Safety of blood group A2-to-O liver transplantation: an analysis of the United Network of Organ Sharing database. Transplantation. 2012;94:526-531. [PMID: 22874840 DOI: 10.1097/tp.0b013e31825c591e]

Listing for blood type A2 donors is highly variable and impacts waitlist outcomes among blood type O liver transplantation candidates in the United States

Blood type O liver transplantation (LT) candidates in the United States face the highest waitlist mortality due to the broader compatibility of type O grafts. Although blood-type-compatible transplant is a gold standard, type O candidates might benefit from listing for A2 donors, whose antigen is known for its decreased immunogenicity. This study examined the trends and impact on waitlist outcomes of listing for A2 donors among 67 756 type O LT candidates listed between 2010 and 2023 using data from the United Network for Organ Sharing database. The number of A2-to-O LTs increased steadily, with 117 LTs performed in 2023. A total of 61.1% of type O candidates were listed as A2 donors, with considerable regional variations. Fine-Gray competing risk analysis revealed that listing for A2 donors was associated with reduced waitlist dropout rates (subdistribution hazard ratio: 0.94, P < .001) and increased transplant probabilities (subdistribution hazard ratio: 1.07, P < .001), especially in regions with longer wait times, among candidates with listing Model for End-Stage Liver Disease-Na scores between 15 and 34, and candidates listed after the Acuity Circles policy implementation. These findings suggest that encouraging listing for A2 donors could improve waitlist outcomes for type O candidates.

The Consequences of HLA Screening in the Prevention of Graft-Versus-Host Disease in Living Donor Liver Transplantation

AIMS

To study the effects of routine HLA screening and the policy of avoiding donor-dominant one-way HLA match to prevent graft-versus-host disease (GVHD) after living donor liver transplantation (LDLT).

PATIENTS AND METHODS

The records of potential living liver donors and recipients who attended our center between 2007 and 2018 were reviewed retrospectively.

RESULTS

Of the 149 patients who underwent LDLT and survived longer than 3 months, two developed GVHD despite our strict policy. The first patient presented with grade II GVHD limited to the skin. She was treated successfully by briefly discontinuing immunosuppression and switching to everolimus. In the second case, the policy had been relaxed due to the availability of a single donor for ABO-incompatible transplantation without any intervention to decrease anti-A antibody levels (special case: A2 to O). Nevertheless, the patient presented with grade I GVHD limited to skin and was treated successfully by adding oral methylprednisolone to tacrolimus and mycophenolate mofetil. To the best of our information, this is the second reported case who recovered from GVHD after LDLT from a donor, homozygous at HLA A, B and DR and a recipient, heterozygous for all. Sixteen potential donors (1.2% of all candidates) of 14 recipients were disqualified solely on the basis of the HLA results; five of these patients died due to unavailability of another donor.

CONCLUSION

The results support the policy of avoiding HLA combinations that preclude immune recognition of graft lymphocytes as foreign to decrease the risk of GVHD after LDLT.

Integrated transcriptomics and histopathology approach identifies a subset of rejected donor livers with potential suitability for transplantation

BACKGROUND

Liver transplantation is an effective treatment for liver failure. There is a large unmet demand, even as not all donated livers are transplanted. The clinical selection criteria for donor livers based on histopathological evaluation and liver function tests are variable. We integrated transcriptomics and histopathology to characterize donor liver biopsies obtained at the time of organ recovery. We performed RNA sequencing as well as manual and artificial intelligence-based histopathology (10 accepted and 21 rejected for transplantation).

RESULTS

We identified two transcriptomically distinct rejected subsets (termed rejected-1 and rejected-2), where rejected-2 exhibited a near-complete transcriptomic overlap with the accepted livers, suggesting acceptability from a molecular standpoint. Liver metabolic functional genes were similarly upregulated, and extracellular matrix genes were similarly downregulated in the accepted and rejected-2 groups compared to rejected-1. The transcriptomic pattern of the rejected-2 subset was enriched for a gene expression signature of graft success post-transplantation. Serum AST, ALT, and total bilirubin levels showed similar overlapping patterns. Additional histopathological filtering identified cases with borderline scores and extensive molecular overlap with accepted donor livers.

CONCLUSIONS

Our integrated approach identified a subset of rejected donor livers that are likely suitable for transplantation, demonstrating the potential to expand the pool of transplantable livers.

