Pretransplant Human Leukocyte Antigen Antibodies Research Articles

Living Donor Kidney Transplantation in Patients With Donor-Specific HLA Antibodies After Desensitization With Immunoadsorption.

Due to the current organ shortage, living donor kidney transplantation is increasingly performed across HLA (human leukocyte antigen) or ABO antibody barriers. There is still uncertainty about the risk of antibody-mediated rejection (AMR) episodes, which may limit long-term graft survival. From March 2007 to December 2016, 58 sensitized living donor kidney transplant candidates were identified and 38 patients eventually included in the study: 36 patients (95%) had pre-transplant and pre-desensitization Luminex-detected donor-specific HLA antibodies (DSA), and 17/36 patients (47%) in addition had a positive crossmatch result. Two patients had no detectable DSA but a positive CDC B-cell crossmatch result. Patients were treated with pre- and post-transplant apheresis and powerful immunosuppression including the anti-CD20 antibody rituximab (N = 36) in combination with thymoglobulin (N = 20) or anti-IL2 receptor antibody (N = 18). The results of the 38 successfully desensitized and transplanted patients were retrospectively compared to the results of 76 matched standard-risk recipients. Desensitized patients showed patient and graft survival rates similar to that of standard-risk recipients (P = 0.55 and P = 0.16, respectively). There was a trend toward reduced death-censored graft survival in desensitized patients (P = 0.053) which, however, disappeared when the 34 patients who were transplanted after introduction of sensitive Luminex testing were analyzed (P = 0.43). The incidence of rejection episodes without borderline changes were in desensitized patients with 21% similar to the 18% in standard-risk patients (P = 0.74). Thirty-six patients had pre-transplant HLA class I and/or II DSA that were reduced by 85 and 81%, respectively, during pre-transplant desensitization (P < 0.001 for both). On day 360 after transplantation, 20 of 36 (56%) patients had lost their DSA. The overall AMR rate was 6% in these patients, but as high as 60% in 5 (14%) patients with persistent and de novo DSA during year 1; 2 (40%) of whom lost their graft due to AMR. Eleven (31%) patients with persistent DSA but without de novo DSA had an AMR rate of 18% without graft loss while one patient lost her graft without signs of AMR. Our desensitization protocol for pre-sensitized living donor kidney transplant recipients with DSA resulted in good graft outcomes with side effects and rejection rates similar to that of standard-risk recipients. Adequate patient selection prior to transplantation and frequent immunological monitoring thereafter is critical to minimize rejection episodes and subsequent graft loss.

Pre-transplant HLA Antibodies and Delayed Graft Function in the Current Era of Kidney Transplantation.

Delayed graft function (DGF) occurs in a significant proportion of deceased donor kidney transplant recipients and was associated with graft injury and inferior clinical outcome. The aim of the present multi-center study was to identify the immunological and non-immunological predictors of DGF and to determine its influence on outcome in the presence and absence of human leukocyte antigen (HLA) antibodies. 1,724 patients who received a deceased donor kidney transplant during 2008–2017 and on whom a pre-transplant serum sample was available were studied. Graft survival during the first 3 post-transplant years was analyzed by multivariable Cox regression. Pre-transplant predictors of DGF and influence of DGF and pre-transplant HLA antibodies on biopsy-proven rejections in the first 3 post-transplant months were determined by multivariable logistic regression. Donor age ≥50 years, simultaneous pre-transplant presence of HLA class I and II antibodies, diabetes mellitus as cause of end-stage renal disease, cold ischemia time ≥18 h, and time on dialysis >5 years were associated with increased risk of DGF, while the risk was reduced if gender of donor or recipient was female or the reason for death of donor was trauma. DGF alone doubled the risk for graft loss, more due to impaired death-censored graft than patient survival. In DGF patients, the risk of death-censored graft loss increased further if HLA antibodies (hazard ratio HR=4.75, P < 0.001) or donor-specific HLA antibodies (DSA, HR=7.39, P < 0.001) were present pre-transplant. In the presence of HLA antibodies or DSA, the incidence of biopsy-proven rejections, including antibody-mediated rejections, increased significantly in patients with as well as without DGF. Recipients without DGF and without biopsy-proven rejections during the first 3 months had the highest fraction of patients with good kidney function at year 1, whereas patients with both DGF and rejection showed the lowest rate of good kidney function, especially when organs from ≥65-year-old donors were used. In this new era of transplantation, besides non-immunological factors, also the pre-transplant presence of HLA class I and II antibodies increase the risk of DGF. Measures to prevent the strong negative impact of DGF on outcome are necessary, especially during organ allocation for presensitized patients.

