Background and aims Gastrointestinal symptoms remain common in adults with cystic fibrosis (CF) despite cystic fibrosis transmembrane conductance regulator modulator use, suggesting persistent and heterogeneous gut dysfunction. This prospective observational study tests the hypothesis that distinct gut symptom phenotypes in CF can be observed and linked to underlying mechanisms. Methods Adults from three UK CF centres completed the Gastrointestinal Symptom Rating Scale, Patient Assessment of Constipation Symptoms and a bowel-habit questionnaire. Latent class analysis using an ordinal logistic model was applied to 36 symptom indicators. Associations between phenotypes and demographic, clinical, and treatment variables were examined using generalised linear models. Results Three hundred participants completed questionnaires (54% male; median 31 years). We identified four symptom phenotypes: mild; moderate-constipation predominant; moderate-diarrhoea predominant and severe. The severe phenotype was associated with gastroesophageal reflux (RRR 2.86; 95%CI: 1.30-6.31; p=0.009), distal intestinal obstruction syndrome (RRR 2.46; 95%CI: 1.04-5.81; p=0.04), proton pump inhibitor (RRR 3.29; 95%CI 1.39-7.74; p=0.007), and laxative use (RRR 6.13; 95%CI 2.54-14.84; p<0.001). CF-related liver disease was associated with both moderate-constipation and diarrhoea phenotypes, respectively (RRR 2.08; 95%CI 1.13-3.81; p=0.018; RRR 2.11; 95%CI 1.03-4.29; p=0.04). There was a lower likelihood of long-term oral antibiotic use in the moderate-constipation phenotype (RRR 0.53; 95%CI 0.3-0.92; p=0.025) and moderate-diarrhoea phenotype (RRR 0.46; 95%CI 0.24-0.91; p=0.025). Conclusions Four distinct symptom phenotypes were identified, independent of demographics and pancreatic status, but associated with specific complications and medication profiles. These phenotypes provide a framework for mechanistic studies within the GRAMPUS-CF cohort and precision management of CF-related gut disease. ### Competing Interest Statement This author discloses the following: DP speaker/board honoraria from Vertex RS Research Grants from Sanofi and Nestle, Consultant to Enterobiotix. Alan Smyth reports support for this study from UK CF Trust Strategic Research Centre Grant (SRC023); patent on Alkyl quinolones as biomarkers of Pseudomonas aeruginosa infection and uses thereof (Pub-Chem Patent Summary US-2016131648-A1 https://pubchem.ncbi.nlm.nih.gov/patent/US-2016131648-A1); speaker honoraria from Vertex Pharmaceuticals (paid to institution); and participation on the Data Safety Monitoring Board and US Cystic Fibrosis Foundation (2019-present). ### Funding Statement This work was funded by a UK CF Trust Strategic Research Centre Grant (SRC023). This work was supported by the National Institute for Health and Care Research (NIHR) Nottingham Biomedical Research Centre. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Cambridge South Research Ethics Committee (23/EE/0092) gave ethical approval for this work on the 14th June 2023 I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Requests should be addressed to the chief investigator via the study email address (grampuscf{at}nottingham.ac.uk). Requests will be assessed on a case-by-case basis. Applications should state the research question being addressed and include a link to the researcher's published protocol. This will be reviewed by the research team and a final decision to share data will be the responsibility of the chief investigator. Data sharing is specifically mentioned in the participant information sheet and consent for this has been obtained. Applications will be considered from the time that our own data analysis is complete (expected to be 31/12/26), for a maximum of 7 years after study completion.

