eGPA and Local Inflammation Within the Ear, Nose and Throat Area

Impact of Mepolizumab Treatment on the Nasal Microbiome and Local and Systemic Immune Response in Eosinophilic Granulomatosis With Polyangitis (eGPA)

Rationale: Eosinophilic Granulomatosis with Polyangiitis (eGPA), eosinophilic asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) are airway diseases where eosinophils and interleukine-5 are involved in the pathogenesis. eGPA differs from the other diseases with respect to involvement of other organs. The investigators hypothesize that nasal microbiome dysbiosis with a central augmenting role for S. Aureus plays an important role in disease expression. The investigators expect that anti-interleukin-5 treatment with mepolizumab restores the changes of the nasal microbiome and immune responses to a healthy control phenotype. To study this, the nasal microbiome, the local and systemic immune response and the effect of mepolizumab treatment will be assessed.

See Brief summary.

Inclusion Criteria:

• 18 years of age

  • able to give informed consent
  • In CRSwNP group: availability of bilateral nasal polyps as diagnosed by endoscopy or CT scan
  • In Severe asthma group: clinical diagnosis of asthma with forced expiratory volume at one second(FEV1) <80% AND either FEV1 reversibility >12% initial or documented positive metacholine challenge (PC20 < 8 mg/ml)
  • In eGPA group: Fulfilling the 2022 ACR/EULAR criteria for eGPA (Wechsler et al., 2017)
  • In GPA group: fulfilling the American College of Rheumatology (ACR)/EULAR GPA criteria (Robson et al., 2022)
  • In healthy controls: absence of asthma symptoms, no bronchial hyperresponsiveness

Exclusion Criteria:

• unable to give informed consent
• Active smoking < (less than) 6 months from baseline visit
• Concomitant use of dupilumab within 6 months of baseline visit
• pregnant or breastfeeding woman
• in CRSwNP group: current use of asthma medication, eGPA
• in healthy controls: chronic use of local anti-inflammatory agents
• in healthy controls: use of immunosuppressive medication
• in healthy controls: use of antibiotics within the last month (before start study/screening/)