Importance of HLA-DR matching in cadaveric renal transplantation: a prospective one-center study of 170 transplants

Low Hydrophobic Mismatch Scores Calculated for HLA-A/B/DR/DQ Loci Improve Kidney Allograft Survival

We evaluated the impact of human leukocyte antigen (HLA) disparity (immunogenicity; IM) on long-term kidney allograft survival. The IM was quantified based on physicochemical properties of the polymorphic linear donor/recipient HLA amino acids (the Cambridge algorithm) as a hydrophobic, electrostatic, amino acid mismatch scores (HMS\AMS\EMS) or eplet mismatch (EpMM) load. High-resolution HLA-A/B/DRB1/DQB1 types were imputed to calculate HMS for primary/re-transplant recipients of deceased donor transplants. The multiple Cox regression showed the association of HMS with graft survival and other confounders. The HMS integer 0–10 scale showed the most survival benefit between HMS 0 and 3. The Kaplan–Meier analysis showed that: the HMS=0 group had 18.1-year median graft survival, a 5-year benefit over HMS>0 group; HMS ≤ 3.0 had 16.7-year graft survival, a 3.8-year better than HMS>3.0 group; and, HMS ≤ 7.8 had 14.3-year grafts survival, a 1.8-year improvement over HMS>7.8 group. Stratification based on EMS, AMS or EpMM produced similar results. Additionally, the importance of HLA-DR with/without -DQ IM for graft survival was shown. In our simulation of 1,000 random donor/recipient pairs, 75% with HMS>3.0 were re-matched into HMS ≤ 3.0 and the remaining 25% into HMS≥7.8: after re-matching, the 13.5 years graft survival would increase to 16.3 years. This approach matches donors to recipients with low/medium IM donors thus preventing transplants with high IM donors.

HLA Amino Acid Polymorphisms and Kidney Allograft Survival

Background

The association of HLA mismatching with kidney allograft survival has been well established. We examined whether amino acid (AA) mismatches (MMs) at the antigen recognition site of HLA molecules represent independent and incremental risk factors for kidney graft failure (GF) beyond those MMs assessed at the antigenic (2-digit) specificity.

Methods

Data on 240 024 kidney transplants performed between 1987 and 2009 were obtained from the Scientific Registry of Transplant Recipients. We imputed HLA-A, -B, and -DRB1 alleles and corresponding AA polymorphisms from antigenic specificity through the application of statistical and population genetics inferences. GF risk was evaluated using Cox proportional-hazards regression models adjusted for covariates including patient and donor risk factors and HLA antigen MMs.

Results

We show that estimated AA MMs at particular positions in the peptide-binding pockets of HLA-DRB1 molecule account for a significant incremental risk that was independent of the well-known association of HLA antigen MMs with graft survival. A statistically significant linear relationship between the estimated number of AA MMs and risk of GF was observed for HLA-DRB1 in deceased donor and living donor transplants. This relationship was strongest during the first 12 months after transplantation (hazard ratio, 1.30 per 15 DRB1 AA MM; P < 0.0001).

Conclusions

This study shows that independent of the well-known association of HLA antigen (2-digit specificity) MMs with kidney graft survival, estimated AA MMs at peptide-binding sites of the HLA-DRB1 molecule account for an important incremental risk of GF.

In a population of 240 024 kidney transplant recipients using the data of the Scientific Registry of Transplant recipients, the authors demonstrate that, independently of HLA antigen mismatches, estimated amino-acid mismatches at peptide-binding sites of the HLA-DRB1 molecule, accounts for an increased graft failure risk. Supplemental digital content is available in the text.

