ABO-compatible Transplantation Research Articles

Kidney Transplantation with ABO-Incompatible Donors: A Comparison with Matched ABO Compatible Donor Transplants.

Introduction:ABO-incompatible kidney transplantation (ABOiKTx) expands the living donor pool. There is limited long-term outcome data from India especially in comparison with ABO-compatible kidney transplantation (ABOcKTx). Here we report outcomes of the first 100 ABOiKTx compared to ABOcKTx from our center.Methods:Between August 2013 and December 2019, 100 consecutive ABOiKTx were compared with 100 ABOcKTx done during the same period.Controls were matched for age, donor characteristics, HLA mismatches, and date of transplantation.Results:Mean (SD) follow up period was 25.9 ± 20.5 and 27.2 ± 20.6 months in ABOi and ABOcKTx respectively. Patient survival at 1 and 5 years post-transplant was 93.3 and 73.5% vs. 95.4 and 93% (P = 0.03), while graft survival rates were 85 and 60% vs. 93.1 and 83% in ABOi and ABOcKTx respectively (P = 0.03). The incidence of antibody-mediated rejections was 15% vs. 4%, and that of T-cell-mediated rejections was 10 vs. 12% respectively. Infections, malignancies, and surgical complications were similar. Level of anti ABO titers, HLA mismatches, recipient age, donor age, and presence of diabetes did not impact graft survival amongst ABOiKTx. The predicted survival and incidence of acute rejections and infections in the later 50 ABOiKTx transplants were better than the first 50 ABOiKTx when compared to their respective controls.Conclusion:Outcomes of ABOiKTx were inferior to ABOcKTx but tends to improve as more experience is gained. Incidence of ABMR was higher but infections and surgical complications were comparable. This data provides evidence that ABOiKTx is viable option for those without a ABO compatible donor.

HLA class II positivity by lysate crossmatch in renal transplant scenario-dangerous if ignored!!!

The detection of antibodies before transplantation is an important step in assessment of patient immunological risk and exclusion of incompatible donors. Many centers have now implemented donor-specific antibody (DSA) along with complement-dependent cytotoxicity crossmatch (CDC XM) for renal transplant cases. A 34-year-old male with end-stage kidney disease was referred for an ABO-compatible transplant from his mother. The CDC XM done 30 days before transplant was negative. DSA XM was negative for Class I (median fluorescence intensity [MFI] 189) and positive for Class II (MFI 1671). Since CDC and DSA Class I were negative, the nephrologists went ahead with the transplantation. On day 6 posttransplant, serum creatinine showed a rising trend (up to 2.13 mg/dl), and therefore, renal biopsy was done which showed mild acute tubular necrosis with positive C4d staining. DSA XM performed on day 15 posttransplant showed negative Class I (MFI 148) and positive Class II (MFI 9987) confirming antibody-mediated rejection (AMR). The patient was started on steroids, and intravenous immunoglobulin and serial plasma exchanges were performed. Then, DSA Class II levels came down to 1602. DSA levels have been monitored periodically and Class II MFI values have been ranging from 2000 to 4000. The patient is maintained on routine immunosuppression, and a graft is intact with serum creatinine level between 1.7 and 1.8 mg/dl 8 months posttransplant. DSA-isolated Class II positivity in renal transplant recipients correlates strongly with AMR and should be considered clinically significant.

Outcome of desensitization in human leukocyte antigen and ABO incompatible living donor kidney transplantation: Single center experience of first 200 incompatible transplants.

