Identifying the Causes and Risk Factors of Pulmonary Exacerbations in Cystic Fibrosis

Inclusion Criteria: For Adult Participants 1. Confirmed diagnosis of cystic fibrosis (CF), defined as presence of two pathogenic CF-causing CFTR mutations AND clinical features consistent with a diagnosis of CF, OR presence of at least one pathogenic CF-causing CFTR mutation AND sweat chloride (before use of CFTR modulators) \>60mmol/L AND clinical features consistent with a diagnosis of CF. 2. Age ≥ 16 years and receiving care from a UK Adult Cystic Fibrosis Centre for main study. 5-16yrs for Paediatric pilot study (see below). 3. Have had at least 1 previous exacerbation of CF lung disease, treated with oral or intravenous antibiotics, in the previous 12 months. 4. Able to understand the patient information sheet, willing to consent to study protocol and to returning home samples 5. Has a home spirometry device and able to use this For those taking part in Group-B, additional inclusion criteria include 6. Willing to attend for additional face to face visits at 4 weeks, 26 weeks, and if they become unwell For those taking part in home monitoring (as part of Group-B at Manchester) 7. Has wireless internet at home 8. Willing to allow to home access to set up monitoring devices, collect these back in at end of study, and to carry out other visits to perform calibration or intermittent home air sampling. For Paediatric Participants 1. Confirmed diagnosis of cystic fibrosis (CF), defined as presence of two pathogenic CF-causing CFTR mutations AND clinical features consistent with a diagnosis of CF, OR presence of at least one pathogenic CF-causing CFTR mutation AND sweat chloride (before use of CFTR modulators) \>60mmol/L AND clinical features consistent with a diagnosis of CF. 2. Receiving care from an eligible Paediatric CF Centre. 3. Age 5-16 years 4. Have had at least 1 previous exacerbation of CF lung disease, treated with antibiotics. 5. Able to understand the study and/or willing to assent to study protocol. 6. Parents or guardians able to understand the study and willing to consent to take part, including helping with home sampling 7. Has a home spirometry device and able to use this For Healthy Volunteers 1. Healthy subject, male or female, aged 16-65 years 2. No active lung condition, chronic inflammatory disorder or infection 3. Not been on antibiotics or anti-inflammatory agents of any sort (including inhaled or systemic corticosteroids) for at least 90 days. 4. No recent (defined as within the previous 4 weeks) acute viral symptoms 5. Willing to sign the consent form and provide the samples. Exclusion Criteria: 1. Unable to produce sputum, spontaneous or induced, at visit 1. If subject is normally able to produce sputum and still wishes to take part, visit 1 can be repeated on up to two additional occasions if this is needed to obtain sputum sample. 2. For the first visit, participants should be clinically stable at the time of the visit. This is defined as no acute change in their baseline symptoms or presence of new viral symptoms. They should not be on additional antibiotics or anti-viral therapies for any reason (above their usual medications), and should have completed any such additional therapies at least 4 weeks prior to visit 1. 3. Subjects with infection with Mycobacteria tuberculosis 4. Subjects with active ABPA, defined as receiving treatment for ABPA currently or within the last 12 months, or those considered at risk of requiring treatment for ABPA in the next 12 months. 5. Subjects receiving long term oral steroids at an equivalent dose of 10mg or more per day of prednisolone. 6. Subjects receiving any other form of long term immune-suppressant therapy. 7. Subjects with non-tuberculous mycobacteria (NTM) infection who are undergoing active eradication therapy. Subjects with chronic NTM infection who are not on eradication therapy, and not expecting to start this within the next 12 months, are not excluded. 8. Subjects who are unable to complete home spirometry who have previously been shown poor adherence to home monitoring requests 9. Any other condition, co-morbidity or other feature that, in the opinion of the investigator would render the subject unable to complete the protocol or unsuitable for inclusion. 10. For home monitoring, any subject where the investigator or their team has concern about staff safety when performing home visits. Patients taking part in other long term trials or observational studies are eligible to take part in CF-Tracker. Local investigators should judge whether the burden of additional research visits will be manageable.