Donor-specific and -nonspecific HLA antibodies and outcome post lung transplantation.

Donor-specific antibodies (DSAs) against human leukocyte antigen (HLA) are associated with chronic lung allograft dysfunction (CLAD) and mortality post lung transplantation, but data concerning prevalence, time of onset, persistence and effects on long-term outcome remain scarce.We assessed the association between HLA antibodies and CLAD-free and graft survival in a cohort of 362 patients. We stratified our analysis according to DSA status, persistence of antibodies and timing of antibodies (pre-transplant, early or late post-transplant).Within our cohort, 61 (17%) patients developed DSAs (mostly against HLA-DQ), which was associated with worse CLAD-free and graft survival (p<0.0001 and p=0.059, respectively). Persistent (hazard ratio (HR) 3.386, 95% CI 1.928-5.948; p<0.0001) as well as transient (HR 2.998, 95% CI 1.406-6.393; p=0.0045) DSAs were associated with shorter CLAD-free survival compared with patients without DSAs. Persistent DSAs (HR 3.071, 95% CI 1.632-5.778; p=0.0005) but not transient DSAs were negatively associated with graft survival compared with patients without DSAs, likely due to the higher incidence of restrictive CLAD. HLA non-DSAs and pre-transplant HLA antibodies had no effect on post-transplant outcome.We demonstrated an important difference in prognosis between persistent and transient DSAs. Moreover, the observed association between DSAs and restrictive CLAD suggests an overlap between antibody-mediated rejection and restrictive CLAD that needs further investigation.

Pre-transplant Sensitization for Patient Awaiting Lung Transplant: Are We Concerned?

The goal of this paper is to highlight the changes in detection, management, and prognosis of pre-transplant sensitized candidates and recipients. With improvements in technology, human leukocyte antigen (HLA) antibody testing has identified a significant proportion of lung transplant candidates with pre-transplant HLA antibody detection. Pre-transplant antibodies are associated with worse early outcomes after lung transplant if not addressed with targeted antibody therapy. There are promising new therapy plans to address pre-transplant HLA antibodies and potentially ameliorate the early risk of antibody-mediated graft injury. Pre-transplant sensitization continues to be a difficult problem in lung transplant. Detailed HLA antibody reports allow for precise identification of antibodies. The future challenge is how to manage these antibodies pre- and peri-transplant.

Pretransplant human leukocyte antigen antibodies detected by single-antigen bead assay are a risk factor for long-term kidney graft loss even in the absence of donor-specific antibodies.

Clinical relevance of ELISA- and single-antigen bead assay (SAB)-detected pretransplant HLA antibodies (SAB-HLA-Ab) for kidney graft survival was evaluated retrospectively in 197 patients transplanted between 2002 and 2009 at the University Clinic Frankfurt. Having adjusted for retransplantation and delayed graft function, a significantly increased risk for death-censored graft loss was found in patients with pretransplant SAB-HLA-Ab [HR: 4.46; 95% confidence interval (CI): 1.47-13.48; P = 0.008]. The risk for increased graft loss was also significant in patients with pretransplant SAB-HLA-Ab but without SAB-detected donor-specific Ab (SAB-DSA) (HR: 4.91; 95% CI of 1.43-16.991; P = 0.012). ELISA was not sufficient to identify pretransplant immunized patients with an increased risk for graft loss. In immunized patients, graft loss was predominantly present in patients who received transplants with a mismatch on the HLA-DR locus. In conclusion, even if our study is limited due to small sample size, the results show an increased risk for long-term graft loss in patients with pretransplant SAB-HLA, even in the absence of DSA. SAB-HLA-Ab-positive patients, being negative in ELISA or CDC assay, might profit from a well-HLA-DR-matched graft and intensified immunosuppression.