Although desensitization is well established, concerns about graft outcome, patient survival and rejection still exist. The present study aims at comparing outcomes of renal transplant recipients across simultaneous ABO and human leukocyte antigen (HLA) incompatibility barriers to those with ABO or HLA incompatibility alone. This was a retrospective study conducted from October 2015 to December 2018. All patients with a clinical diagnosis of chronic kidney disease, who were prospective HLA incompatible (HLAi) and/or ABO incompatible (ABOi) renal transplant recipients were included. A total of 400 cases including 36 ABOi transplants, 154 HLAi transplants, 10 simultaneously ABO and HLA incompatible transplants, and 200 ABO (ABOc) and HLA (HLAc) compatible kidney transplants from living donors were included. There were significantly more number of blood transfusions, previous transplants and pregnancies in HLAi transplant recipients relative to the ABOi or the control group. Mean number of therapeutic plasma exchange procedures per patient and mean plasma volume processed per procedure were slightly higher in the ABOi + HLAi category. The incidence of graft dysfunction due to suspected antibody-mediated rejection during first year was highest in the ABOi + HLAi group, followed by ABOc + HLAi and ABOi + HLAc, lowest in the ABOc + HLAc category. Mean time to first episode of graft dysfunction was significantly shorter with incompatible transplants. There were no kidney transplant recipient deaths in the study. Patient outcome and graft outcomes observed with incompatible transplants were not worse than those observed with compatible transplants.

Effect of Different Rituximab Doses on B Cell Count, Anti-A/B Antibody Titer, Graft Function, and Infectious Complications in ABO-Incompatible Renal Transplantation: A Prospective Study

BackgroundABO-incompatible kidney transplantation (ABOiKT) has been accepted as a viable and cost-effective modality with outcomes comparable to ABO-compatible transplants, but there is a concern regarding higher infectious complications in ABOiKT because of the heightened immunosuppression.The desensitization protocol normally includes antibody removal, B cell depletion by rituximab (RTX), and immunomodulation with intravenous immunoglobulin. Efforts have been made over the years to decrease the dose of RTX in an effort to decrease the infective complications. There is limited literature about the minimum effective dose of RTX, which can cause an effective B cell depletion. This prospective study was designed to correlate the RTX dose with peripheral absolute B cell count, graft function, graft and patient survival, and infective complications. MethodsThis study included 52 adult ABOiKT recipients with anti-A/B antibody titer up to a maximum of 1:512. The participants were divided into 2 groups of 26 each according to the RTX dosage used: Group A received 100 mg/patient, and Group B received 200 mg/patient. RTX was given 14 days prior to transplant after B cell measurement by flow cytometry. The outcomes were compared after 1 year of follow-up. ResultsBoth the dosages effectively depleted the absolute B cell count. Although patient survivals, graft survival, graft function, acute rejection episodes, and post-transplant hospital stay were similar in both groups, infective complications were significantly higher in group B. ConclusionA low dose (100 mg/patient) of RTX produces effective depletion of B cells while lowering the infective complications in ABOiKT.

Regional Report on Organ Transplantation in Trinidad and Tobago.

Regional Report on Organ Transplantation in Trinidad and Tobago.

BKV VIRURIA AND VIREMIA DO NOT PREDICT HOSPITALIZATION FOR INFECTIONS AFTER KIDNEY TRANSPLANTATION

BK polyoma virus (BKV) infection after kidney transplantation, resulting from either reactivation of latent infection in the recipient or transmission through the donor kidney, is understood to be related to the intensity of immunosuppression. Infections after transplantation being a function of immunosuppression burden in general, we hypothesized that early BKV viruria and viremia could indicate the likelihood of individuals needing hospitalization for all infections. We conducted a retrospective study among living donor renal transplant recipients in a program without the routine use of induction immunosuppressive agents, to explore the association between BKV viruria at two months post transplantation and viremia, with hospitalisation for any infection. The electronic case records of all patients who underwent renal transplantation between 8/5/2016 (start of the program) to 31-10- 2019 at IQRAA hospital Kerala, were reviewed to collect data on BKV viruria, viremia and hospitalisation for infections. A total of 149 patients had undergone transplantation during the study period of which nine were excluded from analysis (four patients within two months of transplantation, three patients with non-functioning graft within two months, one death within two months and one patient lost to follow up). 48 patients (34.28%) were detected urine BKV positive by polymerase chain reaction (PCR) around two months after transplantation, 74 patients tested negative and no data were available in 18. 24 out of the 48 patients with viruria had documented viremia by PCR. Among the rest 16 had no viremia, while data were missing in eight. Of the 122 patients with urine BKV data available 100 were ABO compatible (ABOc) transplants and the rest ABO incompatible (ABOi). 39 patients out of the 122 patients (31.96%) with urine BKV data available required hospitalization for infection. The median time to first hospitalization for infection was 139 days The most common causes for first hospital admission with infection after transplantation included lower respiratory tract infection and urinary tract infection/graft pyelonephritis in seven patients each, followed by Cytomegalovirus infection in five. No significant association was documented for hospitalization with infection either for BKV Viruria (χ2 (1, N = 122) =0.28, p = 0.59) or BKV viremia(χ2 (1, N = 58) =0.41, p = 0.51). ABOi transplantation was also not found to be significantly associated with BKV viruria (χ2 (1, N = 122) =0.09, p = 0.75). In this retrospective single centre study of living donor recipients BKV viruria at two months post renal transplant and BKV viremia were not found to be associated with hospitalization for any infection. Viral load cut offs to define severity of infection were not used and could have led to the inclusion of patients with lesser degree of immunosuppression confounding the results.

