Molecular diagnosis of cystic fibrosis by RNA obtained from nasal epithelial cells.

BACKGROUND: The diagnosis of cystic fibrosis (CF) is established when characteristic clinical signs are coupled with biallelic CFTR pathogenic variants. No previously reported non-canonical splice site variants have to be considered as variants of uncertain significance unless their effect on splicing has been validated. METHODS: Two variants identified by next-generation sequencing were evaluated. We assayed their effects on splicing employing RNA analysis and real-time expression quantification from RNA obtained from the nasal epithelial cells of a patient with clinically suspected CF and of two patients with milder phenotypes (CFTR-related disorders). RESULTS: The variant c.164+2dup causes skipping of exon 2 (p.(Ser18_Glu54del)) and exon 2 plus 3 (p.(Ser18Argfs*16)) in CFTR mRNA. Exon 2 expression in the patient heterozygous for c.164+2dup was decreased to 7 % of the exon 2 expression in the controls. The synonymous variant c.1584G>A causes a partial skipping of exon 11. The exon 11 expression in the two patients heterozygous for this variant was 22 % and 42 % of that of the controls, respectively. CONCLUSION: We conclude that variant c.164+2dup affects mRNA processing and can be considered a CF-causing variant. The results of the functional assay also showed that the p.(Glu528=) variant, usually categorized as a neutral variant based on epidemiological data, partially affects mRNA processing in our patients. This finding would allow us to reclassify the variant as a CFTR-related variant with incomplete penetrance. RNA obtained from nasal epithelial cells is an easy and accurate tool for CFTR functional studies in patients with unclassified splice variants.

SARS-CoV-2 infection in children with cystic fibrosis: A cross-sectional multicenter study in Spain. New waves, new knowledge.

INTRODUCTION: The association between viral infections and pulmonary exacerbations in children with cystic fibrosis (cwCF) is well established. However, the question of whether cwCF are at a higher risk of COVID-19 or its adverse consequences remains controversial. METHODS: We conducted an observational, multicenter, cross-sectional study of cwCF infected by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) between March 2020 and June 2022, (first to sixth COVID-19 pandemic waves) in Spain. The study aimed to describe patients' basal characteristics, SARS-CoV-2 clinical manifestations and outcomes, and whether there were differences across the pandemic waves. RESULTS: During study time, 351 SARS-CoV2 infections were reported among 341 cwCF. Median age was 8.5 years (range 0-17) and 51% were female. Cases were unevenly distributed across the pandemic, with most cases (82%) clustered between November 2021 and June 2022 (sixth wave, also known as Omicron Wave due to the higher prevalence of this strain in that period in Spain). Most cwCF were asymptomatic (24.8%) or presented with mild Covid-19 symptoms (72.9%). Among symptomatic, most prevalent symptoms were fever (62%) and increased cough (53%). Infection occurring along the sixth wave was the only independent risk factor for being symptomatic. Just eight cwCF needed hospital admission. No multisystem inflammatory syndrome, persisting symptoms, long-term sequelae, or deaths were reported. CONCLUSIONS: Spanish current data indicate that cwCF do not experience higher risks of SARS-CoV-2 infection nor worse health outcomes or sequelae. Changes in patients' basal characteristics, clinical courses, and outcomes were detected across waves. While the pandemic continues, a worldwide monitoring of COVID-19 in pediatric CF patients is needed.

Impact of SARS-CoV-2 infection in patients with cystic fibrosis in Spain: Incidence and results of the national CF-COVID19-Spain survey.

BACKGROUND: Given the high incidence of confirmed infection by SARS-CoV-2 and mortality by COVID-19 in the Spanish population, its impact was analysed among persons with Cystic Fibrosis (CF) as a group at risk of a worse evolution. The possible causes of the incidence observed in them are explained and how CF Units have faced this health challenge is detailed. METHODS: Retrospective descriptive observational study, for which a Spanish CF Patients with Confirmed COVID-19 Registry is created, requesting information on number of people affected between 8 March-16 May 2020 and their clinical-demographic characteristics from the CF Units participating in the European Cystic Fibrosis Society Patient Registry (ECFSPR). The accumulated incidence is calculated, compared with that of the general population. Additionally, a survey (CF-COVID19-Spain) is carried out on prevention of SARS-CoV-2 infection, workings of CF Units and possible reasons for the incidence observed. RESULTS: COVID-19 was diagnosed in eight CF patients, one of whom had received a lung transplant. The accumulated incidence was 32/10000 in CF patients and 49/10000 in the general population. General death rate was 5.85/10000 while no CF patients included in the ECFSPR died. The characteristics of those affected and the results of the survey are described. CONCLUSIONS: Despite being considered a disease at high risk of severe COVID-19, the low incidence and mortality in CF patients in Spain contrasts with the figures for the general population. The possible factors that would explain such findings are discussed, with the help of the results of the CF-COVID19-Spain survey.

[Tolerance of two inhaled hypertonic saline solutions in patients with cystic fibrosis]. / Tolerabilidad de la inhalación de dos soluciones salinas hipertónicas en pacientes con fibrosis quística.

BACKGROUND AND OBJECTIVE: The aim of our study was to evaluate the tolerance of two inhaled hypertonic saline solutions (HS) in patients with cystic fibrosis. PATIENTS AND METHOD: Eighty one cystic fibrosis (CF) patients (44 males; mean age 23.63 years) inhaled 5 ml of 7% inhaled HS solution and, in those patients who did not tolerate HS, we evaluated the tolerance of a 7% HS (at dose of 5 ml) added to 0.1% hyaluronic acid at least twenty-four hours later. RESULTS: Twenty one (26%) patients did not tolerate the HS solution immediately after its inhalation. Cough was the most common symptom. Patients over 18 years of age showed worse tolerance to HS than patients younger than 18 years of age. Those patients that did not tolerate HS had a worse lung function that the ones that showed good tolerance. Eighty-one percent of patients who did not tolerate the HS alone tolerated well the HS with hyaluronic acid. CONCLUSIONS: CF patients cannot tolerate inhaled HS immediately after nebulisation. Patients over 18 years and those with worse lung function tolerate HS worst. Hyaluronate acid added to 7% HS solution improves the tolerability.