Impact of Intermediate Cystic Fibrosis Classification on Parents' Perceptions of Child Vulnerability and Protectiveness

This cross-sectional, mixed-method study examined factors associated with parent perceptions of child vulnerability and protectiveness in three groups: cystic fibrosis (CF-group, n = 40), intermediate CF classification (I-group, n = 20), and healthy (H-group, n = 50). A composite indicator structural equation (CISE) using Bayesian estimation tested two mediational models: psychological and biological. Significant results ( p < .05) from the psychological model showed I-group and CF-group parents perceived their children to be more vulnerable than H-group parents but reported lower levels of protectiveness than H-group parents. Perceptions of vulnerability mediated protectiveness for CF- and I-groups. The biological model showed I-group children had significantly less severe genotype and phenotype, and lower sweat chloride levels than the CF-group; I-group parents had lower expectations about children developing CF symptoms. Both models showed negative associations between children's ages and protectiveness. Psychological factors explained perceptions of child vulnerability and protectiveness; biological factors explained protectiveness. Parent perceptions of vulnerability and protectiveness are separate, independent constructs.

Similar performance of Brasfield and Wisconsin scoring systems in young children with cystic fibrosis

BACKGROUND

To assess the severity of lung disease in cystic fibrosis (CF), scoring systems based on chest radiographs (CXRs), CT and MRI have been used extensively, although primarily in research settings rather than for clinical purposes. It has recently been shown that those based on CXRs (primarily the Brasfield and Wisconsin systems) are as sensitive and valid as those based on CT. The reproducibility and correlation of both systems to pulmonary function tests (PFTs) were recently investigated and were found to be statistically identical. However, the relative performance of these systems has not been specifically assessed in children younger than 5 years old with mild lung disease, a critical age range in which PFTs is rarely performed.

OBJECTIVE

To investigate and compare the performance of the Brasfield and Wisconsin systems in children 0-5 years old with predominantly mild lung disease.

MATERIALS AND METHODS

Fifty-five patients 0-5 years old with 105 CXRs were included in the study. Given that the goal was to compare system performance in mild disease, only the first two CXRs from each patient were included (all but five patients had two images). When only one image was available in the target age range, it only was included. Agreement between the Brasfield and Wisconsin systems was assessed using a 2X2 contingency table assuming binary classification of CF lung disease using CXR scoring systems (mild vs. non-mild). In the absence of PFTs or another external gold standard for comparison, the Wisconsin system was used as an arbitrary gold standard against which the Brasfield was compared. Correlation between the two systems was assessed via a concordance correlation coefficient (CCC) for repeated measures.

RESULTS

Scores were rated as mild or non-mild based on published numerical cutoffs for each system. The systems agreed on 89/105 (85%) and disagreed on 16/105 (15%) of the CXRs. Agreement between the two systems was statistically significant (P < 0.001). Relative sensitivity and specificity of the Brasfield system (which since using the Wisconsin as the gold standard reflects relative agreement rather than absolute performance of the Brasfield) was also fairly high (85% and 84%, respectively). Relatively high correlation between the two systems was also estimated (r = 0.72).

CONCLUSION

The current study, powered to find at least a mild correlation between the two systems, confirms the Brasfield and Wisconsin systems are in agreement when assessing CF lung disease even in patients younger than 5 years of age with predominantly mild disease.

Clinical arrays of laboratory measures, or "clinarrays", built from an electronic health record enable disease subtyping by severity

The severity of diseases has often been assigned by direct observation of a patient and by pathological examination after symptoms have appeared. As we move into the genomic era, the ability to predict disease severity prior to manifestation has improved dramatically due to genomic sequencing and analysis of gene expression microarrays. However, as the severity of diseases can be exacerbated by non genetic factors, the ability to predict disease severity by examining gene expression alone may be inadequate. We propose the creation of a "clinarray" to examine phenotypic expression in the form of clinical laboratory measurements. We demonstrate that the clinarray can be used to distinguish between the severities of patients with cystic fibrosis and those with Crohn's disease by applying unsupervised clustering methods that have been previously applied to microarrays.

Mucoviscidose : du bon usage des explorations fonctionnelles respiratoires

INTRODUCTION

Neonatal screening for cystic fibrosis (CF) leads to early dedicated specialist care for all patients.

BACKGROUND

Pulmonary function tests (PFT) are mandatory for routine monitoring of CF patients. The aim of this article is to review the current guidelines for PFTs in CF, particularly the type of test, the age and the clinical status of the patient.

VIEWPOINT

The regular use of spirometry is generally accepted. Many other tests are used but their clinical value in the routine follow-up of CF patients remains to be established.

CONCLUSION

Further efforts should be made to evaluate the value of PFTs in CF, particularly in very young children.

Cystic Fibrosis and Formes Frustes of CFTR-Related Disease

Cystic fibrosis (CF) is the commonest genetic cause of bronchiectasis in the Caucasian population. Since identification of the putative gene in 1989, the molecular basis of the condition has become clearer with characterisation of the unique pathophysiology. The small airways are the primary site of lung disease, with an intense but localised inflammatory picture, dominated by neutrophils. The clinical heterogeneity is explained to some degree by the distinct molecular consequences of the many mutations that have been recognised to affect the CF transmembrane conductance regulator (CFTR) gene; however other genes appear to modify the phenotype as well as environmental exposure. It has become increasingly apparent that certain conditions may result from CFTR dysfunction without fulfilling diagnostic criteria for CF. In some cases this may result in single organ disease for which the term CF (or CFTR)-related disease has been advocated. Congenital bilateral absence of the vas deferens is the most clearly characterised of these. In other cases where a mild CF phenotype is apparent, atypical CF is probably a better term. It remains unclear whether carrier status predisposes to certain conditions such as chronic rhinosinusitis or pancreatitis.

Ontology-based knowledge base model construction-OntoKBCF

Semantic web technologies are used in the construction of a bio-health knowledge base model, which, when coupled with an Electronic Health Record (EHR), is to be used by clinicians. Specifically, this ontology provides the basis for a domain knowledge resource that attempts to bridge biological and clinical information. The prototype is focused on a Cystic Fibrosis exemplar, and the content of the model includes: Cochrane reviews; a time-oriented description; gene therapy; and the most common cystic fibrosis gene mutations. The facts within the model range from nucleo-base mutation and amino acid change to clinical phenotype. The knowledge is represented by layers from the micro level to the macro level. Here, emphasis is placed upon the details between levels (i.e., the vertical axis) and these are made available to bridge the knowledge from different levels. The description of gender, age, mutation and clinical manifestations are clues for matching points within an EHR system. OWL is the ontology representation language used and the output from Protégé-OWL is a XML-based file format, which facilitates further application and communication.

Classification of nutritional status in cystic fibrosis

PURPOSE OF REVIEW

Nutritional status impacts on the progression of cystic fibrosis. Current guidelines recommend the use of anthropometric indicators to classify nutritional status and identify malnutrition. However, the current nutrition-classification systems are problematic. I summarize these problems and review recent progress in the development of evidence-based anthropometric criteria for classifying nutritional status in cystic fibrosis patients.

