Females with cystic fibrosis have a larger decrease in sweat chloride in response to lumacaftor/ivacaftor compared to males

AIM

To explore which patient-related factors influence sweat test response to CFTR modulators, as well as examining the correlation between the sweat chloride response and ppFEV₁ or BMI response, using systematically collected real-life clinical data.

METHODS

160 CF patients were identified who had used lumacaftor/ivacaftor for at least six months. Of these patients, age, sweat chloride levels, ppFEV₁ weight and BMI at the start of treatment and after 6 months were collected retrospectively. Pearson and Spearman tests were performed to assess correlations.

RESULTS

Females compared to males in this group showed a larger response in sweat chloride (mean difference 10.6 mmol/l, 95% CI: 5.7-15.4) and BMI (mean difference 0.27 kg/m², 95% CI: 0.01-0.54). A modest but significant correlation was found between patient weight and sweat chloride response (Pearson R = 0.244, p = 0.001), which diminished upon correction for the other factors. The correlation between sex and sweat chloride response remained; R = 0.253, p = 0.001. Sweat chloride response did not correlate with ppFEV₁ change or BMI change at 6 months after start of therapy.

CONCLUSION

Sweat chloride response is larger in females compared to males, which also explains the negative correlation of weight with the response in sweat chloride concentration after start of lumacaftor/ivacaftor. Sweat chloride response does not correlate with the responses in ppFEV₁ and BMI. This information may help the interpretation of sweat test results acquired for the follow up and evaluation of CFTR modulating treatments, and warrants further investigation into the underlying mechanisms of sex differences in response to CFTR modulators.

Early-life antibiotic exposure increases the risk of developing allergic symptoms later in life: A meta-analysis

This study systematically reviewed and quantified the relationship between exposure to antibiotics during the first 2 years of life and the risk of allergies/atopies including hay fever, eczema, food allergy, positive skin prick testing (SPT), or elevated allergen-specific serum/plasma immunoglobulin (Ig) E levels later in life. PubMed and Web of Science databases were searched for observational studies published from January 1966 through November 11, 2015. Overall pooled estimates of the odds ratios (ORs) were obtained using fixed or random-effects models. Early-life exposure to antibiotics appears to be related to an increased risk of allergic symptoms of hay fever, eczema, and food allergy later in life. The summary OR for the risk of hay fever (22 studies) was 1.23, 95% confidence interval (CI):1.13-1.34; I² : 77.0%. The summary OR for the risk of eczema (22 studies) was 1.26, 95% CI: 1.15-1.37; I² : 74.2%, and the summary OR for food allergy (3 studies) was 1.42, 95% CI: 1.08-1.87; I² : 80.8%. However, no association was found for antibiotics exposure early in life and objective atopy measurements including positive SPT or elevated allergen-specific serum/plasma IgE levels.

Serum retinol levels and pulmonary function in children and adolescents with cystic fibrosis

BACKGROUND

It has been suggested that higher serum retinol levels could have protective effects on pulmonary function (PF) in patients with cystic fibrosis (CF). However, serum retinol levels will be transiently decreased during pulmonary exacerbation. Therefore, the extent of chronic pulmonary inflammation should be included when describing the association between PF and serum retinol. We assessed the longitudinal relation between serum retinol, immunoglobulin G (IgG) and PF in paediatric CF patients.

METHODS

We studied the serum retinol, IgG and forced expiratory volumes in one second (FEV(1)% pred.) of 228 CF patients during a seven-year follow up period. The cross-sectional and longitudinal relations between these variables were assessed.

RESULTS

Serum retinol, with medians levels between 1.2 and 1.4 μmol/l, were relatively stable, while median serum IgG gradually increased during the age years. The FEV(1)% pred. was longitudinally inversely associated with serum IgG and age, but not with serum retinol. Each g/l increase in serum IgG level was associated with an accelerated yearly decline in FEV(1)% pred. of 0.5% (95% CI -0.8 to -0.1, p=0.008), and each year increase in age was associated with a 1.7% (95% CI -2.1 to -1.3, p=0.000) decline in FEV(1)% pred. This effect was not observed with respect to serum retinol levels (95% CI -1.9 to 2.2, p=0.570).