Identification of gene expression profile in tolerizing murine cardiac allograft by costimulatory blockade

The induction of specific tolerance would be the ultimate achievement in transplant immunology, but the precise mechanisms of immunologic tolerance remain largely unknown. Here, we investigated global gene expression analysis in tolerizing murine cardiac allografts by means of oligonucleotide microarrays. Tolerance induction was achieved in cardiac allografts from BALB/c to C57BL/6 mice by daily intraperitoneal injection of anti-CD80 and anti-CD86 monoclonal antibodies (mAbs). Comparative analysis revealed 64 genes to be induced more extensively in the tolerizing than in the syngeneic isografts, and 16 genes than in the rejecting allografts. Two genes were specifically upregulated in the tolerizing allografts. In the tolerizing allografts there were induced marked expressions of a number of genes for pro-inflammatory factors, including interferon-gamma-inducible cytokines and chemokines, as well as apoptosis-related genes, which were also upregulated in the rejecting allografts. Moreover, these gene expression patterns continued to be upregulated more than 70 days posttransplant. These results provide evidence that immunologic tolerance can be induced and maintained in the presence of prominent pro-inflammatory gene expression in vivo.

Systemic immune response to peripheral nerve transplants across major histocompatibility class-I and class-II barriers

The use of peripheral nerve transplantation in limb reconstruction has been limited by tissue rejection. In order to identify the major histocompatibility antigens involved in tissue rejection, mutant strains of inbred mice, differing from the parent strain (C57BL/6) by either major histocompatibility complex Class I (B6.C-H2bml mice) or Class II (B6.C-H2bml2 mice), were used in models of nerve transplantation. One, 2, and 3 weeks after nerve or skin transplantation, the immune response in the recipient animal was monitored with use of lymphocyte-dependent cytotoxicity and complement-dependent cytotoxicity assays. Skin transplants were used for comparison as the gold standard of a nonvascularized graft with an easily observable success or failure. There was no significant cellular immune response by the lymphocyte-mediated cytotoxicity assay when nerve or skin transplants involved an isolated Class-I or Class-II mismatch, but there was a significant response 2 weeks after transplantations across a combined Class-I and Class-II barrier for nerve (p < 0.04) or skin (p < 0.03). An antibody response to the grafts occurred for both skin and nerve transplants but only when a combined barrier was involved. This preliminary study, using a mouse model, suggests that nerve transplantation-may be performed without systemic evidence of rejection with only a partial cross match of the major histocompatibility complexes, thus decreasing the complexity of tissue typing necessary for tissue banking.

[Kidney transplantation and HLA-DR compatibility evaluated by genomic analysis: one center study]

The actual effect of HLA-DR matching in renal transplantation remains controversial. Since DNA analysis has been shown to be more reliable than serological typing, a re-evaluation of the impact of DR-matching on graft prognosis is required. In this study, 224 cadaver kidney transplantations performed in our center were retrospectively matched according to Restriction Fragment Length Polymorphism DR incompatibilities and compared to prospective serological DR-matching. Transplant outcome was evaluated using graft survival, first rejection onset and rejection frequency. In 18.8% individuals, a discrepancy between serology and DNA typing for at least one antigen was noted. Serology particularly failed to type recipients (21.7%) and 43.2% of the total missed antigens were serologically "blank" or unidentified ("X") alleles. A graft survival rate of 100% after one year was observed for transplantations with no DNA DR mismatch (n = 31). Furthermore, there was a definite correlation between DNA matching and (i), the percentage of individuals with one or more than one acute rejection episode (18% and 41.8% at one year for O incompatibility and pooled 1 and 2 incompatibilities respectively, p < 0.05); (ii), the mean of acute rejection per individual (p < 0.001); and (iii), the rejection onset time (p < 0.01). No correlation between serological matching and the acute rejection episodes parameters was noted. Since HLA typing could be performed in less than 2 hrs using new molecular biology techniques, we conclude that prospective DNA typing should improve kidney transplantation outcome in the near future.

The influence of HLA matching on renal allograft survival at a single pediatric center

Between January 1, 1969, and February 2, 1988, 331 pediatric renal transplants were performed at a single pediatric center. Of these 225 were first cadaveric allografts. Graft allocation was independent of the outcome of human lymphocyte antigen (HLA) matching. The results of class I antigen matching were analyzed in 224 transplants, and actuarial graft survivals were calculated. Class II antigen matching was analyzed in 80 patients from January 1, 1982, and submitted to the same analysis. HLA matching could not be demonstrated to be beneficial. It is proposed that any matching benefit is small and obscured in our series by the dominance of other factors.

