Background: Rejection and graft thrombosis are the main reasons leading to early graft loss after pancreas transplantation. Identifying parameters that forecast these complications would be helpful. Complement activation might occur during rejection and thrombosis leading to elevated complement split products. This prospective study analyses the plasma complement 3d (C3d) levels in the early post-pancreas transplant (PTx) period to test its predictive value to determine rejection and thrombosis.
Material/Methods: Plasma C3d levels were measured after isolated PTx (n=2), simultaneous pancreas and kidney transplantation (SPKT, n=20) and pancreas re-transplantation (n=3).
Results: Pancreas rejection was observed in 3, pancreas thrombosis in 4, and kidney rejection in 7 patients. Patients after isolated kidney transplantation (IKT) served as controls. Within 40 days after PTx and IKT C3d levels were significantly elevated compared to volunteers and long-term kidney transplant recipients (p<0.001). C3d levels increased during 40 days after PTx, but dropped after IKT. During pancreas rejection episodes mean C3d levels were elevated (14.0±3.5 mg/l) compared to those obtained during graft thrombosis (9.1±1.6 mg/l; p=0.012) or periods of normal graft function (10.6±1.9 mg/l; p=0.046). A slight elevation of C3d was observed during kidney rejection episodes in SPKT (12.7±2.0 mg/l; p=0.074) but not during kidney rejection after IKT.
Conclusions: C3d plasma levels increase during episodes of pancreas rejection and decrease in pancreas transplant thrombosis. However, single C3d values have no predictive diagnostic value after SPKT.

Keywords: Complement 3d