CONCLUSIONS

In this large sample of children and adolescents with CF, we found no evidence that higher serum retinol levels had protective effects on PF.

Survey of clinical infant lung function testing practices

BACKGROUND

Data supporting the clinical use of infant lung function (ILF) tests are limited making the interpretation of clinical ILF measures difficult.

OBJECTIVES

To evaluate current ILF testing practices and to survey users regarding the indications, limitations and perceived clinical benefits of ILF testing.

METHODS

We created a 26-item survey hosted on the European Respiratory Society (ERS) website between January and May 2010. Notifications were sent to members of the ERS, American Thoracic Society and the Asian Pacific Society of Respirology. Responses were sought from ILF laboratory directors and pediatric respirologists. The survey assessed the clinical indications, patient populations, equipment and reference data used, and perceived limitations of ILF testing.

RESULTS

We received 148 responses with 98 respondents having ILF equipment and performing testing in a clinical capacity. Centers in North America were less likely to perform ≥50 studies/year than centers in Europe or other continents (13% vs. 41%). Most respondents used ILF data to either "start a new therapy" (78%) or "help decide about initiation of further diagnostic workup such as bronchoscopy, chest CT or serological testing" (69%). Factors reported as limiting clinical ILF testing were need for sedation, uncertainty regarding clinical impact of study results and time intensive nature of the study.

CONCLUSIONS

Clinical practices associated with ILF testing vary significantly; centers that perform more studies are more likely to use the results for clinical purposes and decision making. The future of ILF testing is uncertain in the face of the limitations perceived by the survey respondents.

Lung clearance index: evidence for use in clinical trials in cystic fibrosis

The ECFS-CTN Standardisation Committee has undertaken this review of lung clearance index as part of the group's work on evaluation of clinical endpoints with regard to their use in multicentre clinical trials in CF. The aims were 1) to review the literature on reliability, validity and responsiveness of LCI in patients with CF, 2) to gain consensus of the group on feasibility of LCI and 3) to gain consensus on answers to key questions regarding the promotion of LCI to surrogate endpoint status. It was concluded that LCI has an attractive feasibility and clinimetric properties profile and is particularly indicated for multicentre trials in young children with CF and patients with early or mild CF lung disease. This is the first article to collate the literature in this manner and support the use of LCI in clinical trials in CF.

Is static hyperinflation a limiting factor during exercise in adolescents with cystic fibrosis?

Increased work of breathing is considered to be a limiting factor in patients with cystic fibrosis (CF) performing aerobic exercise. We hypothesized that adolescents with CF and with static hyperinflation are more prone to a ventilatorily limited exercise capacity than non-static hyperinflated adolescents with CF. Exercise data of 119 adolescents with CF [range 12-18 years], stratified for static hyperinflation, defined as ratio of residual volume to total lung capacity (RV/TLC) > 30%, were obtained during a progressive bicycle ergometer test with gas analysis and analyzed for ventilatory limitation. Static hyperinflation showed a significant, though weak association (Φ 0.38; P < 0.001) with a ventilatorily limited exercise capacity (breathing reserve index at maximal effort >0.70; FEV(1)  < 80% predicted and reduced exercise capacity, defined as VO(2peak)  < 85% predicted). Analysis of association for increasing degrees of hyperinflation showed an increase to Φ 0.49 (P < 0.001) for RV/TLC > 50%. In adolescents with static hyperinflation, peak work rate (W(peak) ; 3.1 ± 0.7 W/kg (75.1 ± 17.3% of predicted), peak oxygen uptake (VO(2peak) /kg (ml/min/kg); 39.2 ± 9.2 ml/min/kg (91.0 ± 20.3% of predicted), peak heart rate (HR(peak) ; 176 ± 19 beats/min) were significantly (P < 0.05) decreased when compared with non-static hyperinflated adolescents (W(peak) 3.5 ± 0.5 W/kg (81.4 ± 10.0% of predicted)); VO(2peak) /kg (ml/min/kg); 43.1 ± 7.5 ml/min/kg (98.0 ± 15.1% of predicted); and HR(peak) 185 ± 14 beats/min). Additionally, no difference was found in the degree of association of FEV(1) (%) and RV/TLC (%) with VO(2peak) /kg(pred) and W(peak) /kg(Pred) , but we found the RV/TLC (%) to be a slightly stronger predictor of VO(2peak) /kg(pred) and W(peak) /kg(Pred) than FEV(1) (%). These results indicate that the presence of static hyperinflation in adolescents with CF by itself does not strongly influence ventilatory constraints during exercise and that static hyperinflation is only a slightly stronger predictor of W(peak) /kg(Pred) and VO(2peak) /kg(Pred) than airflow obstruction (FEV(1) (%)).

