Non-HLA Antibodies to Immunogenic Epitopes Predict the Evolution of Chronic Renal Allograft Injury

Chronic allograft injury (CAI) results from a humoral response to mismatches in immunogenic epitopes between the donor and recipient. Although alloantibodies against HLA antigens contribute to the pathogenesis of CAI, alloantibodies against non-HLA antigens likely contribute as well. Here, we used high-density protein arrays to identify non-HLA antibodies in CAI and subsequently validated a subset in a cohort of 172 serum samples collected serially post-transplantation. There were 38 de novo non-HLA antibodies that significantly associated with the development of CAI (P<0.01) on protocol post-transplant biopsies, with enrichment of their corresponding antigens in the renal cortex. Baseline levels of preformed antibodies to MIG (also called CXCL9), ITAC (also called CXCL11), IFN-, and glial-derived neurotrophic factor positively correlated with histologic injury at 24 months. Measuring levels of these four antibodies could help clinicians predict the development of CAI with >80% sensitivity and 100% specificity. In conclusion, pretransplant serum levels of a defined panel of alloantibodies targeting non-HLA immunogenic antigens associate with histologic CAI in the post-transplant period. Validation in a larger, prospective transplant cohort may lead to a noninvasive method to predict and monitor for CAI (read more).

Rapamycin Paradox Resolved

A small molecule acts through separate mechanisms to exert very different effects—extend mammalian life span or impair glucose homeostasis (read more)

Age is an important predictor of kidney transplantation outcome

Background. Donor and recipient age may have an impact on the renal transplant outcome. Kidney transplantation from older donors may result in a worse outcome, and the survival benefit of kidney transplantation compared with dialysis may be reduced. The aim of this study was to evaluate the impact of donor and recipient age on kidney transplant outcome.
Materials and methods. Two hundred and twenty-three recipients of kidney transplants performed at our institution between 2002 and 2007 were analysed. The role of donor and recipient age matching on survival rate were investigated performing the Kaplan–Meier survival time analysis by decades, considering the donor’s age of 60 and 70 years. The Cox proportional hazard uni- and multivariate regressions were also performed. Finally, Kaplan–Meier survival time analysis was performed to assess survival rates of patients transplanted stratified by donor age compared with wait-listed renal transplant candidates.
Results. Elderly recipients had a significant lower graft and patient survival as well as a significantly higher risk of graft loss and patient death. Recipients younger and older than 65 years of age were at higher risk of graft loss if they received grafts from donors >65 years [hazard ratio (HR) = 2.59, 95% confidence interval (CI): 1.12–6 and HR = 5.65, 95% CI: 2.31–13.79, respectively]. Elderly recipients displayed a worse survival compared with transplant candidates on the waiting list.
Conclusions. Age is an important predictor of kidney transplantation outcome. Kidney transplantation does not offer a significant survival benefit in the intermediate term, compared to the waiting list, to elderly recipients transplanted with grafts from older donors. However, it cannot be excluded that it is still possible that there is a long-term benefit of transplantation over dialysis in this group of patients (read more).

The First Report of Orthotopic Liver Transplantation in the Western World

Until the present time, the first experimental liver transplant which led to the development of human liver transplantation is attributed to C. Stuart Welch who performed a heterotopic transplant in the canine species in 1955. In 1956, Jack Cannon is credited with the first animal orthotopic liver transplant although the species was not disclosed. This report is intended to set the historical record straight by acknowledging that Vittorio Staudacher in 1952 was the first to perform a liver transplant in a large animal model (read more).