BACKGROUND:Cystic fibrosis (CF) transmembrane conductance regulator modulators improve lung function, however, effects on cough frequency, physical activity, and sleep have not been assessed in clinical studies. METHODS:After a 12-week, phase 4 pilot feasibility study, we conducted a 13-week, phase 3b, open-label study in participants with CF aged ≥12 years previously naïve to elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) to assess the effects of ELX/TEZ/IVA on cough frequency, physical activity, and sleep using wearable cough monitors and actigraphy sensors (VX-445-126). RESULTS:In study VX-445-126 (N = 81), participants treated with ELX/TEZ/IVA experienced a 91.7% reduction in cough frequency (cough events per day) (95% CI, 89.2% to 93.6%; 241.3 coughs per day at baseline to 20.3 coughs per day) from baseline at the average of week 8 through week 12 (primary endpoint). Total steps per day (secondary endpoint) increased by 638 (95% CI, 298 to 977) at the average of week 8 through week 12. Time spent above sedentary physical activity per day, time spent on moderate-to-vigorous physical activity per day, and total mean activity count per day all increased from baseline at the average of week 8 through week 12 (other efficacy endpoints). While no changes in sleep activity patterns were observed in actigraphy data, patient-reported measures of sleep quality improved (other efficacy endpoints). ELX/TEZ/IVA was generally safe and well-tolerated. CONCLUSIONS:ELX/TEZ/IVA treatment led to a > 90% reduction in daily cough frequency, with sustained improvements in physical activity and better perceptions of sleep quality.

BACKGROUND:The terminal ileum (TI) is commonly affected in people with cystic fibrosis (pwCF), but limited quantitative information is available on its appearance and dimensions. This study aimed to use magnetic resonance imaging (MRI) to: 1) measure the diameter of the distal TI in healthy volunteers (HVs) and pwCF; 2) test the hypothesis that the diameter of the TI in pwCF is larger than in HVs. METHODS:Twenty-six adult pwCF (23 on modulators) and 30 HVs participated. A commercial image analysis platform (Entrolytics, Motilent, UK) was used to measure the long and short axes diameters of the TI on cross-sectional images, along the most distal 5 cm before the ileo-caecal valve. The cross-sectional area of the TI was calculated assuming an elliptical shape. RESULTS:(mean±SD) pwCF had a larger TI compared with HVs: the long axis TI diameter (1.6 ± 0.3 cm for HVs versus 2.7 ± 0.7 cm for pwCF, p < 0.0001), the short axis TI diameter (1.2 ± 0.3 cm versus 2.2 ± 0.6 cm respectively, p < 0.0001) and the TI cross-sectional area (1.6 ± 0.7cm2 versus 4.9 ± 2.5cm2 respectively, p < 0.0001). Sixty-five% of pwCF showed heterogeneous, faeces-like chyme presence in the TI. CONCLUSIONS:This study showed that the TI is enlarged and filled with heterogeneous, faeces-like chyme in pwCF compared with HVs. These findings are in keeping with earlier surgical reports. Increased chyme viscosity and/or impaired motility may lead to accumulation of chyme in the TI in pwCF. New treatments correcting these abnormalities such as secretagogues could be evaluated using the new MRI-derived TI diameter and area endpoints.

BACKGROUND:The activation of T lymphocytes is implicated in delayed-onset drug hypersensitivity. However, currently defined cellular and genetic risk factors are not sufficient for the development of comprehensive predictive tools, translatable across conventional drug classes, new modalities, and diverse reaction phenotypes. OBJECTIVE:We sought to assess the frequency of interactions between drugs, HLA proteins, and T-cell receptors within human populations and the role of TNF-α as a critical regulator. METHODS:To study the frequency and functionality of T-cell responses, a novel in vitro culture system was used to mimic the inflammatory microenvironment, achieved through 6-day culture of PBMCs from drug-naive and drug-tolerant individuals with a panel of drugs(metabolites) commonly associated with hypersensitivity, and TNF-α. T-cell proliferation was measured through [3H]-thymidine incorporation, and cytokine analysis was performed using the ELISpot assay. RESULTS:T-cell responses to antibiotics were frequently detectable in drug-tolerant and drug-naive individuals following the addition of TNF-α. Ninety percent and 60% of drug-naive individuals produced detectable T-cell responses to vancomycin and piperacillin, respectively. Similarly, T-cell responses to dapsone, sulfamethoxazole, and/or reactive nitroso metabolites were present at high frequencies (>65%). Drug immunogenicity was inhibited by the introduction of TNF-α antagonists and HLA-blocking antibodies. Assays performed using PBMC components (CD3+, CD4+, CD8+, CD45RO+, and CD45RA+) show that drugs readily prime and activate naive T cells, with CD4+CD45RA+ T cells preferentially activated. CONCLUSIONS:We challenge the central dogma that tolerant individuals do not express the correct immunologic receptors to mount a drug-specific T-cell response and that the cellular machinery for response elicitation is not limited to hypersensitive patients.

