S. Bui

Clinical phenotype and genotype of children with borderline sweat test and abnormal nasal epithelial chloride transport.

RATIONALE The diagnosis of cystic fibrosis (CF) is based on a characteristic clinical picture in association with a sweat chloride (Cl(-)) concentration greater than 60 mmol/L or the identification of two CF-causing mutations. A challenging problem is the significant number of children for whom no definitive diagnosis is possible because they present with symptoms suggestive of CF, a sweat chloride level in the intermediate range between 30 and 60 mmol/L, and only one or no identified CF-causing mutation. OBJECTIVES To investigate the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein in the airways of children with intermediate sweat tests and inconclusive genetic findings in correlation with clinical phenotype and genotype. METHODS We developed a composite nasal potential difference (NPD) diagnostic score to discriminate patients with CF from non-CF patients. We tested NPD in 50 children (age, 6 mo to 18 yr) with equivocal diagnoses and correlated the NPD diagnostic score with clinical phenotypes and genotypes. MEASUREMENTS AND MAIN RESULTS Fifteen of the 50 children had NPD scores in the CF range. Eight of the 15 carried two CFTR mutations compared with only 5 of the 35 children with normal NPD scores (P = 0.01). They were significantly younger at evaluation and had recurrent lower respiratory tract infections, chronic productive coughs, and chronic Staphylococcus aureus colonization significantly more often than the 35 children with normal NPD results. CONCLUSIONS Evaluation of CFTR function in the nasal epithelium of children with inconclusive CF diagnoses can be a useful diagnostic tool and help clinicians to individualize therapeutic strategy.

Measurement of nasal potential difference in young children with an equivocal sweat test following newborn screening for cystic fibrosis

Background A challenging problem arising from cystic fibrosis (CF) newborn screening is the significant number of infants with hypertrypsinaemia (HIRT) with sweat chloride levels in the intermediate range and only one or no identified CF-causing mutations. Objectives To investigate the diagnostic value for CF of assessing CF transmembrane conductance regulator (CFTR) protein function by measuring nasal potential difference in children with HIRT. Methods A specially designed protocol was used to assess nasal potential difference (NPD) in 23 young children with HIRT (3 months–4 years) with inconclusive neonatal screening. Results were analysed with a composite score including CFTR-dependent sodium and chloride secretion. Results were correlated with genotype after extensive genetic screening and with clinical phenotype at follow-up 3 years later. Results NPD was interpretable for 21 children with HIRT: 13 had NPD composite scores in the CF range. All 13 were finally found to carry two CFTR mutations. At follow-up, nine had developed a chronic pulmonary disease consistent with a CF diagnosis. The sweat test could be repeated in nine children, and six had sweat chloride values ≥60 mmol/l. Of the eight children with normal NPD scores, only two had two CFTR mutations, both wide-spectrum mutations. None had developed a CF-like lung disease at follow-up. The sweat test could be reassessed in five of these eight children and all had sweat chloride values <60 mmol/l. CF diagnosis was ruled out in six of these eight children. Conclusion Evaluation of CFTR function in the nasal epithelium of young children with inconclusive results at CF newborn screening is a useful diagnostic tool for CF.

Intravenous peripherally-inserted central catheters for antibiotic therapy in children with cystic fibrosis ☆

BACKGROUND We aimed to evaluate the use of central catheters introduced by a peripheral vein (PICC) in children with CF. METHODS A descriptive study in patients in whom a PICC (Beckton Dickinson) was inserted. RESULTS 24 children aged (median (range) 10.2 years (0.3-17.3) undergoing 44 procedures were included. PICC was successfully inserted in 93.2% (41/44) of cases. Total procedure duration was (median (range)) 32.5 (10-105) minutes. The operators encountered few difficulties, median (range) 2 (1-10) (1 (absence) to 10 (maximal)); median (range) 1 (1 to 5) attempt per child). No major side effects or infections were observed. PICC obstruction in 5 (12%) cases was successfully unblocked in 4 cases (urokinase). The catheter was functional throughout the antibiotic course in 40/41 cases. A final Doppler scan (30 cases) showed total permeability of the central veins in all cases. Satisfaction index of the operators and the patients were high: median (range) 9.5 (1-10) and 8.0 (6-10) (scale: 1 (worse) to 10 (best)), respectively. CONCLUSION PICCs are simple to use, and may be safely inserted in the ward. Such catheters are well tolerated, may increase the well-being of children with CF and prove an effective means by which to deliver IV therapy in this population.