Hematologic aspects of renal insufficiency

Renal dysfunction gives rise to a variety of hematologic disturbances, including anemia, leukocyte dysfunction, and coagulopathy. The anemia of renal failure has been attributed to a relative deficiency of erythropoietin, but contributing factors include an absolute deficiency of iron or folate. Other contributing factors include heavy metal toxicity, blood loss, and hemolysis. The treatment of the anemia of renal disease has advanced with the development of recombinant human erythropoietin. At doses from 15-500 micrograms/kg triweekly in selected patients, normalization of hemoglobin is presently possible. Transfusion may still have a role in patients with renal disease, although more as preconditioning for renal transplantation. In non-HLA matched transplantation, donor-specific transfusion, as well as immunosuppressives, may exert some benefit in graft survival. The coagulopathy of renal disease consists of an acquired qualitative platelet defect best remedied by dialysis but also treated successfully by cryoprecipitate or DDAVP. Infectious complications of uremia include diminished leukocyte chemotaxis, phagocytosis, and bactericidal activity. Cell-mediated immune defects and hypogammaglobulinemia have also been described. The pathophysiology involved in the protean hematologic manifestations of uremia are discussed; additionally, we describe therapeutic recommendations to deal with anemia, bleeding and infectious complications of renal failure.

Corneal allograft rejection following immunization

Five patients developed corneal allograft rejection after immunization. One patient, a 33-year-old woman, received a tetanus toxoid booster nine months after a corneal transplant for keratoconus. Within four days she developed a graft rejection that required a penetrating keratoplasty two years later. Six months later, after hepatitis B immunization, the patient reported decreased vision and the graft was cloudy, but visual acuity was 20/20. The other four patients developed graft rejection after influenza immunization. Two of these four graft rejection episodes were successfully treated with high-dose corticosteroid therapy; all episodes occurred within several weeks of influenza immunization. Patients should be prudently counseled regarding the possible risks of immunization to corneal allograft survival.

Treatment with cyclosporin and risks of graft rejection in male kidney and heart transplant recipients with non-O blood

In a consecutive series of 146 kidney transplant recipients treated with cyclosporin A a strong correlation between matching for the HLA-A, HLA-B, and HLA-DR loci specificities and outcome of the grafts was observed in male recipients with non-O blood groups. Such a beneficial effect of matching was not found in female patients or male patients with blood group O. In these patients survival of the grafts at one year was good irrespective of the number of HLA-A, B, and DR mismatches. Also in 47 male heart transplant recipients immune responsiveness against mismatched HLA antigens was related to blood group. A significantly higher incidence of rejection episodes was observed in male patients with non-O blood groups (n = 32) than in those with blood group O (n = 15). Matching for HLA-DR reduced the number of acute rejection episodes in male patients with non-O blood. These findings may help explain the controversial reports about the importance of HLA matching in organ transplantation. Furthermore, as most candidates for heart transplantation are male and not of blood group O, the higher incidence of graft rejection in these patients underscores the need for an exchange strategy of donor hearts.

Long-term follow-up in London Transplant Group recipients of cadaver renal allografts. The influence of HLA matching on transplant outcome

The London Transplant Group followed 1341 patients with cadaver renal transplants, none of whom received cyclosporine, for six months to 14 years to determine the effect on graft survival of matching donor and recipient for HLA Class I antigens (HLA-A, -B, and -C) and Class II antigens (HLA-DR, -MT, and -DQ). Long-term graft survival was greatly improved by matching for HLA Class I antigens, especially HLA-B. Transplants that could not be matched for both B-locus antigens but were completely matched for Bw4/Bw6 also did very well. In addition, since 1978, excellent results have been obtained with HLA-DR and -DRw52/53 (HLA-MT) matching, but not with HLA-DQ matching. Multivariate analysis using the Cox regression model confirmed that combination Class I and Class II matching produced significant improvements in graft survival. Thus, transplants matched for HLA-DR plus HLA-B and those matched for HLA-MT plus HLA-B had excellent results--even better than those reported with cyclosporine treatment. Double HLA-MT incompatibilities yielded the poorest results. We conclude that this approach of combining the broad and narrow specificities of Class I and II is extremely practical and that appropriate matching of tissue types is clinically important.