The increasing need for ABO blood group genotyping and quality assurance implications for laboratory implementation

ABO blood group antigens are critical determinants of immunologic self and non-self and are ubiquitously expressed on all cellular tissues. Antibodies against non-self ABO antigens are naturally present and can mediate pathologic reactions against incompatible transfused blood cells and transplanted tissues. Laboratory testing for ABO antigens and isoagglutinins is essential for safe and effective transfusion and transplantation. Testing for ABO antigens has traditionally depended on serologic testing. However, there is increasing need for evaluation of genetic analysis of ABO antigens, to enable evaluation of ABO blood group in cases where serologic testing may be ambiguous or impossible to accurately perform. The clinical need for ABO genotyping is being addressed by the development of multiple molecular diagnostic approaches. Recent data have clearly demonstrated the potential utility of ABO genotyping in solid organ transplantation, yet widespread implementation has been slow. We propose that this lag is related to practical considerations in laboratory testing, including limited regulatory guidance on the performance and reporting of these assays and the absence of widely available external proficiency testing programs for quality assurance. Here we describe approaches to ABO genotyping, current initiatives in developing ABO genotyping proficiency testing programs, and laboratory quality assurance considerations for ABO genotyping.

Including the liver in the visceral allograft: Impact on donor-specific anti-HLA antibodies and long-term outcomes

Humoral immunity emerges as a risk factor for graft failure after visceral transplantation (VTx) and development of donor-specific anti-HLA antibodies (DSAs) has been linked with poor outcomes. In most cases, a simultaneous liver transplant can be safely performed in sensitized patients with DSA and appears protective against lymphocytotoxic antibodies. We investigated the incidence of acute (AR) and chronic rejection (CR) in 32 VTx without any B cell-depleting pre-treatment (6 isolated intestinal transplants (IT) and 26 liver-containing, multivisceral transplants (MVT) and assessed the presence of donor-specific antibodies (DSA) pre- and post-transplantation. Twenty-one patients (65 %) developed AR, 15 (57 %) of the MVT and 6 (100 %) of the IT (p = 0.05). CR occurred in 4 IT (60 %, p < 0.001). At one month, de novo DSA were present in 71 % of VTx (66 % MVT vs 100 % IT, p = 0.09). At the last available follow-up, 69 % of the MVT and 50 % of the IT patients were DSA-free. De novo DSA seemed more persistent (7/19, 37 %) than pre-Tx DSA (1/6, 17 %; p = n.s.), de novo DSA were more frequently specific for HLA class II than class I, 16/19 (84 %) vs. 7/19 (37 %; p = 0.003), and HLA-DQ was their most frequent target HLA. DQ mismatches appeared to be a risk factor for developing de novo DSA. In conclusion, liver-containing visceral allografts have superior short- and long-term outcomes compared with liver-free allografts. De novo DSA develop early and frequently after VTx performed without B cell-depleting induction therapy, but the exact role of DSA in the pathogenesis of rejection remains unclear.

Outcomes of ABO-incompatible liver transplantation in end-stage liver disease patients co-infected with hepatitis B and human immunodeficiency virus

BACKGROUND

Human immunodeficiency virus (HIV)-positive patients coinfected with hepatitis B virus (HBV) are eligible for liver transplantation (LT) in Africa and Southeast Asia, particularly China. However, the outcome of HIV-HBV coinfected patients referred for ABO-incompatible LT (ABOi-LT) is unknown.

AIM

To clarify the outcome of ABOi-LT for HIV-HBV coinfected patients with end-stage liver disease (ESLD).

METHODS

We report on two Chinese HIV-HBV coinfected patients with ESLD who underwent A to O brain-dead donor LT and reviewed the literature on HIV-HBV coinfected patients treated with ABO-compatible LT. The pretransplantation HIV viral load was undetectable, with no active opportunistic infections. Induction therapy consisted of two sessions of plasmapheresis and a single dose of rituximab in two split doses, followed by an intraoperative regimen of intravenous immunoglobulin, methylprednisolone, and basiliximab. Post-transplant maintenance immunosuppressive agents consisted of tacrolimus and mycophenolate mofetil, and prednisone.

RESULTS

At the intermediate-term follow-up, patients showed undetectable HIV viral load, CD4(+) T cell counts greater than 150 cells/μL, no HBV recurrence, and stable liver function. A liver allograft biopsy showed no evidence of acute cellular rejection. Both patients survived at 36-42 mo of follow-up.

CONCLUSION

This is the first report of ABOi-LT in HIV-HBV recipients with good intermediate-term outcomes, suggesting that ABOi-LT may be feasible and safe for HIV-HBV coinfected patients with ESLD.

