Analyses of 1,236 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 characterized 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, FEV1) were collected from 19 countries using the ERN LUNG International PCD Registry. Genetic data were evaluated according to ACMG guidelines. We assessed regional distribution of implicated genes and genetic variants as well as genotype correlations with laterality defects and FEV1. RESULTS: 1236 individuals carried 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%; 47-100%) and laterality defects (mean 42%; 28-69%) varied widely among the 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). In the group of individuals with CCNO (-3.26), CCDC39 (-2.49), and CCDC40 (-2.96) variants, FEV1 z-scores were significantly lower, while the group of DNAH11 (-0.83) and ODAD1 (-0.85) variant individuals had significantly milder FEV1 z-score reductions compared to the whole PCD cohort. CONCLUSION: This unprecedented multinational dataset of DNA variants and information on their distribution across countries facilitates interpretation of genetic epidemiology of PCD and provides prediction of diagnostic and phenotypic features such as the course of lung function.

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.

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.

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.

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.

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.

Cystic fibrosis related bone disease in children: Can it be predicted?

BACKGROUND&AIMS: Cystic fibrosis (CF) -related bone disease (CFBD) is an important complication of CF, and low BMD in childhood is a precursor of CFBD. Here, we aimed to investigate bone turnover biomarkers, including osteocalcin (OC), receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) in relation to low BMD in children with CF (cwCF). We also evaluated factors which could affect bone turnover with particular emphasis on fat-free mass (FFM), forced expiratory volume in 1 s (FEV1), hand grip strength (HGS), and functional capacity and physical activity. METHODS: Sixteen cwCF aged 8-18 years with moderate low BMD (group1) and 64 cwCF with normal BMD (group2) were enrolled. Serum RANKL, OC, and OPG were determined by immunoenzymatic assays. Multiple parameters including pancreatic status, lung functions, body mass index (BMI), FFM measured by bioelectric impedance analysis (BIA), 6-minute walk test, vitamin D, nutritional intake, HGS, functional capacity and physical activity, serum and urine biomarkers were compared between the two groups. RESULTS: We found similar serum levels of RANKL (p = 0.501), OC (p = 0.445), OPG (p = 0.380), and RANKL/OPG ratio (p = 0.449) between group1 and group2 in cwCF. BMI z-score (p < 0.001), FFMI z-score (p < 0.001), FEV1 z-score (p = 0.007), and right-HGS (%pred) (p = 0.009) significantly differed between the two groups. Multivariate linear regression revealed that the only factors that predicted BMD were FFMI z-score and HGS %pred. CONCLUSION: Serum OC, OPG, RANKL and RANKL/OPG ratio did not predict BMD in cwCF. FFMI z-score and HGS %pred measured by non-invasive and practical methods were the best predictors of BMD.

Plastic bronchitis during childhood: Diversity of presentation, etiology, treatment, and outcomes.

OBJECTIVE: Plastic bronchitis (PB) is a rare disease in children, and reliable data are scarce. Here, we aimed to analyze the clinical features, management, and outcomes in children with PB. METHODS: The medical data of patients who were followed up with a diagnosis of PB between January 2010 and March 2022 were retrospectively analyzed. RESULTS: The median age of 15 patients was 9 (interquartile range: 4-10) years with a male/female ratio of 12/3. Initial symptoms included recurrent pneumonia (33.3%), persistent atelectasis (33.3%), cast expectoration (26.6%), and intense, persistent cough (6.6%). The most common underlying diagnosis was asthma (n = 12, 80%), and six of the patients were newly diagnosed. The most common radiological findings were atelectasis as a consequence of major airway obstruction on chest X-ray or computed tomography. Five patients, all diagnosed as having asthma, had recurrent PB and required multiple airway procedures for treatment and diagnosis. During a median 7-year follow-up of five patients, occasionally cast expectoration was observed in one patient with asthma who had poor compliance with inhaled corticosteroids. CONCLUSION: PB is a common reflection of the different underlying etiologies in the pediatric age group, and treatment and outcomes are closely related to these. It should be kept in mind that asthma can be a predisposing factor for the development of PB.

Patients with cystic fibrosis who could not receive the CFTR modulator treatment: What did they lose in 1 year?