A current era analysis of ABO incompatible listing practice and impact on outcomes in young children requiring heart transplantation

Heart transplantation from ABO incompatible (ABOi) donors has evolved into a progressively accepted therapy in young children. We assessed the recent practice of ABOi listing impact on waitlist and post-transplant outcomes. Using the Pediatric Heart Transplant Society registry, we compared clinical presentation, waitlist parameters, and post-transplant survival of children < 2 years of age listed for ABOi vs ABO compatible (ABOc) heart transplant between January 2010 and June 2018 with sub-analysis of blood group O recipients. Among 2,039 patients, ABOi listing increased significantly with time from 49% (2010) to 72% (2017). ABOi-listed patients had lower age and body surface area, and higher proportion of congenital heart disease, mechanical ventilation, and high urgency status (all p < 0.01). Use of mechanical circulatory support was similar between groups. Of 1,288 patients reaching transplant, 239 (18.6%) received an ABOi organ (15%-40%/year). Death while waiting, removal from the waitlist, and waitlist survival were similar between groups. Time to transplant was significantly shorter for ABOi listing in blood group O patients (p < 0.02), approaching significance (p = 0.057) for all blood groups. Post-transplant survival was similar except for lower survival of patients listed ABOc but transplanted ABOi. These patients showed increasing need for mechanical circulatory support and high urgency listing while waiting. In the current era, primary listing for ABOi heart transplant has become routine for the majority of children < 2 years old, resulting in shorter waitlist time, especially in blood group O. Post-transplant survival is similar despite ABOi-listed children still showing a higher risk profile.

Latest developments in living kidney donation.

Although the first successful kidney transplantation 65 years ago was performed with a living donor kidney, the number of living donor kidney transplantations has increased especially during the last 2 decades. The enlargement of living donor programs was made possible by new modes of living donation and by expansion of the living donor pool. At the same time, the long-term risks of kidney donation have been better delineated. In this review, the latest developments on these topics are summarized. While the results of ABO-incompatible living kidney transplantation are superior to those of deceased donor transplantation, recent meta-analyses show a reduced patient and graft survival as compared with ABO compatible transplantation as well as increased risk of severe infection and bleeding. Kidney paired donation programs can be extended by including compatible couples and by advanced donation, although the latter raises ethical concerns. Living donors appear to have a higher risk of end-stage renal disease and this is especially true for obese donors and probably also for black donors with an APOL1 high-risk genotype. The importance of psychosocial outcomes after living kidney donation is increasingly recognized. Living donor kidney transplantation remains the optimal treatment option for patients with end-stage renal disease. To increase the donor pool, a well developed paired kidney donation program and sufficient reimbursement of costs associated with donation are essential ingredients. Other ways of expanding the donor pool, such as ABO-incompatible transplantation, use of higher risk donors, providing donors with financial incentives and advanced donation are associated with medical, ethical and logistical complications. There should be a careful selection and follow-up of living kidney donors with attention for medical consequences as well as for psychosocial outcomes.

