The aim of research is to identify markers of acute rejection by VOC analysis in exhaled breath of bilateral-lung transplanted patients. 120 bi-lung transplanted patients will be divided into two groups : patients with acute rejection diagnosed on transbronchial biopsies and patients with no acute rejection. Exhaled breath will be collected for VOC analysis woth electronic nose and mass spectrometry. VOC profiles will be compared between the two groups of patients.

Prospective single-center study. A single visit, no follow-up. The visit will take place before or within five days from date of transbronchial biopsies (BTB). It will include a noninvasive collection of exhaled breath for VOC analysis. VOC analysis will be conducted using two types of devices: "electronic nose" and mass spectrometry.

200 bi-lung transplanted patients will be enrolled and divided into two groups.

• Group A, Acute rejection: 100 patients. Diagnosis of acute rejection retained on transbronchial biopsies or functional anomalies with the necessity of modifying the immunosuppressive regimen.
• Group B, control: 100 patients. Patients without respiratory functional abnormality and normal transbronchial biopsy.

VOC, detected by electronic nose and identified by mass spectrometry, will be compared between patients with a confirmed diagnosis of acute rejection (group A) and patients without rejection (control group B)

The duration of participation of each patient is 1 day. The duration of the inclusion period is estimated at 54 months from the first inclusion. The expected total duration of the research is 54 months

Inclusion Criteria:

• Bi-pulmonary transplant patient
• Acute rejection group: Patients with transbronchial biopsies performed as part of their usual follow-up or for functional abnormality ; Diagnosis of acute rejection retained on the following arguments: histological lesions of cellular rejection or histological lesions of humoral rejection or normal histology but diagnosis of "functional rejection" retained and immunosuppressive treatment indicated
• Control group: Patients benefiting from systematically programmed transbronchial biopsies as part of post-transplant follow-up with normal histology and absence of functional respiratory abnormality

Exclusion Criteria:

• Patient unable to realize a vital capacity measure
• Neoplasia currently treated
• Unresolved acute bronchial complication (stenosis or dehiscence)
• Immunosuppressive treatment of acute rejection already begun
• Patient who has already participated in the protocol and already included in one of the two study groups