Approach to the sensitized kidney transplant candidate

CPRA: calculated panel reactive antibody; CDC: complement-dependent cytotoxicity; HLA: human leukocyte antigen; IVIG: intravenous immune globulin; MCS: median channel shift; RIS: relative intensity score; PP: plasmapheresis; DSAs: donor-specific antibodies; MFI: mean fluorescence intensity.
* Some transplant centers offer kidney paired donation as a potential option to sensitized kidney transplant candidates prior to consideration of HLA desensitization.
¶ A virtual crossmatch refers to the use of results from single-antigen bead testing to assess whether a patient has antibodies directed against a particular donor's HLA antigens and to predict the results of a physical crossmatch test.
Δ This estimation is based upon the patient's kidney allocation points, determined by the amount of accrued waiting time and allocation priority afforded by the patient's CPRA.
◊ Patients with a negative CDC crossmatch and negative flow cytometry crossmatch can either be DSA negative, crossmatch negative or DSA positive, crossmatch negative. Patients in either category are still at risk for developing active and/or chronic antibody-mediated rejection.
§ The RIS is used to determine the overall specificity and strength of DSAs. To calculate the RIS, 10 points are assigned for each DSA in the strong-binding range (MFI ≥10,000), 5 points for each moderate-intensity DSA (MFI 5000 to 9999),and 2 points for each weak DSA (MFI <5000).
¥ Criteria for an acceptable crossmatch after desensitization may vary by transplant center. The authors of this topic define an acceptable crossmatch as a negative CDC crossmatch in a ≥1:2 dilution of patient sera, a negative flow cytometry crossmatch, or a positive flow cytometry crossmatch with MCS ≤250.
‡ In patients listed for deceased-donor transplant who have not received a transplant within 6 months of initial desensitization therapy, PP is added to IVIG and rituximab to reduce the levels of circulating anti-HLA antibodies.