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Background We have found antibodies against denatured HLA class I antigens in the serum of allograft recipients which were not significantly associated with graft failure. It is unknown whether transplant recipients also have denatured HLA class II and MICA antibodies. The effects of denatured HLA class I, class II, and MICA antibodies on long-term graft outcome were further investigated based on their ability to fix complement c1q. Materials and methods In this 4-year retrospective cohort study, post-transplant sera from 975 kidney transplant recipients were tested for antibodies against denatured HLA/MICA antigens and these antibodies were further classified based on their ability to fix c1q. Results Thirty percent of patients had antibodies against denatured HLA class I, II, or MICA antigens. Among them, 8.5% and 21.5% of all patients had c1q-fixing and non c1q-fixing antibodies respectively. There was no significant difference on graft survival between patients with or without antibodies against denatured HLA/MICA. However, when these antibodies were further classified according to their ability to fix c1q, patients with c1q-fixing antibodies had a significantly lower graft survival rate than patients without antibodies or patients with non c1q-fixing antibodies (p = 0.008). In 169 patients who lost renal grafts, 44% of them had c1q-fixing antibodies against denatured HLA/MICA antigens, which was significantly higher than that in patients with functioning renal transplants (25%, p < 0.0001). C1q-fixing antibodies were more significantly associated with graft failure caused by AMR (72.73%) or mixed AMR/CMR (61.9%) as compared to failure due to CMR (35.3%) or other causes (39.2%) (p = 0.026). Conclusions Transplant recipients had antibodies against denatured HLA class I, II, and MICA antigens. However, only c1q-fixing antibodies were associated with graft failure which was related to antibody mediated rejection. [ABSTRACT FROM AUTHOR]

In human cancers, over-expression of HLA-E is marked by gene expression. However, immunolocalization of HLA-E on tumor cells is impeded by the HLA-Ia reactivity of commercial anti-HLA-E monoclonal antibodies (MAbs). So there was a clear need to develop monospecific anti-HLA-E MAbs for reliable immunodiagnosis of HLA-E, particularly considering the prognostic relevance of HLA-E in human cancer. HLA-E overexpression is correlated with disease progression and poor survival of patients, both of which are attributed to the suppression of anti-tumor activity of cytotoxic T cells mediated by HLA-E. The suppression mechanism involves the binding of HLA-E-specific amino acids located on the α1 and α2 helices of HLA-E to the inhibitory receptors (CD94/NKG2a) on CD8+ T lymphocytes. An anti-HLA-E MAb that recognizes these HLA-E-specific sequences can not only be a monospecific MAb with potential for specific immunolocalization of HLA-E but can also block the sequences from interacting with the CD94/NKG2a receptors. We therefore developed several clones that secrete such HLA-E-specific MAbs; then we assessed the ability of the MAbs to bind to the amino acid sequences interacting with the CD94/NKG2a receptors by inhibiting them from binding to HLA-E with peptides that inhibit receptor binding. Elucidation of the immunomodulatory capabilities of these monospecific MAbs showed that they can induce proliferation of CD8+ T cells with or without co-stimulation. These novel MAbs can serve a dual role in combating cancer by blocking interaction of HLA-E with CD94/NKG2a and by promoting proliferation of both non-activated and activated CD8+ cytotoxic αβ T cells. [ABSTRACT FROM AUTHOR]

The US Food and Drug Administration approved intravenous immunoglobulin (IVIg), extracted from the plasma of thousands of blood donors, for removing HLA antibodies (Abs) in highly sensitized patients awaiting organ transplants. Since the blood-of healthy individuals has HLA Abs, we tested different IVIg preparations for reactivity to HLA single antigen Luminex beads. All preparations showed high levels of HLA-1a and -1b reactivity. Since normal nonalloimmunized males have natural antibodies to the heavy chains (HCs) of HLA antigens, the preparations were then tested against iBeads coated only with intact HLA antigens. All IVIg preparations varied in level of antibody reactivity to intact HLA antigens. We raised monoclonal Abs against HLA-E that mimicked IVIg's HLA-1a and HLA-1b reactivity but reacted only to HLA-1 HCs. Inhibition experiments with synthetic peptides showed that HLA-E shares epitopes with HLA-1a alleles. Importantly, depleting anti-HLA-E Abs from IVIg totally eliminated the HLA-1a. reactivity of IVIg. Since anti-HLA-E mAbs react with HLA-1a, they might be useful in suppressing HLA antibody production, similar to the way anti-RhD Abs suppress production. At the same time, anti-HLA-E mAb, which reacts only to HLA-1 HCs, is unlikely to produce transfusion-related acute lung injury, in contrast to antibodies reacting to intact-HLA. [ABSTRACT FROM AUTHOR]

Abstract: The current evidence clearly points towards donor specific alloantibody as a major cause of allograft loss. In order to mitigate allograft loss due to antibodies, treating the source of antibody production, the plasma cell is essential. Therapies that lack effect on the terminally differentiated (long-lived) plasma cell, such as rituximab, intravenous immune globulin and, plasmapheresis were the therapies used prior to 2007. In studies, their ability to remove antibody was found to be incomplete and/or cost prohibitive. In 2007, a proteasome inhibitor, bortezomib, was used for the first time in transplant due to its ability to deplete plasma cells. Through multiple case reports it has demonstrated consistent success in DSA reduction and removal, with only a few reports of failure to date. This review discusses the plasma cell, the alloantibody, and the current data supporting proteasome inhibitor use in transplant. [Copyright &y& Elsevier]