This review explores the changing landscape of drug safety in patients with cystic fibrosis (CF) prescribed Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulator therapy. While serious adverse reactions are infrequent, they can necessitate treatment withdrawal and thereby negatively impact clinical outcomes. The CFTR correctors (vanzacaftor, elexacaftor, tezacaftor, lumacaftor) and potentiators (ivacaftor, deuterated ivacaftor) target the underlying CFTR defect to improve protein function.The CF patient population encounter a high prevalence of non-immediate adverse drug reactions and T-cell mediated hypersensitivity to β-lactam antibiotics are among the most well characterised. Piperacillin has been defined as a leading drug culprit within non-immediate drug allergy in patients with CF, with a growing body of evidence alluding to the central role of T-lymphocytes. The prevalence of reactions in CF is likely due to factors including exaggerated inflammation, overactive immune states and cumulative drug exposure. While the introduction of the CFTR modulators has led to improvements in patients inflammatory and immune states, some patients have been reported to develop drug-related allergies.Uniquely, patients presenting with drug hypersensitivity have been found to later tolerate CFTR modulators, often without the need for desensitisation protocols. This phenomenon has led us to hypothesise that increased levels of inflammation and dysregulation of regulatory T-cells in CF patients could propagate adverse reactions to CFTR modulators that resolve alongside underlying infection. The introduction of CFTR modulator therapies has been highly transformative for patients with CF, therefore, adverse reactions to these compounds that lead to cessation of treatment are serious and important to understand.

BACKGROUND:Advancements in clinical care and scientific research in cystic fibrosis (CF) have transformed, and continue to shape, nutritional management and related practices. Front line clinicians delivering nutritional support require 'living guidelines' with regular updates to address emerging issues in the rapidly changing world of CF. In this paper we wish to provide context and framework recommendations on key issues that are becoming increasingly important in clinical practice where current international nutrition guidelines provide limited or no recommendations. METHODS:The study was developed by an international multidisciplinary working group made up of previous authors of the ESPEN-ESPGHAN-ECFS 2024 guidelines. Key topics were identified and new internationally recognised expert authors were allocated to provide additional expertise as required. Statements were produced and a modified Delphi was used to gain consensus. RESULTS:The working group developed recommendations to complement current guidelines on the quality of diet, the changes in pancreatic enzyme supplementation in the age of modulator therapy, evaluation and treatment of overweight and obesity, withdrawing tube feeding, nutritional support in cancer and nutrition care in older adults. These were endorsed by the ECFS Nutrition Group. The topics identified and examined in this paper represent issues that will need to be addressed in the next revision of the ESPEN-ESPGHAN-ECFS guideline. This paper therefore serves as a preliminary step in preparation for this update.

BACKGROUND:Physical inactivity is a common and potentially modifiable trait in individuals with chronic airways disease, yet disease-specific physical activity profiles and clinical determinants remain poorly defined. METHODS:We conducted a systematic review and meta-analysis in accordance with PRISMA guidelines to characterise physical activity profiles across the spectrum of chronic airways disease. Studies reporting objectively measured physical activity in adults with COPD, asthma, noncystic fibrosis bronchiectasis, cystic fibrosis or primary ciliary dyskinesia were included. Primary outcomes were daily step count and time spent in moderate-to-vigorous physical activity (MVPA). Univariate and multivariate regression analysis was used to explore disease-specific determinants and associations with established clinical outcome measures. RESULTS:236 studies (353 cohorts, n=25 278 with chronic airways disease) met the eligibility criteria. The mean daily step count was 5494 (95% CI 5152-5636) and MVPA was 48.2 min·day-1 (95% CI 33.8-62.6), with the lowest levels observed in COPD. Physical activity levels were consistently lower than matched healthy controls. Disease-specific determinants of physical activity remained elusive; body mass index and percent predicted forced expiratory volume in 1 s (FEV1) were significant in COPD and asthma. Step count associated positively with FEV1 % pred and 6-min walk distance, and negatively with modified Medical Research Council scores. CONCLUSION:Physical inactivity is highly prevalent across chronic airways diseases and is consistently associated with established clinical outcome measures. These findings highlight the clinical relevance of objective physical activity assessment and support its consideration within the treatable traits framework as part of routine disease evaluation and management.