No positive effect of rhdnase on the pulmonary colonization in children with cystic fibrosis

BACKGROUND

Long-term clinical trials have shown that daily treatment with recombinant human deoxyribonuclease (rhDNAse) in patients with mild to moderate cystic fibrosis (CF) improves lung function and decreases the number of respiratory exacerbations. The aim of this study was to analyze the effect of rhDNAse on the bacterial colonization of the airways in children with CF.

METHODS

This was a retrospective cohort study. From the database of the CF Center Utrecht, we selected two groups, an rhDNAse group (daily 2.5 mg rhDNAse) and a control group (no rhDNAse). Primary outcome parameter was the difference in change in bacterial colonization between the treatment and control group during 1.5-year. Secondary outcome parameters were changes in lung function (FEV1) and pulmonary exacerbations.

RESULTS

Children treated with rhDNAse showed no significant changes in bacterial colonization during the treatment period, apart from an increase of P. aeruginosa positive cultures, both compared to baseline (53.1% versus 25%, p < 0.05) and control group (no change during study period, 37% versus 37%). The change in FEV1 after one year of treatment was +4.0% in the treatment group versus -0.3% in the control group (p = 0.22). There were no significant changes in number of pulmonary exacerbations.

CONCLUSIONS

This study showed no significant beneficial decrease in bacterial airway colonization during 1.5-year of treatment with rhDNAse. The positive effects of rhDNAse on the lung function can therefore not be explained by a change in airway colonization.

Pulmonary consolidation and inflammation: inflammatory pseudotumour in young children

Here we report two children with a pulmonary inflammatory pseudotumour; a rare entity in children, that often initially presents as a pneumonia, but with the possibility of serious consequences if unrecognised and untreated. One of the children presented is 6 months which is extremely young for this tumour. Difficulties in presentation, management strategies and prognosis are described. Certainly, this is a condition that should be considered even in a very young child with an inflammatory condition presenting as a solid lesion in the lung which does not resolve or even progresses.

Comparing 6 and 10 sec exhalation time in exhaled nitric oxide measurements in children

Standard exhalation time for Fractional exhaled Nitric Oxide (FeNO) measurements is 10 sec but this is difficult for young children. Recommended exhalation time for children is 6 sec, but this was never substantiated in literature. We aimed to investigate the agreement between FeNO values measured with exhalation times of 6 and 10 sec and the preference of children for either method. The study population comprised children aged 5-17 years visiting the Pediatric Pulmonology outpatient clinic. FeNO values, measured during 6 (FeNO-6) and 10 (FeNO-10) sec (random order) using the single-breath online (SBOL) technique, were compared. Preferences for exhalation times were related to FVC values. Ninety-eight children (mean age 10.6 years) were included. Median FeNO-6 (15.2 ppb) and FeNO-10 (13.6 ppb) did not differ significantly (P = 0.259). Mean difference between FeNO-6 and FeNO-10 was -0.3 ppb, limits of agreement ranging from -5.8 ppb to +5.3 ppb. Sixty percent of children with a Forced Vital Capacity (FVC) less than 3 L preferred the FeNO-6 method. We found good agreement between FeNO-6 and FeNO-10, so they can be used interchangeably. An exhalation time of 6 sec was preferred by the majority of subjects with a FVC below 3 L.

