ABO Genotyping finds more A to B kidney transplant opportunities than lectin-based subtyping.

ABO compatibility is important for kidney transplantation, with longer waitlist times for blood group B kidney transplant candidates. However, kidneys from non-A (eg, A) subtype donors, which express less A antigen, can be safely transplanted into group B recipients. ABO subtyping is routinely performed using anti-A lectin, but DNA-based genotyping is also possible.

A blueprint for electronic utilization of ambiguous molecular HLA typing data in organ allocation systems and virtual crossmatch.

Virtual crossmatch (VXM) compares a transplant candidate's unacceptable antigens to the HLA typing of the donor before an organ offer is accepted and, in selected cases, supplant a prospective physical crossmatch. However, deceased donor typing can be ambiguous, leading to uncertainty in compatibility prediction. We have developed a prototype web application that utilizes ambiguous HLA molecular typing data to predict which unacceptable antigens are present in the donor HLA genotype as donor-specific antibodies (DSA).

Mapping molecular HLA typing data to UNOS antigen equivalents.

Background: Histocompatibility labs must convert molecular HLA typing data to antigen equivalencies for entry into the United Network for Organ Sharing (UNOS) UNet system. While an Organ Procurement and Transplantation Network (OPTN) policy document provides general guidelines for conversion, the process is complex because no antigen mapping table is available. We present a UNOS antigen equivalency table for all IPD-IMGT/HLA alleles at the A, B, C, DRB1, DRB3/4/5, DQA1, and DQB1 loci.

Histocompatibility considerations for kidney paired donor exchange programs.

Purpose Of Review: To highlight the role of histocompatibility testing in kidney paired donor (KPD) exchange programs as well as the new technological advances that may have an effect on KPD.

Recent Findings: Technological advances in human leukocyte antigen (HLA) antibody identification using the Luminex single-antigen bead multiplexing platform have facilitated virtual cross-matching and the ability to accurately match donor/recipient pairs through KPD. A knowledge of the limitations of this assay is the key to proper interpretation of the data and maximization of this new technology.

A virtual crossmatch protocol significantly increases access of highly sensitized patients to deceased donor kidney transplantation.

Background: Patients with preexisting antihuman leukocyte antigen (HLA) antibodies (sensitized patients) are more likely to have a positive crossmatch with possible donors and have a lower likelihood of receiving a renal transplant with longer wait times. A virtual crossmatch protocol using solid-phase technology to determine the specificity of anti-HLA antibodies may improve the probability of identifying a crossmatch-negative compatible donor and increase access of sensitized patients to kidney transplantation.

Methods: A virtual crossmatch protocol was implemented on October 1, 2006 with solid-phase HLA antibody characterization for all sensitized patients on the waiting list.

Trends in HLA antibody screening and identification and their role in transplantation.

HLA testing has been a staple in transplantation since the recognition that antibodies, directed against lymphocytes, were associated with allograft failure. This seminal finding led to the discovery of the MHC and the appreciation of the importance of HLA testing in transplantation. Early approaches focused on the importance of HLA matching, and were an important aspect of deceased organ donor allocation.