Quantitative Microbial Risk Assessment (QMRA) is a well-established framework for assessing the risk of airborne transmission. However, deterministic approaches fail to identify the relative importance of variable factors affecting infection risk such as natural ventilation. In this work, a QMRA model of a naturally ventilated UK hospital respiratory ward is extended using a Monte Carlo simulation, incorporating stochastic effects. The model couples transient airflow data from a network-based ventilation model, CONTAM, with an airborne infection model. The stochasticity allows for the variation of the infectiousness of the infector, accounting for population heterogeneity, and weather on the day of the outbreak, influencing airflow and natural ventilation. Results show that effects of external weather conditions on indoor airflow dominate infection risk outcomes (i.e., particular days experience inherently high or low risk), regardless of the infector’s infectiousness. This is predominantly driven by the wind direction and, consequently, inter-zonal indoor airflow patterns. Results demonstrate the complexity of natural ventilation, with higher ventilation rates not always leading to decreased infection risk but instead, increasing the transport of infectious pathogens between zones and therefore, exposure. The interplay between natural and mechanical ventilation is also explored. This work highlights nuances present when assessing outbreaks and further highlights the complex role that indoor airflow and ventilation play in long-range airborne transmission. By extending existing QMRA models to include stochastic effects, it is possible to investigate a wider range of scenarios and thus, provide a more realistic quantification of infection risk and the factors that affect airborne transmission.

INTRODUCTION:The apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) is crucial for inflammasome assembly and activation of several inflammasomes, including NLRP3. ASC aggregates are detected in human sera post pyroptotic cell death, but their inflammasome origin remains unclear. METHOD:This study aimed to develop a method to detect ASC aggregates originating from NLRP3 inflammasomes. Initially, human monocytes, macrophages, and THP-1 ASC reporter cells were employed to validate the detection of ASC/NLRP3-positive events through flow cytometry. RESULTS:The presence of ASC/NLRP3 specks was confirmed in cell supernatants from monocytes and macrophages treated with LPS and nigericin or ATP. Flow cytometry analysis identified double-positive specks in patient sera from inflammatory conditions when compared with healthy controls. Elevated ASC/NLRP3 specks were observed in conditions such as cryopyrin-associated periodic syndrome and Schnitzler's syndrome. CONCLUSION:We validated fluorescence-activated cell sorting as a reliable method for detecting ASC/NLRP3 specks in human sera, with potential diagnostic and monitoring applications in certain systemic autoinflammatory diseases.

Asthma is a complex airways disease that affects over 350-million people worldwide. It is estimated that up to 10

BACKGROUND:Whether improvements in gastrointestinal (GI) symptoms observed with Elexacaftor/Tezacaftor/Ivacaftor (ETI) treatment are sustained in the longer-term requires exploration. This study investigated how GI-symptoms change with longer-term ETI use in pancreatic insufficient adults with cystic fibrosis (awCF). METHODS:Participants completed up to three abdominal symptom questionnaires, employing the validated CFAbd-Score. Changes in total CFAbd-Score and its five domains, pain, gastroesophageal reflux-disease (GERD), disorders of bowel movement (DBM), disorders of appetite (DA) and quality of life (QOL), were analysed pre-ETI (T0) and at ≤1.5 years (T1) and 2-4 years of ETI-therapy (T2). RESULTS:A total of 165 CFAbd-Scores from 68 participants were analysed (median age: 34 years; IQR: 28-39). Total CFAbd-Score significantly (p < 0.05) and clinically meaningfully decreased from 20.4 ± 1.6 pre-ETI (median:40 weeks pre-treatment) to 15.3 ± 1.9 and 16.8 ± 1.6 at T1 (median: 25 weeks of ETI) and T2 (median: 148 weeks of ETI), respectively. The CFAbd-Score´s domains DA and QoL only significantly decreased between T0 and T1, whereas DBM only significantly decreased after 2-4 years of ETI therapy (T2). GERD scores were significantly lower at both T1 and T2. CONCLUSION:While GI symptoms in awCF significantly improve within the first 1.5 years of ETI-therapy, they appear to somewhat wane with longer-term use, despite GI-symptom burden still being lower compared to pre-ETI. However, we cannot differentiate whether this results from reduced adherence, a decrease in ETI effects, or long-term changes in diet, gut microbiota or symptom perception. The longer-term impact of ETI and other potential modulator therapies on GI symptoms requires ongoing monitoring.

