Risk factors and prognosis of late acute rejection in Chinese kidney transplant recipients

Aim: Accumulating literature indicates that late acute rejection (LAR) after kidney transplantation portends an unfavourable prognosis. There are no data on the incidence of LAR in Asian subjects, or its risk factors and associated clinical outcomes.

Methods: We conducted a retrospective single-centre case-+control study to investigate the incidence, risk factors and prognosis of LAR in Chinese kidney transplant recipients. Subjects with or without LAR were matched for age, gender, era of transplantation, allograft type, and maintenance immunosuppression regimen.

Results: Thirty-two episodes of LAR occurred within an observation period of 12 years giving an incidence rate of 0.46 episodes per 1000 patient-years. Acute rejection within the first year after transplantation was associated with an increased risk of LAR (OR 3.59, P = 0.041). In patients receiving maintenance immunosuppression regimen with steroid, cyclosporin A (CsA) and mycophenolate or an m-TOR inhibitor, patients with LAR showed lower trough CsA levels prior to and at the time of rejection compared to Controls (86.0 ± 26.1 vs. 105.6 ± 13.3 μg/L, P = 0.049; and 75.7 ± 35.7 vs. 106.0 ± 20.5 μg/L, P = 0.032, respectively). Trough CsA level below 80 μg/L was associated with the development of LAR (OR 10.82, P = 0.032). Patients with LAR showed an inferior allograft survival (P < 0.001) while patient survival rates were similar (P = 0.122).

Conclusions: Late acute rejection is uncommon in Chinese kidney transplant recipients but is associated with reduced allograft survival. Risk factors include acute rejection in the first post-transplant year and trough CsA level below 80 μg/L in patients on CsA-based maintenance immunosuppression. Minimization of immunosuppression in apparently stable kidney transplant recipients must be exercised with caution.