Altered Immunogenicity of Donor Lungs via Removal of Passenger Leukocytes Using Ex Vivo Lung Perfusion

Passenger leukocyte transfer from the donor lung to the recipient is intrinsically involved in acute rejection. Direct presentation of alloantigen expressed on donor leukocytes is recognized by recipient T cells, promoting acute cellular rejection. We utilized ex vivo lung perfusion (EVLP) to study passenger leukocyte migration from donor lungs into the recipient and to evaluate the effects of donor leukocyte depletion prior to transplantation. For this purpose, female pigs received male left lungs either following 3 h of EVLP or retrieved using standard protocols. Recipients were monitored for 24 h and sequential samples were collected. EVLP-reduced donor leukocyte transfer into the recipient and migration to recipient lymph nodes was markedly reduced. Recipient T cell infiltration of the donor lung was significantly diminished via EVLP. Donor leukocyte removal during EVLP reduces direct allorecognition and T cell priming, diminishing recipient T cell infiltration, the hallmark of acute rejection.