Endothelial Chimerism After ABO-Incompatible Kidney Transplantation

Background. Endothelial chimerism in transplanted organs can be defined as the presence of recipient-derived endothelial cells in the donor organ. The mechanism of endothelial chimerism is not well understood and remains controversial. The purpose of this study was twofold. First, we investigated the presence of chimerism in renal allografts of ABO-incompatible kidney transplantation recipients. Second, we analyzed the association between chimerism and the clinical course and histopathological changes.
Methods. We investigated the presence of chimerism in renal allografts of ABO-incompatible kidney transplantation recipients by immunohistochemical detection of blood type A and B antigens and assessed the association between chimerism, the clinical course, and histopathological changes. Among a total of 56 patients (29 blood group A incompatible and 27 blood group B incompatible), 49 cases (28 blood group A incompatible and 21 blood group B incompatible) were enrolled in this study. Blood group antigens were stained using immunohistochemistry.
Results. Twelve of the 49 patients (12/49, 24.5%) exhibited endothelium chimerism in a biopsy sample. Among the 12 patients with endothelium chimerism, 7 patients (7/12, 59%) had acute and chronic active antibody-mediated rejection and 2 patients (2/12, 17%) had severe calcineurin inhibitor toxicity. The graft survival rate in the chimerism group was significantly lower than that in the no-chimerism group ([chimerism vs. no-chimerism] 3 years, 83.3% vs. 97.1%; 5 years, 74.1% vs. 97.1%; 8 years, 46.3% vs. 97.1%; P<0.0001).
Conclusions. Endothelial chimerism seems to be a hallmark of vigorous immune or nonimmune responses, such as antibody-mediated rejection or calcineurin inhibitor toxicity, and not of the induction of tolerance (read more).

Can Immune Cell Function Assay Identify Patients at Risk of Infection or Rejection? A Meta-Analysis

Background. The Cylex ImmuKnow cell function assay (CICFA) is being considered as a possible tool for identification of infection and rejection in transplant recipients. However, the predictive capability of CICFA is still unclear.
Methods. Herein, we performed a meta-analysis to assess the efficacy of CICFA in identifying risks of infection and rejection posttransplantation. After a careful review of eligible studies, sensitivity, specificity, and other measures of the accuracy of CICFA were pooled. Summary receiver operating characteristic curves were used to represent the overall test performance.
Results. Nine studies met the inclusion criteria. The pooled estimates for CICFA in identification of infection risk were poor, with a sensitivity of 0.58 (95% confidence interval [CI]: 0.52–0.64), a specificity of 0.69 (95% CI: 0.66–0.70), a positive likelihood ratio of 2.37 (95% CI: 1.90–2.94), a negative likelihood ratio of 0.39 (95% CI: 0.16–0.70), and a diagnostic odds ratio of 7.41 (95% CI: 3.36–16.34). The pooled estimates for CICFA in identifying risk of rejection were also fairly poor with a sensitivity of 0.43 (95% CI: 0.34–0.52), a specificity of 0.75 (95% CI: 0.72–0.78), a positive likelihood ratio of 1.30 (95% CI: 0.74–2.28), a negative likelihood ratio of 0.96 (95% CI: 0.85–1.07), and a diagnostic odds ratio of 1.19 (95% CI: 0.65–2.20).
Conclusion. The current evidence suggests that CICFA is not able to identify individuals at risk of infection or rejection. Additional studies are still needed to clarify the usefulness of this test for identifying risks of infection and rejection in transplant recipients (read more).

Regeneration and outcome of dual grafts in living donor liver transplantation

In living donor liver transplantation (LDLT), the essential aims are to provide an adequate graft volume to the recipient and to keep a sufficient remnant liver volume in the donor. In some instances, these aims cannot be met by a single donor and LDLT using dual grafts from two donors is a good solution. From 2002 to 2009, five recipients in our hospital received dual graft LDLT. Two recipients received one right lobe and one left lobe grafts; the other three received two left lobe grafts. The mean final liver regeneration rate was 91.2%. Left lobe graft atrophy in the long term was observed in recipients who received a right and a left lobe grafts. The initial bigger volume graft in all recipients was noted to have better regeneration than the smaller volume grafts. Portal flow and bilateral grafts volume size discrepancy were considered as two major factors influencing graft regeneration in this study. We also noted that the initial graft volume correlated with portal flow in the separate grafts and finally contribute to individual graft regeneration. Because of compensatory hypertrophy of the other graft, recipients who experienced atrophy of one graft did not show signs of liver dysfunction (read more).