Pediatric renal transplantation

This article outlines the current status of pediatric renal transplantation and emphasizes a practical approach to patient management. It discusses two areas of renal transplantation in children in which results differ significantly between children and adults. These areas are renal transplantation in the very young child and transplantation in children with renal failure secondary to urologic disease.

Detection of HLA class I and II antigens in rejected human corneal allografts

We compared the distribution of HLA-ABC (class I) and HLA-DR (class II) antigens on fresh human donor corneal tissue, donor corneas following a 72-hour storage in McCarey-Kaufman (M-K) medium, and corneal buttons from patients with allograft rejection and with chronic herpetic stromal keratitis. Incubation in M-K media had little or no effect on the distribution of HLA antigens as compared with fresh tissue. In contrast to control corneas, both HLA class I and II antigens were detected on corneal endothelial cells, cells in the stroma, and on basal epithelial cells in rejected allografts. Corneal endothelium in herpetic buttons did not express detectable HLA antigens. HLA-DR positive Langerhan's cells were demonstrated in the central corneal epithelium of rejected allografts, as well as in herpetic corneas, but not in control corneas except at the limbus. Based upon these observations, a theory of corneal allograft rejection in humans is proposed based upon the induction of class I HLA-ABC and class II HLA-DR antigens on cells in the donor button by a factor(s) associated with cellular inflammation.

Organ transplantation and the immune response gene. Clinical correlations and donor requirements

Major gains have been made in the area of clinical organ transplantations due to recent studies concerning the human histocompatibility locus (HLA). These basic science findings, along with developments in clinical pharmacology have allowed for a much broader use of donor sources, and a significant prolongation in clinical life span for these transplantation recipients.

Effect of class II antigen matching on renal allograft survival in miniature swine

The benefit of class II major histocompatibility complex (MHC) antigen matching to renal allograft survival, in the absence of immunosuppression, has been studied in partially inbred miniature swine. Permanent (greater than 6 mo) renal allograft survival was found in 30% of recipients of either class II only or fully matched grafts. Analysis of the survival of the class II-only matched grafts by specific recipient/donor haplotype combinations indicated that survival was regulated by at least three genetic factors, including antigen gene dose, a class I MHC allele-dependent effect, and non-MHC-linked immune response phenomenon. Animals accepting class II-matched kidneys developed spontaneous tolerance to the graft, despite mounting an initial immune response marked by renal damage and the development of serum cytotoxic antibodies directed at the donor MHC antigens. The antibodies were only of the IgM class, suggesting that conversion of the humoral response to IgG was blocked. After acceptance of the kidney, three out of five animals showed specific prolongation of donor skin grafts. At the time of rejection of these skin grafts, no decrease in renal function nor reappearance of anti-donor antibodies was observed.

The effect of individual HLA antigens on graft survival rates in kidney transplant patients

We have used information available in the UCLA International Transplant Registry to study the effect of HLA antigens on graft survival outcome. All results showed that of all antigens tested, the presence of DRl in the recipient was associated with the highest graft survival rate. There was a positive matching effect for most DR antigens that were either presumed homozygous or heterozygous in the recipient. A regression analysis not only confirmed the association of DR1 and low immune response, but also suggested a greater importance of the DR rather than A or B locus to graft survival rates. Recipients with DR1.5 had the highest survival rates when DR1 was compared with other DR antigens and the heterozygous combinations of the two groups. This suggests that presence of heterozygous DR antigens may have combined effects on graft survival.

