ANTI-REJECTION PROPHYLAXIS BY BLOCKING SELECTIN DEPENDENT CELL-ADHESION AFTER RAT ALLOGENEIC AND XENOGENEIC LUNG TRANSPLANTATION

Objective: Adhesion molecules regulate the infiltration of leukocytes into the graft during rejection after lung transplantation. The first step of the adhesion cascade is mediated by selectins. Sialyl-Lewis(X) is a ligand of P-selectin. The purpose of the study was to evaluate S LX, a synthetic oligosaccharide analog of Sialyl-Lewis(X), for anti-re jection prophylaxis after allogeneic and xenogeneic left lateral, orth otopic rat lung transplantation. Methods: In groups A and B, allogenei c lung transplantation was performed using fully incompatible rat stra ins (donors: Dark-Agouti (RT1a); recipients: Lewis (RT11)). In group A (n = 10), recipients recieved 200 mu g/d SLX i.v. on day 0-4. Group B rats (n = 10) served as untreated controls. The animals were sacrific ed on days 5 and 10, respectively. In groups C and D, xenogenic lung t ransplantation was performed using Gold Syrian hamsters as donors and Lewis rats as recipients. In group C (n = 10), recipients recieved 200 mu g/d SLX i.v. on day 0-4. Group D rats (n = 10) served as untreated controls. The animals were sacrificed on days 2 and 5, respectively. Rejection was graded by histology from 0 (no rejection) to 5 (necrosis ). By immunhistology, alveolar, interstitial CD11a, CD18 and VLA-4 pos itive leukocytes were counted. Results: Histologically, there were a l ower grade of rejection (A: 2.7 +/- 0.6; B: 4.0 +/- 0.0; P < 0.05) and fewer CD11a positive leukocytes (A: 66 +/- 27; B: 186 +/- 73; P < 0.0 5) on day 5 in the SLX-treated allograft group compared to the untreat ed group. In xenotransplantation, SLX also reduced the grade of reject ion (C: 3.3 +/- 0.5; D: 4.7 +/- 0.5; P < 0.05) and the number of CD11a positive leukocytes (C: 145 +/- 22; D: 176 +/- 20; P < 0.05) on day 2 . Conclusions: It is concluded, that the administration of SLX signifi cantly reduces allograft rejection. After discontinuation treatment wi th SLX unmodified rejection appeared. SLX also modifies xenograft reje ction, but to a lesser extent, and xenograft necrosis appeared during treatment in this model. (C) 1997 Elsevier Science B.V.