RECENT FINDINGS

Percentage of ideal body weight as a malnutrition index is flawed. In children with cystic fibrosis, this index underestimates the severity of underweight in short patients and overestimates it in tall patients. In adults with cystic fibrosis, percentage of ideal body weight based on the Metropolitan Life Insurance reference weights for medium/large frames overestimates the severity of underweight. Body-mass-index percentile for children and body mass index for adults as underweight indices have been proven to be valid. Strong associations between body mass index and lung function are also observed, but cutoff values to maintain a desirable level of lung function can vary.

SUMMARY

Body mass index should replace the use of percentage of ideal body weight for classifying underweight in cystic fibrosis patients. More research is needed to identify appropriate indicators to classify short stature in children with cystic fibrosis.

Clinical scoring systems in cystic fibrosis

The first cystic fibrosis (CF) scoring system was published in 1958. Since then, many other scoring systems were developed. Clinical parameters, details about statistical evaluations, and recent strategic uses of scores were identified. Several similar scores aiming to assess chronic illness severity (Shwachman-Kulczycki score and a modification, Cooperman, Berneze-score and the NIH score) have not been evaluated and are out of date, given the changing natural history of CF. Of the current scoring systems, the modified Shwachman score by Doershuk is perhaps most reliable for describing follow-up studies. Scores designed for acute changes and short-term evaluation were also developed. The modified Huang score may be useful in the prognostic evaluation of patients with end-stage disease. It could also be used for discrimination of adult patients with differing disease severity and for longitudinal evaluation. Scores assessing pulmonary exacerbations could help provide consensus among clinicians regarding the need for intervention. Most of these scores require further evaluation. Although scores could provide an objective measure of disease severity, progression, need for and response to interventions, including value in selecting patients for lung transplantation and as an outcome measure for research studies, no scoring system can fulfill all these objectives. Nevertheless, there is a need for the development of a modern day longitudinal score that is sensitive, valid and reproducible, to reflect the milder disease status of patients.

Reproducibility of a Scoring System for Computed Tomography Scanning in Cystic Fibrosis

INTRODUCTION

Computerized tomography (CT) scanning shows promise as an outcome surrogate for cystic fibrosis (CF) lung disease progression. The scoring system used to convert the CT image to numeric data is an essential determinant of the performance of CT scanning.

METHODS

Three radiologists independently scored 16 high-resolution CT scans performed on children in the Wisconsin CF Neonatal Screening Project. The test scans were selected to provide a broad range of disease severity. The scoring system provided subscores for the presence and severity of 5 findings of CF lung disease. The sum of the subscores provided a total score. The CT scans were then read again by each of the radiologists at least 11 months later. Using Mixed Effects Linear Model Analysis, the sources of error (scan-to-scan variation, interrater variance, and intrarater variance) were calculated.

RESULTS

For the total score, the scan-to-scan variation was 14.48, interrater variance was 0.28, and intrarater variance was 0.45, with an overall reproducibility of 95%. The square root of scan-to-scan variance, a measure of sensitivity, was 3.81. Evaluation of the subscores showed higher reproducibility for bronchiectasis and hyperinflation (95% and 88%, respectively). The bronchiectasis score was more sensitive than the air-trapping score (1.46 vs. 0.89).

DISCUSSION

This system was developed to provide a reproducible method that could be used to evaluate the lobar location, severity, and extent of a broad spectrum of CT features of CF lung disease, especially in children. This study demonstrates that the overall score is both sensitive to variation in the severity of lung disease and reproducible.

Redefining disease? The nosologic implications of molecular genetic knowledge

How will developments in genetic knowledge affect the classification of disease? Leaders in genetics have suggested that knowledge of the role of genes in disease can determine nosology. Diseases might be defined by genotype, thus avoiding the limitations of more empirical approaches to categorization. Other commentators caution against disease definitions that are detached from the look and feel of disease, and argue for an interplay between genotypic and phenotypic information. Still others attribute nosologic change to social processes. We draw on an analysis of the scientific literature, our conversations with genetics clinicians, and reviews of patient organization Web sites to offer a revised interpretation of the nosologic implications of molecular genetic knowledge. We review the recent histories of three diseases--hemophilia, Rett syndrome, and cystic fibrosis--to argue that nosologic change cannot be explained by either biologic theories of disease etiology or sociologic theories of social tendencies. Although new genetic information challenges disease classifications and is highly influential in their redesign, genetic information can be used in diverse ways to reconstruct disease categories and is not the only influence in these revisions. Ironically, genetic information is likely to play a central role in producing a new, but still empirical, classification scheme.

[Exhaled nitric oxide: a new biomarker for respiratory pathologies]

There has been a growing interest for exhaled biomarkers. We review studies examining NO as a potential marker of airway inflammation, enabling noninvasive repeated monitoring of airway inflammation. The measurement technique has been standardized. We have determined the local normal levels for the Liège region. The exhaled NO level is elevated in asthma, and can predict asthma exacerbation. Exhaled NO has a value for the diagnosis of cystic fibrosis and primary ciliary dyskinesia.

The efficacy and safety of meropenem and tobramycin vs ceftazidime and tobramycin in the treatment of acute pulmonary exacerbations in patients with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is characterized by chronic pulmonary infection with acute pulmonary exacerbations (APEs) requiring IV antibiotic treatment. We report on a blinded comparative trial of IV meropenem (40 mg/kg to 2 g q8h) or ceftazidime (5 mg/kg to 2 g q8h), each of which was administered with IV tobramycin (at a serum peak of > or = 8 microg/mL and a trough of < 2 microg/mL), as treatment for CF patients with APEs.

METHODS

Patients who were > or = 5 years of age who were infected with ceftazidime-susceptible Pseudomonas aeruginosa were stratified by lung function and randomized to treatment with meropenem/tobramycin or ceftazidime/tobramycin. Patients infected with Burkholderia cepacia complex or ceftazidime-resistant P aeruginosa were assigned to receive open-label meropenem/tobramycin. Clinical response was assessed by spirometry to determine the change in percent predicted FEV1 and by a clinical acute change score (ACS).

RESULTS

One hundred two patients were randomized to meropenem/tobramycin (n = 50) or ceftazidime/tobramycin (n = 52). Nineteen patients received open-label meropenem/tobramycin. FEV1 was improved at the end of treatment (EOT) with meropenem/tobramycin (mean [+/- SD] increase, 38.8 +/- 52.3%) and with ceftazidime/tobramycin (mean increase, 29.4 +/- 35.1%; p < 0.0001 vs baseline values). The proportion of patients with > or = 15% relative increase from baseline FEV1 (satisfactory response) at day 7 was 62% for the meropenem/tobramycin group and 44% for the ceftazidime/tobramycin group (p = 0.04). The median time to FEV1 response was 4 days for meropenem/tobramycin therapy vs 6 days for ceftazidime/tobramycin therapy. Similarly, FEV1 improved in the open-label group (mean increase, 12.5 +/- 25.7%; p = 0.05). ACS improved in all three groups at EOT (p < 0.0001 vs baseline values).