Outcomes and complications following ABO-incompatible kidney transplantation performed after desensitization by semi-selective immunoadsorption - a retrospective study.

Because of the current organ shortage, ABO-incompatible (ABOi) transplantations have been increasingly performed in recent years. The results seem comparable to those of compatible transplantations, but there have also been reports of increased side effects possibly because of the desensitization therapy. To address an increase in severe infectious complications, we compared the outcomes of 48 ABOi transplant recipients to outcomes of 96 matched ABO-compatible (ABOc) controls transplanted at Heidelberg University Hospital from August 2005 to April 2018. Over a follow-up period of 8years, ABOi transplant recipients had comparable graft and patient survival as well as graft function compared with ABOc patients. T-cell-mediated and antibody-mediated rejections were not different between groups. In ABOi transplant recipients, urosepsis (22.9% vs. 8.5%; P=0.019) and pneumonia with opportunistic pathogens (8.3% vs. 1.0%, P=0.025) appeared more frequently. As a consequence, a significantly higher number of deaths from infection have been observed after ABOi transplantations (6.3% vs. 0%, P=0.010). High-titer recipients (isoagglutinin titer of ≥1:256) showed a higher incidence of BK virus replication and postoperative bleeding complications. ABO-incompatible transplantations can be performed with results that are not different from results after ABOc transplantations. However, an increased rate of serious infectious complications must be taken into account.

Broadening ABO Incompatibility Pediatric Heart Transplantation, Even in Children 2 Years and Older

Purpose Blood type ABO incompatibility (ABOi) is becoming increasingly utilized in heart transplantation. We sought to identify whether this increase was mostly in infants or older children as well. Methods Pediatric patients ( Results From 2000-2017, there were 415 ABOi transplants completed in children up to 13 years of age. ABOi transplantation volume over time is shown in Figure 1. Of ABOi transplants, 70% (n=291) were done in North America (NA) and 28% (n=115) in Europe. The proportion of ABOi transplants was 4.6% in NA and 4.5% in Europe (p=0.87). When examined by era, this proportion has increased from 3.5% (2000-2008) to 5.3% (2009-2017), p Conclusion Willingness to accept ABOi allografts has continued to increase in the recent era, especially among pediatric candidates >2 years old. The trends in ABOi transplants are similar between NA and Europe. In the U.S., 1/5th of the recipients listed as ABOi transplant acceptable ultimately received ABOi transplant. Survival among the expanding group of ABOi pediatric heart transplant recipients compares favorably to ABO compatible transplants. These outcomes should encourage centers to use ABOi donors, particularly in select older children.

ABO-identical matching has no superiority in long-term survival in comparison to ABO-compatible matching in lung transplantation

BackgroundEven though identical blood group matching between recipient and donor is preferred, it is still not clear by how much this improves the outcome for patients who received a lung transplant (LTx), or whether there is any survival benefit. Earlier studies have yielded ambiguous results and few have investigated long-term survival. The aim of this study is, therefore, to explore the different outcomes of identical and compatible recipient and donor blood group matching to determine whether identical matching is superior (LTx).MethodBetween January 1990 to June 2016, 297 patients underwent primary LTx, 10 patients underwent heart and lung transplantation (HLTx), and 18 patients required re-transplantation (Re-LTx) at Skåne University Hospital in Lund. With a total of 325 transplantations at our center, 262 were ABO-identically matched while 53 were ABO-compatible. For survival analyses, the end-point used was retransplantation-free survival in addition to excluding HLTx (n = 10), assessed by Cox regression and Kaplan-Meier.ResultsABO-compatible patients had a median of 49 days (2–641), and ABO-identical patients had a median of 89 days (1–1717) (p = 0.048) on the transplant waiting list. Patients with a limited survival up to 1-year showed significant difference in survival rate for ABO-compatible recipients compared to ABO-identical recipients (p < 0.05), however no significant difference was shown in overall survival between the two groups (p > 0.05), with the same pattern shown in patients with a limited survival rate up to ten years, emphysema-patients, when excluding single-LTx and patients transplanted before 2005 and after 2005, respectively (p > 0.05).ConclusionRecipients who received ABO-compatible matched grafts showed a similar survival rate to recipients who received ABO-identical matched grafts in the present study. Cytolomegalovirus and Ebstein Barr Virus mismatch were also identified as risk factors particular among emphysema patients. Since ABO-identical transplantations and ABO-compatible transplantations showed similar results, the present selection-bias of preferring ABO-identical lungs could be adjusted to increase organ allocation. It might also be possible to shorten recipient waiting list time, as an identical match showed over 80% higher time on the waiting list than a compatible, non-identical match.

