Objective: To study on treating organ transplant rejection with low doses of CsA and CTLA4-Ig.
Methods: We set up a rat's cardiac transplant rejection model by Ono's way. The experimental rats were divided into four groups: group A: without any treatment; group B: intraperitoneal injection of CsA at 10 mg / (-1) / (-1) 1 - 7 days; after operation group C: intraperitoneal injection of 100 microgram CTLA4-Ig after 2nd operative day; group D: intraperitoneal injection of CsA 2 mg / (-1) / (-1) 1- 7 days after operation. 50 microgram CTLA4-Ig was given intraperitoneally on the 2nd day postoperation. The survival days of allograft, serum concentration of IL-2, and histological changes were tested.
Results: The allograft survival time of the four groups was 7.2 +/- 0.7 (group A), 19.4 +/- 2.07 (group B), 31.6 +/- 1.8 (group C) and 24.6 +/- 2.07 (group D) respectively. There were significantly differences among the groups (P < 0.05). The survival time in group D was more prolonged than that in group B (P < 0.05). The concentration of IL-2 was significantly decreased after operation. Significant difference was observed between the control group and each treated group (P < 0.01). In group A, B, C and D allograft rejection was graded IV, II, I and I respectively.
Conclusion: CTLA4-Ig had a stronger immunosuppression than did CsA. The low doses of CsA and CTLA4-Ig had show a synergistic immunosuppression in allograft transplantation.