinical outcomes than the eligible group. This highlights their need for life-changing drugs to improve clinical outcomes.

Impact of interruption of CFTR modulator therapies.

Novel drug therapy targeting the defective cystic fibrosis transmembrane conductance regulator protein has the potential to significantly enhance the quality of life for numerous patients with cystic fibrosis. However, in some countries social insurance does not pay for modulators because these drugs are extremely expensive. This study sought to understand the impact on the health of children whose modulator treatments were interrupted because of legal procedures and delivery processes. Our study identified that the significant increase in percent-predicted forced expiratory volume levels (FEV1) and BMI z-score values associated with modulator therapies decreased sharply with their discontinuation. Significant worsening in FEV1, BMI z-scores, and BW z-scores were detected in the first follow-up visit after therapy discontinuation within 1 month. Eight patients had a reduction of FEV1 of more than 10%. The findings suggest that modulatory treatment continuation is important, and it is crucial that treatment is not interrupted.

Association between upper and lower respiratory disease among patients with primary ciliary dyskinesia: an international study.

Introduction: Nearly all patients with primary ciliary dyskinesia (PCD) report ear-nose-throat (ENT) symptoms. However, scarce evidence exists about how ENT symptoms relate to pulmonary disease in PCD. We explored possible associations between upper and lower respiratory disease among patients with PCD in a multicentre study. Methods: We included patients from the ENT Prospective International Cohort (EPIC-PCD). We studied associations of several reported ENT symptoms and chronic rhinosinusitis (defined using patient-reported information and examination findings) with reported sputum production and shortness of breath, using ordinal logistic regression. In a subgroup with available lung function results, we used linear regression to study associations of chronic rhinosinusitis and forced expiratory volume in 1 s (FEV1) accounting for relevant factors. Results: We included 457 patients (median age 15 years, interquartile range 10-24 years; 54% males). Shortness of breath associated with reported nasal symptoms and ear pain of any frequency, often or daily hearing problems, headache when bending down (OR 2.1, 95% CI 1.29-3.54) and chronic rhinosinusitis (OR 2.3, 95% CI 1.57-3.38) regardless of polyp presence. Sputum production associated with daily reported nasal (OR 2.2, 95% CI 1.20-4.09) and hearing (OR 2.0, 95% CI 1.10-3.64) problems and chronic rhinosinusitis (OR 2.1, 95% CI 1.48-3.07). We did not find any association between chronic rhinosinusitis and FEV1. Conclusion: Reported upper airway symptoms and signs of chronic rhinosinusitis associated with reported pulmonary symptoms, but not with lung function. Our results emphasise the assessment and management of upper and lower respiratory disease as a common, interdependent entity among patients with PCD.

Galectin-3 levels in children with cystic fibrosis.

Cystic fibrosis (CF) is a multisystemic disease in which airway obstruction, infection, and inflammation play a critical role in the pathogenesis and progression of CF lung disease. The carbohydrate-binding protein Galectin-3 is increased in several inflammatory and fibrotic diseases and has recently been forwarded as a biomarker in these diseases. We aimed to define the role of serum Galectin-3 in children with CF by comparison with healthy subjects. This is a cross-sectional, case-control study. 143 CF and 30 healthy subjects were enrolled in the study. Peripheral blood and sputum concentrations of Galectins-3, interleukin (IL)-17A, IL-8, and neutrophil elastase (NE) were determined with commercial ELISA kits. There was no significant difference between the groups in age and gender (p = 0.592, p = 0.613, respectively). Serum Galectin-3 and NE concentrations were higher in the patient group than in healthy controls (p = 0.002, p < 0.001, respectively). There were no significant differences between groups according to IL-17A and IL-8 concentrations. Serum Galectin-3 was correlated with age (r = 0.289, p < 0.001) and body mass index (BMI) (r = 0.493, p < 0.001) in children with CF. Sputum Galectin-3 levels are negatively correlated with percent predictive forced expiratory volume in 1 s (FEV1) (r = - 0.297, p = 0.029), FEV1 z-score, (r = - 0.316, p = 0.020), percent predictive forced vital capacity (FVC) (r = - 0.347, p = 0.010), and FVC z-score (r = - 0.373, p = 0.006).   Conclusion: The study shows that serum Galectin-3 levels increased in clinically stable CF patients, and serum Galectin-3 response may depend on age, gender, and BMI. The sputum Galectin-3 was found to be negatively correlated with patients' lung functions. What is known: • Galectin-3 is a key regulator of chronic inflammation in the lung, liver, kidney, and tumor microenvironment. What is new: • Children with cystic fibrosis (CF) have higher serum Galectin-3 concentrations than healthy children. • Serum Galectin-3 expression influenced by age, BMI, and gender in children with CF.