Gene expression in CD4+ T-cells reflects heterogeneity in infant wheezing phenotypes

Although a marked increase in the reporting of wheezing symptoms since the mid-1970s has been described, the underlying immunopathology of the different wheezing phenotypes has not been clarified. Since differences in gene expression might be involved, the objective of the present study was to identify gene expression profiles in CD4+ T-cells from two distinct infant wheezing phenotypes. The gene expression profiles of peripheral CD4+ T-cells were compared by means of microarray analysis of six transient wheezers, six persistent wheezers and seven healthy controls. The differentially expressed genes were subsequently validated by RT-PCR. The differential gene expression profiles reflected common immunological pathways involved in apoptosis or proliferation of T-cells. Furthermore, both wheezing phenotypes showed decreased expression of the complement component 5 receptor 1 gene, a gene involved in the regulation of bronchial responsiveness. Moreover, differences in gene expression profiles were found in genes involved in the immune response against respiratory syncytial virus, such as those encoding signal transducer and activator of transcription 1 and an inflammatory mediator showing enhanced production in asthma (prostaglandin E(2) receptor 2). The present findings suggest that clinical symptoms of wheeze are reflected in common immunological pathways, whereas differences between wheezing phenotypes are, in part, reflected in distinct gene expression profiles.

Radiological and functional changes over 3 years in young children with cystic fibrosis

The aim of the present study was to evaluate airway disease progression assessed by chest radiology, expiratory interrupter resistance (Rint,exp) and spirometry in young children with cystic fibrosis (CF) over a 3-yr period. Two chest radiographs combined with two R(int,exp) measurements were performed with a 3-yr interval in 21 preschool children (age (mean+/-sd) 3.2+/-0.9 yrs) and 30 schoolchildren with CF (age 7.2+/-1.9 yrs). Chest radiographs were scored using five different CF scoring systems and Rint,exp measurements were expressed as height-adjusted Z-scores. Spirometry was assessed in schoolchildren and the results were expressed as a percentage of predicted values. Chest radiograph scores worsened significantly over the 3-yr period and a tendency towards more pronounced changes was observed, especially for the Wisconsin score, in preschool children. Most preschool and schoolchildren had Rint,exp Z-scores within the normal range at start and follow-up, and the annual change in Rint,exp Z-score was not significant. In schoolchildren, only the forced expiratory volume in one second as a percentage of forced vital capacity declined significantly during the study period. In summary, in young children with cystic fibrosis, chest radiograph scores worsen significantly over time even while lung function remains stable.

[Wheezing and cough related to congenital airway abnormalities in young infants]

Two girls developed symptoms of wheezing which started shortly after birth. The symptoms did not respond to bronchodilators. At the age of 5 months, the first infant developed severe respiratory distress with decreased left-sided breathing sounds on auscultation. The chest X-ray showed left-sided hyperinflation. Bronchoscopy revealed isolated malacia of the left main stem bronchus. The second patient, who had a history ofcor vitium, was referred to a paediatric pulmonologist in an academic hospital for chronic coughing and wheezing. Bronchoscopy and CT angiogram, performed at the age of 14 months, revealed tracheal malacia due to compression from a right descending aortic arch. Broncho- and tracheomalacia are disorders which may rarely result in severe respiratory distress. These disorders should be considered when unexplained symptoms of wheezing or coughing are present in young infants, especially if the symptoms start shortly after birth and persist without signs of viral infection.

Thoracic excursion measurement in children with cystic fibrosis

BACKGROUND

Measurement of thoracic excursion (TEM) during maximal ventilation is part of the physiotherapy assessment in children with cystic fibrosis (CF).

OBJECTIVES

The purpose of our study was to examine the reliability of TEM and its relation with pulmonary function.

METHODS

Thoracic excursions were measured using a measuring tape. Thirty children participated in an intra-observer and inter-observer reliability study. Reliability was determined by calculating the typical error in repeated measurement, limits of agreement and correlation coefficients. Cross-sectional data from the annual check-ups were used to measure the relation between TEM and pulmonary function.

