In a murine model of lung ischemia-reperfusion injury (IRI), we previously demonstrated that lymphocytes increase in the alveolar space during the ischemic period. We hypothesized that these lymphocytes play an important role during ischemia in the development of lung IRI. In the present study, severe combined immunodeficiency (SCID) mice, lacking T cells, were used to further investigate our hypothesis. SCID and control mice underwent 90 minutes of left lung ischemia followed by 4 hours of reperfusion. A significant decrease in neutrophils, together with lower levels of interleukin-1beta, was found in SCID mice after reperfusion. We concluded that lymphocytes invading the lung during ischemia trigger an inflammatory response upon reperfusion. Antilymphocyte therapies in the donor should be further investigated as treatment strategies against IRI.