A BEAT-PCD consensus statement: a core outcome set for pulmonary disease interventions in primary ciliary dyskinesia.

Background: Consistent use of reliable and clinically appropriate outcome measures is a priority for clinical trials, with clear definitions to allow comparability. We aimed to develop a core outcome set (COS) for pulmonary disease interventions in primary ciliary dyskinesia (PCD). Methods: A multidisciplinary international PCD expert panel was set up. A list of outcomes was created based on published literature. Using a modified three-round e-Delphi technique, the panel was asked to decide on relevant end-points related to pulmonary disease interventions and how they should be reported. First, inclusion of an outcome in the COS was determined. Second, the minimum information that should be reported per outcome. The third round finalised statements. Consensus was defined as ≥80% agreement among experts. Results: During the first round, experts reached consensus on four out of 24 outcomes to be included in the COS. Five additional outcomes were discussed in subsequent rounds for their use in different subsettings. Consensus on standardised methods of reporting for the COS was reached. Spirometry, health-related quality-of-life scores, microbiology and exacerbations were included in the final COS. Conclusion: This expert consensus resulted in a COS for clinical trials on pulmonary health among people with PCD.

Childhood interstitial lung disease in Turkey: first data from the national registry.

The childhood interstitial lung diseases (chILD) Turkey registry (chILD-TR) was established in November 2021 to increase awareness of disease, and in collaboration with the centers to improve the diagnostic and treatment standards. Here, the first results of the chILD registry system were presented. In this prospective cohort study, data were collected using a data-entry software system. The demographic characteristics, clinical, laboratory, radiologic findings, diagnoses, and treatment characteristics of the patients were evaluated. Clinical characteristics were compared between two main chILD groups ((A) diffuse parenchymal lung diseases (DPLD) disorders manifesting primarily in infancy [group1] and (B) DPLD disorders occurring at all ages [group 2]). There were 416 patients registered from 19 centers. Forty-six patients were excluded due to missing information. The median age of diagnosis of the patients was 6.05 (1.3-11.6) years. Across the study population (n = 370), 81 (21.8%) were in group 1, and 289 (78.1%) were in group 2. The median weight z-score was significantly lower in group 1 (- 2.0 [- 3.36 to - 0.81]) than in group 2 (- 0.80 [- 1.7 to 0.20]) (p < 0.001). When we compared the groups according to chest CT findings, ground-glass opacities were significantly more common in group 1, and nodular opacities, bronchiectasis, mosaic perfusion, and mediastinal lymphadenopathy were significantly more common in group 2. Out of the overall study population, 67.8% were undergoing some form of treatment. The use of oral steroids was significantly higher in group 2 than in group 1 (40.6% vs. 23.3%, respectively; p = 0.040).   Conclusion: This study showed that national registry allowed to obtain information about the frequency, types, and treatment methods of chILD in Turkey and helped to see the difficulties in the diagnosis and management of these patients. What is Known: • Childhood interstitial lung diseases comprise many diverse entities which are challenging to diagnose and manage. What is New: • This study showed that national registry allowed to obtain information about the frequency, types and treatment methods of chILD in Turkey and helped to see the difficulties in the diagnosis and management of these patients. Also, our findings reveal that nutrition should be considered in all patients with chILD, especially in A-DPLD disorders manifesting primarily in infancy.

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.