BACKGROUND: Cystic fibrosis (CF) is an autosomal recessive disorder caused by CF transmembrane conductance regulator (CFTR) genetic variants. CFTR modulators improve pulmonary function and reduce respiratory infections in CF. This study investigated the clinical and laboratory follow-up parameters over 1 year in patients with CF who could not receive this treatment. METHODS: This retrospective cohort study included 2018 and 2019 CF patient data from the CF registry of Turkey. Demographic and clinical characteristics of 294 patients were assessed, who had modulator treatment indications in 2018 but could not reach the treatment. RESULTS: In 2019, patients younger than 18 years had significantly lower BMI z-scores than in 2018. During the 1-year follow-up, forced expiratory volumes (FEV1) and FEV1 z-scores a trend toward a decrease. In 2019, chronic Staphylococcus aureus colonization, inhaled antipseudomonal antibiotic use for more than 3 months, oral nutritional supplement requirements, and oxygen support need increased. CONCLUSIONS: Patients who had indications for modulator treatments but were unable to obtain them worsened even after a year of follow-up. This study emphasized the importance of using modulator treatments for patients with CF in our country, as well as in many countries worldwide.

Evaluation of polysomnography findings in children with genetic skeletal disorders.

Children with genetic skeletal disorders have variable conditions that can lead to sleep-disordered breathing, and polysomnography is the gold standard for diagnosing this condition. We aimed to review polysomnography findings, to assess the severity of sleep apnea, and to investigate the clinical variables predictive of sleep-disordered breathing in these patients. We retrospectively collected the medical records of patients with genetic skeletal disorders who underwent polysomnography for 5 years. Twenty-seven children with various genetic skeletal disorders, including achondroplasia (14), Crouzon syndrome (3), acromesomelic dysplasia Maroteaux type (3), Apert syndrome (2), osteopetrosis (1), Jeune dysplasia (1), Desbuquois dysplasia (1), acrodysostosis (1), and spondyloepiphyseal dysplasia (1) were enrolled. The median age at the first polysomnography was 58 (1st-3rd quartile: 31-113) months. The overall sleep-disordered breathing results were: 19 (70.3%) had obstructive sleep apneas (OSA) (4 mild, 6 moderate, 9 severe), 2 (7.4%) had central apneas, 4 (14.8%) had nocturnal hypoventilation. There was a significant correlation between non-ambulatory status with both total AHI and OSA (p < 0.001, rho: -0.66/p = 0.04, rho: 0.38, respectively). Nine patients received positive airway pressure titration, and the oAHI values of all returned to the normal range. These patients were started with positive airway pressure treatment. Our cohort showed that the majority of the patients with skeletal dysplasia had sleep apnea syndrome characterised mainly by OSA, highlighting the importance of polysomnography screening for sleep disorders. Positive airway pressure therapy represents an effective treatment for sleep-disordered breathing in those patients.

Sinonasal disease among patients with primary ciliary dyskinesia: an international study.

Background: Sinonasal symptoms are a common feature of primary ciliary dyskinesia (PCD); however, literature about their severity and frequency, particularly during the life course, is scarce. Using baseline data from the Ear, nose and throat (ENT) Prospective International Cohort of PCD patients, we describe sinonasal disease in PCD. Methods: We included participants who had a routine sinonasal examination during which they completed a symptoms questionnaire. We compared frequency of reported symptoms and examination findings among children and adults, and identified characteristics potentially associated with higher risk of sinonasal disease using ordinal regression. Results: 12 centres contributed 384 participants; median age was 16 years (IQR 9-22), and 54% were male. Chronic nasal problems were the most common feature, reported by 341 (89%). More adults (33; 24%) than children (10; 4%) described hyposmia. Quality of life was moderately affected by rhinosinusitis among 136 participants with completed SNOT-22 questionnaires (median score 31; IQR 23-45). Examinations revealed nasal polyps among 51 of 345 participants (15%) and hypertrophic inferior nasal turbinates among 127 of 341 participants (37%). Facial pain was detected in 50 of 342 participants (15%). Nasal polyps, hypertrophic turbinates, deviated septum and facial pain were found more commonly in adults than children. The only characteristic associated with higher risk of sinonasal disease was age 10 years and older. Conclusions: Based on our findings, regular sinonasal examinations are relevant for patients with PCD of all ages. There is a need for improved management of sinonasal disease supported by evidence-based guidelines.

Characteristics of Otologic Disease Among Patients With Primary Ciliary Dyskinesia.