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Defibrotide for the prevention of hepatic veno-occlusive disease after hematopoietic stem cell transplantation: a systematic review

Prophylactic use of defibrotide (DF) to prevent veno-occlusive disease (VOD), a relatively common and high-risk complication of hematopoietic stem cell transplantation (HSCT), may be an encouraging modality to reduce morbidity and mortality from VOD. However, conclusions remain unclear. We carried out a systematic review to summarize the state of knowledge. One randomized controlled trial (RCT), four cohort studies and eight case series studies were found, including a total of 1230 patients. The overall mean incidence of VOD in patients using DF was 4.7% (95% CI, 3.3–6.1) which was significantly lower than the data 13.7% (95% CI, 13.3–14.1) across 135 studies using no VOD prophylaxis (p < 0.005). The meta-analysis of the incidence of VOD in controlled trials revealed a statistical reduction in VOD incidence in the DF group (RR = 0.47, 95% CI, 0.31–0.73). The overall mean incidence of severe VOD was 0.8% (95% CI, 0.2–1.4). The RR was 0.31 (95% CI, 0.09–1.06). However, the lack of RCTs and the methodological weaknesses of the studies may preclude making generalizable conclusions. Our review described that DF appears promising for VOD prevention and large RCT is needed for further confirmation (read more).

Evolution and Clinical Pathologic Correlations of De Novo Donor-Specific HLA Antibody Post Kidney Transplant

The natural history for patients with de novo donor-specific antibodies (dnDSA) and the risk factors for its development have not been well defined. Furthermore, clinical and histologic correlation with serologic data is limited. We studied 315 consecutive renal transplants without pretransplant DSA, with a mean follow-up of 6.2 ± 2.9 years. Protocol (n = 215) and for cause (n = 163) biopsies were analyzed. Solid phase assays were used to screen for dnDSA posttransplant. A total of 47 out of 315 (15%) patients developed dnDSA at a mean of 4.6 ± 3.0 years posttransplant. Independent predictors of dnDSA were HLA-DRβ1 MM > 0 (OR 5.66, p < 0.006); and nonadherence (OR 8.75, p < 0.001); with a strong trend toward clinical rejection episodes preceding dnDSA (OR 1.57 per rejection episode, p = 0.061). The median 10-year graft survival for those with dnDSA was lower than the No dnDSA group (57% vs. 96%, p < 0.0001). Pathology consistent with antibody-mediated injury can occur and progress in patients with dnDSA in the absence of graft dysfunction and furthermore, nonadherence and cellular rejection contribute to dnDSA development and progression to graft loss (read more).

Left Lobe Living Donor Liver Transplantation in Adults

Adult left lobe (LL) living donor liver transplantation (LDLT) has not generally been recognized as a feasible procedure because of the problem of graft size. The objectives of this study were to assess the feasibility and short- and long-term results of adult LL LDLT in comparison with right lobe (RL) LDLT. Data on 200 consecutive LL LDLTs, including five retransplants, were retrospectively compared with those of 112 RL LDLTs, in terms of survival, complications and donor morbidity. The mean graft weight to standard volume ratio of LL grafts was 38.7% whereas that of RL grafts was 47.6% (p < 0.0001). The 1-, 5- and 10-year patient survival rates of LL LDLT were 85.6%, 77.9% and 69.5%, respectively, which were comparable to those of RL LDLT (89.8%, 71.3% and 70.7%, respectively). The incidence of small-for-size syndrome was higher in LL LDLT (19.5%) than in RL LDLT (7.1%) (p < 0.01). The overall donor morbidity rates were comparable between LL (36.0%) and RL (34.8%), whereas postoperative liver function tests and hospital stay were significantly better (p < 0.0001) in LL donors. In conclusion, adult LL LDLT has comparable outcomes to that of RL LDLT. LL LDLT is viable and is the first choice in adult LDLT (read more).

Long-term outcomes after transplantation of HLA-identical related G-CSF-mobilized peripheral blood mononuclear cells versus bone marrow

Between 1996 and 1999, 172 patients (median age, 42 years) with hematologic malignancies were randomly assigned to receive either HLA-identical related bone marrow or G-CSF–mobilized peripheral blood mononuclear cells (G-PBMCs) after myeloablative conditioning. Early results showed that transplantation of G-PBMCs, compared with marrow, was associated with significantly superior 2-year disease-free survival (DFS) and overall survival. Ten-year follow-up showed a sustained DFS benefit associated with G-PBMCs (mortality or relapse hazard ratio, 0.64; 95% confidence interval, 0.4-1.0; P = .03), although the likelihood of overall survival was not significantly different between the 2 groups (mortality hazard ratio, 0.75; 95% confidence interval, 0.5-1.2; P = .20). The 10-year cumulative incidence of chronic GVHD and the duration of systemic immunosuppression were similar in the 2 groups. In summary, transplantation of HLA-identical related G-PBMCs, compared with marrow, was associated with superior short-term and long-term DFS, and there was no evidence that this benefit was outweighed by GVHD-related late mortality (read more).