CONCLUSIONS

Therapy with both meropenem/tobramycin and ceftazidime/tobramycin improved pulmonary and clinical status and reduced sputum bacterial burden in CF patients with APEs. A larger proportion of patients receiving meropenem/tobramycin therapy demonstrated a satisfactory FEV1 response at day 7. Resistant P aeruginosa emerged infrequently during treatment with both regimens.

Genetic modifiers of lung disease in cystic fibrosis

BACKGROUND

Polymorphisms in genes other than the cystic fibrosis transmembrane conductance regulator (CFTR) gene may modify the severity of pulmonary disease in patients with cystic fibrosis.

METHODS

We performed two studies with different patient samples. We first tested 808 patients who were homozygous for the DeltaF508 mutation and were classified as having either severe or mild lung disease, as defined by the lowest or highest quartile of forced expiratory volume in one second (FEV1), respectively, for age. We genotyped 16 polymorphisms in 10 genes reported by others as modifiers of disease severity in cystic fibrosis and tested for an association in patients with severe disease (263 patients) or mild disease (545). In the replication (second) study, we tested 498 patients, with various CFTR genotypes and a range of FEV1 values, for an association of the TGFbeta1 codon 10 CC genotype with low FEV1.

RESULTS

In the initial study, significant allelic and genotypic associations with phenotype were seen only for TGFbeta1 (the gene encoding transforming growth factor beta1), particularly the -509 and codon 10 polymorphisms (with P values obtained with the use of Fisher's exact test and logistic regression ranging from 0.006 to 0.0002). The odds ratio was about 2.2 for the highest-risk TGFbeta1 genotype (codon 10 CC) in association with the phenotype for severe lung disease. The replication study confirmed the association of the TGFbeta1 codon 10 CC genotype with more severe lung disease in comparisons with the use of dichotomized FEV1 for severity status (P=0.0002) and FEV1 values directly (P=0.02).

CONCLUSIONS

Genetic variation in the 5' end of TGFbeta1 or a nearby upstream region modifies disease severity in cystic fibrosis.

Symptoms, lactate and exercise limitation at peak cycle ergometry in adults with cystic fibrosis

The purpose of this study was to investigate symptoms, lactate accumulation and limiting factors at peak exercise in cystic fibrosis (CF) patients. In total, 104 CF adults attending an adult CF centre and 27 controls performed progressive cycle ergometry to a symptom-limited maximum. Measurements taken at peak exercise included: heart rate, ventilation, oxygen uptake, carbon dioxide output, oxygen saturation and blood lactate. Symptom scores of perceived breathlessness and muscle effort were recorded using Borg scales. The CF subjects had a lower mean body mass index, forced expiratory volume in one second (FEV(1)) and peak oxygen uptake than controls. Peak lactate concentrations were very similar to controls (mean+/-sd 6.8+/-2.0 mmol x L(-1) versus 7.4+/-1.0 mmol x L(-1)). Symptom scores were no different to controls for either breathlessness (4.5+/-2.0 versus 4.3+/-1.0) or perceived muscle effort (6.1+/-2.0 versus 6.5+/-1.0), with higher scores for muscle effort than breathlessness in both groups. In addition, peak ventilation was lower than the predicted maximum, and high peak heart rates were recorded supporting nonpulmonary factors as important in limiting peak exercise. Peak oxygen uptake was correlated with FEV(1). Comparison of CF subjects with mild or moderate pulmonary disease and controls revealed similar exercise responses. In contrast, those CF patients with severe lung disease (FEV(1) <40% predicted) had significantly higher breathlessness, lower muscle effort scores, lower peak lactate, lower peak heart rate and a mean ventilation exceeding predicted, thus confirming that ventilation was the major factor limiting exercise. In conclusion, cystic fibrosis subjects have a reduced peak exercise capacity, but their exercise response is similar to controls in generating high blood-lactate concentrations and symptoms of muscle effort in excess of dyspnoea. Nonpulmonary factors influence peak performance more in those without severe disease.

Phenotypic and genetic characterization of patients with features of "nonclassic" forms of cystic fibrosis

OBJECTIVE

To determine which features of incomplete or "nonclassic" forms of cystic fibrosis (CF) are associated with deleterious CF transmembrane conductance regulator gene ( CFTR ) mutations, and to explore other etiologies for features not associated with deleterious CFTR mutations.

STUDY DESIGN

Clinical features were compared between 57 patients with deleterious mutations in each CFTR and 63 with no deleterious mutations. The Shwachman Bodian Diamond syndrome gene ( SBDS ) was sequenced to search for mutations in patients with no deleterious CFTR mutations and steatorrhea to determine if any had unrecognized Shwachman-Diamond syndrome (SDS).

RESULTS

The presence of a common CF-causing mutation, absence of the vas deferens, and Pseudomona aeruginosa in the sputum correlated with the presence of two deleterious CFTR mutations, whereas sweat chloride concentration, diagnostic criteria for CF, and steatorrhea did not. However, sweat chloride concentration correlated with CFTR mutation status in patients infected with P aeruginosa. One patient had disease-causing mutations in each SBDS .

CONCLUSIONS

Presence of a common CF-causing mutation, absence of the vas deferens and/or P aeruginosa infection in a patient with features of nonclassic CF are predictive of deleterious mutations in each CFTR , whereas steatorrhea in the same context is likely to have etiologies other than CF transmembrane conductance regulator (CFTR) dysfunction.

Randomized, double-blind, placebo-controlled, dose-escalating study of aerosolized interferon gamma-1b in patients with mild to moderate cystic fibrosis lung disease

Interferon gamma-1b (IFN-gamma1b) is a pleiotropic cytokine with immunomodulatory activities that could decrease bacterial burden, inflammation, and obstruction in patients with CF. Patients with CF (> or =12 years old, FEV1 > or =40% predicted) were randomly assigned to sequential dose cohorts inhaling 500 microg IFN-gamma1b, 1,000 microg IFN-gamma1b, or placebo by Respirgard II nebulizer thrice weekly for 12 weeks. Sputum bacterial density and spirometry were measured. Safety, antibiotic use, hospitalization, and sputum neutrophils, elastase, DNA, IL-8, and myeloperoxidase were also evaluated. Sixty-six patients (mean age, 24 years, with mean baseline FEV1 of 74 +/- 20 (SD) percent predicted) were studied. One patient had bronchospasm after the first dose of IFN-gamma1b; the overall withdrawal rate was 15% (5 in the placebo group, 2 in the 500-microg IFN-gamma1b group, and 3 in the 1,000 microg IFN-gamma1b group). The 500-microg IFN-gamma1b dose was well-tolerated, but the 1,000-mug dose cohort, who had a higher baseline bacterial density than placebo patients (mean difference, 1.2 log(10) CFU/g sputum, 95% confidence interval (CI), 0.1,2.8, P=0.04), had 24% more hospitalizations for exacerbation than placebo patients (95% CI, 2,45%, P=0.05). There was a 0.12-l difference between the 500-microg IFN-gamma1b and placebo groups with respect to the 12-week change in FEV1 (active group minus placebo group, 95% CI, -0.03,0.26, P=0.11), as compared to a 0.01-l difference between the 1,000-microg IFN-gamma1b and placebo groups (95% CI, -0.16,0.17, P=0.96). No effects of IFN-gamma1b were seen in sputum bacterial density or inflammatory biomarkers at 12 weeks. Aerosolized IFN-gamma1b did not improve pulmonary function, reduce sputum bacterial density, or affect inflammatory sputum markers in patients with mild-moderate lung disease.

