Immunosuppression for delayed or slow graft function in primary cadaveric renal transplantation: use of low dose tacrolimus therapy with post-operative administration of anti-CD25 monoclonal antibody.

BACKGROUND: Patients who develop delayed graft function (DGF) following cadaveric renal transplantation have inferior survival to those who do not. Calcineurin inhibitors (CNI) may prolong recovery from DGF. Patients with DGF are therefore routinely treated with either polyclonal antilymphocyte preparations or monoclonal anti-CD3 monoclonal antibodies and delayed introduction of CNI. The purpose of this study was to evaluate the efficacy of the anti-CD25 monoclonal antibody basiliximab (BSLIX) started post-operatively in patients at high risk for DGF combined with low dose tacrolimus (TAC).
METHODS: Patients who received a primary cadaveric renal transplant only after August 1998 were included in this retrospective study (n = 143). All patients received TAC and mycophenolate Mofetil (MMF) pre-operatively. At 6 h post-operatively, graft function was assessed clinically by urine output and serum creatinine. Those patients who had a urine output < 300 cc/6 h or a rising serum creatinine were presumed to be at risk for DGF (n = 46). These patients were treated with 20 mg BSLIX and had TAC dose reduced to maintain a trough blood level of < 5 ng/mL. Basiliximab was repeated at day 5. Patients not felt to be at risk for DGF were treated with standard TAC dose with trough level target of 9-12 ng/mL. Patients at risk were classified as DGF if they needed dialysis or as slow graft function (SGF) if they did not. The combined group (SGF/DGF) were analysed together. Patients with SGF/DGF had their TAC dose increased to achieve trough levels of 9-12 ng/mL when renal function improved. Patient groups were compared for demographics, need for dialysis, serum creatinine, glomerular filtration rate (GFR), TAC trough levels, MMF dosage, complications and 1- and 2-yr actuarial graft survival.
RESULTS: Patients with SGF/DGF had a longer length of stay (8 vs. 5.7 d), were more likely to be black (41.3 vs. 25.7%), and required more post-operative haemodialysis (HD) (52.2 vs. 4.1%). SGF/DGF and non-SGF/DGF patients had similar rates of rejection (28.2 vs. 19.6%, p = 0.28) and steroid resistant rejection (SRR) (6.5 vs. 2.1%, p = 0.32). There were no differences in the rate of cytomegalovirus (CMV) infection (4.3 vs. 6.1%). Serum creatinine was higher and GFR lower at all time points in the SGF/DGF patients. The 1 and 2 yr actuarial survival in the non-SGF/DGF patients was 97.6 and 97.6% compared with 1 and 2 yrs actuarial survival of 94.1% and 80.0% in the SGF/DGF patients, p = 0.04. There were no differences in patient survival. There were no differences in actuarial survival for the SGF/DGF patients who received dialysis compared with those who did not receive dialysis. Comparison of patients who received HD (n = 28) to those who did not (n = 115), regardless of group demonstrated no difference in 1 and 2 yrs actuarial survival, 100 and 94.1% in HD patients vs. 98.2 and 92.5% in non-HD patients.
CONCLUSIONS: The clinical diagnosis of SGF/DGF can be made 6 h post-operatively based on urine output and serum creatinine. Basiliximab can be started post-operatively in these patients and decreased levels of TAC can be used to achieve acceptably low rates of rejection in these patients. However, SGF/DGF patients, regardless of their need for dialysis, have worse function at 1 yr and lower 2-yr actuarial graft survival compared with non-SGF/DGF patients. Most of the poor survival can be attributed to the SGF group. Further strategies to either prevent SGF/DGF or to optimize treatment in these patients are needed.