Plasma and Radiologic Biomarkers of Response to ECP in Lung Transplant Recipients With CLAD

This study is for people who have had a lung transplant and developed a condition called chronic lung allograft dysfunction (CLAD), which is a type of chronic rejection. Doctors often treat CLAD with a procedure called extracorporeal photopheresis (ECP), but it can take up to six months to know if the treatment is working. The goal of the study is to find early signs (biomarkers) that show whether ECP is helping, so patients can get the right care sooner. For participants in the study, small blood samples will be collected at three points during ECP treatment and, for some participants, two MRI scans of the lungs will be performed-one before starting ECP and one after finishing treatment. The MRI uses a safe contrast dye to help us see changes in lung blood flow and tissue. Investigators will also look at certain immune cells in the blood. This is not a study of a new drug or treatment-participants will receive the same ECP therapy their doctor already recommended. The study will help researchers understand how ECP works and identify markers that predict who benefits most. There is no direct benefit to participants, but participation may help improve care for future lung transplant patients.