Cystic fibrosis and lung transplantation — Determination of the survival benefit

INTRODUCTION

Cystic fibrosis is a well acknowledged indication for lung transplantation; however, the optimal timing for transplantation remains debatable. Liou et al. described a score for calculating 5-year probability of survival for patients with cystic fibrosis and concluded that only patients with a probability of survival < 30% gained a survival benefit from transplantation; those between 30% and 50% had equivocal survival effects from transplantation and those > 50% suffered negative effects. The aim of the present study was to determine the validity and applicability of this model.

METHODS

Data from patients with cystic fibrosis transplanted between January 1995 and July 2001 were retrospectively reviewed. Survival score according to Liou was calculated from data collected before transplantation. Patients were classified according to 5-year probability of survival (group 1: < 30%, group 2: 30%-50%, groups 3-5: > 50%). Actuarial survival rates were calculated separately for each group and compared with the predicted probability of survival.

RESULTS

During the observation period 27 patients were transplanted for cystic fibrosis. Three patients had to be excluded from further analysis because of incomplete pretransplant data. Fifteen patients were classified as group 1 and nine patients as group 2. No patients were eligible for groups 3 to 5. There were nine female patients and six males in group 1, mean age 22.1 +/- 4.9 years. Mean survival time was 918 +/- 787 days; 1-, 3- and 5-year survival rates were 66.6%. Three male patients and six females were classified as group 2, mean age 26.2 +/- 12.2 years. Mean survival time for this group was 701 +/- 617 days, and 1-, 3- and 5-year survival rates were 66.6%.

CONCLUSION

We found that only patients with a 5-year probability of survival < 50% had been transplanted. For patients in groups 1 and 2 we report identical 5-year survival rates of 66.6%. According to our experience, cystic fibrosis patients with a 5-year probability of survival < 30% and also those between 30% and 50% gain a clear survival benefit from bilateral lung transplantation.

Hidden Depletion of Fat-Free Mass and Bone Mineral Density in Adults With Cystic Fibrosis

BACKGROUND

Weight loss is associated with reduced survival in patients with cystic fibrosis (CF).

OBJECTIVE

We hypothesized that some adult patients with a normal body mass index (BMI) have evidence of hidden fat-free mass (FFM) and bone mineral density (BMD) depletion that is linked to more severe disease.

DESIGN

Fat mass (FM), FFM, and BMD were determined by dual-energy x-ray absorptiometry (DXA) and by bioelectric impedance in 56 adults in clinically stable condition and 20 age-matched healthy subjects. FM index and FFM index (FFMI) [kilograms per meter squared] of the right arm, leg, and trunk (ratio to height squared) were calculated. Lung function, including the maximum inspiratory pressure (MIP) and sustained MIP (SMIP), physical activity, serum C-reactive protein (CRP) and the number of exacerbations in the previous year were recorded.

RESULTS

Patients had a lower total FFM than healthy subjects (p < 0.01), while FM was similar. Of the 56 patients, 30 patients had a normal BMI, of which 12 patients had a low FFM (hidden loss) by DXA. The right arm, leg, and trunk FFMI and BMD at hip sites were less in these patients than in those with a normal BMI and normal FFM (all p < 0.01). This group had a lower FEV(1), SMIP, more frequent exacerbations, and greater circulating CRP (all p < 0.05).

CONCLUSIONS

In adults with CF, apparent or hidden loss of FFM, rather than weight loss, was related to overall disease severity. Hidden depletion of FFM was associated with increased loss of BMD and systemic inflammatory activity.

Pseudomonas aeruginosa and cystic fibrosis: correlation between exoenzyme production and patient's clinical state

In this study, we investigated the correlation between the production by Pseudomonas aeruginosa isolates of four exoenzymes (protease, elastase, neuraminidase, and phospholipase C (PLC)) and the clinical state of cystic fibrosis (CF) patients. We studied 212 P. aeruginosa isolates from 22 CF patients chronically infected with this bacterium. Patients were classified into three clinical groups according to a modified Shwachman-Kulczycki-Khaw (SKK) scoring system. The production of enzymes by isolates from patients in the three populations was analyzed and compared using four statistical tests: chi-square, Mann-Whitney U, principal component analysis, and discriminant analysis. Isolates from patients with excellent or good clinical status (group I, SKK score >/=71) had higher elastase and neuraminidase activities than isolates from the other patients. In contrast, PLC activity, a common characteristic of CF isolates, was higher in isolates from patients with poor or weak clinical status (group III, SKK score </=55). PLC also appeared to be the best parameter for differentiating between groups I and III. Enzyme production was highly variable in group II isolates (SKK score, 56-70). Our results suggest that P. aeruginosa isolates from patients with good clinical status produce large amounts of neuraminidase, and that PLC production may be involved in the decrease in pulmonary function.

Metabolic alkalosis contributes to acute hypercapnic respiratory failure in adult cystic fibrosis

BACKGROUND

and study objectives: Patients with end-stage cystic fibrosis (CF) develop respiratory failure and hypercapnia. In contrast to COPD patients, altered electrolyte transport and malnutrition in CF patients may predispose them to metabolic alkalosis and, therefore, may contribute to hypercapnia. The aim of this study was to determine the prevalence of metabolic alkalosis in adults with hypercapnic respiratory failure in the setting of acute exacerbations of CF compared with COPD.

DESIGN

Levels of arterial blood gases, plasma electrolytes, and serum albumin from 14 consecutive hypercapnic CF patients who had been admitted to the hospital with a respiratory exacerbation were compared with 49 consecutive hypercapnic patients with exacerbations of COPD. Hypercapnia was defined as a PaCO(2) of > or = 45 mm Hg.

RESULTS

Despite similar PaCO(2) values, patients in the CF group were significantly more alkalotic than were those in the COPD group (mean [+/- SD] pH, 7.43 +/- 0.03 vs 7.37 +/- 0.05, respectively; p < 0.01). A mixed respiratory acidosis and metabolic alkalosis was evident in 71% of CF patients and 22% of COPD patients (p < 0.01). The mean concentrations of plasma chloride (95.1 +/- 4.9 vs 99.8 +/- 5.2 mmol/L, respectively; p < 0.01) and sodium (136.5 +/- 2.8 vs 140.4 +/- 4.5 mmol/L, respectively; p < 0.01) were significantly lower in the CF group, and the levels of serum albumin were significantly reduced (27.4 +/- 5.8 vs 33.7 +/- 4.8 mmol/L, respectively; p < 0.01).

