Inclusion Criteria:  routinely performed surveillance bronchoscopy and when indicated including serial FB and CB in the same session in patients wo had undergone lung transplant male or female subject of at least 18 years of age written informed consent after participant's information signed by patient  Exclusion Criteria:  age < 18 years Lacking ability to form an informed consent (including impaired judgement, communication barriers) Contraindication against bronchoscopy (e.g. co-morbidities) INR > 2 or Thrombocytes < 50000 Double antiplatelet drugs (e.g. ASS and Clopidogrel) within 7 days before biopsy Anticoagulation with NOAK within 48 hours before biopsy Moderate or severe pulmonary hypertension (mPAP > 30 mmHg, RV/RA >30 mmHg)