Clinimetric properties of bronchoalveolar lavage inflammatory markers in cystic fibrosis

The Standardisation Committee of the European Cystic Fibrosis Society Clinical Trial Network has undertaken the evaluation of clinical end-points for therapeutic interventions regarding their use in multicentre clinical trials in cystic fibrosis (CF). This review of biomarkers in bronchoalveolar lavage (BAL) is part of the group’s work. The aims of this project were: 1) to review the literature on reliability, validity and responsiveness of BAL in patients with CF; 2) to gain consensus of the group on the feasibility of BAL; and 3) to gain consensus on answers to key questions regarding the promotion of BAL to surrogate end-point status. Assessment of BAL inflammatory markers in the literature indicates that their reliability, validity and responsiveness are adequate for clinical trials. After discussion of the practical characteristics it was concluded that BAL has an attractive validity profile, albeit with limited feasibility. It is particularly applicable to multicentre trials in preschool children with CF and early or mild lung disease. This is the first article to collate the literature in this manner. This provides a rationale to support the use of BAL in early clinical trials in preschool children with CF. Review of the literature provides rationale to support the use of BAL in well-designed early-phase clinical trials in CF http://ow.ly/qGInZ

The CF-CIRC study: a French collaborative study to assess the accuracy of Cystic Fibrosis diagnosis in neonatal screening

BackgroundCystic fibrosis (CF) is caused by mutations in the gene encoding for the CF transmembrane conductance regulator (CFTR) protein, which acts as a chloride channel after activation by cyclic AMP (cAMP). Newborn screening programs for CF usually consist of an immunoreactive trypsinogen (IRT) assay, followed when IRT is elevated by testing for a panel of CF-causing mutations. Some children, however, may have persistent hypertrypsinogenemia, only one or no identified CFTR gene mutation, and sweat chloride concentrations close to normal values. In vivo demonstration of abnormal CFTR protein function would be an important diagnostic aid in this situation. Measurements of transepithelial nasal potential differences (NPD) in adults accurately characterize CFTR-related ion transport. The aim of the present study is to establish reference values for NPD measurements for healthy children and those with CF aged 3 months to 3 years, the age range of most difficult-to-diagnose patients with suspected CF. The ultimate goal of our study is to validate NPD testing as a diagnostic tool for children with borderline results in neonatal screening.Methods/DesignWe adapted the standard NPD protocol for young children, designed a special catheter for them, used a slower perfusion rate, and shortened the protocol to include only measurement of basal PD, transepithelial sodium (Na+) transport in response to the Na+ channel inhibitor amiloride, and CFTR-mediated chloride (Cl-) secretion in response to isoproterenol, a β-agonist in a Cl- free solution.The study will include 20 children with CF and 20 healthy control children. CF children will be included only if they carry 2 CF-causing mutations in the CFTR gene or have sweat chloride concentrations > 60 mEq/L or both. The healthy children will be recruited among the siblings of the CF patients, after verification that they do not carry the familial mutation.DiscussionA preliminary study of 3 adult control subjects and 4 children older than 12 years with CF verified that the new protocol was well tolerated and produced NPD measurements that did not differ significantly from those obtained with the standard protocol. This preliminary study will provide a basis for interpreting NPD measurements in patients with suspected CF after neonatal screening. Earlier definitive diagnosis should alleviate parental distress and allow earlier therapeutic intervention and genetic counseling.

Selection of Pseudomonas aeruginosa reference genes for RT-qPCR analysis from sputum of cystic fibrosis patients.

The prerequisite to monitor gene expression is the selection of reference genes for normalization of RT-qPCR results. Using 13 sputum samples collected from 9 CF patients, we demonstrated that PA2875 and PA3340 are better reference genes than the previously used clpX and oprL genes.