Blood Type A1 Mismatch Does Not Affect Heart Transplant Outcomes at One Year

There are subtypes within blood type A, termed non-A1, that have reduced expression of A antigen on cell surfaces. This can result in the development of anti-A1 antibodies. There is limited information regarding the impact of this in heart transplant (HTx) recipients. We conducted a single-center cohort study of 142 Type A HTx recipients in which we compared outcomes of a match group (an A1/O heart into an A1 recipient or a non-A1/O heart into a non-A1 recipient) with a mismatch group (an A1 heart into a non-A1 recipient or a non-A1 heart into an A1 recipient). At one year post-transplant, there were no differences between the groups in survival, freedom from non-fatal major adverse cardiovascular events, freedom from any treated rejection, or freedom from cardiac allograft vasculopathy. There was an increased hospital length of stay in the mismatch group (13.5 vs. 17.1 days, p = 0.04). Our study showed that A1 mismatch was not associated with worse outcomes at one year post-HTx.

Quick preparation of ABO-incompatible living donor liver transplantation for acute liver failure

Acute liver failure is life-threatening and has to be treated by liver transplantation urgently. When deceased donors or ABO-compatible living donors are not available, ABO-incompatible (ABO-I) living donor liver transplantation (LDLT) becomes the only choice. How to prepare ABO-I LDLT urgently is an unsolved issue. A quick preparation regimen was designed, which was consisted of bortezomib (3.5 mg) injection to deplete plasma cells and plasma exchange to achieve isoagglutinin titer ≤ 1: 64 just prior to liver transplantation and followed by rituximab (375 mg/m2 ) on post-operative day 1 to deplete B-cells. Eight patients received this quick preparation regimen to undergo ABO-I LDLT for acute liver failure from 2012 to 2019. They aged between 50 and 60 years. The median MELD score was 39 with a range from 35 to 48. It took 4.75 ± 1.58 days to prepare such an urgent ABO-I LDLT. All the patients had successful liver transplantations, but one patient died of antibody-mediated rejection at post-operative month 6. The 3-month, 6-month, and 1-year graft/patient survival were 100%, 87.5%, and 75%, respectively. In conclusion, this quick preparation regimen can reduce isoagglutinin titers quickly and make timely ABO-I LDLT feasible for acute liver failure.

Excellent outcome following emergency deceased donor ABO-incompatible liver transplantation using rituximab and antigen specific immunoadsorption

BACKGROUND

The acceptance of ABO-incompatible (ABOi) liver grafts will expand the donor pool for a patient in urgent need for a liver transplantation (LT). Here we report our results with emergency ABOi DD (deceased donor) LT using rituximab and antigen specific immunoadsorption.

PATIENTS AND METHODS

2009 to 2019 we performed 20 ABOi DD LTs (adults n = 17, children n = 3) for patients in urgent need for a LT. Immunosuppression consisted of rituximab (n = 20) and basiliximab (n = 15) or anti-thymocyte globuline (n = 4), intravenous immunoglobulin (IVIG; n = 6), tacrolimus, prednisolone and mycophenolate mofetil. Fifteen patients were treated with IA (n = 14) or both IA and plasmapheresis (PP; n = 1) pre-transplant and 18 patients were treated with IA (n = 15) or both IA and PP (n = 3) post-transplant. The median pre-transplant MELD- score was 40 (range 18-40). Patient and graft survival and complications were compared to a 1:4 case matched control group of ABO-identical or compatible (ABOid/c) DDLT.

RESULTS

The 1-, 3- and 5-year patient and graft survival rates were 85, 85 and 78% for the ABOi recipients and not significantly different compared to ABOid/c controls. Only one ABOi patient developed antibody-mediated rejection.

CONCLUSION

Patient and graft survival after emergency ABOi DDLT using rituximab and immunoadorption was equal to ABOid/DDLT. ABOi DD LT was a successful approach to expand the donor pool for patients in urgent need for a liver graft.

Complementary Roles of Cadaveric and Living Donor Liver Transplantation in Acute Liver Failure

BACKGROUND

Living donor liver transplantation may complement cadaveric transplantation in acute liver failure (ALF) patients.

METHODS

Between 2008 and 2017, 89 patients were treated for ALF; 15 patients (17%) recovered with intensive care treatment; 31 (35%) died without transplant. The records of the remaining 43 patients (median (range) age: 14 (1-62)) who underwent transplantation were evaluated.