Abstract: This study defines 10 epitopes by murine monoclonal antibodies, of which seven are new and three were previously defined by alloantibodies. Of particular interest, three antibodies reacted with almost all Bw4-associated antigens except that each was negative with one or two of the antigens. One was negative with B13, one negative with A25, and another negative with B13 & A24 antigens. These monoclonal antibodies exhibited reactivity contrary to Bw4 allosera, which typically react with all Bw4-associated antigens. All monoclonal antibodies were tested with a panel of 97 human leukocyte antigen (HLA) class I (A, B, and Clocus) rHLA single antigens (SA) individually coupled to different microsphere beads. Identifying HLA antigens sharing distinct epitopes can be helpful when selecting patient–donor transplantation pairs, explaining antibodies against rare specificities, or against non–donor-specific antigens (NDSA). This study adds seven new HLA class I epitopes to 103 already defined epitopes and provides more evidence that a monoclonal antibody and alloantibody can target the same epitope. The fact that mAbs can target the same epitopes targeted by allosera, makes mAbs useful in studies of cross-reactivity in HLA. [Copyright &y& Elsevier]

Abstract: This study defines 96 epitopes targeted by human leukocyte antigen (HLA) antibodies reported in the sera of normal healthy males with no history of deliberate alloimmunizations and in cord blood. These epitopes are accessible for antibody binding on either the intact or the dissociated forms of recombinant HLA class I single antigens. Sixty percent of the epitopes are accessible on dissociated antigens, are defined mostly by hidden amino acids, and are designated as cryptic epitopes. All 96 epitopes are located exclusively on A-, B-, or C-locus antigens except for one interlocus epitope. All sera in this study were tested in parallel, using single antigen beads that bear either intact or dissociated HLA antigens and antibodies with nearly identical specificities were identified in all tested sera. Because the specificities of these naturally occurring antibodies are unavoidably detected when testing for specificities of alloantibodies, it may be necessary to clearly differentiate the two forms of antibody. To date, the relevance of these antibodies in transplantation is unknown, but even if they are determined to be irrelevant to graft rejection, awareness of the newly identified epitopes could prove useful in avoiding the unnecessary exclusion of potential transplant donors. [Copyright &y& Elsevier]

Abstract: The important role of preformed human leukocyte antigen (HLA) antibodies in the outcome of organ transplants has been well demonstrated for the past 40 years. During this same period, the significance of HLA antibody formation after transplantation was largely ignored. Only in the past 10 years has become increasingly clear that HLA antibodies formed posttransplantation are the major cause of allograft failure. We provide here an updated review of the critical evidence implicating HLA antibodies in chronic rejection. It has now also been shown that antibodies formed soon after transplantation are much more toxic to the graft than antibodies formed after the first year. This is likely a result of adaptation of the graft after the first year, possibly through endothelial cell replacement. On the basis of this new finding, a policy of monitoring for antibody development after 3, 6, 9, and 12 months, with yearly checks thereafter, is suggested. Another important new development is the use of bortezomib, a fresh new agent for the removal of antibodies. Because this is the first agent to act on plasma cells, its use is promising. Early data on successful removal of antibodies are reviewed here. [Copyright &y& Elsevier]

We earlier reviewed the reasons to believe that HLA antibodies are the cause of chronic rejection. In this review we shall focus on two questions: first, why is it important to test transplant recipients for alloantibody post-transplantation? Recent large-scale prospective studies on the effect of alloantibodies on graft survival showed that rates of graft failure more than doubled in recipients who had alloantibodies compared with antibody-free patients. The causal relationship between alloantibody and transplant rejection—especially chronic rejection—has been demonstrated both experimentally and clinically. We recommend universal testing of allograft recipients for antibodies since that will help clinicians identify this obvious risk factor and take appropriate action to minimize deterioration of transplant function. Second, why is it important to identify HLA antibody epitopes? Since HLA antibody is a potential cause of graft rejection, identifying the epitope—or antigenic determinant—to which an antibody binds, becomes very important. Such identification lets clinicians target the real transplant antigen and may lay a foundation for the development of new treatments and/or new matching strategies to reduce the occurrence of antibody-mediated rejection (AMR). Now that natural HLA antibodies have been identified; it is important to distinguish these from donor-specific epitopes. The establishment of 103 HLA class I epitopes, 83 class II, and 7 major-histocompatibility-complex class I-related chain A (MICA) epitopes is reviewed. Single antigen bead technology has been important in identifying the epitopes by experiment. [Copyright &y& Elsevier]

It is apparent from calculations that for paired kidney donation programs, a national program will provide optimum benefit. To obviate major problems associated with donors traveling long distances, we propose shipping donor kidneys. Evidence is provided from the United Network for Organ Sharing (UNOS) Kidney Transplant Registry, that 14 873 immediate functioning kidneys from deceased head-trauma donors with an average cold ischemia time of 18.3 h had 85.7% three-yr graft survival compared with 87.8% survival of 23 369 transplants from living donors with 2.4 h of ischemia. Grafts from 10 368 deceased donors with 13–24 h cold ischemia time had three-yr graft survival of 82.6% compared with 84.2% for 1153 transplants with up to six h cold ischemia time. After adjusting for major confounding factors, cold ischemia does not significantly influence graft survival. We conclude that shipment of donor kidneys can be performed safely and will significantly increase paired donor transplants. [ABSTRACT FROM AUTHOR]

Abstract: Antibodies to MICA and MICB antigens were sought in the sera of 139 kidney transplant recipients. MICA*001, *002, *007, *008, and MICB*002 antigens were produced in Escherichia coli and then tested using enzyme-linked immunosorbent assay plates. Among 35 normal sera, 6% had MIC antibodies, and among 14 sera from pregnant women, 21% had MIC antibodies. Among 34 patients with functioning transplants with human leukocyte antigen (HLA) antibodies, 24% had MIC antibodies, and 19% of 32 patients without HLA antibodies had MIC antibodies. Among 46 patients who lost grafts with HLA antibodies, 26% had MIC antibodies, and among 27 failed patients without HLA antibodies, 37% had MIC antibodies. We conclude that antibodies to MIC are produced in the course of immunization by pregnancies and kidney transplants. They also occurred more frequently in rejected patients (30%) than in those with functioning grafts (21%). [Copyright &y& Elsevier]