Transplantation 1983

Renal transplantation has entered a new era of optimism characterized by steady increases in our scientific appreciation of the transplant event and improving allograft survival rates. Advances in tissue typing, methods of preventing rejection including an appreciation of the blood transfusion effect and the discovery of new immunosuppressive drugs such as cyclosporin A, and methods of rejection treatment have been responsible for this new era. With renewed impetus, continued advances can only increase an optimistic approach to renal transplantation.

Histocompatibility in cardiac transplantation with particular reference to immunopathology of positive serologic crossmatch

Cardiac allografting was carried out in 33 patients during the past 2 years. Twenty-one (64%) of the patients are alive and others lived for different periods after transplantation. The number of HLA-AB and HLA-DR antigens matched or mismatched was not significantly different between the surviving and deceased patients. However, 100% (4 of the 4) of the patients with a positive serum crossmatch with donor T lymphocytes are deceased as compared to the 25% (7 of the 28) mortality rate for crossmatch-negative patients. All four of the deceased patients with a positive crossmatch had demonstrable deposition of immunoglobulins in the capillaries of the donor heart at autopsy, whereas no immunoglobulin or fibrinogen deposition was seen in the hearts of crossmatch-negative patients. Three of the four patients with positive crossmatches had sera cytotoxic to lymphocytes of more than 25% of the persons, of a 42 member panel, whereas in the remaining one the serum was cytotoxic to less than 5% of the panel members. In crossmatch-negative patients, the sera were cytotoxic to less than 20% of the panel members with one exception. The relevance of cytotoxic antibodies to lymphocytes of panel members, crossmatch, and tissue deposition of immunoglobulins is discussed.

HLA-DR-MT matching improves graft survival rate in cadaver kidney transplantation. A prospective multicenter analysis of the South German Cooperative Study Group for Kidney Transplantation

The influence of prospective HLA-DR matching on the graft survival rate was investigated in a multicenter analysis of 85 transplants. Simultaneously in a retrospective analysis of graft outcome the importance of matching for MT-antigens MT1, MT2 and MT3 as a newly defined B-cell alloantigen system was evaluated. HLA-DR antigens and MT-specificities were determined on B-cells enriched by nylon-wool filtration using locally well characterised HLA-DR antisera and the antiserum set of the 8th International Histocompatibility Workshop ("disease set") which allowed the definition of the HLA-DR specificities HLA-DR 1-9 and of the MT-antigens MT1-3. HLA-DR matching showed a significantly improved graft outcome only in HLA-DR identical donor-recipient combinations. In 11 of 60 patients with one HLA-DR compatibility additional matching for two MT-antigens, however, improved the two year graft survival rate from 60% to 91%. Altogether 17 patients were matched for two MT-specificities with their kidney donor and showed a superior prognosis of 94% at two years compared to 53% or 17% of recipients with one or zero MT compatibility. Graft outcome in this patient group was also superior to that of HLA-DR identical or HLA-AB identical grafts. These data suggested that the MT-system rather than the HLA-DR antigens may be of critical importance in cadaver kidney transplantation. In addition a favorable influence of pretransplant blood transfusions on less HLA-DR matched grafts was confirmed.

The quality of life of hemodialysis and transplant patients

This study demonstrates the application of a more comprehensive methodology for evaluating quality of life of hemodialysis and transplant patients and provides some heuristic data. Physiologic and psychologic measures were combined to assess the quality of life of 59 patients treated for endstage renal disease (ESRD). Patients with successful cadaveric transplants gave evidence of greater physical and occupational rehabilitation than patients on chronic hemodialysis. On measures of subjective quality of life, however, successful transplant and hemodialysis patients were similar in reporting normal affect whereas failed transplant patients showed a diminished quality of life. These results suggest that cadaveric transplantation may have limited value as an intervention to improve quality of life for patients with ESRD. Moreover, the results demonstrate the usefulness of questionnaire techniques adapted from psychological research for evaluating the quality of life of patients following medical intervention.