Allergic Bronchopulmonary Aspergillosis in Cystic Fibrosis: MR Imaging of Airway Mucus Contrasts as a Tool for Diagnosis

Purpose To assess the diagnostic accuracy of mucus contrast characterization by using magnetic resonance (MR) imaging to discriminate allergic bronchopulmonary aspergillosis (ABPA) in cystic fibrosis (CF). Materials and Methods The study was approved by the local Ethics Committee, and all patients or their parents gave written informed consent. One hundred ten consecutive patients with CF were screened between January 2014 and July 2015. All patients underwent a non-contrast material-enhanced MR protocol that included routine T1-weighted and T2-weighted sequences. The presence of mucus with both high T1 and low T2 signal intensities and the so-called inverted mucoid impaction signal (IMIS) sign was qualitatively and quantitatively assessed by two physicians who were blinded to all other data. The reference standard for a diagnosis of ABPA was the criteria of the Cystic Fibrosis Foundation Consensus Conference. ABPA status was followed up for 1 year. Reproducibility was assessed by using the κ test, correlation was assessed by using the Spearman coefficient, and diagnostic accuracy was assessed by calculating the sensitivity and specificity of IMIS. Results One hundred eight patients with CF were included (mean age, 20 years ± 11 [standard deviation]; range, 6-53 years): 18 patients with ABPA and 90 patients without ABPA. At the lobar level, inter- and intrareader reproducibility were very good (κ > 0.90). IMIS had 94% sensitivity (95% confidence interval [CI]: 73%, 99%) and 100% specificity (95% CI: 96%, 100%) for the diagnosis of ABPA. A complete resolution of IMIS was observed in patients with ABPA after 3 months of specific treatment that was significantly correlated with decrease in total immunoglobulin E level (ρ = 0.47; P = .04). Conclusion The IMIS sign was both specific and sensitive for the diagnosis of ABPA in CF. Allergic fungal inflammation appears to induce characteristic modifications of mucus contrasts that are assessable by using a noninvasive, contrast material-free, and radiation-free method.

Exploring the expression of Pseudomonas aeruginosa genes directly from sputa of cystic fibrosis patients

Acquisition of Pseudomonas aeruginosa is known as a negative prognostic factor in patients with cystic fibrosis. We started a pilot study to evaluate Ps. aeruginosa gene expression directly from the sputum of infected patients. Total RNA was purified from 15 sputum samples collected from 10 patients, and the expression levels of five genes from Ps. aeruginosa were measured by RT‐qPCR. Expression of algD, algR, antB, lasB and pqsA genes was determined in sputa that contained Ps. aeruginosa cells. The resultant data provided an overview of the expression of these genes in CF patients. Except for the correlation between algD expression and the mucoid phenotype, the gene expression profile could not be associated with the clinical status of patients. However, beyond the heterogeneity of the Ps. aeruginosa phenotype in sputum, we observed a correlation between the expression of antB and pqsA and a low level of lasB transcripts.

Nouvelles thérapeutiques ciblant le canal chlorure dans la mucoviscidose

Since the discovery of chloride secretion by the Cystic Fibrosis Transport regulator CFTR in 1983, and CFTR gene in 1989, knowledge about CFTR synthesis, maturation, intracellular transfer and function has dramatically expanded. These discoveries have led to the distribution of CF mutations into 6 classes with different pathophysiological mechanisms. In this article we will explore the state of art on CFTR synthesis and its chloride secretion function. We will then explore the consequences of the 6 classes of mutations on CFTR protein function and we will describe the new therapeutic developments aiming at correcting these defects.

Evaluation and management of fungal risk in Cystic Fibrosis: first results of a national French study

175 Evaluation and management of fungal risk in Cystic Fibrosis: first results of a national French study S. Leroy1, V. Conseil1, B. Coltey2, Y. Lemeille2, S. Dominique3, G. Gargala3, P. Domblides4, I. Accoceberry4, G. Loeuille5, I. Durand-Joly5, A. Fanton6, O. Vagnier6, F. Dalle6, A. Boldron5, C. Llerena2, C. Pinel2, J.L. Ginies7, M. Pihet7, C. Person7, J. Bouchara7, N. Wizla1, C. Marguet3, L. Favenne3, S. Bui4, L. Delhaes1. 1CHRU, Lille, France; 2CHU, Grenoble, France; 3CHU, Rouen, France; 4CHU, Bordeaux, France; 5CHG, Dunkerque, France; 6CHU, Dijon, France; 7CHU, Angers, France