CONCLUSION

Metabolic alkalosis contributes to hypercapnic respiratory failure in adults with acute exacerbations of CF. This acid-base disturbance occurs in conjunction with reduced total body salt levels and hypoalbuminemia.

Impact of inhaled corticosteroids on the risk of early Pseudomonas aeruginosa acquisition in cystic fibrosis

AIM

To investigate the role of inhaled corticosteroids (IC) on the risk of Pseudomonas aeruginosa acquisition before the age of 10 y in cystic fibrosis (CF) patients.

METHODS

For each subject the cumulative dose kg(-1) of IC received for each year of age was calculated until the end of follow-up. The age at CF diagnosis, the nutritional status (NS) and the number of respiratory exacerbations (RE) were used as surrogate measures for the severity of CF.

RESULTS

A total of 83 patients (40 M, 43 F) entered the study. Their median length of follow-up was 4.4 y, for a total of 386 person-years at risk. Twenty-three patients acquired P. aeruginosa at a median age of 4.6 y (range 0.4-9.9 y). The estimated survival without P. aeruginosa acquisition was 65% at 10 y of age. The effect of different risk factors (IC, NS, RE and age at CF diagnosis) on the probability of P. aeruginosa acquisition was evaluated: none of them was significantly associated with the risk of P. aeruginosa acquisition. In particular, patients receiving very high cumulative doses of IC (4th quartile) had a non-significantly increased risk of P. aeruginosa acquisition compared with those receiving low doses of IC (1st quartile) (hazard ratio = 1.73, 95% confidence limits 0.40-7.38).

CONCLUSION

This retrospective study was not able to demonstrate any role of IC in increasing the risk of P. aeruginosa acquisition. This complication seems to occur at a constant pace that is independent of CF severity and age. Prospective multi-institutional randomized studies are needed to investigate the effects of high-dose IC in CF patients.

Molekulargenetische Grundlagen der zystischen Fibrose als Beispiel genetischer Erkrankungen in der Pneumologie

The generalized exocrinopathy cystic fibrosis (CF) is caused by molecular lesions in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The basic defect of this autosomal-recessive disorder manifests in decreased permeability for chloride ions across the apical epithelial membrane. Of the more than 1,000 known CFTR mutations the most frequent mutation F508del occurs on about 70% of North- and Mideuropean CF chromosomes. CFTR mutations are also causatively involved in male infertility, pancreatitis and several airway diseases like disseminated bronchiectasis. The differential diagnosis between CF, other CFTR-opathies and diseases of unrelated etiology can be achieved by the assessment of clinical symptoms, CFTR mutation analysis and electrophysiological bioassays (sweat test, nasal potential difference, intestinal current measurements).

Decreased bone mineral density in normal-growing patients with cystic fibrosis

AIM

To study bone mineral density (BMD) in normal-growing patients with cystic fibrosis (CF) and its relation to clinical and biochemical markers of nutrition and lung function.

METHODS

Seventy consecutive patients aged 6-49 y with CF were investigated using dual X-ray absorptiometry and the findings related to anthropometric data. Energy intake was calculated and basal metabolic rate and serum values for calcium, phosphorus, calcitonin and 25(OH) calcidiol measured. Working capacity, lung function and pseudomonas colonization were determined as parameters of physical fitness and severity of pulmonary disease.

RESULTS

The average z-score of BMD was decreased in the lumbar spine in both children and adults, being -0.7 +/- 1.0 and -0.5 +/- 1.0, respectively, as was the femoral neck BMD z-score, being -0.3 +/- 0.9 and -1.1 +/- 1.0 for children and adults, respectively. BMD was correlated to lung function and working capacity, but not to anthropometric data at multiple regression analysis compensating for age and calcitonin. No correlation was found with energy intake, basal metabolic rate or biochemical markers, with the exception of calcitonin.

CONCLUSION

BMD z-scores were significantly lower than those in the normal population despite normal anthropometry. Osteoporosis was rare. The strongest correlation was found with lung function. Our data indicate that BMD at all ages might be a sensitive indicator of the general status of patients with CF.

[Protein repair therapy in cystic fibrosis]

In the past few years since the cloning of the gene defective in cystic fibrosis, much has been learned on the function of the protein cystic fibrosis transmembrane conductance regulator (CFTR) and on the mechanisms regulating its expression. Based on the current understanding of the processes involved in lung disease progression, a number of approaches have been developed using not only gene therapy, but also pharmacological agents. Several of these agents have been reported to restore function to CFTR with specific mutations.

Expansion and uncertainty: cystic fibrosis, classification and genetics

This paper presents an empirical examination of geneticization, the process where genetic explanations gain ascendancy in medical and social discourse. By focusing on Cystic Fibrosis (CF), this study shows how genetic explanations play a role in the reclassification of Cystic Fibrosis. One result of this geneticization is a nosological expansion, where the boundaries of the disease expand to include a certain form of male infertility. In addition this paper highlights the uncertainty in the CF classification system that results from the use of genetic explanations.

Pharmacokinetics and bioavailability of aerosolized tobramycin in cystic fibrosis

STUDY OBJECTIVES

To describe the pharmacokinetics and bioavailability of inhaled tobramycin (TOBI; Chiron Corporation; Seattle, WA), 300-mg dose, delivered by a nebulizer (PARI LC Plus; Pari Respiratory; Richmond, VA) and a compressor (Pulmo-Aide, model 5650D; DeVilbiss Health Care; Somerset, PA) in cystic fibrosis (CF) patients during the pivotal phase III trials.

DESIGN

Data from two identical, 24-week, randomized, double-blind, placebo-controlled, parallel-group studies.

SETTING

US sites randomized 258 patients with CF to receive tobramycin, 300 mg twice daily, in three 28-day on/28-day off treatment cycles.

MEASUREMENT

Tobramycin sputum concentrations were assessed 10 min after the first and last doses were administered in the 20-week study. Serum tobramycin concentrations were assessed before and 1 h after the first and last doses had been administered. The population estimate of the apparent clearance was used to estimate the bioavailability fraction.

RESULTS

The mean peak sputum concentration was 1,237 microg/g. About 95% of patients achieved sputum concentrations > 25 times the minimum inhibitory concentration of the Pseudomonas aeruginosa isolates. One hour after the dose, the mean serum concentration was 0.95 microg/mL. Tobramycin did not accumulate in the sputum or serum over the course of the study. Pharmacokinetic data were best represented by a two-compartment model with biexponential decay and slope estimates comparable to those following parenteral administration. The estimated systemic bioavailability after aerosol administration was 11.7% of the nominal dose.

CONCLUSIONS

The administration of tobramycin, 300 mg bid, in a 28-day off/28-day on regimen produced low serum tobramycin concentrations, reducing the potential for systemic toxicity. High sputum concentrations ensure efficacious antibiotic levels at the site of the infection. Inhaled tobramycin significantly improved the therapeutic ratio over that of parenteral aminoglycosides.