RESULTS

The etiologic factors were toxic agents (10; mushrooms: 8; herbs: 2), hepatitis viruses (7; A: 1; B: 6), Wilson's disease (7), autoimmune hepatitis (4), and Budd-Chiari syndrome (2); 13 cases were idiopathic. Cadaveric organs (whole, split, reduced) were transplanted to 32 patients; 11 patients underwent living donor transplantation. One patient (2%) died of septic shock on the second postoperative day. Bacterial infection was the most common early (< 3 months) complication in the remaining patients (31/42; 74%), followed by delirium (5/42; 12%) and acute rejection requiring steroid pulse (5/42; 12%). Seven other patients died during median (range) follow-up of 94 (14-142) months: various infections (5), leukemia (1), and acute myocardial infarction (1). The 1-, 5-, and 10-year survival rates were 100%, 96%, and 92% in children and 94%, 82%, and 65% in adults respectively.

CONCLUSIONS

Cadaveric organ sharing and transplantation from living donors when appropriate yield a high survival rate, despite high early morbidity, in ALF patients whose conditions deteriorate despite intensive care treatment. Efforts to eliminate preventable causes of acute liver failure will lead to more efficient use of health care resources.

Anaesthetic implications and transfusion practices in ABO incompatible living donor liver transplantation: Case series

ABO incompatible liver transplants (ABOi LT) are considered as a life-saving option when compatible donor grafts are unavailable. Fourteen adults (right lobe graft) and three children (left lateral segment/lobe) who underwent ABOi LT from living donors between 2011 and 20 period were analysed for transfusions and desensitisation protocols. All recipients received packed red blood cells (PRBC) of their own group. AB plasma that does not contain any antibody was transfused in eight patients and donor group plasma in others. None of the patients developed transfusion related complications. Plasmapheresis and rituximab/bortezumab desensitisation was practised in 11 patients, only rituximab in four, only plasmapheresis in one, and no treatment in a 1 year child. Rejection was manifest in three patients while nine patients developed infections and sepsis. A working knowledge of the blood and product transfusions in ABOi LT is crucial for the anaesthesiologist. Perioperative management and impact of desensitisation protocol are discussed.

The Potential Significance of ABO Genotyping for Donor Selection in Kidney Transplantation

Background

The ABO blood group system is clinically important in kidney transplantation, but ABO genotyping fails to attract sufficient attention in some countries and regions. We identified one case of early graft dysfunction due to an ABO genotype mismatch. Here, we performed ABO genotyping in blood samples, analyzed grouping discrepancies, and investigated the weak A subgroup frequency in kidney transplantation candidates.

Methods

Blood samples from 302 uremic patients with grouping discrepancies and 356 uremic patients with type A blood were analyzed using standard serologic serotyping techniques. The ABO genotypes and alleles were analyzed by polymerase chain reaction sequence-specific primer (PCR-SSP) and sequence-based typing (PCR-SBT).

Results

All 302 uremic patients with grouping discrepancies carried weak ABO subgroup alleles and 77.48% carried irregular ABO antibodies. The discrepancy rate between serotyping and genotyping was 42.38%, and the mismatching rate of donor selection according to serotype reached 88.74%. And 2.53% of 356 uremic patients with type A blood were determined to be in the weak A subgroup, which was a higher percentage than that observed in the healthy Chinese population (0.53%) by serological screening, but much lower than that observed in Caucasians (20%).

Conclusion

We revealed the high risk of blood type misjudgment and genetically ABO-mismatched transplantation if serological test was performed only in blood-group typing. Improved precision of ABO genotyping is crucial for successful kidney transplantation and reasonable organ allocation.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

ABO-Incompatible Liver Transplantation - A Review of the Historical Background and Results

ABO-incompatible liver transplantation (ABOi LT) using conventional immunosuppression has been considered a contraindication due to the high risk for antibody-mediated complications potentially resulting in graft loss. However, organ shortage has led to the development of anti-A/B antibody reducing immunosuppressive protocols which have made the outcome after living donor (LD) ABOi LT equivalent to that achieved with LD ABO-compatible (ABOc). The experience of deceased donor (DD) ABOi LT is however still limited. In this article, we discuss the historical background and the results after ABOi LT, in the setting of both LD and DD transplantation. We also discuss the remaining hurdles and future strategies in the breaching of the ABO barrier for LT.