Background: The ABO incompatible kidney transplants have been performed successfully from large numbers of living donors and some blood type A2 deceased donors. However, there are few reports to support the feasibility of ABO incompatible transplants from non-A2 deceased donors. This problem was examined in the United Network for Organ Sharing (UNOS) data file. Patients and methods: The UNOS Registry data of kidney transplants performed between 1995 and 2003 from 256 centers was utilized for Kaplan–Meier curves and log-rank tests to compare graft and functional graft survival rates. Results: Deceased donor transplants from all ABO incompatible donors had the same graft survival rates, as that from ABO compatible donors regardless of whether the blood group incompatibility was A (A1), A2 or B. Graft survival from 201 ABO incompatible donors was 66.9% at 5 yr, compared with 66.7% for ABO compatible donors (p = 0.83). Non-A2 incompatible donors also yielded comparable survival rates to ABO compatible donors. From living donors, ABO incompatible donors yielded significantly lower graft survival rates than the ABO compatible group, although long-term graft survival rates of those who survived >1 yr did not differ significantly. Conclusion: Except higher initial graft loss possibility because of insufficient removal of antibodies, non-A2 kidneys yielded equivalent graft survival rates to ABO compatible transplants. In addition to A2 incompatibilities, Blood group A1 and B incompatibilities can also be considered in ABO incompatible transplants. [ABSTRACT FROM AUTHOR]

In the two and a half years following our initial paper on the humoral theory of transplantation, many publications have emerged in support of the hypothesis, with no studies in opposition. It is accepted that the role of antibodies is incontrovertible in hyperacute rejection, although what fraction of acute rejection is humoral remains to be determined. A recent large-scale prospective trial showing that transplant patients with antibodies have twice the failure rate as those without antibodies suggests that chronic rejection is also caused by antibodies. Together with serum creatinine, HLA antibodies are, therefore, the best predictor of graft function in kidney patients. [Copyright &y& Elsevier]

Abstract: We discuss the potential mechanisms of antibody-induced primary endothelium injury, which includes complement-dependent pathway (membrane attack complex formation, recruitment of inflammatory cells, and complement-complement receptor-mediated phagocytosis) and complement independent pathway antibody-dependent cell cytotoxicity. Secondary to endothelium injury, the following pathological reactions are found to be responsible for progressive tissue injury and final graft function loss: platelet activation and thrombosis, pathological smooth muscle and endothelial cell proliferation, and humoral and/or cellular infiltrate-mediated parenchyma damage after endothelium injury. We also introduce three categories of therapeutic strategy in the prevention and treatment of antibody-mediated rejection: (1) inhibition and depletion of antibody producing cells (immunosuppressants, antilymphocyte antibodies, splenectomy); (2) removal or blockage of preexisting or newly developed antibodies (immunoadsorption, plasmapheresis/plasma exchange, intravenous immunoglobulin); and (3) impediment or postponement of antibody-mediated primary and secondary tissue injury (anticoagulation, glucosteroids). In conclusion, because alloantibodies have destructive effect on allografts, alloantibody monitoring becomes extremely important. It will help clinicians to determine a patient¿s humoral responses against allograft and will therefore direct clinicians to optimize and/or minimize immunosuppressive drug therapy. [Copyright &y& Elsevier]

Background: The methods used to allocate cadaveric kidneys in the United States have been criticized as being unfair to minorities because of an over-emphasis on HLA matching. We evaluated a new HLA-matching method that might alleviate this problem.Methods: We used data from the United Network for Organ Sharing (UNOS) Kidney Transplant Registry to evaluate and project the outcome of cadaveric kidney transplantation. An HLA-matching method based on compatibility at 10 key amino acid residues of HLA-A and B molecules and a limited number of HLA-DR types was evaluated with use of the HLA types of the patients currently on the national waiting list and waiting lists in Los Angeles and Birmingham, Alabama.Results: With national kidney sharing, the projected 10-year rate of graft survival for transplants in which there were no HLA-A, B, or DR mismatches was 66 percent, as compared with 39 percent for transplants with more than two HLA-A, B, or DR mismatches. With local sharing, 43 percent of patients could be fully matched, and they had a projected 10-year graft-survival rate of 50 percent. When one HLA-DR mismatch was allowed, the projected 10-year graft survival was 46 percent, and 67 percent of patients waiting locally could receive such grafts. Even in Alabama, where 68 percent of the patients on the waiting list are black, 48 percent of waiting patients could obtain a matched kidney.Conclusions: Inserting two new HLA-matching categories into the UNOS point system for cadaveric kidney allocation would increase the number of patients for whom matches could be found in local pools. [ABSTRACT FROM AUTHOR]

Comments on HLA histocompatibility typing and transplantation of cadaveric kidneys. Details a prospective trial which began four years ago in all US transplantation centers, to determine whether the results of transplantation would improve with the nationwide shipment of kidneys from cadaveric donors to waiting patients undergoing dialysis when there was a match at the HLA-A, B, and DR loci. Study methods, results, more.

Presents a study to determine the feasibility of a national allocation of cadaveric kidneys by HLA matching. Background; Methods; Results; Conclusions; Graft-survival rates; Projected costs.

