Influence of HLA-A, B, and DR matching on the outcome of kidney transplant survival in preimmunized patients

HLA Genotyping in Patients with End-Stage Renal Disease Waiting For Cadaveric Renal Transplantation in Federation of Bosnia and Herzegovina

AIM

The research was conducted by genotyping two Human Leukocyte Antigen (HLA) gene classes. The main objective of this research was to investigate distribution and frequency of the allelic groups, genotypes and haplotypes in the gene loci of HLA class I (HLA-A*, -B*, -C*) and HLA class II (HLA-DRB1*, -DQB1*) in patients included in the program of cadaveric renal transplantation.

MATERIAL AND METHODS

Our study covered 186 blood samples of patients who are registered on the list for cadaveric renal transplantation in Federation of Bosnia and Herzegovina and included 59 control, healthy unrelated individuals. For the HLA typing, we have used three different methods: micro lymphocyte cytotoxicity test (MLCT), Polymerase Chain Reaction (PCR) - Sequence Specific Primers (SSP) and PCR - Sequence-Specific Oligonucleotides (SSO) or Luminex technology. All patients and cadaveric donors were tested using the three methods because the system is polymorphic.

RESULTS

Analysis of the results of genotyping HLA class I gene loci identified dominant HLA-A*02, HLA-B*35, HLA-C*07 allelic groups. Analysis of the HLA class II gene loci genotyping showed that HLA-DRB1*11 and HLA-DQB1*03 loci had the highest incidence in HLA class II.

CONCLUSION

Based on our results and previous research, there were no observed differences between allelic frequencies and genotypes of healthy people and people with ESRD. Differences between allelic groups occurred, but they were not statistically significant, except HLA-C*01 (p = 0.020).

Cellular and molecular parameters in human renal allograft rejection

Acute rejection of human renal allografts is frequent postransplantation complication. In addition, it is a risk factor for chronic rejection, the most common cause of failure of long-term allografts. Renal allografts are rejected as a result of an immune response directed against alloantigens on the graft that are absent from the host, and the most important of these are the HLA antigens. The application of molecular diagnostic methods has revealed a differential intra-renal gene expression of cytokines, chemokines and their receptors, and cytotoxic attack molecules in acute and chronic rejection processes. Differential expression of T cell costimulatory molecules B7 and CD40/CD40L, and endothelium adhesion molecules ICAM-1 and VCAM-1 has also been reported during acute rejection. These molecules play an important role in mediating the recruitment of lymphocytes into rejecting allografts and costimulation of T cell activation. Based on experimental data, it seems that it is likely that the blockade of T cell costimulatory pathways can be used in human in the future to selectively prevent transplant rejection without generally suppressing the immune system.

In vitro response of peripheral blood mononuclear cells to phytohemagglutinin and interleukin-2

The serological determination of class II antigens is still a mandatory test prior to allotransplantation. It is known that these antigens are normally expressed on B lymphocytes and monocytes. The B lymphocytes that constitute 10% to 15% of total blood lymphocytes are the cells currently used for HLA-DR typing. To avoid HLA-DR typing difficulties, or even impossibilities that are frequently encountered among some patient groups, we studied the response of peripheral blood mononuclear cells--as an alternative source of cells for class II antigen typing--to in vitro mitogen and interleukin-2 activation and propagation. Although the patients included in this study were selected having previously known HLA-DR typing difficulties, all could be adequately typed by this method.

Typing of HLA class II and class I antigens using PHA-activated, IL-2-propagated T lymphocytes

We describe here a simple procedure, by which HLA class II antigens can be accurately and reliably identified in those patients where there is minimal or absent expression of HLA-DR,DQw antigens on B cells, or when the total number of leukocytes recovered from the patients do not permit reliable typing. Ficoll-Hypaque-separated peripheral blood mononuclear leukocytes, fresh or cryopreserved, were activated by PHA and then propagated in IL-2-containing medium until enough cells for typing were obtained (usually 7-14 days). At this stage, the cultured cells were shown to be primarily T cells (greater than 90% CD3+). Since the activated T cells propagate in the presence of IL-2, even a small number (10(4] of fresh or cryopreserved patients' cells suffice for this protocol. To date we have been able to successfully HLA-DR,DQw type 34/34 bone marrow transplantation candidates and 12/12 long-term dialysis patients, who were untypable using fresh cells. HLA-DR,DQw antigens on activated T cells from normal individuals were identical to those found on their uncultured B cells. In addition, class I antigens that were undetectable on the uncultured cells of one patient could be identified on activated T cells. The HLA antigens identified on the patients' activated T cells were confirmed by phenotypic analysis of cells from family members.

