Identifying Serum Cytokine Profiles of Distinct Inflammatory Phenotypes in Severe Asthma

A prospective observational study of 90 adults diagnosed with severe asthma and on regular follow-up and 15 control subjects will be investigated. Stable (controlled or partly-controlled) status (of all) and exacerbated-status (if any) serum cytokine levels [IL-4, IL-5, IL-10, IL-13, IL-25, IL-33, thymic stromal lymphopoietin (TSLP), IL-17A, periostin) will be evaluated. Also nasopharyngeal brush samples will be obtained for respiratory tract panel work-up with PCR in exacerbated patients. Effect of viral infections' on cytokine response in different inflammatory phenotypes will be evaluated.

Inclusion criteria

(for disease groups):

• Patients diagnosed with severe asthma and followed-up at least 6 months at our clinic
• Asthma that can only be complete or partly controlled with Global Initiative for Asthma (GINA) 4-5 treatment
• Asthmatics that are eligible for the defined phenotypes
• At least one perennial allergen sensitivity for the atopic groups

Inclusion criteria

(for control group):

• Non-asthmatics (without clinical and pulmonary function test evidence)
• Non-atopics (proved by skin prick tests)
• Serum eosinophil count <300/cells

Exclusion criteria

(for disease groups):

• <18 year-old
• Smoking history within the last 1 year prior to the study
• Asthmatics with inadequate inhaler technique and/or adherence problems
• Comorbidities: malignancy history, connective tissue disorders, rheumatological disorders, hyperthyroidism, coronary heart diseases, diabetes mellitus, active hepatic diseases, akut kidney injury, any autoimmune diseases
• Organ transplantation history
• Pregnancy
• Other pulmonary problems: chronic obstructive pulmonary disease (COPD), bronchiectasis, interstitial lung diseases, pulmonary thromboemboli
• During stable period investigation

• Asthma control test <20
• Upper respiratory tract infections within 1 month before admission
• Exacerbation and/or systemic steroid use within 1 month before admission
• Atopic patients that only have seasonal allergen sensitivity

Inclusion criteria

(for control group):

• <18 year-old
• Smoking history within the last 1 year prior to the study
• Asthmatics with inadequate inhaler technique and/or adherence problems
• Comorbidities: malignancy history, connective tissue disorders, rheumatological disorders, hyperthyroidism, coronary heart diseases, diabetes mellitus, active hepatic diseases, akut kidney injury, any autoimmune diseases
• Organ transplantation history
• Pregnancy
• Other pulmonary problems: COPD, bronchiectasis, interstitial lung diseases, pulmonary thromboemboli
• Without consent