OBJECTIVE -- To determine whether short-term improvement in pancreas graft survival with simultaneous pancreas-kidney (SPK) transplants translated into improved long-term survival, then to examine the implications of that determination. RESEARCH DESIGN AND METHODS -- We analyzed data for 14,311 diabetic patients who received a first SPK transplant between October 1987 and November 2007, using Kaplan-Meier analysis for graft survival rates and Cox regression analysis for year-of-transplant effect. RESULTS -- Overall, from 1995 to 2004, 5-year pancreas graft survival stayed about the same (70-71%). Limiting analysis to grafts that survived more than 1 year, 5-year survival from 1987 to 2004 ranged from 80 to 84%. With 1987-1989 as reference, the adjusted hazard ratio for graft failure by year of transplant increased to 1.49 (95% CI 0.97-2.30) in 2000-2004. CONCLUSIONS -- Long-term pancreas graft survival has remained unchanged despite the dramatic decreases in technical failures and early acute rejection rates that have contributed to prolonged SPK graft survival. [ABSTRACT FROM AUTHOR]

The article presents the results of a case study regarding kidney graft and patient survival with and without a simultaneous pancreas utilizing contralateral kidneys from the same donor. The study found that by utilizing the contralateral kidneys, kidney allograft outcome in simultaneous pancreas-kidney (SPK) transplantation recipients was higher than that in kidney-alone (KA) recipients. SPK was not associated with improved long-term kidney allograft and patient survival compared with KA.

Reports on research into the presence of specific HLA haplotypes in patients with either primary sclerosing cholangitis or primary biliary cirrhosis. Presence of HLA-DRw52a antigen; Presence of ulcerative colitis; Association between primary biliary cirrhosis and specific HLA haplotypes; Conclusion.

A letter to the editor is presented about kidney paired donation in the U.S.

BACKGROUND Widespread implementation of kidney paired donation programs could require transportation of donated organs over long distances. The resultant increase in cold ischemia time might reduce the beneficial effect of living donor transplantation. OBJECTIVE To investigate the effect of cold ischemia time on the long-term outcomes of living donor kidneys. DESIGN AND INTERVENTION For this retrospective cohort study, data from adults who had received a living donor kidney between January 1990 and September 2005 were obtained from the United Network for Organ Sharing. Previous renal transplantation was an exclusion criterion. The cohort was divided into 4 subgroups based on the duration of cold ischemia experienced by the graft (0-2 h [reference group], 2-4 h, 4-6 h and 6-8 h). Patients whose grafts had experienced no or >8 h of cold ischemia time were excluded. Graft outcomes were then compared between the subgroups. OUTCOME MEASURES The end points were serum creatinine level 1 year after transplantation, and rates of delayed graft function (DGF; need for dialysis within 1 week of transplantation), acute rejection (within 1 year of transplantation) and 10-year allograft survival. RESULTS The 38,467 patients analyzed had a median age of 43 years, and 58.3% were male. Cold ischemia time was 0-2 h in 85.1% of cases, 2-4 h in 12.1% of cases, 4-6 h in 1.8% of cases and 6-8 h in 1.0% of cases. The unadjusted rate of DGF was 4.9% in the reference cold-ischemia-time group, compared with 5.8%, 8.4% and 7.5% in the 2-4 h, 4-6 h and 6-8 h groups, respectively. When adjusted for potential confounders (e.g. recipient race/ethnicity and history of diabetes mellitus) using multivariate regression, the probability of DGF was found to differ significantly from the reference group only in the 4-6 h group (8.3% vs 4.7%; P<0.001). Analysis of the patients who had a functioning allograft and serum creatinine data at 1 year after transplantation (approximately 70% of the total cohort) revealed no significant differences in serum creatinine level between the reference cold-ischemia-time group and any of the other groups. In the subset of patients who had at least 1 year of follow-up (n=35,693), the unadjusted rate of acute rejection was 27.0% in the reference group, compared with 21.4%, 19.7% and 41.6% in the 2-4 h, 4-6 h and 6-8 h groups, respectively. After adjustment, the corresponding values were 26.5%, 20.5%, 18.9% and 27.9%, respectively, indicating that the risk of acute rejection was not greater in the 2-4 h, 4-6 h or 6-8 h cold-ischemia-time groups than in the reference group. There was no significant difference in overall or death-censored 10-year allograft survival between the cold-ischemia-time groups (P=0.15 and P=0.45, respectively). CONCLUSION Although cold ischemia time of up to 8 h is associated with a slightly increased risk of DGF following living donor kidney transplantation, there seems to be no adverse knock-on effect on graft rejection, function or survival. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor regarding a previously published article which discussed mismatching errors in heart transplants.

Background: In October 1987, the United Network for Organ Sharing (UNOS) established a national kidney-sharing program to increase the number of HLA-matched transplantations. Since then, over 7500 cadaveric kidneys have been shipped to centers in 48 states for transplantation to HLA-matched patients. We evaluated the efficacy of the program during its first 12 years of operation. Methods: We compared the rates of rejection and actuarial graft survival for 7614 HLA-matched and 81,364 HLA-mismatched cadaveric kidney transplantations reported to the UNOS Scientific Registry between October 1987 and September 1999. To assess the effects of the extended period of ischemia associated with shipping HLA-matched kidneys, we identified 3562 pairs of cadaveric kidneys in which one kidney went to an HLA-matched recipient and the other went to an HLA-mismatched recipient. Results: The estimated 10-year rate of graft survival was 52 percent for HLA-matched transplants, as compared with 37 percent for HLA-mismatched transplants. The estimated half-lives of the transplants were 12.5 years and 8.6 years, respectively, and the mean duration of cold ischemia was 23 hours and 22 hours, respectively. After adjustment for the effects of demographic characteristics, at 10 years the overall rates of graft survival and the rates of functional-graft survival (with data censored on patients who died with a functioning graft) were 10 percent and 11 percent higher, respectively, for HLA-matched transplants than for HLA-mismatched transplants. Among 3562 pairs of kidneys, HLA-matched transplants had higher rates of survival, a lower incidence of episodes of rejection, and a lower risk of loss as a result of rejection. Conclusions: A superior graft outcome with little increase in the duration of cold ischemia justifies national sharing of HLA-matched kidney transplants. (N Engl J Med 2000;343:1078-84.) [ABSTRACT FROM AUTHOR]

