Donor selection in pediatric kidney transplantation using DR and DQ eplet mismatching: A new histocompatibility paradigm.

It is now appreciated that more HLA-DR mismatching at the time of the first renal transplant is associated with higher degrees of sensitization, lower rates and longer times to retransplantation, and worse graft outcomes in children who are subsequently retransplanted. As such, our pediatric renal transplant program preferentially uses 0 or 1 HLA-DR-mismatched kidneys and reserves 2 DR-mismatched kidneys for recipients with an eminent need for a kidney. Based on a new HLA class II epitope matching strategy that is designed to minimize dnDSA production to DR and DQ antigens, we evaluated the prevalence of DR and DQ eplet mismatching for dd offers made to our pediatric wait-listed candidates.

Donor-specific antibodies present at the time of kidney transplantation in immunologically unmodified patients increase the risk of acute rejection.

Background: Human leukocyte antigens (HLA) class II donor-specific antibodies (DSAs) are associated with microcirculation inflammation, transplant glomerulopathy and ultimately graft loss. There is however no data on allograft outcomes in deceased donor kidney transplant recipients who have not received any desensitization prior to transplantation.

Methods: We prospectively evaluated the association of HLA DR and DQ DSAs on rejection and short-term graft survival in patients who did not receive desensitization prior to transplantation.

Sharing kidneys across donor-service area boundaries with sensitized candidates can be influenced by HLA C.

The United Network for Organ Sharing (UNOS) implemented the virtual crossmatch system in UNet as a way to improve the likelihood of a negative crossmatch when kidneys are shared with HLA-sensitized candidates across donor service area (DSA) boundaries. The role of HLA C in that process is not universally appreciated. We recently experienced an unexpected positive flow T and B cell crossmatch for an imported, HLA zero-mismatched kidney because of donor-specific HLA C antibodies and transplanted it into the backup candidate.

Renal graft survival is not influenced by a positive flow B-cell crossmatch.

Introduction: The influence of a positive B-cell crossmatch on graft outcome in renal transplantation is controversial.

Methods: We analyzed graft survival using Kaplan-Meier estimates for recipients of deceased donor kidneys who were either regraft transplant patients (n = 198) from 1990 to August 20, 2004, or primary transplant patients (n = 361) from December 15, 2000 to August 8, 2004, each of whom had a flow T- and B-cell IgG crossmatch performed before transplantation. The flow B-cell crossmatch (FBXM) was not used to decide whether or not to transplant.

Successful renal transplantation despite low levels of donor-specific HLA class I antibody without IVIg or plasmapheresis.

We prospectively transplanted 10 primary kidney recipients with deceased donor organs (nine kidney and one pancreas/kidney) when their flow cytometric T-cell IgG, HLA class I donor-specific crossmatch was positive but the AHG T-cell crossmatch was negative, with a median follow-up of 1.8 yr. No pre- or peri-operative IVIg or plasmapheresis was administered to any patient.

Transplantation of A2 and A2B kidneys from deceased donors into B waiting list candidates increases their transplantation rate.

Transplant centers in the Midwest Transplant Network began transplanting kidneys from A2 or A2B donors into blood group B and O patients in 1986. Since 1991, an OPTN/UNOS variance has permitted us to allocate these kidneys preferentially into B and O waiting list patients. With more than 10 years of experience we have noted the following: 1.

Improving access to kidney transplantation without decreasing graft survival: long-term outcomes of blood group A2/A2B deceased donor kidneys in B recipients.

Background: The transplantation of blood group A2/A2B deceased donor kidneys into B recipients could improve access to transplantation for blood group B recipients. However, this practice is controversial, and long-term data are lacking. This study analyzed the long-term outcomes of A2/A2B deceased donor kidneys transplanted into selected B recipients.

ABO blood group influences a candidate's likelihood of receiving an HLA zero antigen mismatch kidney.