HLA-A,B and DR matching in corneal transplantation

One hundred eighty-five consecutive corneal transplants were performed in recipients selected on the basis of the best available HLA-A,B and DR match. Endothelial rejection-free transplant survival in this group was compared to a retrospective historical control group of 199 consecutive transplants performed in recipients selected on the basis of age and longest wait criteria. The two groups were comparable with regards to primary diagnosis, preoperative corneal vascularization, donor and recipient age, and operative techniques. Thirty-eight transplants in the study group and 28 transplants in the control group were at high risk for endothelial transplant rejection. At 12 months, the estimated rejection-free survival (Kaplan-Meier method) of the high-risk study group transplants was 87% compared to 74% for the high-risk historical control group and transplants. This difference did not reach the significant level of 0.05 with the log-rank test. The 12-month estimated rejection-free survival of low-risk study group and historical control group transplants were similar. In the study group, the 12-month estimated rejection-free survival of well-matched transplants was 95% compared to 83% for poorly matched transplants (log rank, P less than 0.02). These findings suggest that a relationship exists between HLA-A,B and DR compatibility of donor and recipient and the corneal rejection-free transplant survival.

Clinical utility of serologic HLA-DR antigen identification using activated T lymphocytes

Clinical experience has shown that it is often difficult to identify HLA-DR antigens on peripheral blood from long-term dialysis patients, leukemic patients, or blood in poor condition due to age of specimen or delivery conditions. We have found that we can accurately detect HLA-DR antigens on peripheral blood T cells that have been activated with PHA and expanded with commercially available Interleukin 2. An advantage of this technique is that a minimal number of peripheral blood cells is required at the initiation of T-cell activation. The expansion of T cells to a number sufficient for HLA-DR analysis requires 7 to 10 days. To test the validity of this protocol, we analyzed the HLA-DR antigens on a total of 13 normal donors using both conventional techniques and activated T cells. In every case, HLA-DR detection was identical by both methods, and no false positive or negative reactions were observed. Next, we used activated T cells to analyze the HLA-DR antigens in patients that had been difficult or impossible to DR type using conventional methods. We successfully identified HLA-DR antigens on 16 of 16 bone marrow transplant candidates who were previously untypable. We also identified HLA-DR antigens in all of the eight renal dialysis patients who had been untypable on several previous occasions. Subsequent phenotypic analysis of family members for those patients confirmed that the HLA-DR antigens genetically transmitted from family were detected by this method. In summary, we consider that activated T cells can be used effectively and reliably for analysis of HLA-DR antigens for patients who are otherwise difficult to type by conventional methods.

Renal transplantation in the United Kingdom and Ireland--the centre effect

A detailed audit was done of eight of the twenty-nine transplant centres serving the UK and Ireland. These 8 centres account for one-third of the total renal transplant operations in these two countries. Information was obtained from each centre by means of a comprehensive questionnaire, a 1 1/2 day visit by the three authors, and an analysis of 50 consecutive first cadaver transplants. The 8 centres were chosen in the knowledge that 4 had high and 4 had low 3-month graft-survival rates. Our audit confirmed a centre effect, with a range in 1-year patient survival of from 82% to 96% and of first cadaver graft survival of from 54% to 82%. The two main factors affecting success rate were the rate of irreversible acute rejection and death with a functioning kidney. Our investigations suggested that the centre variation in acute rejection was influenced by blood transfusion and the variation in mortality by steroid dose and recipient age. Careful and well-organised clinical management cannot be easily quantified but was thought to have an important influence. Widespread adoption of pre-transplant blood transfusion and increasing use of cyclosporin will probably contribute to the further lessening of the centre effect which has already been observed over the past few years.