Background: Attempts have recently been made to expand the number of cadaveric kidneys available for transplantation by using kidneys from donors without heartbeats in addition to those from brain-dead donors with beating hearts. We studied the efficacy of transplanting kidneys from donors without heartbeats on the basis of aggregate results from the Kidney Transplant Registry of the United Network for Organ Sharing. Methods: We compared the early function and survival rates of 229 kidney grafts from donors without heartbeats with those of 8718 grafts from cadaveric donors with heartbeats. All transplantations were performed at 64 U.S. transplantation centers. Cox proportional-hazards analysis was used to evaluate 10 major risk factors for graft failure. Results: The survival rate at one year was 83 percent for kidney grafts from donors without heartbeats, as compared with 86 percent for grafts from donors with heartbeats (P = 0.26). Among the kidneys from donors without heartbeats, the survival rate at one year was 89 percent for grafts from donors who had died of trauma, as compared with 78 percent for grafts from donors who had died of other causes (P = 0.04). The survival rates were high for grafts from donors without heartbeats despite the poorer early function of these grafts; 48 percent of the recipients required dialysis within the first week after transplantation, as compared with 22 percent of the recipients of grafts from donors with heartbeats. The primary-failure rate for kidneys from donors without heartbeats was 4 percent, as compared with 1 percent for kidneys from donors with heartbeats. Conclusions: Transplantation of kidneys from donors whose hearts have stopped beating, especially those who have died of trauma, is often successful, and the use of kidneys from such donors could increase the overall supply of cadaveric kidney transplants. (N Engl J Med 1998;338:221-5.) [ABSTRACT FROM AUTHOR]

Background: In the United States, increasing numbers of persons are donating kidneys to their spouses. Despite greater histoincompatibility, the survival rates of these kidneys are higher than those of cadaveric kidneys. We examined the factors influencing the high survival rates of spousal-donor kidneys. Methods: Kidney-transplant data from the United Network for Organ Sharing Renal Transplant Registry were used to calculate graft-survival rates with Kaplan–Meier analysis. Results: The three-year survival rates were 85 percent for kidneys from 368 spouses, 81 percent for kidneys from 129 living unrelated donors who were not married to the recipients, 82 percent for kidneys from 3368 parents, and 70 percent for 43,341 cadaveric kidneys. The three-year survival rate for wife-to-husband grafts was 87 percent, which was the same as for husband-to-wife grafts if the wife had never been pregnant. If the wife had previously been pregnant, the three-year graft-survival rate was 76 percent (P = 0.40). The three-year graft-survival rate among recipients of spousal grafts who did not receive transfusions preoperatively was 81 percent, as compared with 90 percent for recipients who received 1 to 10 transfusions preoperatively (P = 0.008). The superior survival rate of grafts from unrelated donors could not be attributed to better HLA matching, white race, younger donor age, or shorter cold-ischemia times, but might be explained by damage due to shock before removal in 10 percent of the cadaveric kidneys. Conclusions: Spouses are an important source of living-donor kidney grafts because, despite poor HLA matching, the graft-survival rate is similar to that of parental-donor kidneys. This high rate of survival is attributed to the fact that the kidneys were uniformly healthy. (N Engl J Med 1995;333:333-6.) [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article regarding the equitable allocation of HLA-compatible kidneys for local pools and for minorities by Takemoto and colleagues in the September 22, 1994 issue.

A response by Steve Takemoto and colleagues to a letter to the editor about their article related to the analysis of risk factors for graft failure in the September 17, 1993 issue is presented.

HLA-E expressed on the surface of melanoma cells and shed into circulation are known to inhibit killing of tumor cells by binding to CD94/NKGA2 receptors on cytotoxic T- and NKT cells. Interferon (IFN)- γ is known to promote HLA-E over-expression on the cell surface and shedding. The shed HLA-E heavy chain may expose cryptic epitopes to elicit antibodies (Abs). The anti-HLA-E Abs may bind to shed HLA-E or to the tumor cell surface to block its interaction with CTL/NKT cells. This is the basis for a melanoma cell vaccine that will generate anti-HLA-E Abs. The objective of this study was to characterize the antibody response and characterize the cross-reactivity of the antibodies produced in melanoma patients immunized with autologous melanoma cells treated with IFN γ. Anti-HLA-E murine mAbs and serum anti-HLA-E Abs in healthy individuals were known to react with HLA-Ia alleles, which is attributed to the presence of peptide sequences shared between HLA-E and HLA-Ia. Therefore, pre- and post-immune (weeks 4 and 24) serum Abs reacting to both HLA-E and HLA-Ia alleles were measured by multiplex Luminex®-based immunoassay. To ascertain whether the reactivity of the serum Abs to HLA-Ia was due to anti-HLA-E Abs, the shared-peptides were used to inhibit anti-HLA-E and HLA-Ia reactivities. The level of anti-HLA-E IgG in sera has increased post-immunization from its pre-immune level. Concomitantly, the HLA-Ia reactivity of the sera was also augmented. The reactivity of both anti-HLA-E Abs and HLA-Ia were inhibited by the shared-peptides. The HLA-Ia reactivity of the anti-HLA-E Abs in patients' sera is similar to the HLA-Ia reactivity of the anti-HLA-E mAbs and anti-HLA-E Abs in normal sera. The results establish the immunogenicity of HLA-E and also ascertain that the HLA-Ia reactivity of the anti-HLA-E Abs is due to shared-peptide epitopes. [ABSTRACT FROM AUTHOR]