The improving utility of renal transplantation in the management of end-stage renal disease

The results achieved by treating patients with end-stage renal failure with allotransplantation have improved dramatically since the 1950s when immunosuppression was induced by total body irradiation and there was a lack of HLA typing. Although long-term hemodialysis offers prolonged survival and partial rehabilitation for many individuals with end-stage renal disease, the technique is inconvenient and time consuming. Patients are restricted by necessary proximity to the machine, dietary limitations, potential failure of access sites, and complications of various organ systems. Despite the availability of dialysis and the federal funds to partially pay for treatment, long-term dialysis still remains a costly process for the individual in need of care. During the same period when dialysis techniques improved and became widely available, transplantation of the human kidney became an established and justified treatment for some patients with end-stage renal disease. Those with successful kidney allografts may achieve remarkable recovery and are often able to return to normal lives. One of the more striking improvements in the results of renal transplantation in recent years had been the decline in morbidity and mortality. Mortality by the end of the first year after transplantation during which time most deaths occur, is currently less than 5 percent in a number of major medical units. In part, this decline represents a change in philosophy by transplant teams, who now tend to decrease immunosuppression and sacrifice the kidney rather than the patient in instances of inexorable rejection. In addition, declining mortality is directly attributable to improved methods of preventing, discovering, and treating patients with potential or real infections. More recently, in some centers, the rate of successful engraftment has shown gratifying improvement due to refinements in tissue typing, improved cross matching, new immunosuppressive therapies, and pretransplant conditioning with blood products. These recent improvements are the primary focus of this review. Unfortunately, until very recently, rates of functional survival of allografts have not been satisfactory.

Vascular and renal distribution of HLA--DR-like antigens

Tissue sections of ethanol-fixed, paraffin-embedded specimens from human kidney, placenta and umbilical cord were studied by indirect immunofluorescence with a rabbit antiserum to HLA--DR antigens from B lymphocytes. Capillary walls in the kidney showed specific staining both in glomeruli and around tubuli. Conversely, HLA--DR-like antigens were not detected in the walls of larger vessels, in tubular cells, or in the epithelium of Bowman's capsule. HLA-DR-like antigens of kidney elements thus seemed to be restricted to capillary endothelial cells. In specimens from umbilical cord and placenta, HLA--DR-like antigens were not detected in the walls of capillaries or larger vessels. Isolated endothelial cells from the umbilical vein were likewise negative.

Urine i-TXB2 in renal allograft rejection

Immunoreactive thromboxane B2 (i-TXB2) was measured in daily urine samples from twelve patients after renal transplantation. In 21 of 30 rejection episodes, the increase in i-TXB2 preceded both the increase in serum beta 2-microglobulin (beta 2-MG) and the clinical diagnosis of rejection. In 26 of 30 rejection episodes, the increase in urine i-TXB2 preceded the increase in serum creatinine. The degree of change in i-TXB2 is greater than that of either serum beta 2-MG or creatinine. Urinary i-TXB2 was very high in one patient with deep venous thrombosis, but it did not rise in patients with urinary tract infection, pneumonia, or acute tubular necrosis. Thus, urinary i-TXB2 seems to be an early indicator of clinical renal allograft rejection.

Influence of HLA matching in cadaveric renal transplantation: experience from one Scandiatransplant center

The outcome of 461 prospectively HLA-A, -B and -C typed and 193 prospectively HLA-DR typed cadaveric kidney transplants in one center was followed. We found a significant beneficial effect on graft survival both of HLA-A and -B as well as of HLA-DR matching between donor and recipient, while no effects of HLA-C compatibility could be detected. The effect of HLA-DR matching was clearly more pronounced than that of HLA-A and -B matching, and a possible influence of matching for HLA-A and -B could only be seen in the HLA-DR mismatched combinations. Pretransplant blood transfusions were associated with an increased graft survival only in patients receiving HLA-DR mismatched transplants. We conclude that major emphasis should be laid on obtaining HLA-DR compatibility in clinical renal transplantation.