Prevalence, Course and Impact of HLA Donor-Specific Antibodies in Liver Transplantation in the First Year

The presence of preformed donor-specific HLA antibodies (DSA) in liver transplant recipients is increasingly recognized; however, the prevalence of DSA and their impact on early allograft function remains unknown. We prospectively followed serum DSA levels of 90 consecutive liver transplant recipients from baseline to 4 months. Twenty recipients (22.2%) had preformed DSA. No antibody-targeting treatments were undertaken. Seven days after transplantation, DSA levels decreased markedly in all but three patients. Day 7 protocol biopsies showed diffuse C4d deposition along the portal stroma, central vein, subendothelial and stromal space in the patients with persistent high DSA levels. The rate of acute cellular rejection was not significantly different in patients with DSA. The transaminase and bilirubin levels remained comparable during the first year despite the presence of DSA. The three patients with persistently high DSA levels continue to have normal allograft function. We conclude that in most cases, DSA disappear after liver transplant, however in rare instances where they persist, there is evidence of complement activation in the liver allograft, without significant clinical impact in the first year (read more).

Comparison of C4d Detection on Erythrocytes and PTC-C4d to Histological Signs of Antibody-Mediated Rejection in Kidney Transplantation

C4d on erythrocytes (EC4d), C4d peritubular capillary deposition (PTC-C4d) staining and histology were compared in a cross-sectional cohort of 146 renal allograft biopsies (132 patients). EC4d levels paralleled PTC-C4d staining, but were more predictive of peritubular capillaritis (PTC). Donor-specific antibodies (DSA), PTC-C4d, EC4d and PTC were analyzed in an independent longitudinal follow-up cohort (96 biopsies, 76 patients). Seventy-six samples were PTC and EC4d concordant, 11 positive and 65 negative, 7 PTC-EC4d+ and 13 PTC+EC4d−. EC4d levels were related to DSA occurrence. With ABMR defined by PTC and DSA, all apparently discordant patients, EC4d negative, were correctly reassigned comparing EC4d level curves with rejection kinetics, with positive EC4d samples predating biopsy or late biopsies compared with ABMR flare-ups. All EC4d-positive patients without PTC or DSA had permanent high EC4d levels unrelated to rejection. EC4d was more abundant in PTC-positive (mean = 108.5%± 3.4; n = 50) than PTC-negative samples (mean = 88.1%± 1.3; n= 96; p < 0.0001). Sensitivity, specificity, positive predictive value and negative predictive value of PTC-C4d and EC4d for PTC were, respectively, 75%, 79%; 64%, 76% (p < 0.05); 28%, 46% (p < 0.05) and 93%, 94%. Values were similar for DSA. A noninvasive blood test, EC4d, and particularly longitudinally monitoring EC4d levels, may increase surrogate ABMR testing options (read more).

Lymphodepletion and Homeostatic Proliferation: Implications for Transplantation

Control of the alloimmune response requires elimination and/or suppression of alloreactive immune cells. Lymphodepleting induction therapies are increasingly used to accomplish this goal, both as part of tolerance induction protocols or to reduce the requirements for maintenance immunosuppression in the peritransplant setting. However, it is well recognized that lymphopenia induces compensatory proliferation of immune cells, generally termed ``homeostatic proliferation,'' which favors the emergence of memory T cells. Paradoxically therefore, the result may be a situation that favors graft rejection and/or makes tolerance difficult to achieve or sustain. Yet all depletion is not alike, particularly with respect to the timing of reconstitution and the types of cells that repopulate the host. Thus, to design more effective induction strategies it is important to understand the homeostatic mechanisms, which exist to maintain a balanced repertoire of naïve and memory T and B cells in the periphery and how they respond to lymphodepletion. Here we will review the biology of homeostatic proliferation stimulated by lymphopenia, the effects of specific depleting agents on reconstitution of the T- and B-cell immune repertoire, drawing from both from animal models and human experience, and potential strategies to enhance allodepletion while minimizing the adverse effects of homeostatic proliferation (read more).