Luminex multiplex immunoassays enable simultaneous monitoring of Abs against multiple Ags in autoimmune, inflammatory, and infectious diseases. The assays are used extensively to monitor anti-HLA Abs in transplant patients for donor organ selection, desensitization, and assessing the risk for graft rejection. To monitor IgG Abs, fluoresceinated IgG constant H chain-binding polyclonal F(ab9)2 (IgHPolyFab) is used as the fluoresceinated secondary Ab (2nd-Ab), whereas IgG subclasses are monitored with Fc-specific monoclonal whole IgG (FcMonoIgG). The fluorescent signal from the 2nd-Ab is measured as mean florescence intensity (MFI). When IgHPolyFab is used, the signal is amplified as a result of the binding of multiple polyclonal Fabs to the C region of primary IgH. The reliability of such amplification for Ab measurements was not validated, nor were MFIs compared with 1:1 binding of FcMonoIgG to primary Abs. Comparing the MFIs of anti-HLA Abs obtained with IgHPolyFab and FcMonoIgG against normal human sera, IVIg, and allograft recipients' sera, it was observed that the number of HLA-Abs was notably higher with IgHPolyFab than with FcMonoIgG. The MFIs of anti-HLA Abs also remained higher with IgHPolyFab in the normal sera and in IVIg, but the reverse was true when the autologous and allogeneic IgG concentrations were augmented in allograft recipients. Indeed, MFIs of the de novo allo-HLA Abs were markedly higher with FcMonoIgG than with IgHPolyFab. Serum titration established the superiority of FcMonoIgG for monitoring MFIs of de novo allo-HLA Abs in allograft recipients. Avoiding false amplifications of the number and MFIs of anti-HLA IgG with FcMonoIgG may minimize immunosuppressive therapies, maximize the number of donors for patients waiting for allografts, and enable better prediction of graft rejection. [ABSTRACT FROM AUTHOR]

Background: A considerable proportion of patients awaiting kidney transplantation is immunized by previous transplantation(s). We investigated how allograft nephrectomy (Nx) and withdrawal of maintenance immunosuppression (WD-MIS) in patients with a failed renal allograft contribute to allosensitization. Methods: HLA antibodies (HLAabs) were analyzed before and after Nx and/or WD-MIS using a single antigen bead assay. Patients were grouped as follows: (A) Nx and concomitant WD-MIS (n = 28), (B) Nx (n = 14) and (C) WD-MIS (n = 12). In a subgroup of patients, the epitope specificity of HLAabs was determined by adsorption and elution of sera with recombinant single HLA allele–expressing cell lines. Results: Following Nx and/or WD-MIS, HLAabs were detectable in 100, 100 and 92% of patients in Groups A, B and C, respectively. In patients of all groups, de novo donor-specific HLAabs (DSAs) were found. After Nx, an increase in the breadth [percent panel reactive antibody (%PRA)] and mean fluorescence intensity of class I HLAabs was predominant. In contrast, an increase of class II HLAabs prevailed following WD-MIS. Experimental analysis of the epitope specificities revealed that 64% of the class I HLAabs classically denoted as non-DSA were donor epitope-specific HLAabs (DESA). Conclusions: Both Nx and WD-MIS contribute to alloimmunization with differing patterns concerning class I and II HLAabs. Nx preferentially increased class I HLAabs and most of the observed class I HLAabs were DESA. Considering that class I, but not class II, HLA molecules are constitutively expressed, our results support the hypothesis that the increase of HLAabs following Nx might have been caused by removal of the adsorbing donor tissue (sponge hypothesis). [ABSTRACT FROM AUTHOR]

The presence of IgG against pathogens in the cord blood (CB) of vaccinated mothers is attributed to transplacental transfer. However, previous studies using lymphocytotoxicity assay showed anti-HLA IgG in mother’s blood (MB) but not in CB, perhaps due to non-transfer of anti-HLA IgG or assay limitations in detecting anti-HLA IgG. Anti-HLA IgG of native and purified sera of 16 MB and CB pairs were measured using an array of microbeads coated with HLA-I/-II molecules on a Luminex platform. Two cases showed no anti-HLA-I IgG in either MB or CB; four MB cases displayed polyallelic HLA-reactive IgG, with negligible or no reactivity by the corresponding CB sera. Notably, anti-HLA-I reactivity in cases 3–6/11/12 and anti-HLA-II reactivity in cases 1/3/4/6/8/11–13 were restricted to CB, with lower or no HLA-reactivity in MB. Mothers’ HLA typing is done for HLA-A*, HLA-B* and DRB1* alleles. The mother in case 14 carried DRB1*11:01, the allele-reactive IgG is seen in both native and the purified fraction of sera of MB but not in CB. Also in cases 15 (DRB1*01:01) and 16 (B*49:01 and DBR1*07:01), the allele-reactive IgGs are seen in both native and purified fractions of MB but not in CB confirming the earlier reports on the absence of materno-fetal transfer of anti-HLA IgG. However, the mother of case 6 is homozygous for DRB1*03:01 and the allele-reactive IgG occurred in both MB and CB, confirming the presence of anti-HLA autoantibodies. In Case 13, the mother (HLA-A*24 and HLA-A*52) and CB carried allele-reactive IgG in both native and purified sera, indicating the possible occurrence of transplacental transfer of the IgG. Further confirmation is restricted by the paucity of detailed molecular HLA typing for both the parents and fetuses. While 37.5% of the native IgG in CB and 18.8% in MB showed DRB3*03:01 reactivity, 100% of purified IgG from both CB and MB showed anti-DRB3*03:01 and anti-DPA1*02:01\ DPB1*23:01 antibodies. Several CB cases showed high-prevalence IgG reacting to a single allele of HLA-I and/or HLA-II with minimal or no cross-reactive IgG in CB or in the MB, suggesting the presence of de novo antibodies, possibly against non-inherited maternal HLA or inherited parental HLA haplotypes by the fetus. [ABSTRACT FROM AUTHOR]