Pneumonia and parapneumonic effusion are uncommon in adults with CF. Clinical presentation and recovery may change following introduction of CFTR modulators (HEMT). Further prospective studies are needed. https://bit.ly/3BktB2N.

BACKGROUND:The introduction of CFTR modulators has been transformative for many people with cystic fibrosis (CF). The drugs are generally well tolerated although adverse reactions such as delayed-type T-cell mediated hypersensitivity and drug-induced liver injury (DILI) have been reported. Here, we characterise a novel underlying immunological mechanism driving DILI post Elexacaftor/Tezacaftor/Ivacaftor (ETI) administration. METHODS:Liver-infiltrating T-cells were isolated, post liver biopsy, using a collagenase digestion protocol. Phenotypic analysis of isolated T-cell populations was conducted using flow cytometry and mass cytometry (CyTOF). Lymphocyte transformation tests (LTT) were conducted to detect CFTR modulator-specific T-cell proliferation ([3H]-thymidine). Cytokine analysis was performed using intracellular cytokine staining and enzyme-linked immunospot assays. RESULTS:Liver function tests and histological examination of liver tissue revealed elevated alanine transaminase levels and evidence of perivenular zone three confluent necrosis and hepatocyte loss with mixed inflammatory infiltrate of lymphocytes. T-cells isolated from a percutaneous liver punch biopsy were associated with a dominant CD8+ cellular phenotype. Phenotypic analysis also revealed a CD45RO+ memory phenotype alongside expression of trafficking and migratory markers, such as CXCR3 and LFA-1. In vitro antigen specificity testing demonstrated significant proliferative T-cell responses after exposure to Ivacaftor, Ivacaftor M1 and Ivacaftor M6 metabolites within populations of CD3+ liver-infiltrating T-cells, but not peripheral blood mononuclear cells. CONCLUSIONS:CFTR modulator-specific T-cells appear to be localised to sites of liver injury and not present at high frequencies within peripheral blood. Our findings align with pathomechanisms of immune-mediated DILI, during which drug-activated T-cells migrate towards sites of inflammation, infiltrate tissues and induce hepatotoxicity.

Background: CFTR modulator therapy has unprecedented positive effects on people with CF (pwCF). However, immunogenic reactions to CFTR modulator therapy may lead to drug discontinuation. We aimed to identify pwCF, intolerant to CFTR modulator therapy due to suspected immunogenic adverse events (iAE). Methods: This survey assessed the types of reaction (e.g. rash, liver injury, drug fever) including reactions after reexposure and was completed by ECFS CTN Centers. Results: Response rate to the survey was 74 %. 89 CF centers treating approximately 12000 to 17500 pwCF in 28 countries participated and 75 (84 %) CF centers reported discontinuation of CFTR modulator therapy. 37 (41.1 %) of CF centers reported iAE affecting 200 (1.1 - 1.7 %) pwCF. Detailed information about iAEs was provided for 41 of 200 (20.5 % of affected) pwCF. Of the iAEs reported in detail 33/41 (80.5 %) were associated with elexacaftor/tezacaftor/ivacaftor modulator therapy, 6 (14.6 %) with lumacaftor/ivacaftor and 2 (4.9 %) with tezacaftor/ivacaftor. 72 % of pwCF with iAE were re-exposed to CFTR modulator therapy. 32 % of re-exposed pwCF reported a second iAE. Rash and elevated liver enzymes were most frequently reported iAEs. Conclusions: iAE were mostly transient. Drug allergy to CFTR modulator therapy was rare, but highly relevant for individual pwCF.