Willingness of the United States general public to participate in kidney paired donation

Availability of kidney paired donation (KPD) is increasing in the United States, and a national system through UNOS is forthcoming. However, little is known about attitudes toward KPD among the general public, from which donors (particularly non-directed) are drawn. In a national study, we assessed the public's attitudes regarding participation in KPD. Among 845 randomly selected participants, 85.2% of respondents were either “extremely willing” or “very willing” to participate in KPD. Experiences with the medical or organ transplant systems, such as undergoing surgery, having a primary medical provider, a living will, a friend who donated or received an organ, and considering donation after death, were associated with increased willingness. However, increased age, male sex, African American race, Hispanic ethnicity, distrust of the medical system, and not understanding organ allocation were associated with less willingness. We identify strong support for KPD but some important potential barriers to participation which should be considered as KPD programs are implemented (read more).

Pretransplant Donor-Specific HLA Class-I and -II Antibodies Are Associated with an Increased Risk for Kidney Graft Failure

Pretransplant risk assessment of graft failure is important for donor selection and choice of immunosuppressive treatment. We examined the relation between kidney graft failure and presence of IgG donor specific HLA antibodies (DSA) or C1q-fixing DSA, detected by single antigen bead array (SAB) in pretransplant sera from 837 transplantations. IgG-DSA were found in 290 (35%) sera, whereas only 30 (4%) sera had C1q-fixing DSA. Patients with both class-I plus -II DSA had a 10 yr graft survival of 30% versus 72% in patients without HLA antibodies (p < 0.001). No significant difference was observed in graft survival between patients with or without C1q-fixing DSA. Direct comparison of both assays showed that high mean fluorescence intensity values on the pan-IgG SAB assay are generally related to C1q-fixation. We conclude that the presence of class-I plus -II IgG DSA as detected by SAB in pretransplant sera of crossmatch negative kidney recipients is indicative for an increased risk for graft failure, whereas the clinical significance of C1q-fixing IgG-DSA could not be assessed due to their low prevalence (read more).

A Novel ELISPOT Assay to Quantify HLA-Specific B Cells in HLA-Immunized Individuals

Quantification of the humoral alloimmune response is generally achieved by measuring serum HLA antibodies, which provides no information about the cells involved in the humoral immune response. Therefore, we have developed an HLA-specific B-cell ELISPOT assay allowing for quantification of B cells producing HLA antibodies. We used recombinant HLA monomers as target in the ELISPOT assay. Validation was performed with human B-cell hybridomas producing HLA antibodies. Subsequently, we quantified B cells producing HLA antibodies in HLA-immunized individuals, non-HLA-immunized individuals and transplant patients with serum HLA antibodies. B-cell hybridomas exclusively formed spots against HLA molecules of corresponding specificity with the sensitivity similar to that found in total IgG ELISPOT assays. HLA-immunized healthy individuals showed up to 182 HLA-specific B cells per million total B cells while nonimmunized individuals had none. Patients who were immunized by an HLA-A2-mismatched graft had up to 143 HLA-A2-specific B cells per million total B cells. In conclusion, we have developed and validated a highly specific and sensitive HLA-specific B-cell ELISPOT assay, which needs further validation in a larger series of transplant patients. This technique constitutes a new tool for quantifying humoral immune responses (read more).

Very Early Recurrence of Anti-Phospholipase A2 Receptor-Positive Membranous Nephropathy After Transplantation

Membranous nephropathy is a common cause of adult nephrotic syndrome, with recent evidence suggesting that 70% of idiopathic disease is associated with anti-Phospholipase A₂ receptor autoantibodies. We describe a 63-year-old man with membranous nephropathy who underwent a kidney transplant and developed recurrent membranous nephropathy with fine granular co-localization of Phospholipase A₂ receptor and IgG evident on transplant biopsy on day 6 and elevated circulating levels of serum anti-Phospholipase A₂ receptor autoantibody that declined over time in conjunction with improvement in the serum creatinine and urinary protein. This is a very early case of Phospholipase A₂ receptor-associated recurrent membranous nephropathy with circulating anti-Phospholipase A₂ receptor autoantibody, which supports the emerging evidence that idiopathic membranous nephropathy is an autoimmune disease (read more).

ABO-Incompatible Kidney Transplantation Enabled by Non-Antigen-Specific Immunoadsorption.