National sharing of HLA zero-mismatched kidneys has improved long-term graft survival. The distribution of those HLA-matched kidneys by ABO blood group, however, has not been examined. Utilizing the UNOS/OPTN (United Network for Organ Sharing/Organ Procurement Transplantation Network) database, we analysed 112 971 kidney waiting list registrations added during 6/3/95-31/12/00, and 8162 HLA zero-mismatched (0 mm) primary kidney transplants in the USA during 1/1/88-31/3/02.

The risk for Chagas' disease in the Midwestern United States organ donor population is low.

Purpose: Several recent publications have increased awareness that transplanted organs can transmit infectious diseases. In light of the recent report describing the transmission of Trypanosoma cruzi infection by an organ donor in the United States (MMWR 2002: 51: 210), we have tested archived serum samples from our Organ Procurement Organization's (OPO's) deceased organ donors and live donors from 23 October 1995 through 1 March 2002.

Methods: A total of 1117 serum samples from 558 locally recovered deceased donors, 178 imported deceased donors, and 212 live donors were tested (several duplicates were included).

Cold ischaemia time added to kidneys can be minimized by completing the final cross-match before organs are taken from the operating room.

Unlabelled: Minimizing the amount of cold ischaemia time (CIT) added to cadaveric kidneys before their transplantation is an important goal since longer CIT is associated with worse long-term graft outcome. Our organ procurement organization (OPO) and HLA laboratories have taken the approach of performing the histocompatibility testing, including the final cross-match, as early in the donor process as possible.

Methods: The data in this study were collected from all consecutive final cross-matches done for cadaveric kidney (n = 113) and simultaneous pancreas + kidney (SPK) (n = 25) transplants done with organs recovered from donors in the Midwest Transplant Network OPO from 1 January 2001 to 9 May 2002.

HLA points assigned in cadaveric kidney allocation should be revisited: an analysis of HLA class II molecularly typed patients and donors.

The points now assigned for the quality of HLA match have received significant scrutiny to be modified in an effort to help reduce disparity in access to kidneys of minority groups, and since differences in graft survival between groups of patients in each of the HLA matched groups is less now than in the past. We analyzed long-term (5-year) graft survival in 746 DR DNA typed recipients of cadaveric kidneys transplanted from 1994-2001 whose donors were also DR DNA typed, with allocation based on those DNA-based typings. Five-year graft survival was not significantly different for recipient groups irrespective of if they had zero (84%), one (92%), two (89%), or three to four B, DR mismatches (79%) (log-rank = 0.

Flow cytometry beads rather than the antihuman globulin method should be used to detect HLA Class I IgG antibody (PRA) in cadaveric renal regraft candidates.

HLA Class I antibody screening can be performed by flow cytometry using a mixture of 30 distinct bead populations each coated with the Class I antigen phenotype derived from different cell lines. In this study we compared the efficacy of Class I antibody screens done by flow cytometry beads with the antihuman globulin (AHG) method for patients awaiting cadaveric renal retransplantation. Class I panel reactive antibody (PRA) screening by flow cytometric beads of 21 regraft serum samples that had all been found to be negative by AHG DTT Class I PRA, revealed that 57.

Increased access to transplantation for blood group B cadaveric waiting list candidates by using A2 kidneys: time for a new national system?

Since blood group B end-stage renal disease (ESRD) patients have less access to donor kidneys and a higher minority composition than any other blood group, the United Network for Organ Sharing (UNOS) approved a voluntary national kidney allocation variance to allow organ procurement organizations (OPOs) to preferentially allocate A2 and A2B kidneys to B candidates. The Midwest Transplant Network OPO has preferentially allocated and transplanted kidneys from blood group A2 and A2B donors to our blood group B waiting list candidates for more than 7 years to increase access to kidneys for the B candidates on our OPO-wide waiting list. Between 1994 and 2000, a total of 121 blood group B ESRD patients from our OPO-wide cadaveric kidney waiting list were transplanted.