Introduction: Highly sensitized patients with end-stage renal disease are less likely to receive a kidney transplant and have a higher risk of acute rejection (AR) and graft loss compared to non-sensitized candidates. We design a retrospective cohort study to evaluate the incidence of acute rejection as well as patient and graft survival in kidney transplants performed in highly immunized patients. We also evaluated efficacy and safety of the immunosuppressive treatments used.
Material and Methods: We collected clinical and laboratory data from highly sensitized patients who received a kidney transplant in our hospital between 2007 and 2015. Only those with preformed donor-specific antibodies (DSA) or a panel reactive antibody (PRA) above 50% were considered highly sensitized.
Results and Discussion: Of the 361 patients who received a kidney transplant in that period of time, 27 were highly sensitized recipients. In addition to thymoglobulin, tacrolimus, mycophenolic acid and steroids, 70.4% (n=18) received intravenous immunoglobulin +/- plasmapheresis as induction treatment. Fourteen patients (51.9%) presented biopsy-proven acute rejection (78.6% of them were antibody-mediated rejections), with a median presentation of 13 days. In patients with PRA> 50%, incidence of AR was 42.9% (n=9) compared to 83.3% in patients with DSA (n=5).
Mean creatinine at diagnosis was 3.8 mg/dl (SD=2) and proteinuria was 4.1 g/day. 85.7% of the patients had a positive response to rejection treatment: mean creatinine was 1.7 mg/dl (SD=1) and proteinuria was 0.59 g/day one month after the episode.
Median follow-up was 4 years. There were two graft losses in the group of patients with AR (7.4%) and none in the group without rejection. Death-censored graft survival was 92.6% (100% in the group without AR vs 85.7% in the group with AR, ns). Patient survival was 95% (100% in the group without AR vs 92,9% in the group with AR, ns).
Patients with AR had a higher incidence of serious bacterial infections (66.7% vs 33.3%, ns), CMV infection (57.1% vs 42.9%, ns) and significant leukopenia (58.3% vs. 41.7%, ns) than patients without acute rejection. There was a similar incidence of BK virus replication.
Conclusions: The incidence of AR in highly sensitized patients was 51.9%, with a favorable response to treatment in 85.7% of cases. The incidence of graft loss was 7.4%, lower than that described in other series. Patient and graft survival was 95% and 92.6% respectively. There was a high rate of complications associated with the treatment of rejection in this patients.