Organ procurement and transplantation network/united network for organ sharing histocompatibility committee collaborative study to evaluate prediction of crossmatch results in highly sensitized patients.

BACKGROUND: The requirement for a prospective crossmatch limits some organ allocation to local areas. The delay necessitated by the crossmatch restricts the distance across which offers can be made without unduly increasing the ischemia time. A collaborative study involving 14 transplant centers was undertaken by the Organ Procurement and Transplantation Network/United Network for Organ Sharing (OPTN/UNOS) Histocompatibility Committee to evaluate the accuracy with which the detection of unacceptable human leukocyte antigen (HLA) antigens by most advanced solid phase immunoassays can predict crossmatch results. In addition, using actual patients' unacceptable HLA antigens, the number of compatible donors that would have been available from the OPTN deceased kidney donors during 2002 to 2004 were investigated. METHODS: Panel reactive antibodies were performed by conventional or solid phase assays, and crossmatches were performed by cytotoxicity or flow cytometry. Analyses were stratified for T and B cell and by method of identifying unacceptable HLA antigens and crossmatch techniques. RESULTS: Combination of solid phase immunoassays and flow cytometry crossmatches resulted in a higher prediction rates of positive T cell (86.1%-93.5%) and B-cell crossmatches (91%-97.8%). Prediction of negative crossmatches based on different combination of panel reactive antibodies and crossmatch techniques varied from 14.3% to 57.1%. Furthermore, numerous potential compatible donors were identified for each patient, regardless of their ethnicity, in the OPTN database, when predicted incompatible ones were excluded. CONCLUSIONS: The above results showed that with the advent of solid phase immunoassays, HLA antibodies can now be accurately detected resulting in prediction of crossmatch outcome. This should facilitate organ allocation and prevents shipment of organs to distant incompatible recipients.

Renal transplantation at Oregon Health and Science University: recent results and protocols.

Renal transplants have been performed at the University Hospital, Portland, OR since 1959. In the 5-year period between January 1997 and December 2001, 736 kidney-only transplants were performed at our institution. Living donor transplants comprise an increasing proportion of the transplants performed. Our patient and graft survival rates, both short- and long-term reflect the close collaboration between the transplantation medicine and transplantation surgery faculties, and the excellent support from nurse-coordinators, histocompatibility laboratory specialists and the organ procurement organization. Since September 2001, we have used a risk-based immunosuppression algorithm. The incidence of acute rejection within the first 3 months following transplantation ranged from 7-18% in the different risk groups. We have incorporated surveillance renal allograft biopsies into our standard of care and biopsies are performed at 3 months and one year after transplantation. The incidence of subclinical rejection was 15% on the 3-month surveillance biopsies and 4% on the one-year biopsies. The majority of these rejection episodes were CCTT type I acute rejection, which responded to treatment with pulse steroids. Since 1991, we have been transplanting kidneys from blood group A2 donors into blood group B or O recipients. Graft survival is similar to that in patients receiving an ABO compatible transplant. We have recently adopted the use of intravenous immune globulin to abrogate a positive crossmatch and allow transplantation of a kidney from a living donor. Six patients have been successfully transplanted using this protocol. In an effort to speed up the work-up of recipients waiting for a deceased donor kidney transplant, we have implemented a computer-driven algorithm. By generating a list of patients who should be crossmatched, and by automating generation of work sheets and reports, this computer-driven program has expedited deceased donor workups.