BACKGROUND: ABO-incompatible kidney transplantation performed after desensitization with antigen-specific immunoadsorption (IA) results in good outcomes. However, a unique single-use IA device is required, which creates high costs. METHODS: From August 2005 to August 2010, 19 patients were desensitized for ABO-incompatible living donor kidney transplantation. Six patients treated with a single-use antigen-specific IA device and 12 patients treated with a reusable non-antigen-specific IA device were analyzed. RESULTS: Six patients who received antigen-specific IA had a median of 5 IA treatments and 12 patients with non-antigen-specific IA had a median of 6 IA treatments preoperatively. Median average titer drop in Coombs technique was 1.2 in antigen-specific IA and 1.7 in non-antigen-specific IA. In two patients with antigen-specific IA and four patients with non-antigen-specific IA, additional plasmapheresis treatments were necessary for recipient desensitization. Despite six treatments with antigen-specific IA and 12 plasmapheresis treatments, one patient with a starting isoagglutinin titer of 1:1024 (Coombs) could not be transplanted. The 18-month graft survival rate for the 17 ABO-incompatible living donor kidney transplants was 100%. One male recipient who was desensitized with antigen-specific IA died 44 months after transplantation from sudden cardiac death with a serum creatinine of 1.2 mg/dL. At last follow-up, a median of 13 months after transplantation, median serum creatinine for 16 patients was 1.5 mg/dL, median glomerular filtration rate as estimated by the modification of diet in renal disease formula 54 mL/min/1.73 m, and median urinary protein-to-creatinine ratio 0.1, with no differences between treatments. CONCLUSIONS: A reusable non-antigen-specific IA device allows high number of treatments at reasonable cost, and at the same time might deplete human leukocyte antigen-alloantibodies (read more)

MHC Class II Tetramers [BRIEF REVIEWS]

MHC class II tetramers have emerged as an important tool for characterization of the specificity and phenotype of CD4 T cell immune responses, useful in a large variety of disease and vaccine studies. Issues of specific T cell frequency, biodistribution, and avidity, coupled with the large genetic diversity of potential class II restriction elements, require targeted experimental design. Translational opportunities for immune disease monitoring are driving the rapid development of HLA class II tetramer use in clinical applications, together with innovations in tetramer production and epitope discovery (read more).

A pilot programme of organ donation after cardiac death in China

China's aims are to develop an ethical and sustainable organ transplantation system for the Chinese people and to be accepted as a responsible member of the international transplantation community. In 2007, China implemented the Regulation on Human Organ Transplantation, which was the first step towards the establishment of a voluntary organ donation system. Although progress has been made, several ethical and legal issues associated with transplantation in China remain, including the use of organs from executed prisoners, organ scarcity, the illegal organ trade, and transplantation tourism (read more).

Clinical relevance of HLA donor-specific antibodies detected by single antigen assay in kidney transplantation

Clinical relevance of donor-specific antibodies (DSAs) detected by a single antigen Luminex virtual crossmatch in pre-transplant serum samples from patients with a negative cytotoxicity-dependent complement crossmatch is controversial. The aim of this study was to analyse the influence of a pre-transplant positive virtual crossmatch in the outcome of kidney transplantation. Methods. A total of 892 patients who received a graft from deceased donors after a negative cytotoxicity crossmatch were included. Presence of anti-human leucocyte antigen (HLA) antibodies was investigated using a Luminex screening assay and anti-HLA specificities were assigned performing a Luminex single antigen assay. Results. Graft survival was significantly worse among patients with anti-HLA DSA compared to both patients with anti-HLA with no DSA (P = 0.001) and patients without HLA antibodies (P < 0.001) using a log-rank test. No graft survival differences between anti-HLA with no DSA and no HLA antibodies patient groups were observed (P = 0.595). Influence of both anti-Class I and anti-Class II DSA was detected (P < 0.0001 in both cases). When the fluorescence values were stratified in four groups, no significant differences in graft survival were observed among the groups with fluorescence levels >1500 (global P < 0.05). Conclusions. The presence of preformed HLA DSA in transplanted patients with a negative cytotoxicity crossmatch is associated with a lower allograft survival. The detection of anti-HLA with no DSA has no influence in the graft outcome. Finally, there were no demonstrable effects of mean fluorescence intensity (MFI) values > 1500 on graft survival (read more).