Lung transplantation: effect of cyclosporine A on the frequency of cytolytic lymphocytes recovered from blood and the bronchoalveolar space.

The frequency of donor-specific cytolytic cells within the inflammatory infiltrate produced in the graft after canine unilateral lung transplantation was measured using a limiting dilution assay. Two groups of recipient animals were studied; animals in the first group were treated with oral cyclosporine A for 4 days after transplantation, after which the drug was withdrawn thereby allowing acute rejection to begin as evidenced by histologic examination; animals in the second group were treated with cyclosporine A for the duration of the experiment and developed a subacute, alveolar manifestation of rejection. Frequency analysis was performed for lymphocytes isolated from the peripheral blood and, using the technique of bronchoalveolar lavage, lung allograft for each recipient animal both before transplantation and at various times after the operation. The group of recipients that was treated with cyclosporine A for 4 days showed an increase in the frequency of donor-specific cytolytic cells in the blood and lavage-derived lymphocyte populations that reached peak values (four to eight and five to eighteen times the preoperative level, respectively) between days 9 and 14 after operation. The frequency of these cells remained constant at a preoperative level into the peripheral blood of recipient animals treated long term with cyclosporine A; however, the frequency within the graft-derived lymphocyte population increased to reach peak values (12 to 25 times the preoperative level) between days 5 and 15 after operation. In conclusion, these results show that although cyclosporine A modifies pulmonary rejection pathologic conditions, this drug does not prevent the sequestration of donor-specific cytolytic cells within the allograft.