BACKGROUND:Obesity is associated with poor asthma control, increased asthma morbidity, and decreased response to inhaled corticosteroids. We hypothesized that obesity would be associated with decreased bronchodilator responsiveness in children and adolescents with asthma. In addition, we hypothesized that subjects who were obese and unresponsive to bronchodilator would have worse asthma control and would require more asthma controller medications.

Summary Rationale: Ivacaftor, a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator, decreases sweat chloride concentration, and improves pulmonary function in 6% of cystic fibrosis (CF) patients with specific CFTR mutations. Ivacaftor increases chloride transport in many other CFTR mutations in non-human cells, if CFTR is in the epithelium. Some CF patients have CFTR in the epithelium with residual CFTR function. The effect of ivacaftor in these patients is unknown. Methods: This was a series of randomized, crossover N-of-1 trials of ivacaftor and placebo in CF patients ≥8 years old with potential residual CFTR function (intermediate sweat chloride concentration, pancreatic sufficient, or mild bronchiectasis on chest CT). Human nasal epithelium (HNE) was obtained via nasal brushing and cultured. Sweat chloride concentration change was the in vivo outcome. Chloride current change in HNE cultures with ivacaftor was the in vitro outcome. Results: Three subjects had decreased sweat chloride concentration (−14.8 to −40.8 mmol/L, P<0.01). Two subjects had unchanged sweat chloride concentration. Two subjects had increased sweat chloride concentration (+23.8 and +27.3 mmol/L, P<0.001); both were heterozygous for A455E and pancreatic sufficient. Only subjects with decreased sweat chloride concentration had increased chloride current in HNE cultures. Conclusions: Some CF patients with residual CFTR function have decreased sweat chloride concentration with ivacaftor. Increased chloride current in HNE cultures among subjects with decreased sweat chloride concentrations may predict clinical response to ivacaftor. Ivacaftor can increase sweat chloride concentration in certain mutations with unclear clinical effect.

An optimized mNGS assay for pulmonary microbes demonstrates significant inoculation of the lower airways of immunocompromised children with diverse bacteria, fungi, and viruses. Potential pathogens can be identified based on absolute and relative abundance. Ongoing investigation is needed to determine the pathogenic significance of outlier microbes in the lungs of immunocompromised children with pulmonary disease.

Background: Cystic fibrosis transmembrane conductance regulator (CFTR) modulators are disease-modifying medications for cystic fibrosis (CF) and are shown to be efficacious for only specific CFTR mutations. CFTR mutation frequency varies by ancestry, which is different from but related to demographic racial and ethnic group. Eligibility for CFTR modulator therapy has not been previously reported by race and ethnicity.Methods: We conducted a cross-sectional study of patients in the 2018 CF Foundation Patient Registry. We analyzed the percentage of patients in each US Census defined racial and ethnic group eligible for CFTR modulators based on CFTR mutations approved by the US FDA and then based on both mutations and FDA approval by age.We compared lung function based on CFTR modulator eligibility and prescription.Findings: Based on CFTR mutations alone, 92.4% of non-Hispanic White patients, 69.7% of Black/African American patients, 75.6% of Hispanic patients, and 80.5% of other race patients eligible for CFTR modulators. For each CFTR modulator, Black/ African American patients were least likely to have eligible mutations, and non-Hispanic White patients were most likely. There was no difference in the disparity between racial and/or ethnic groups with the addition of current FDA approval by age. The lowest pulmonary function in the cohort was seen in non-Hispanic White, Black/African American, and Hispanic patients not eligible for CFTR modulators.Interpretation: Patients with CF from minority groups are less likely to be eligible for CFTR modulators. Because people with CF who are racial and ethnic minorities have increased disease severity and earlier mortality, this will further contribute to health disparities.

Short-acting β-adrenergic receptor agonists (SABAs) are the most commonly prescribed asthma medications worldwide. Response to SABAs is measured as bronchodilator drug response (BDR), which varies among racial/ethnic groups in the United States. However, the genetic variation that contributes to BDR is largely undefined in African Americans with asthma. To identify genetic variants that may contribute to differences in BDR in African Americans with asthma, we performed a genome-wide association study (GWAS) of BDR in 949 African-American children with asthma, genotyped with the Axiom World Array 4 (Affymetrix, Santa Clara, CA) followed by imputation using 1000 Genomes phase III genotypes. We used linear regression models adjusting for age, sex, body mass index (BMI) and genetic ancestry to test for an association between BDR and genotype at single-nucleotide polymorphisms (SNPs). To increase power and distinguish between shared vs. population-specific associations with BDR in children with asthma, we performed a meta-analysis across 949 African Americans and 1830 Latinos (total = 2779). Finally, we performed genome-wide admixture mapping to identify regions whereby local African or European ancestry is associated with BDR in African Americans. We identified a population-specific association with an intergenic SNP on chromosome 9q21 that was significantly associated with BDR (rs73650726, p = 7.69 × 10). A trans-ethnic meta-analysis across African Americans and Latinos identified three additional SNPs within the intron of PRKG1 that were significantly associated with BDR (rs7903366, rs7070958 and rs7081864, p ≤ 5 × 10). Our results failed to replicate in three additional populations of 416 Latinos and 1615 African Americans. Our findings indicate that both population-specific and shared genetic variation contributes to differences in BDR in minority children with asthma, and that the genetic underpinnings of BDR may differ between racial/ethnic groups.