The impact of pre-transplant allosensitization on outcomes after lung transplantation

Allosensitization can be a significant barrier to transplantation for some patients, and previous studies suggested that pre-transplant allosensitization was associated with worse outcomes after lung transplantation. However, human leukocyte antigen (HLA) antibody testing has evolved significantly over the past 10 years, and current assays are highly sensitive and specific. We examined the impact of pre-transplant allosensitization on post-transplant outcomes in the era of solid-phase multiplex HLA antibody detection assays in this retrospective, single-center study of 304 adult transplant recipients between January 1, 2006, and December 31, 2012. We accepted donor organs for allosensitized patients if a virtual crossmatch was compatible with all previously identified antibodies. In univariate and multivariate Cox proportional hazards models, pre-transplant allosensitization, the calculated panel reactive antibody, and the number of pre-transplant HLA antibodies were not associated with the development of acute cellular rejection, lymphocytic bronchiolitis, donor-specific HLA antibodies, chronic lung allograft dysfunction, or graft failure. Pre-transplant allosensitization does not adversely affect outcomes after lung transplantation when the potentially reactive HLAs are avoided in the donor by a virtual crossmatch with the recipient.

The Clinical Significance of Human Leukocyte Antigen Antibody Development in Kidney Transplantation

BackgroundThis retrospective study uses the LAT-M (One Lambda Inc., Calif) screen assay to reexamine the impacts (a), of pretransplant human leukocyte antigen (HLA) antibody on long-term graft survival; (b) posttransplant HLA antibody on long-term graft survival and (c) immunosuppressive regimen on posttransplant HLA antibody development. Patients and methodsPretransplant sera from 222 renal transplant recipients and posttransplant sera from 216 renal transplant recipients were studied for the impact of HLA antibody on long-term graft survival. ResultsAmong the patients who did not display pretransplant HLA antibodies, 85% enjoyed 5-year and 59% 10-year graft survival, whereas the patients who tested positive were 83% and 83% (P = .5596). Among the patients who did not show posttransplant HLA antibodies, 99% enjoyed 5-, 91% 10-, and 65% 15-year graft survival, whereas for the 44 patients who tested positive they were 59%, 44%, and 30%, respectively (P < .0001). Patients prescribed cyclosporine + myfortic (odds ratio 0.17, P = .05) or FK + Cellcept (odds ratio 0.36, P = .04) showed the lowest posttransplant HLA antibody development. ConclusionBoth regimens improve graft survival.

Effect of Pretransplant Human Leukocyte Antigen Antibodies Detected by Solid-Phase Assay on Heart Transplant Outcomes