Cystic fibrosis: keeping it in the family

Nearly all men with cystic fibrosis (CF) are infertile, although assisted conception has allowed an increasing number of women with CF to become pregnant. We report on the case of a couple investigated for infertility who conceived a child with CF. The father had previously undergone a laparotomy for meconium peritonitis as a neonate, and the mother had recently been given a diagnosis of asthma. Both parents fulfilled the United States Cystic Fibrosis Foundation diagnostic criteria for cystic fibrosis. We discuss the mild CF phenotype and the impact of the diagnosis on this family.

Disease severity associated with cystic fibrosis mutations deltaF508 and S549R(T-->G)

We compared the clinical severity associated with the two cystic fibrosis (CF) mutations S549R(T-->G) and deltaF508. Clinical and biochemical variables of CF were compared in two age- and sex-matched groups of CF children in the United Arab Emirates (UAE). The clinical severity of mutations S549R(T-->G) and deltaF508 showed comparable patterns, with very low Shwachman scores and high sweat chloride levels. We conclude that patients homozygous for the CF mutations deltaF508 and S549R(T-->G) have a severe clinical presentation and illness and are indistinguishable on clinical grounds.

Defining an exacerbation of pulmonary disease in cystic fibrosis

Despite the importance of pulmonary exacerbations in CF in both clinical and research settings, both published evidence and consensus are lacking concerning the criteria used to define an exacerbation. The use of hospitalization as a surrogate measure presupposes uniformity among clinicians in diagnosis and treatment of exacerbations. Our aims were to evaluate consensus among clinicians about the variables considered helpful in diagnosing an exacerbation requiring treatment. A comprehensive list of symptoms, signs, and investigations used to define exacerbations was compiled from published trials. A written self-administered questionnaire included the list in age-appropriate groups to survey opinion about the helpfulness of each item, and the estimated proportion of patients admitted within a month of diagnosis of an exacerbation. This was sent to all clinicians managing CF patients in Australia. There were replies from 59/91 clinicians (65%), 41/60 (68%) from those managing children and 18/31 (58%) from those managing adults. Responses of those managing children and adults differed for 7/32 variables (Mann-Whitney test, P < 0.05). Clinic grouping did not show greater consensus among responses of pediatricians (Kruskal-Wallis test, P = 0.362). Consensus, >74% or <26% of respondents rating a variable helpful/very helpful, was found in only 50% of variables listed. Estimated admission rate within a month of diagnosis was 61% (30-100%) for those managing adults and 48% %5-100%) for pediatricians. A lack of consensus was found among clinicians managing CF about the variables considered in diagnosing an exacerbation. The estimated proportion admitted within a month of diagnosis was very variable. This demonstrated inhomogeneity in approach to diagnosis and management of an exacerbation suggests a significant heterogeneity of clinical care.

Categories of deltaF508 homozygous cystic fibrosis twin and sibling pairs with distinct phenotypic characteristics

Cystic fibrosis (CF), the most common severe autosomal recessive trait among Caucasians, is caused by molecular lesions in the cystic fibrosis transmembrane conductance regulator gene (CFTR). The course of the multi-organ disease CF is highly variable, suggesting the influence of environmental factors and/or modulating genes other than CFTR on the disease phenotype. To evaluate the cause of CF disease variability, the European CF Twin and Sibling Study collected data on two clinical parameters most sensitive for the course and prognosis of CF, ie weight predicted for height (wfh)% (representative for the nutritional status) and FEVPerc (representative for the pulmonary status) for a cohort of 277 sibling pairs, 12 pairs of dizygous twins and 29 pairs of monozygous twins. Of these 318 CF twin and sib pairs, 114 were reported to be homozygous for the most frequent CF disease-causing lesion, deltaF508. Intra-pair discordance was assessed by the intra-pair differences with wfh% and FEVPerc and by DELTA, a composite parameter defined by linear combination of wfh% and FEVPerc in order to describe discordance with respect to the overall disease severity. Monozygous twins had a significantly lower DELTA than dizygous twins (P = 0.05) indicating that CF disease severity is modulated by an inherited component in addition to the CFTR gene itself. Extreme phenotypes are considered to be more informative for the analysis of any quantitative trait. Thus, we aimed to quantify disease severity and intra-pair discordance in order to select pairs with the extreme phenotypes DIS (discordant patient pairs), CON+ (concordant and mildy affected patient pairs) and CON- (concordant and severely affected patient pairs). The algorithm reliably discriminated between pairs DIS, CON+ and CON- among the cohort of deltaF508 homozygotes. The selected pairs from these categories demonstrated non-overlapping properties for wfh%, FEVPerc and the intra-pair difference of both parameters.

Wisconsin cystic fibrosis chest radiograph scoring system: validation and standardization for application to longitudinal studies

This study was designed to achieve a final modeling, validation, and standardization plan for the Wisconsin cystic fibrosis (CF) chest radiographic scoring system. Sixty chest radiographs were selected to reflect a range of severity of lung pathology in children with CF. Seven experienced volunteer raters (three radiologists and four pediatric pulmonologists) from five institutions were recruited to evaluate and score the films. Analysis of scores revealed that the subcomponents of the Wisconsin system showed considerable variation from rater to rater, but reliability assessment indicated satisfactory Cronbach's alpha coefficients (0.83-0.90) among the seven raters. It was found that an additive method of total score computation is significantly more reliable (P < 0.05) than either the original multiplicative model or the traditional Brasfield scoring system. Comparison of radiologists and pulmonologists revealed a marked, systematic difference in scoring with the former group being more conservative in interpretation of abnormalities than the pulmonologists, and some of the raters showing very limited sensitivity. Quantitative chest radiology applied to children with cystic fibrosis studied long-term in longitudinal research projects requires the careful use of sensitive scoring methods and careful selection and training of multiple raters. This is particularly important since pulmonologists and radiologists can differ systematically in interpreting/scoring abnormalities.

Skinfold measurements in children with cystic fibrosis: monitoring fat-free mass and exercise effects

Monitoring fat free mass (FFM), an indicator of nutritional status and a predictor of exercise performance in children, is particularly important in patients with cystic fibrosis (CF). We assessed validity of the skinfold method for measuring FFM, and its changes with exercise training, in children with CF. A total of 14 children with moderately severe symptoms of CF (age 10-18 years) were followed longitudinally and measured three times, before (at 0 and 6 months) and after exercise training (at 12 months). Separately, single measurements were conducted in 12 children with mild symptoms of CF and in 13 healthy controls. FFM was calculated from four skinfold measurements, and compared with estimations from total body water measured with deuterium dilution. The FFM calculated from skinfolds was 1.7% (P < 0.05) and 3.3% (P < 0.005) higher than that estimated with deuterium oxide dilution in patients with CF and controls, respectively. Limits of agreement were similar in patients with moderate and mild symptoms and in controls. The measurements in patients with moderate symptoms showed similar bias and limits of agreement at 6 and 12 months as compared to 0 months. Changes in FFM measured with both methods were significantly correlated before exercise (r = 0.82, P < 0.0005), and after exercise training (r = 0. 60, P < 0.05).