Comparative analysis of ABO-incompatible kidney transplantation with ABO-compatible transplantation: A single-center experience from Eastern India

This study aimed to compare the outcomes of ABO-incompatible kidney transplantation (ABOiKT) with ABO-compatible kidney transplantation (ABOcKT) in a singlecenter study. A total of 30 consecutive ABOiKT recipients (ABOiKTR) from April 2014 to June 2015 were included in this study. All the patients received rituximab 200 mg/body for B-cell depletion. Plasmapheresis was done for anti-ABO antibody removal. The target anti-ABO titer was kept at <1:8. The outcomes of this group of patients were compared with that of thirty ABOcKT recipients. Both the groups received similar induction therapy with antithymocyte globulin and methylprednisolone. After a follow-up period of one year, the outcomes of both the groups were compared in terms of patient survival, graft survival, graft function, incidence of rejections, infective complications, and duration of posttransplant hospital stay. The patient survival in both the groups of patients was 96.67%. The death-censored graft survival was 96.67% in both the groups. The average serum creatinine level, estimated glomerular filtration rate, incidence of rejections, infective episodes, and posttransplant hospital stay were comparable in both the groups. The outcomes of ABOiKT were comparable with ABOcKT and as such, this modality can expand the living donor pool substantially.

Severe Passenger Lymphocyte Syndrome and Acute Rejection in ABO Compatible but non-Identical Liver Transplant Recipient from Hepatitis C Viremic Donor

We report a burdensome case of transplantation of a HCV-viremic liver graft into a HCV-viremic recipient with minor AB0 mismatch.

Current state of transfusion practices for ABO-incompatible pediatric heart transplant patients in the United States and Canada.

ABO compatibility restriction on solid organ transplantation limits organ availability. In an effort to increase organ availability, pediatric ABO-incompatible heart transplants (ABOiHT) are now performed with similar outcomes to ABO-compatible transplants. Transfusion support can be challenging and currently there are no standard guidelines for blood product support, ABO isohemagglutinin (IH) titer cutoffs for transplant eligibility, or therapeutic intervention for these patients. The study aim was to survey current blood bank and antibody reduction practices for pediatric ABOiHT in the United States and Canada. A Web-based survey was sent to 50 US and Canadian pediatric blood bank directors. Participants were queried regarding pre-, intra-, and postoperative blood product support; ABO IH titer testing; and antibody reduction practices in ABOiHT recipients. We analyzed 21 responses from US and Canadian centers that perform pediatric ABOiHT. There is wide variation in the type of blood products transfused and the modification of these products among respondents in the pre-, intra-, and postoperative settings. The frequency of testing ABO IH titers, implementing therapeutic intervention, and the type of therapeutic intervention also vary greatly among the institutions. Transfusion support of children with ABOiHT varies widely among blood banks in the United States and Canada. The choice of blood products and modifications utilized, titer thresholds for organ selection and medical decision points, and antibody reduction strategies are not standardized from center to center. As pediatric ABOiHTs become more common, a better understanding of optimal transfusion support and therapeutic intervention is needed.