Introduction The significance of pretransplant human leukocyte antigen antibodies (HLA-Abs), especially donor-specific HLA-Abs (DSA), as detected by single antigen bead assay (SAB), is not well characterized in cardiac transplantation (CTX). We analyzed the significance of DSA detected by SAB in predicting crossmatch (XM) results and post-transplant rejection. Materials and methods We performed a retrospective study of 85 CTX with negative cytotoxicity XM. We tested pretransplant sera collected within 24 hours of transplantation by flow cytometric XM (FXM) and SAB. DSA identified by SAB were utilized to perform a virtual crossmatch (VXM). Positive VXM was defined as the presence of DSA at mean fluorescence intensity (DMFI) > 1500. Additionally, to analyze the significance of low-level DSA weakly positive VXM was DMFI 300 to 1500. We defined a negative VXM as MFI < 300. VXM results were correlated with FXM results and with posttransplant rejection. Results Patients in the weakly positive and negative VXM had similar posttransplant rejections. DMFI > 1500 correlates well with FXM results (accuracy = 90%). Patients with DMFI > 1500 had a higher incidence of antibody-medicated rejection (AMR; P = .0052), AMR grade I ( P < .0001), cell-mediated rejection (CMR) grade > 1R/1A ( P = .018), and CMR grade > 2R/3A ( P = .057). Similarly patients with positive FXM had a higher incidence of AMR ( P = .091), AMR grade 1 ( P < .0001), CMR grade > 1R/1A ( P = .05), and CMR grade > 2R/3A ( P = .56). Conclusions In conclusion, SAB defined DMFI > 1500 can be used as a surrogate for FXM. Recipients with DMFI > 1500 pretransplant and positive FXM have significantly higher rates of AMR and CMR compared to recipients with DMFI < 1500 or negative FXM.

HLA Antibodies and the Occurrence of Early Adverse Events in the Modern Era of Transplantation: A Collaborative Transplant Study Report

Adverse events occurring early after kidney transplantation were reported to influence graft outcome. In a prospective multicenter study initiated in 2001, we investigated the relationship between human leukocyte antigen (HLA) alloantibodies, early adverse events, and graft outcome. Pretransplant presence of HLA class I antibodies was associated with a higher rate of no immediate function (NIF) of the graft (odds ratio [OR] 1.78, P=0.023) and acute rejection episodes (ARE) during the first 3 months after transplantation (OR 2.53, P<0.001). NIF and ARE during posttransplant days 15 to 90 were associated with increased risk of graft loss to year 3 (OR 2.06 and 3.75, P=0.006 and P<0.001, respectively). ARE within the first 2 posttransplant weeks did not increase the risk significantly, especially if they occurred in nonsensitized patients without antibodies. Graft survival at 3 years in patients with both NIF and ARE during the first 3 months was significantly lower (81.3%+/-6.2%) than in patients who did not experience NIF or ARE (95.1%+/-1.0%, P<0.001). Importantly, neither NIF nor ARE had an impact on subsequent graft survival if good graft function (serum creatinine <130 mumol/L) was observed at the end of the third month. Our results show that NIF and ARE associated with pretransplant antibodies against HLA class I, and they suggest that early diagnosis and treatment of adverse events with the aim of obtaining normal 3-month graft function should be pursued rigorously. Good 3-month graft function is associated with excellent long-term survival, even in patients with pretransplant HLA antibodies and posttransplant adverse events.

Pretransplant HLA Antibodies Are Associated with Reduced Graft Survival After Clinical Islet Transplantation

Despite significant improvements in islet transplantation, long-term graft function is still not optimal. It is likely that both immune and nonimmune factors are involved in the deterioration of islet function over time. Historically, the pretransplant T-cell crossmatch and antibody screening were done by anti-human globulin--complement-dependent cytotoxicity (AHG-CDC). Class II antibodies were not evaluated. In 2003, we introduced solid-phase antibody screening using flow-based beads and flow crossmatching. We were interested to know whether pretransplant human leukocyte antigen (HLA) antibodies or a positive flow crossmatch impacted islet function post-transplant. A total of 152 islet transplants was performed in 81 patients. Islet function was determined by a positive C-peptide. Results were analyzed by procedure. Class I and class II panel reactive antibody (PRA) > 15% and donor-specific antibodies (DSA) were associated with a reduced C-peptide survival (p<0.0001 and p<0.0001, respectively). A positive T- and or B-cell crossmatch alone was not. Pretransplant HLA antibodies detectable by flow beads are associated with reduced graft survival. This suggests that the sirolimus and low-dose tacrolimus-based immunosuppression may not control the alloimmune response in this presensitized population and individuals with a PRA > 15% may require more aggressive inductive and maintenance immunosuppression, or represent a group that may not benefit from islet transplantation.