RATIONALEDespite improved diagnostics, pulmonary pathogens in immunocompromised children frequently evade detection, leading to significant morbidity and mortality.OBJECTIVESTo develop a highly sensitive metagenomic next generation sequencing (mNGS) assay capable of evaluating the pulmonary microbiome and identifying diverse pathogens in the lungs of immunocompromised children.METHODSWe collected 41 lower respiratory specimens from 34 immunocompromised children undergoing evaluation for pulmonary disease at 3 children’s hospitals from 2014-2016. Samples underwent mechanical homogenization, paired RNA/DNA extraction, and metagenomic sequencing. Sequencing reads were aligned to the NCBI nucleotide reference database to determine taxonomic identities. Statistical outliers were determined based on abundance within each sample and relative to other samples in the cohort.MEASUREMENTS & MAIN RESULTSWe identified a rich cross-domain pulmonary microbiome containing bacteria, fungi, RNA viruses, and DNA viruses in each patient. Potentially pathogenic bacteria were ubiquitous among samples but could be distinguished as possible causes of disease by parsing for outlier organisms. Samples with bacterial outliers had significantly depressed alpha-diversity (median 0.58, IQR 0.33-0.62 vs. median 0.94, IQR 0.93-0.95, p<0.001). Potential pathogens were detected in half of samples previously negative by clinical diagnostics, demonstrating increased sensitivity for missed pulmonary pathogens (p<0.001).CONCLUSIONSAn optimized mNGS assay for pulmonary microbes demonstrates significant inoculation of the lower airways of immunocompromised children with diverse bacteria, fungi, and viruses. Potential pathogens can be identified based on absolute and relative abundance. Ongoing investigation is needed to determine the pathogenic significance of outlier microbes in the lungs of immunocompromised children with pulmonary disease.

Rationale: Members of racial or ethnic minorities make up an appreciable proportion of patients with cystic fibrosis (CF) and have worse outcomes than non-Latino white individuals. Between 1,999 and 2014, the CF Foundation Patient Registry reported an increase in minorities from 5 to 8.2% for Latinos, from 3 to 4.6% for black individuals and from 1.4 to 3.1% for "Other."Objectives: To evaluate the representation of racial and ethnic minorities in pharmacology clinical trials for CF. Methods:We analyzed pharmacology clinical trials in CF published between 1999 and 2015 by searching PubMed and published study reference lists for qualifying study reports. We examined whether the race and ethnicity of study subjects were reported and, if so, what percentage of subjects represented major minority groups.Measurements and Main Results: Among 147 pharmacology clinical trials, only 19.7% reported the race or ethnicity of study subjects. Latinos were verified as included in 7.5% of clinical trials, black individuals in 6.8%, and Asians in 2.0%. Inclusion of subjects described as "Other race" was reported in 7.5% of trials. In 29 clinical trials that reported race and ethnicity, the percentage of minorities included as subjects was 2.0% for Latinos, 1.0% for black individuals, and 0.1% for Asians.Conclusions: Although CF disproportionately affects non-Latino white individuals, members of other racial or ethnic groups are proportionally underrepresented in CF pharmacology clinical trials. Inadequate inclusion of minorities and failure to report the racial or ethnic background of study subjects limits information about factors influencing drug response and may contribute to health disparities for minorities with CF.Keywords: cystic fibrosis; minority groups; ethnic groups; clinical trials

Background Hispanic patients with cystic fibrosis (CF) have decreased life expectancy compared to non-Hispanic white patients. Pulmonary function is a main predictor of life expectancy in CF. Ethnic differences in pulmonary function in CF have been understudied. The objective was to compare longitudinal pulmonary function between Hispanic and non-Hispanic white patients with CF. Methods This cohort study of 15,018 6–25 years old patients in the CF Foundation Patient Registry from 2008 to 2013 compared FEV1 percent predicted and longitudinal change in FEV1 percent predicted in Hispanic to non-Hispanic white patients. We used linear mixed effects models with patient-specific slopes and intercepts, adjusting for 14 demographic and clinical variables. We did sub-analyses by CFTR class, F508del copies, and PERT use. Results Hispanic patients had lower FEV1 percent predicted (79.9%) compared with non-Hispanic white patients (85.6%); (−5.8%, 95% CI −6.7% to −4.8%, p<0.001), however, there was no difference in FEV1 decline over time. Patients on PERT had a larger difference between Hispanic and non-Hispanic white patients in FEV1 percent predicted than patients not on PERT (−6.0% vs. −4.1%, p=0.02). The ethnic difference in FEV1 percent predicted was not statistically significant between CFTR classes (Class I–III: −6.1%, Class IV–V: −5.9%, Unclassified: −5.7%, p>0.05) or between F508del copies (None: −7.6%, Heterozygotes: −5.6%, Homozygotes: −5.3%, p>0.05). Conclusions Disparities in pulmonary function exist in Hispanic patients with CF early in life and then persist without improving or worsening over time. It is valuable to investigate the factors contributing to pulmonary function in Hispanic patients with CF.