RESULTS

In the intra-observer reliability study the typical error was 0.31 cm, the limits of agreement were +/-0.86 cm. Pearson's r and ICC were 0.96 and 0.95, respectively. In the inter-observer reliability study these values were 0.56 cm, +/-1.55 cm, 0.85 and 0.85, respectively. TEM correlated significantly with height (0.31, P<0.001), FVC (0.44, P<0.001), FEV1 (0.41, P<0.001) and TLC (0.19, P<0.05), and there was a significant inverse correlation with RV%TLC (-0.45, P<0.001).

CONCLUSIONS

TEM is a reliable assessment tool. Thoracic excursion is significantly, although moderately correlated with pulmonary function.

Applicability of interrupter resistance measurements using the MicroRint in daily practice

This study was performed to evaluate the applicability of a simple device (MicroRint) for measuring airway resistance, to derive normal values and to compare values with maximal expiratory flow volume (MEFV) parameters in asthmatic and healthy children. Repetitive R(int) measurements were performed in 125 healthy children and 107 asthmatic children (age range 0.8-16.8 years). In 42 asthmatic patients R(int) and MEFV values were compared and in 29 asthmatic children bronchodilation testing was performed. Successful R(int) measurements were possible in 91% of the children. The mean coefficient of variation of repeated measurements was 7.1 (+/-6.1)%. R(int) values of healthy children showed a significant curvilinear correlation with age (r=-0.80, P < 0.001) and height (r=-0.81, P < 0.001). In asthmatic and healthy children R(int) values were comparable. A significant inverse correlation was found between R(int) and MEFV values (for FEV1 and R(int) r=-0.80, P < 0.001). After bronchodilation there was a significant increase in FEV1 and decrease in R(int), but changes between the two parameters did not correlate. In conclusion, the interrupter technique is feasible and repeatable in children and has a significant correlation with other parameters of airway caliber. Baseline values do not discriminate healthy from asthmatic children.

Children with mild asthma: do they benefit from inhaled corticosteroids?

In children with mild asthma, who show hardly any abnormalities in pulmonary function, objective measurement of the effect of inhaled corticosteroids is difficult. The short term effect of fluticasone propionate (FP) in these children was evaluated, using both subjective and objective parameters. A total of 68 children (5-10 yrs old) were randomly assigned to either FP 250 microg or placebo twice daily as metered-dose inhaler via spacer during 12 weeks. Symptom scores, use of rescue medication, wheezing, parent global evaluation and pulmonary function tests including forced expiratory volume in one second (FEV1), peak expiratory flow (PEF) and bronchial responsiveness (provocation dose of methacholine causing a 20% fall in FEV1 (PD20)) were evaluated. FP-treated versus placebo-treated children showed significant changes in percentage symptom-free days, use of beta2-mimetics, morning and evening PEF, FEV1 % pred and wheezing. No significant improvements were found in parent global evaluation, absolute values of FEV1 nor PD20. These findings show that inhaled corticosteroids are effective in children with mild asthma. This effect can be assessed by both objective and subjective parameters. Early start of inhaled corticosteroids should be considered even when pulmonary function is normal.

Measurements of interrupter resistance: reference values for children 3-13 yrs of age

The interrupter technique is a convenient and sensitive technique for studying airway function in subjects who cannot actively participate in (forced) ventilatory function tests. Reference values for preschool children exist but are lacking for children >7 yrs. Reference values were obtained for expiratory interrupter resistance (R(int,e)) in 208 healthy Dutch Caucasian children 3-13 yrs of age. A curvilinear relationship between R(int,e) and height was observed, similar to published airways resistance data measured by plethysmography. No significant differences in cross-sectional trend or level of R(int,e) were observed according to sex. It was found that Z-scores could be used to express individual R(int,e) values and to describe intra- and interindividual differences based on the reference equation: 10logR(int,e)=0.645-0.00668x standing height (cm) kPa x L(-1) x s(-1) and residual SD (0.093 kPa x L(-1) x s(-1)). Expiratory interrupter resistance provides a tool for clinical and epidemiological assessment of airway function in a large age range.