Graft failure and survival are the major problems for patients with aplastic anemia undergoing hematopoietic stem cell transplantation ( HSCT). Previous studies showed that anti- HLA antibodies negatively impact engraftment in HSCT. This retrospective study of 51 pediatric patients with acquired aplastic anemia who underwent allogeneic HSCT at a single institution between 2006 and 2012 investigated the influence of anti- HLA antibodies on the outcome of HSCT. Serum samples collected before HSCT were tested for the presence of anti- HLA antibodies. Pre-existing anti- HLA antibodies were detected in 54.9% (28/51) of patients, among whom 39.2% (20/51) had anti- HLA class I antibodies. Anti- HLA antibodies were associated with worse five-yr survival (78.6% vs. 100%, p = 0.021) and higher treatment-related mortality (21.4% vs. 0%, p = 0.028) compared with antibody-negative patients. Anti- HLA class I antibody-positive patients had poorer five-yr survival (75.0%) than anti- HLA class I& II antibody-positive and antibody-negative patients (87.5% and 100.0%, respectively, p = 0.039). Presence of anti- HLA class I antibodies (p = 0.024) and older age (10 yr or more; p = 0.027) significantly increased the risk of post- HSCT mortality. Pre-existing anti- HLA antibodies negatively affect the outcome of HSCT in pediatric patients with aplastic anemia. Routine testing for anti- HLA antibodies concurrent with efficient treatment should be conducted prior to HSCT. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The clinical relevance of pre-transplant “low-level” donor specific anti-HLA antibodies (DSAs) in crossmatch negative kidney transplant recipients remains unclear. To determine what level of DSA associates with antibody mediated rejection (AMR) could be the way to measure the clinical relevance of pre-transplant “low-level” donor specific anti-HLA antibodies (DSAs) in crossmatch negative kidney transplant recipients. Design and methods: A retrospective analysis of 221 patients from October 2008 to December 2009 was included in this study. Sera were obtained pre-transplant and two weeks post-transplant and tested for DSA using LABScreen single antigen beads. Results: Among the 221 patients, 11 experienced AMR within 200days after transplant (5%). Pre-transplant DSA was associated with AMR at multiple mean fluorescence intensity (MFI) cutoffs (500, 1000, 2000, 3000, 5000; p=0.003, 0.001, 0.007, 0.003, and 0.003, respectively). No correlation was seen between acute T-cell mediated rejection (CMR) and pre-transplant DSA at any of the same MFI cutoffs. There was an increased risk of AMR with higher levels of pre-transplant DSA. Finally, an increase in DSA MFI from pre- to two weeks post-transplant was indicative of a higher probability of AMR. Conclusion: Overall, this data supports using the single antigen bead to detect “low-level” DSA both pre- and post- as having a positive and persistent DSA may be predictive of higher AMR rates and poorer graft survival. [Copyright &y& Elsevier]

Abstract: Donor-specific antibodies (DSA) in sera of sensitized transplant patients are often produced against the specific epitopes on mismatched HLA antigens. In this study, we selected sera from 30 kidney transplant patients with DSA and AMR to define DQ epitopes. Using adsorption and elution assays, we identified 18 antibody reaction patterns to define 6 new epitopes and to confirm 12 previously defined epitopes. In one patient case, one mismatched antigen produced 3 different antibodies and, in another, antibodies were produced against the alpha and beta chains of the same antigen. For some sera, a single epitope can explain reactions for 27 of the 29 DQ beads in the single antigen panel. Several studies highlighted the prevalence of anti-DQ antibodies. In 2011, Almeshari et al. observed DQ DSA in 34/46 (74%) of rejection episodes – 44 patients had DSA and 20 lost their graft due to AMR. Other studies have shown a high prevalence of anti-DQ antibodies and an association with adverse effects on the graft. We conclude that analysis of the epitopes of the DQ antibodies using Adsorption/Elution and testing on single antigen DQ beads helps to better understand the specificities and cross-reactions of DQ antibodies in transplant patients. [Copyright &y& Elsevier]

Long-term clinical outcome of islet transplantation is hampered by the rejection and recurrence of autoimmunity. Accurate monitoring may allow for early detection and treatment of these potentially compromising immune events. Islet transplant outcome was analyzed in 59 consecutive pancreatic islet recipients in whom baseline and de novo posttransplant autoantibodies (GAD antibody, insulinoma-associated protein 2 antigen, zinc transporter type 8 antigen) and donor-specific alloantibodies (DSA) were quantified. Thirty-nine recipients (66%) showed DSA or autoantibody increases (de novo expression or titer increase) after islet transplantation. Recipients who had a posttransplant antibody increase showed similar initial performance but significantly lower graft survival than patients without an increase (islet autoantibodies P < 0.001, DSA P < 0.001). Posttransplant DSA or autoantibody increases were associated with HLA-DR mismatches (P = 0.008), induction with antithymocyte globulin (P = 0.0001), and pretransplant panel reactive alloantibody >15% in either class I or class II (P = 0.024) as independent risk factors and with rapamycin as protective (P = 0.006) against antibody increases. DSA or autoantibody increases after islet transplantation are important prognostic markers, and their identification could potentially lead to improved islet cell transplant outcomes. [ABSTRACT FROM AUTHOR]