Lessons learnt from living donor liver transplantation with ABO-incompatibility: A single-centre experience from southern India

BACKGROUND

Although, ABO-incompatible (ABOi) liver transplantation is considered a high-risk procedure, using newer and more effective preoperative B cell desensitisation techniques, many transplant centres are routinely performing ABOi living donor liver transplantation (LDLT).

METHODS

This was a retrospective study of 12 patients (adult:pediatric = 10:2; M:F = 9:3; median age, 45.5 years [range 1 to 56 years]) who underwent ABOi LDLT at a tertiary care centre.

RESULTS

The median model for end-stage liver disease (MELD)/pediatric end-stage liver disease (PELD) scores were 28 (range 18 to 35) and 30.5 (range 24 to 37), respectively. For desensitisation, we initially used two doses of rituximab and two sessions of plasmapheresis preoperatively. We faced high mortality in the initial seven patients (five deaths) due to overwhelming sepsis from multidrug-resistant (MDR) pathogens. Subsequently, we restricted the rituximab to one dose and performed plasmapheresis only when isoagglutinin titre value was more than 1:64. With this regimen, out of the last five patients, four did well. For the whole cohort, the incidence of antibody-mediated rejection, acute cellular rejection, biliary complications, hepatic artery thrombosis, infection, and 5-year patient survival were 16.7%, 16.7%, 16.7%, 8.3%, 75%, and 40%, respectively. The risk factors for mortality were high MELD score, O blood group, and more intense desensitisation protocol.

CONCLUSIONS

Careful selection of patients and less intense desensitisation protocol are probably important in improving the outcomes in ABOi LDLT.

Race/ethnicity is associated with ABO-nonidentical liver transplantation in the United States

United Network for Organ Sharing (UNOS) policies allow for ABO-nonidentical liver transplantation (LT) in candidates with Model for End-Stage Liver Disease (MELD) scores greater than 30. Previous studies showed ABO-nonidentical LT resulted in an 18% and 55% net gain in livers for B and AB candidates. These results suggested that the current liver ABO allocation policies may need refinement. There are, however, strong associations between ABO blood groups and race/ethnicity. We hypothesized that race/ethnicity is associated with ABO-nonidentical LT and that this is primarily influenced by recipient ABO status. We examined non-status 1 adult candidates registered between July 1, 2013, and December 31, 2015. There were 27 835 candidates (70% non-Hispanic White, 15% Hispanic, 9% Black, 4% Asian, 1% Other/Multiracial). A total of 11 369 underwent deceased donor LT: 93% ABO identical, 6% ABO compatible, and 1% ABO incompatible. Black and Asian race/ethnicity were associated with increased likelihoods of ABO-nonidentical LT. Adjustment for disease etiology, listing MELD, transplant center volume, and UNOS region did not alter this association. Stepwise inclusion of recipient ABO status did eliminate this significant association of race/ethnicity with ABO-nonidentical LT. Blacks and Asians may be advantaged by ABO-nonidentical LT, and we suspect that changes to the existing policies may disproportionately impact these groups.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Liver transplantation with deceased ABO-incompatible donors is life-saving but associated with increased risk of rejection and post-transplant complications

ABO-incompatible (ABOi) liver transplantation (LT) with deceased donor organs is performed occasionally when no ABO-compatible (ABOc) graft is available. From 1996 to 2011, 61 ABOi LTs were performed in Oslo and Gothenburg. Median patient age was 51 years (range 13-75); 33 patients were transplanted on urgent indications, 13 had malignancy-related indications, and eight received ABOi grafts for urgent retransplantations. Median donor age was 55 years (range 10-86). Forty-four patients received standard triple immunosuppression with steroids, tacrolimus, and mycophenolate mofetil, and forty-four patients received induction with IL-2 antagonist or anti-CD20 antibody. Median follow-up time was 29 months (range 0-200). The 1-, 3-, 5-, and 10-year Kaplan-Meier estimates of patient survival (PS) and graft survival (GS) were 85/71%, 79/57%, 75/55%, and 59/51%, respectively, compared to 90/87%, 84/79%, 79/73%, and 65/60% for all other LT recipients in the same period. The 1-, 3-, 5-, and 10-year GS for A2 grafts were 81%, 67%, 62%, and 57%, respectively. In conclusion, ABOi LT performed with non-A2 grafts is associated with inferior graft survival and increased risk of rejection, vascular and biliary complications. ABOi LT with A2 grafts is associated with acceptable graft survival and can be used safely in urgent cases.

