A 52-year-old woman with end-stage renal disease from lupus nephritis is being evaluated for kidney transplantation. She has been receiving hemodialysis three times weekly for the past 3 years. Her 54-year-old brother has volunteered as a living donor and surgery is scheduled for next week. She reports a history of two pregnancies at ages 28 and 31, both resulting in healthy deliveries. She has had no prior transplants or blood transfusions. Pre-transplant immunologic testing is performed. ABO typing shows both the donor and recipient are blood type A. HLA typing reveals her brother has mismatches at the HLA-A and HLA-B loci but is considered an acceptable match. Panel reactive antibody (PRA) testing demonstrates 78% reactivity. Crossmatch testing is then performed by incubating recipient serum with donor lymphocytes. Both the T-cell crossmatch and B-cell crossmatch are positive, with complement-dependent cytotoxicity observed.
Which of the following is the most appropriate next step in management?