Clinicopathological study of de novo membranous nephropathy of ‘stage 0’ after kidney transplantation

De novo membranous nephropathy (dnMN) contributes to graft failure, but the pathophysiology of the disease remains poorly understood. We defined cases exhibiting granular Immunoglobulin G (IgG) immunofluorescence staining but lacking dense deposits on electron microscopy as being of 'dnMN stage 0'; we studied the associated clinicopathological features. We studied 4653 allograft biopsy specimens (from 1747 cases treated in the Department of Urology, Tokyo Women's Medical University) and found 42 cases of allograft membranous nephropathy, of which 28 (1.6%) were diagnosed as dnMN. Of these, five cases (0.06%) fulfilled the criteria for dnMN stage 0. All five cases were diagnosed based on biopsies indicating increased serum levels of creatinine. Proteinuria status varied from negative to 2+. The median period from transplantation to allograft biopsy was 4068 days. Four of the five cases exhibited suspicious antibody-mediated rejection together with dnMN. The glomerular capillaries of all cases were C4d-positive, as were the peritubular capillaries of three of the four ABO-compatible transplants. In terms of IgG subclass, IgG1 and IgG3 predominated in all cases, and phospholipase A2 receptor status (evaluated via immunoreactivity) was negative in all cases. We examined two cases by immunoelectron microscopy using anti-IgG and anti-C4d antibodies. We found subendothelial and intramembranous deposits expressing both IgG and C4d, corresponding to positivity in immunofluorescence analysis. We confirmed the existence of dnMN stage 0 by focusing on granular IgG immunofluorescence positivity.

Cost-Effectiveness Analysis of Everolimus versus Mycophenolate in Kidney Transplant Recipients Receiving No Pharmacological Prophylaxis for Cytomegalovirus Infection: A Short-Term Pharmacoeconomic Evaluation (12 Months)

BackgroundModern immunosuppressive regimens, although associated with improved 1-year graft survival, are associated with adverse effects, including opportunistic infections, diabetes mellitus after transplantation, cardiovascular complications, and de novo malignancies. ObjectivesTo determine the short-term (12 months) cost-effectiveness of everolimus (EVR) versus mycophenolate sodium (MPS) in kidney transplant recipients receiving induction therapy, tacrolimus, prednisone, and no prophylaxis for cytomegalovirus infection. MethodsA Markov state transition model was designed. Data from a single-center prospective trial were used along with data from the center’s medical bills database. The target population comprised adults with low immunological risk submitted to first ABO-compatible transplantation with kidneys recovered from living or deceased donors. The time horizon was 12 months. The interventions included tacrolimus and prednisone plus a single 3-mg/kg dose of rabbit antithymocyte globulin (ATG) and EVR or basiliximab (BAS) and EVR or BAS and MPS. The clinical outcomes considered for this analysis were cytomegalovirus infection/disease, acute rejection, graft dysfunction, surgical complications, graft loss, and life-years gained. ResultsATG/EVR was cost-saving compared with BAS/MPS on all evaluated outcomes; BAS/EVR outperformed BAS/MPS on most of the evaluated outcomes. Results were confirmed by sensitivity analysis. ConclusionsCompared with MPS, EVR is an alternative immunosuppressive agent that is able to provide resource-saving to the health care provider with effectiveness gains for the patient.

Association of RBC Antibodies with Renal Graft Survival

Objectives: In this study, we aimed to determine the independent impact of RBC antibodies on kidney allograft rejection and graft survival. Methods: At the Virginia Commonwealth University Medical Center, 1099 patients who received ABO-compatible kidney transplants between January 1998 and December 2014 were analyzed …

Treatment of large plasma volumes using specific immunoadsorption to desensitize ABO-incompatible kidney-transplant candidates.