A2 /A2 B to B Renal Transplantation: Past, Present, and Future Directions

One component of the new national kidney allocation system (KAS) in the United States that was implemented on December 4, 2014, was the allocation of kidneys from A2 and A2 B (A, non-A1 and AB, non-A1 B) deceased donors into blood group B candidates (A2 /A2 B → B). In so far as this is an important component of the new KAS that has the potential to further increase the access to transplantation for blood group B candidates on the waiting list, most of whom are minority candidates, we will review the body of evidence and historical perspectives that led to its inclusion in the new KAS. This review will also describe prospects for more widespread use of A2 /A2 B → B transplantation and a novel mechanism of humoral immunosuppression in B patients before and after transplantation with an A2 or A2 B kidney.

Molecular deciphering of the ABO system as a basis for novel diagnostics and therapeutics in ABO incompatible transplantation

In recent years ABO incompatible kidney transplantation (KTx) has become a more or less clinical routine procedure with graft and patient survival similar to those of ABO compatible transplants. Antigen-specific immunoadsorption (IA) for anti-A and anti-B antibody removal constitutes in many centers an important part of the treatment protocol. ABO antibody titration by hemagglutination is guiding the treatment; both if the recipient can be transplanted as well as in cases of suspected rejections if antibody removal should be performed. Despite the overall success of ABO incompatible KTx, there is still room for improvements and an extension of the technology to include other solid organs. Based on an increased understanding of the structural complexity and tissue distribution of ABH antigens and the fine epitope specificity of the ABO antibody repertoire, improved IA matrices and ABO antibody diagnostics should be developed. Furthermore, understanding the molecular mechanisms behind accommodation of ABO incompatible renal allografts could make it possible to induce long-term allograft acceptance also in human leukocyte antigen (HLA) sensitized recipients and, perhaps, also make clinical xenotransplantation possible.

Matching donor to recipient in liver transplantation: Relevance in clinical practice

Achieving optimum outcomes after liver transplantation requires an understanding of the interaction between donor, graft and recipient factors. Within the cohort of patients waiting for a transplant, better matching of the donor organ to the recipient will improve transplant outcomes and benefit the overall waiting list by minimizing graft failure and need for re-transplantation. A PubMed search was conducted to identify published literature investigating the effects of donor factors such as age, gender, ethnicity, viral serology; graft factors such as size and quality, recipient factors such as age, size, gender and transplant factors such as major or minor blood group incompatibility and immunological factors. We also report technical and therapeutic modifications that can be used to manage donor-recipient mismatch identified from literature and the authors’ clinical experience. Multiple donor and recipient factors impact graft survival after liver transplantation. Appropriate matching based on donor-organ-recipient variables, modification of surgical technique and innovative peri-transplant strategies can increase the donor pool by utilizing grafts from marginal donors that are traditionally turned down.

ABO-incompatible liver transplantation in acute liver failure: a single Portuguese center study

INTRODUCTION

ABO-incompatible liver transplantation (ABOi LT) is considered to be a rescue option in emergency transplantation. Herein, we have reported our experience with ABOi LT including long-term survival and major complications in these situations.

PATIENT AND METHODS

ABOi LT was performed in cases of severe hepatic failure with imminent death. The standard immunosuppression consisted of basiliximab, corticosteroids, tacrolimus, and mycophenolate mofetil. Pretransplantation patients with anti-ABO titers above 16 underwent plasmapheresis. If the titer was above 128, intravenous immunoglobulin (IVIG) was added at the end of plasmapheresis. The therapeutic approach was based on the clinical situation, hepatic function, and titer evolution. A rapid increase in titer required five consecutive plasmapheresis sessions followed by administration of IVIG, and at the end of the fifth session, rituximab.

RESULTS

From January 2009 to July 2012, 10 patients, including 4 men and 6 women of mean age 47.8 years (range, 29 to 64 years), underwent ABOi LT. At a mean follow-up of 19.6 months (range, 2 days to 39 months), 5 patients are alive including 4 with their original grafts. One patient was retransplanted at 9 months. Major complications were infections, which were responsible for 3 deaths due to multiorgan septic failure (2 during the first month); rejection episodes (4 biopsy-proven of humoral rejections in 3 patients and 1 cellular rejection) and biliary.

CONCLUSION

The use of ABOi LT as a life-saving procedure is justifiable in emergencies when no other donor is available. With careful recipient selection close monitoring of hemagglutinins and specific immunosuppression we have obtained acceptable outcomes.