Importance: Otologic disease is common among people with primary ciliary dyskinesia (PCD), yet little is known about its spectrum and severity. Objective: To characterize otologic disease among participants with PCD using data from the Ear-Nose-Throat Prospective International Cohort. Design, Setting, and Participants: This cross-sectional analysis of baseline cohort data from February 2020 through July 2022 included participants from 12 specialized centers in 10 countries. Children and adults with PCD diagnoses; routine ear, nose, and throat examinations; and completed symptom questionnaires at the same visit or within 2 weeks were prospectively included. Exposures: Potential risk factors associated with increased risk of ear disease. Main Outcomes and Measures: The prevalence and characteristics of patient-reported otologic symptoms and findings from otologic examinations, including potential factors associated with increased risk of ear inflammation and hearing impairment. Results: A total of 397 individuals were eligible to participate in this study (median [range] age, 15.2 [0.2-72.4] years; 186 (47%) female). Of the included participants, 204 (51%) reported ear pain, 110 (28%) reported ear discharge, and 183 (46%) reported hearing problems. Adults reported ear pain and hearing problems more frequently when compared with children. Otitis media with effusion-usually bilateral-was the most common otoscopic finding among 121 of 384 (32%) participants. Retracted tympanic membrane and tympanic sclerosis were more commonly seen among adults. Tympanometry was performed for 216 participants and showed pathologic type B results for 114 (53%). Audiometry was performed for 273 participants and showed hearing impairment in at least 1 ear, most commonly mild. Season of visit was the strongest risk factor for problems associated with ear inflammation (autumn vs spring: odds ratio, 2.40; 95% CI, 1.51-3.81) and age 30 years and older for hearing impairment (41-50 years vs ≤10 years: odds ratio, 3.33; 95% CI, 1.12-9.91). Conclusion and Relevance: In this cross-sectional study, many people with PCD experienced ear problems, yet frequency varied, highlighting disease expression differences and possible clinical phenotypes. Understanding differences in otologic disease expression and progression during lifetime may inform clinical decisions about follow-up and medical care. Multidisciplinary PCD management should be recommended, including regular otologic assessments for all ages, even without specific complaints.

Clinical characteristics of patients requiring lung transplantation referral in national cystic fibrosis registry data.

BACKGROUND: We aimed to determine the number of cystic fibrosis (CF) patients recorded in the Cystic Fibrosis Registry of Türkiye (CFRT) who were in need of lung transplantation (LT) referral and examine clinical differences between patients who were LT candidates due to rapid forced expiratory volume in one second (FEV1) decline and LT candidates without rapid FEV1 decline in the last year to identify a preventable cause in patients with such rapid FEV1 decline. METHODS: All CF patients recorded in the CFRT in 2018 were evaluated in terms of LT. Patients were divided into those with FEV1 below 50% and in need of LT due to a decrease of 20% or more in the previous year (Group 1) and those who did not have FEV1 decline of more than 20% in the previous year but had other indications for LT (Group 2). Demographic and clinical features were compared between the two groups. RESULTS: Of 1488 patients registered in CFRT, 58 had a need for LT. Twenty patients were included in Group 1 and others in Group 2. Our findings did not reveal any significant variations in treatment, chronic infection status, or complications between the two groups. The average weight z-score was significantly higher in Group 1. Positive correlations were detected between weight z-score and FEV1 in 2017 in Group 1 and between FEV1 values in 2017 and 2018 in Group 2. CONCLUSIONS: There appears to be a relationship between the nutritional status and weight z-scores of CF patients and pulmonary function, which may indirectly affect the need for lung transplantation referral.

Evaluation of Clinical Findings in Children with Chylothorax: A Descriptive Study.

OBJECTIVE: Chylothorax refers to the presence of chyle in the pleural space. There are multiple etiologies of chylothorax. Our aim in this study was to evaluate the clinical manifestations, causes, and treatment of chylothorax in childhood and also to show the differences between the 2 age groups admitted to a tertiary care children's hospital. The second aim was to evaluate the clinical and radiologic features of patients diagnosed as having Gorham-Stout disease via chylothorax. MATERIALS AND METHODS: The archives were reviewed for chylothorax documented in the last 31 years. Twenty-two patients (11 girls and 11 boys) were included. Patients were divided into 2 groups: the younger group aged under 24 months and the older group aged over 24 months. RESULTS: A total of 22 patients had chylothorax, and 10 were aged younger than 24 months. In the younger group, etiologies were in order congenital heart surgery, congenital chylothorax, and Gorham-Stout disease. In the older group, etiologies were Gorham-Stout disease, congenital heart surgery, heart failure, heart transplantation, thrombus, intestinal lymphangiectasia, and idiopathic. The most common treatment in the younger group was the medium-chain triglyceride diet (70%), and in the older group, it was sirolimus (50%). CONCLUSION: There is a wide variety of underlying etiologies in childhood, so a multidisciplinary approach is important to identify the underlying diagnosis. The common etiologies were postoperative and Gorham-Stout disease in our study. All patients with Gorham-Stout disease had a good prognosis. Gorham-Stout disease should be considered in patients of any age with a diagnosis of chylothorax who have bone lesions.

