The diagnosis of AMR in lung transplant recipients is difficult and often comes too late, because of lack of standardized definition. The diagnosis is nowadays based on an expert multidisciplinary approach involving clinical, histopathological and immunological criteria.

Hypothesis: the presence of intragraft donor specific antibodies (gDSAs) could be used as a new diagnostic tool for AMR in lung transplant recipients Study Objectives: to evaluate, in lung transplant patients with circulating DSAs, the diagnostic value of gDSAs in AMR and to analyze its prognostic value on graft outcome.

Inclusion criteria:

• Patient older than 18 years
• Transplanted pulmonary or cardiopulmonary patient
• And developing circulating anti-HLA antibodies directed against the graft or "DSA" at a threshold > 1000 of MFI in the 30 days preceding the inclusion visit
• Affiliation to the French social security
• Patient able to understand the objectives and risks related to research and to give informed, dated and signed consent

Exclusion criteria:

• Patient whose anti-HLA antibodies are not directed against the graft (no DSA)
• Contraindication to performing a bronchial fibroscopy with transbronchial biopsies
• Treatment with intravenous immunoglobulin (less than 1 month before inclusion) or Rituximab (less than 6 months before inclusion)
• Plasma exchanges (less than 3 months before inclusion)
• Risk of bleeding predictable (crushing disorder, impossibility of stopping the offending treatments)
• Impossibility of giving the subject informed information
• Subject under the protection of justice Subject under guardianship or curatorship
• Pregnancy
• Breastfeeding