CONCLUSION

In children with cystic fibrosis, skinfold measurements are applicable to monitor fat free mass irrespective of clinical severity of the disease, and repeated measurements at intervals of 6 months are applicable to monitor changes in fat free mass during exercise training.

Thoracoabdominal asynchrony and ratio of time to peak tidal expiratory flow over total expiratory time in adolescents with cystic fibrosis

Thoracoabdominal asynchrony (TAA) and the ratio of time to peak tidal expiratory flow over total expiratory time (TME/TE) have been used to assess airway obstruction in infants and adults. We obtained these measurements using calibrated respiratory inductance plethysmography (RIP) on 15 adolescents and young adults with cystic fibrosis (CF) and varying disease severity. The measurements were then compared to 15 normal age-matched controls. TAA was expressed as a phase angle (phi) calculated from the abdominal (AB) and ribcage (RC) signals acquired from scalar strip chart recordings. Using CODAS (DATAQ Instruments, Akron, OH) software, the analog signals were digitized, and the differentiated sum (AB + RC) signal was used to calculate TME/TE. Forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV1) were obtained using RIP in all subjects. Subjects with CF had a significantly higher mean phi than the control subjects (15 degrees vs. 8 degrees, respectively, P = 0.01). In the CF patients the specificity of a high phi as an indicator of abnormality was 80%, while the sensitivity was 65%. There was no correlation in the magnitude of phi and disease severity as assessed by FVC or FEV1. There was no significant difference in TME/TE between the groups. We conclude that RIP-acquired phi, but not TME/TE, is a simple and useful method to detect the presence of airway obstructive disease. We speculate that the sensitivity of this method will increase in younger patients with more compliant chest walls and less air trapping. Longitudinal studies of phi in infants and young children with lung disease could help in assessing disease severity and progression in this population, in whom repeated measures are few and complex.

The cost of medical care for patients with cystic fibrosis in a health maintenance organization

BACKGROUND

Cystic fibrosis (CF) is the most common life-shortening genetic disorder among white individuals worldwide. Previous estimates of the costs of medical care have been based on expert opinion rather than observed costs. Accurate cost estimates are needed to enable evaluation of the cost-effectiveness of new interventions and prenatal genetic screening recommendations.

OBJECTIVE

To evaluate the cost of medical care for patients (N = 136) served by a health maintenance organization with a CF center.

METHODS

Retrospective analysis of data from computerized cost databases and the Cystic Fibrosis Foundation annual survey. Severity of disease was classified based on the percent predicted forced expiratory volume at 1 second.

RESULTS

The annual cost of medical care in 1996 averaged $13 300 and ranged from $6200 among patients with mild disease to $43 300 among patients with severe disease. Of total costs, 47% were from hospitalization, 18% were from DNase (Pulmozyme), 12% were from clinic visits, and 10% were from outpatient antibiotics. When the observed costs were used to estimate the costs of medical care for the entire population of CF patients in the United States, these costs were estimated to be $314 million per year in 1996 dollars.

CONCLUSIONS

We conclude that the cost of medical care for CF varies greatly with severity but is substantial even among patients with mild disease. These findings underscore the need for strategies to ensure good health insurance coverage and high quality care for all individuals with this condition.

Construct and longitudinal validity of a modified Huang clinical scoring system in adult cystic fibrosis patients

This study reports on the evaluation of a modified Huang scoring system in adult cystic fibrosis patients for construct and longitudinal validity. Two studies were performed. In the first study, the scoring system was applied to 59 adult cystic fibrosis patients prospectively followed at the Montreal Chest Institute. The total score and all the subscores distinguished between patients with the expected mild degree of disease severity seen in patients colonized with only Staphylococcus aureus, compared to the more advanced disease severity seen in patients colonized with Pseudomonas aeruginosa or multiple resistant pseudomonads. The relationship between disease severity assessed by forced expiratory volume in one second per cent predicted and the nonpulmonary function subscores was significant and linear (for the radiological subscore, r2=0.694, p<0.0001) and curvilinear (for the clinical and complications subscores, r2=0.622, p=0.0192 and r2=0.508, p=0.0009 respectively). In the second study, 20 patients retrospectively recorded were added to the prospective group. There was a good association between changes in nonpulmonary function subscores and changes in spirometry over a mean follow-up period of 779+/-204 days, at all levels of disease severity. The contribution of changes in clinical and complications subscores to the changes in total score became progressively more significant with more advanced disease severity. In conclusion, significant evidence for the construct validity of the scoring system as a discriminative instrument and for the longitudinal validity as an evaluative instrument was demonstrated. It may prove of value in assessing outcome of therapeutic interventions in clinical trials in patients with cystic fibrosis.

Clinical and genetic risk factors for cystic fibrosis-related liver disease

OBJECTIVE

The aim of this study was to define the role of possible risk factors for the development of cystic fibrosis (CF)-related liver disease and to analyze the association between liver disease and the different genotypes present in the Israeli CF patient population.

PATIENTS AND METHODS

All patients followed at the seven CF centers in Israel were included in this study. Liver disease was determined by persistently elevated serum liver enzymes and/or bilirubin, and/or significant ultrasonographic changes suggestive of chronic liver disease. The following clinical parameters were evaluated: ethnic origin, age at assessment of liver function, sex, history of meconium ileus, pancreatic function, history of distal intestinal obstruction syndrome, pulmonary function, and cystic fibrosis transmembrane conductance regulator mutation analysis.

RESULTS

Of the 288 patients screened, 80 (28%) had liver disease. Of the 256 patients with pancreatic insufficiency, 80 (31%) had liver disease compared with none of the 32 patients with pancreatic sufficiency. Genotype-phenotype correlation was performed on 207 patients carrying identified mutations that were previously classified according to phenotype severity. Liver disease was found in 56 (32%) of 173 patients carrying mutations associated with a severe phenotype and in 6 (38%) of 16 patients carrying at least one mutation associated with a variable genotype (G85E and/or 5T allele). None of the 18 patients carrying the 3849+10kb C->T mutation had liver disease. Prevalence of liver disease increased with age. No correlation was found between liver disease and severity of lung disease, nutritional status, history of meconium ileus, or distal intestinal obstruction syndrome.

CONCLUSION

CF patients who have pancreatic insufficiency and carry mutations associated with a severe or a variable genotype are at increased risk to develop liver disease.

Use of protein repair therapy in the treatment of cystic fibrosis

Disruption in the biosynthesis or function the cystic fibrosis transmembrane conductance regulator (CFTR) results from over 700 different mutations in the CFTR gene. It is useful to classify these mutations by the nature of the resulting defect. Understanding the molecular mechanism that leads to CFTR dysfunction stimulates the design of therapeutic strategies based on restoration of CFTR function to the mutant protein, or "protein repair therapy." This review links the classification of CFTR mutations to a number of new pharmacologic strategies that lead to enhancement of CFTR function by manipulation of mutant CFTR.