A case-control study of the effects of Aspergillus clinical phenotypes on pulmonary functions in patients with cystic fibrosis.

INTRODUCTION: There are no precise data about the effect of Aspergillus infection on lung function other than allergic bronchopulmonary aspergillosis (ABPA) in patients with cystic fibrosis (pwCF). Here, we aimed to determine clinical phenotypes caused by Aspergillus spp. using laboratory and immunologic parameters and to compare Aspergillus phenotypes in terms of pulmonary function tests (PFT) prospectively. METHODS: Twenty-three pwCF who had Aspergillus isolation from respiratory cultures in the last year (case group) and 20 pwCF without Aspergillus isolation in sputum (control group) were included. Aspergillus immunoglobulin (Ig)-G, Aspergillus IgE, Aspergillus polymerase chain reaction (PCR), galactomannan, total IgE from blood samples, and Aspergillus PCR and galactomannan from sputum, and skin prick test reactivity to Aspergillus antigen were used to distinguish different Aspergillus phenotypes. Pulmonary functions and frequency of pulmonary exacerbations were evaluated during a 1-year follow-up. RESULTS: Of 23 pwCF, 11 (47.8%) had Aspergillus colonization, nine (39.1%) had Aspergillus bronchitis, and three (13%) had ABPA. Aspergillus infection was not associated with worse z-scores of forced expiratory volume in the first second (FEV1) (p = 0.612), forced vital capacity  (p = 0.939), and the median FEV 1% decline (0.0%/year vs. -4.7%/year, p = 0.626). The frequency of pulmonary exacerbations in the Aspergillus infected and noninfected groups was similar. CONCLUSION: Although Aspergillus spp. Isolation in pwCF was not associated with decreased lung function, a further decline was seen in the ABPA subgroup, and frequent pulmonary exacerbations during the 1-year follow-up.

The role of flexible bronchoscopy in the diagnostic pathway of children with unexplained peripheral eosinophilia.

BACKGROUND: Many possible underlying causes can be seen in children with unexplained peripheral eosinophilia (UPE) with suspected pulmonary involvement. Here, we aimed to demonstrate the clinical characteristics and diagnoses of children evaluated for UPE who underwent diagnostic bronchoscopy. METHODS: Thirty-one children who underwent diagnostic bronchoscopy for UPE between 2006-2018 were included. Demographic characteristics, bronchoscopy findings and final diagnosis, and treatments were evaluated. RESULTS: The median age at the time of diagnosis was 5 (0.25-17.5) years. The final diagnoses of 26 patients were as follows: immunodeficiency (n = 6); hyper-IgE syndromes (n = 4), DOCK8 deficiency + HES (idiopathic hypereosinophilic syndrome; n = 1), and severe combined immunodeficiency (n = 1), HES (n = 3), idiopathic chronic eosinophilic pneumonia (ICEP; n = 3), idiopathic pulmonary hemosiderosis (n = 1), B cell lymphoma (n = 1). In one child, an integrin α3 mutation + cytomegalovirus (CMV) pneumonia was detected. Congenital pneumonia was found in one patient, and parasitic infection in another. In two, eosinophilia was attributed to underlying asthma and atopy. In four, the underlying reasons could not be elucidated. Two children with HES and one with ICEP were lost to follow-up. There was no significant relationship between the peripheral eosinophil count at the time of diagnosis and the percentage of bronchoalveolar lavage eosinophils (BAL). Bronchoscopy contributed to the management of 14 (53.9%) patients. CONCLUSIONS: Bronchoscopy has potential diagnostic contribution in patients with UPE suspected of having pulmonary involvement. Numerous various underlying causes may be present in this patient group. There is no relation between peripheral eosinophil count and BAL eosinophil percentage.