ABO-incompatible (ABOi) kidney-transplantation has very good long-term results, i.e. similar to those observed for living-kidney ABO-compatible transplantation. This is because patients are desensitized at pretransplant using apheresis and rituximab therapy, with tacrolimus-based immunosuppression. To assess the efficacy of a single, pretransplant (Day -1), specific immunoadsorption session using Glycosorb® columns (anti-A or anti-B; Glycorex Sweden) to treat large volumes of plasma (up to 18 L). Prospective single-center study evaluating 12 consecutive patients (6 males), aged 40 (23-59) years. Incompatibilities were A into 0 (8), B into 0 (3), and AB into 0 (1). Pretransplant desensitization relied on rituximab (D-30), tacrolimus, mycophenolic acid, and steroids (all started on D-13), and a single session of specific immunoadsorption on D-1. Immunoadsorption was coupled in tandem with a hemodialysis session. Overall, 15 L (11-18) of plasma were treated per patient, i.e., 0.2 (0.11-0.36 L/kg). Isoagglutinin titers were 1/16 (1/5-1/64) before the procedure, decreasing after 6 hours to 1/5 (1/1-1/16 P = 0.008), and to 1/2 (1/1-1/8; P = 0.05) at completion of the session. The next day, i.e., the day of transplantation, there was no rebound of isoagglutinins [1/4 (1/1-1/5); P = ns]. The procedure was well tolerated with no side-effects and no significant changes in hemoglobin level, platelet counts, fibrinogen, or albumin levels. For ABOi kidney-transplantation, a single, longer, specific immunoadsorption session was very efficient at 1-day pre-transplantation with no rebound. These results should be confirmed when isoagglutinin titers are higher (≥120).

Economic Impacts of ABO-Incompatible Live Donor Kidney Transplantation: A National Study of Medicare-Insured Recipients.

The infrequent use of ABO-incompatible (ABOi) kidney transplantation in the United States may reflect concern about the costs of necessary preconditioning and posttransplant care. Medicare data for 26 500 live donor kidney transplant recipients (2000 to March 2011), including 271 ABOi and 62 A2-incompatible (A2i) recipients, were analyzed to assess the impact of pretransplant, transplant episode and 3-year posttransplant costs. The marginal costs of ABOi and A2i versus ABO-compatible (ABOc) transplants were quantified by multivariate linear regression including adjustment for recipient, donor and transplant factors. Compared with ABOc transplantation, patient survival (93.2% vs. 88.15%, p = 0.0009) and death-censored graft survival (85.4% vs. 76.1%, p < 0.05) at 3 years were lower after ABOi transplant. The average overall cost of the transplant episode was significantly higher for ABOi ($65 080) compared with A2i ($36 752) and ABOc ($32 039) transplantation (p < 0.001), excluding organ acquisition. ABOi transplant was associated with high adjusted posttransplant spending (marginal costs compared to ABOc - year 1: $25 044; year 2: $10 496; year 3: $7307; p < 0.01). ABOi transplantation provides a clinically effective method to expand access to transplantation. Although more expensive, the modest increases in total spending are easily justified by avoiding long-term dialysis and its associated morbidity and cost.

ABH-Glycan Microarray Characterizes ABO Subtype Antibodies: Fine Specificity of Immune Tolerance After ABO-Incompatible Transplantation.

Organ transplantation from ABO blood group-incompatible (ABOi) donors requires accurate detection, effective removal and subsequent surveillance of antidonor antibodies. Because ABH antigen subtypes are expressed differently in various cells and organs, measurement of antibodies specific for the antigen subtypes in the graft is essential. Erythrocyte agglutination, the century-old assay used clinically, does not discriminate subtype-specific ABO antibodies and provides limited information on antibody isotypes. We designed and created an ABO-glycan microarray and demonstrated the precise assessment of both the presence and, importantly, the absence of donor-specific antibodies in an international study of pediatric heart transplant patients. Specific IgM, IgG, and IgA isotype antibodies to nonself ABH subtypes were detected in control participants and recipients of ABO-compatible transplants. Conversely, in children who received ABOi transplants, antibodies specific for A subtype II and/or B subtype II antigens-the only ABH antigen subtypes expressed in heart tissue-were absent, demonstrating the fine specificity of B cell tolerance to donor/graft blood group antigens. In contrast to the hemagglutination assay, the ABO-glycan microarray allows detailed characterization of donor-specific antibodies necessary for effective transplant management, representing a major step forward in precise ABO antibody detection.