A missense cystic fibrosis transmembrane conductance regulator mutation with variable phenotype

OBJECTIVE

Cystic fibrosis (CF) has variable clinical presentation. Disease severity is partially associated with the type of mutation. The aim of this study was to report genotype-phenotype analysis of the G85E mutation.

PATIENTS

The phenotype of 12 patients (8 were from the same extended family, and 5 of them were siblings from 2 families) carrying at least one copy of the G85E mutation was evaluated and compared with the phenotype of 40 patients carrying the two severe mutations, W1282X and/or DeltaF508 (group 1), and with 20 patients carrying the splicing mutation, 3849+10kb C->T, which was found to be associated with milder disease (group 2).

RESULTS

A high phenotypic variability was found among the patients carrying the G85E mutation. This high variability was found among patients carrying the same genotype and among siblings. All the studied chromosomes carrying the G85E mutation had the 7T variant in the polythymidine tract at the branch/acceptor site in intron 8. Of the G85E patients, 25% had pancreatic sufficiency and none had meconium ileus, compared with 0% and 32%, respectively, of patients from group 1, and 80% and 0%, respectively, from group 2. Two patients carrying the G85E mutation had sweat chloride levels <60 mmol/L whereas all the others had typically elevated levels >80 mmol/L. Compared with group 2, patients carrying the G85E mutation were diagnosed at an earlier age and had higher sweat chloride levels, with mean values similar to group 1 but significantly more variable. Forced expiratory volume in 1 second (FEV1) was similar in the three groups, with no differences in the slope or in age-adjusted mean values of FEV1. The levels of transcripts lacking exon 9 transcribed from the G85E allele measured in 3 patients were 55%, 49%, and 35% and their FEV1 values were 82%, 83%, and 50% predicated, respectively.

CONCLUSIONS

The G85E mutation shows variable clinical presentation in all clinical parameters. This variability could be seen among patients carrying on the other chromosome the same CFTR mutation, and also among siblings. This variability is not associated with the level of exon 9 skipping. Thus, the G85E mutation cannot be classified either as a severe or as a mild mutation.

The radiographic prevalence of hilar and mediastinal adenopathy in adult cystic fibrosis

BACKGROUND

It has been stated that the hilar and mediastinal lymph nodes in adults with cystic fibrosis are invariably enlarged from chronic inflammation. However, until correlation with computed tomography and magnetic resonance imaging became possible, the visualization of this feature on plain chest radiographs received very little attention, and even the advent of these modalities, little has been written on the subject.

OBJECTIVE AND METHODS

To determine the frequency of positive radiographic evidence of hilar and mediastinal adenopathy, the chest radiographs of 48 adult patients with cystic fibrosis were reviewed.

RESULTS

Adenopathy was found in a total of 25 (52%) of the patients hilar in 22 (46%) and mediastinal in 21 (44%). The adenopathy was chronic and slowly progressive in all of the patients, and in no case did it resolve. The distribution of the adenopathy resembled sarcoidosis in 19 of the 25 patients and lymphoma in another patient.

CONCLUSIONS

The diagnosis of adenopathy was thought to be acceptably accurate: among patients for whom CT scans were also available, CT confirmed the radiographic diagnosis of abnormality in 22 of 24 sets of hilar lymph nodes and all 14 sets of mediastinal lymph nodes. When observed on chest radiography, mediastinal adenopathy was invariably widespread throughout the mediastinum. The presence of adenopathy was correlated with more severe pulmonary involvement, as assessed by the Brasfield scoring system. However, the importance of observing adenopathy radiographically lies in allaying concerns about the development of sarcoidosis or systemic lymphatic disease in these patients and preventing unnecessary concern and investigation.

Cystic fibrosis in Lebanon: distribution of CFTR mutations among Arab communities

Cystic fibrosis (CF) is thought to be rare among the Arab populations from the Middle East and little data have been reported so far. We have studied a sample of 20 families living in Lebanon for several generations and who have at least one child with CF. These families are mainly from the Maronite, Greek Catholic, Greek Orthodox. Shiite or Sunnite groups. We found a 50% rate of consanguineous marriage, independent of the community of origin. The distribution of CF genotypes was determined through the screening of all exons of the CFTR (cystic fibrosis transmembrane conductance regulator) gene by the technique of denaturing gradient gel electrophoresis combined with asymmetric amplification DNA sequencing. A total of ten different mutations accounting for 87.5% of 32 unrelated CF alleles was identified, including two novel putative mutations (E672del and IVS21-28G-->A). Three mutations, delta F508 (37.5%), W1282X (15.6%), and N1303K (9.4%) accounted for 62.5% of CF alleles. Interestingly, in the Maronite group, 66.7% of the delta F508 chromosomes were found to be associated with allele 7 of the IVS8(T)tract, contrasting with the absolute linkage disequilibrium between European delta F508 chromosomes and allele 9. During this study, two previously undescribed polymorphisms (IVS14a + 17del5 and 2691T/C) were also identified.

A cystic fibrosis transmembrane conductance regulator splice variant with partial penetrance associated with variable cystic fibrosis presentations

Some patients express various features of cystic fibrosis (CF) even though essential characteristics of the disease might be absent. Such patients may suffer from respiratory disease without pancreatic insufficiency and normal sweat chloride levels. Others may present as male infertility because of congenital bilateral aplasia of the vas deferens (CBAVD) with no other signs of CF. The 5T allele, a DNA variant in a noncoding region of the cystic fibrosis transmembrane conductance regulator (CFTR) gene that reduces the level of the normal CFTR transcripts, was found in increased frequency among male patients with CBAVD. The purpose of this study was to investigate the possibility that the 5T allele is associated with dysfunction of organs other than the male reproductive system, leading to CF or atypical CF. Analysis of the 5T allele was performed on 148 subjects (29 with CF, 61 with atypical CF, and 58 with CBAVD) carrying 232 chromosomes with unidentified CFTR mutations, and on 142 non-CF chromosomes from healthy subjects of Ashkenazi origin. The frequency of the 5T allele among chromosomes from patients of Jewish Ashkenazi origin with CF and atypical CF (six of 33; 18%) was significantly higher than the frequency in the normal Ashkenazi population (eight of 142; 6%; p = 0.03). Analysis of the clinical presentation of the five patients with CF and the 12 patients with atypical CF carrying the 5T allele indicated that most patients suffered from respiratory disease presenting as asthma like symptoms, nasal polyposis, chronic sinusitis, chronic bronchitis, or bronchiectasis. Six patients had pancreatic insufficiency, two with meconium ileus. Sweat Cl- levels ranged from normal to elevated. Of the six male patients with respiratory disease who were old enough to be evaluated for fertility status, five were fertile and one had pancreatic insufficiency. Among male patients with CBAVD, 41% suffered from respiratory symptoms. Thus, the 5T allele is a variant with partial penetrance causing disease with an extreme variability of clinical presentation: from normal healthy fertile subjects or male patients with CBAVD to those with atypical or typical clinical phenotype of CF.