Aim: In 2008, an international collaborative study of post-transplant monitoring was launched with 44 transplant centers from 17 countries. One aim of the project was to study the time course of antibody development, from time of transplant to months and years post-transplantation, to examine the incidence of antibodies, time to antibody appearance, and time to clinical events. We also investigated possible factors affecting antibody development across multiple centers. Methods: As of May 2012, antibody data for 5,057 serial sera from 470 kidney and 97 heart recipients were submitted. For each patient, 3 to 12 sera were collected at various intervals from 1mo to 14yrs post-transplantation. Antibody testing was done by luminex methodology. Patient data including age, ethnicity, HLA mismatches, immunosuppression, serum creatinine, and clinical events were collected. An Antibody Tracking Program was developed to analyze antibody profile. Results: At the time of this report, analysis was done for 224 patients. Figure shows an example of antibody plot generated by the tracking program. Incidence of donor-specific antibodies (DSA) at first year was approx. 10%. Median time to antibody appearance was 34 mo. Factors increasing DSA development included deceased donors and level of HLA mismatches. We are continuing to receive data from centers, and further investigation of factors affecting DSA production is underway. Conclusions: In studying natural history of antibody development across multiple centers, we are now able to identify some of the common factors that are predictive of DSA production, and gain an insight as to the time course of antibody development and clinical outcome [Fig. 1]. Display Omitted Ozawa: One Lambda Inc.: Employee. Everly: One Lambda Inc.: Employee. Terasaki: One Lambda Inc.: Stockholder. [Copyright &y& Elsevier]

The non-donor-specific anti-HLA-Ia antibodies correlate significantly with lower graft survival in organ transplant patients. Based on our earlier findings that anti-HLA-E murine monoclonal antibodies (MEM-E/02 and 3D12) reacted with different HLA-Ia alleles and the peptides shared by HLA-E and HLA class, Ia alleles inhibited the HLA-Ia reactivity of the anti-HLA-E antibodies in normal non-alloimmunized males, the possibility of that anti-HLA-E IgG may account for the non-donor-specific anti-HLA-Ia antibodies in the allograft recipients was examined by multiplex-Luminex®-immunoassay. About 73% of renal and 53% of liver transplant patients’ sera with high level of anti-HLA-E IgG showed reactivity to different non-donor HLA-Ia alleles. About 50% renal and 52% liver allograft recipients’ sera with low level of anti-HLA-E IgG had no reactivity to any HLA-Ia alleles; however, the IgG isolated from the same sera with protein-G columns showed the presence of anti-HLA-E IgG with HLA-Ia reactivity. Furthermore, both recombinant HLA-E and the IgG-free serum containing soluble HLA-E (sHLA-E) inhibited HLA-Ia reactivity of anti-HLA-E murine monoclonal IgG significantly. The data suggest that the HLA-Ia reactivity of the anti-HLA-E antibody accounts for the non-donor-specific anti-HLA-Ia antibodies. It is proposed that the sHLA-E heavy chain, shed in circulation after organ transplantation, may expose cryptic epitopes of HLA-E to elicit anti-HLA-E IgG antibodies, which may cross react with HLA-Ia alleles due to the peptide sequences shared between them. This study provides a new explanation for the presence of non-donor-specific antibodies for non-existing HLA-Ia alleles, frequently observed and correlated with survival in organ transplant recipients. [ABSTRACT FROM AUTHOR]

Abstract: HLA-E shares several peptide sequences with HLA-class Ia molecules. Therefore, anti-HLA-E antibodies that recognize the shared sequences may bind to HLA-class Ia alleles. This hypothesis was validated with a murine anti-HLA-E monoclonal antibody (mAb) MEM-E/02, which reacted with microbeads coated with several HLA-B and HLA-C antigens. In this report, the hypothesis was reexamined with another mAb 3D12, considered to be specific for HLA-E. The antibody binding is evaluated by measuring mean fluorescence index [MFI] with Luminex Multiplex Flow-Cytometric technology. The peptide-inhibition experiments are carried out with synthetic shared peptides, most prevalent to HLA-E and HLA-Ia alleles. The results showed that mAb 3D12 simulated MEM-E/02 in recognizing several HLA-B and HLA-C antigens. Both 3D12 and MEM-E/02 did not bind to HLA-A, HLA-F and HLA-G molecules. As observed with MEM-E/02, binding of 3D12 to HLA-E is inhibited by the peptides sequences 115QFAYDGKDY123 and 137DTAAQI142. Decrease in binding of mAb 3D12 to HLA class Ia, after heat treatment of antigen coated microbeads, supports the contention that the epitope may be located at the outside of the “thermodynamically stable” α-helix conformations of HLA-E. Several sequence and structure-based web-tools were employed to validate the discontinuous epitopes recognized by the mAbs. The scores obtained by these web-tools distinguished the shared peptide sequences that inhibited the mAb binding to HLA-E. Furthermore, ElliPro web tool points out that both mAbs recognize the conformational discontinuous epitopes (the shared inhibitory peptide sequences) in the secondary structure of the HLA-E molecule. The study favors the contention that the domain of the shared inhibitory peptide sequences may be the most immunogenic site of HLA-E molecule. It also postulates and clarifies that amino acid substitution on or near the binding domains may account for the lack of cross reactivity of 3D12 and MEM-E/02 with HLA-A, HLA-F and HLA-G molecules. [Copyright &y& Elsevier]