ABO Incompatible Living Donor Liver Transplantation in Children: A Single Centre Experience from India

Background

In recent years, paediatric ABO incompatible (ABOi) living donor liver transplant (LT) has shown promising outcomes and can potentially eliminate organ shortage. This study aims to report paediatric ABOi LT experience, including short- and long-term outcomes.

Methods

It is a single-centre retrospective study. Out of 108 LTs, 20 were done in children. We compared the outcomes between ABOi (n = 20) and non-ABOi (n = 220) paediatric living donor liver transplantation (LDLT) performed during the study period. All the children received pre-LT desensitization therapy comprising rituximab and plasmapheresis targeting pre-LT isohemagglutinin (IHA) titres of ≤1:16.

Results

Out of 239 paediatric LDLTs from 2017 to 2022, 19 children (11 females) underwent 20 ABOi LTs (including one retransplant with an ABOi domino allograft) at a median age of 12 (12, 51) months, with the majority being biliary atresia (60%). The median change in CD19 cell%, CD20 cell%, and IHA titres after rituximab from day -14 to day -1 (before LT) was satisfactory. In the first 3 months following LT, acute cellular rejection, culture-proven sepsis, and biliary and vascular complications were seen in 10%, 20%, 20%, and 15%, respectively. None of the ABOi LT recipients developed antibody-mediated rejection. ABOi LT recipients, as compared to non-ABOi LT recipients, had a higher incidence of bile leaks and prolonged hospital stay, with the rest of the complications, including biliary strictures and long-term outcomes, being comparable. At a median follow-up of 21 (14, 33) months, 4 children expired (21%).

Conclusion

ABOi LT in children shows excellent outcomes and can be performed safely with prior desensitization when a compatible liver is unavailable.

Impact of the Pediatric ABO Policy Change on Listings, Transplants, and Outcomes for Children Younger Than 2 Years Listed for Heart Transplantation in the United States

BACKGROUND

We assessed the impact of the liberalized ABO pediatric policy change on candidate characteristics and outcomes for children undergoing heart transplant (HT).

METHODS AND RESULTS

Children <2 years undergoing HT with ABO strategy reported at listing and HT from December 2011 to November 2020 to the Scientific Registry of Transplant Recipients database were included. Characteristics at listing, HT, and outcomes during the waitlist and post-transplant were compared before the policy change (December 16, 2011 to July 6, 2016), and after the policy change (July 7, 2016 to November 30, 2020). The percentage of ABO-incompatible (ABOi) listings did not increase immediately after the policy change (P = .93); however, ABOi transplants increased by 18% (P < .0001). At listing, both before and after the policy change, ABOi candidates had higher urgency status, renal dysfunction, lower albumin, and required more cardiac support (intravenous inotropes, mechanical ventilation) than those listed ABO compatible (ABOc). On multivariable analysis, there were no differences in waitlist mortality between children listed as ABOi and ABOc before the policy change (adjusted hazard ratio [aHR] 0.80, 95% confidence interval [CI] 0.61-1.05, P = .10) or after the policy change (aHR 1.2, 95% CI 0.85-1.6, P = .33). Post-transplant graft survival was worse for ABOi transplanted children before the policy change (aHR 1.8, 95% CI 1.1-2.8, P = .014), but not significantly different after the policy change (aHR 0.94, 95% CI 0.61-1.4, P = .76). After the policy change, ABOi listed children had significantly shorter waitlist times (P < .05).

CONCLUSIONS

The recent pediatric ABO policy change has significantly increased the percentage of ABOi transplantations and decreased waitlist times for children listed ABOi. This change in policy has resulted in broader applicability and actual performance of ABOi transplantation with equal access to ABOi or ABOc organs, and thus eliminated the potential disadvantage of only secondary allocation to ABOi recipients.

Pre-transplant donor specific antibodies in ABO incompatible kidney transplantation - data from the Swiss transplant cohort study

Background

Living donor (LD) kidney transplantation in the setting of ABO blood group incompatibility (ABOi) has been previously reported to be associated with increased risk for antibody-mediated rejection (ABMR). It is however unclear if the presence of pre-transplant donor specific antibodies (DSA) works as an additive risk factor in the setting of ABOi and if DSA positive ABOi transplants have a significantly worse long-term outcome as compared with ABO compatible (ABOc) DSA positive transplants.

Methods

We investigated the effect of pre-transplant DSA in the ABOi and ABOc setting on the risk of antibody-mediated rejection (ABMR) and graft loss in a cohort of 952 LD kidney transplants.

Results

We found a higher incidence of ABMR in ABOi transplants as compared to ABOc transplants but this did not significantly affect graft survival or overall survival which was similar in both groups. The presence of pre-transplant DSA was associated with a significantly increased risk of ABMR and graft loss both in the ABOi and ABOc setting. We could not detect an additional risk of DSA in the ABOi setting and outcomes were comparable between DSA positive ABOi and ABOc recipients. Furthermore, a combination of DSA directed at both Class I and Class II, as well as DSA with a high mean fluorescence intensity (MFI) showed the strongest relation to ABMR development and graft loss.

Conclusion

The presence of pre-transplant DSA was associated with a significantly worse long-term outcome in both ABOi and ABOc LD kidney transplants and our results suggests that the risk associated with pre-transplant DSA is perhaps not augmented in the ABOi setting. Our study is the first to investigate the long-term effects of DSA in the ABOi setting and argues that pre-transplant DSA risk could potentially be evaluated similarly regardless of ABO compatibility status.

Establishment of an adverse effect prevention protocol on plasma exchange using fresh frozen plasma prior to ABO-incompatible living donor kidney transplantation at our hospital

INTRODUCTION

Simple plasma exchange (PE) with fresh-frozen plasma replacement allows antibody removal for ABO-incompatible living donor kidney transplantation, but is associated with a high incidence of allergic reactions. We developed, implemented, and evaluated a protocol for safe preoperative PE.

METHODS

The protocol comprised pretreatment (125 mg methylprednisolone infusion, 400 mg acetaminophen and 30 mg diphenhydramine orally) with a replacement fluid rate < 20 mL/min. Allergic reaction incidence was investigated in controls who underwent ABO-incompatible living donor kidney transplantation between 2016 and March 2020 (group C) and patients who underwent the protocol and procedure between April 2020 and February 2023 (group N).

RESULTS

Ten (group C) and 19 (group N) patients performed 11 and 30 sessions of PE, respectively. Allergic reactions occurred in 81.8% and 36.7% (p = 0.014), respectively, with an odds ratio of the protocol was 0.056 (95% CI 0.0059-0.5380, P = 0.013).

CONCLUSION

Our protocol resulted in a significantly lower incidence of allergic reactions.

ABO-Incompatible Renal Transplant: A Single-Center Experience from India

Introduction

In view of ever-increasing end-stage renal disease (ESRD) population but inadequate availability of suitable donors, ABO-incompatible (ABOi) transplantation can be an important void filler. However, at present, ABOi transplantation is limited to a few centers in India and there is a lack of adequate experience and expertise to guide this program to other centers in the country.

Methods

Data of all the ABOi transplants performed from 2012 to 2021 in a tertiary care hospital was retrospectively analyzed. The anti-ABO antibody (IgG) titers (≤1:4) were considered safe before transplantation. Desensitization included rituximab, plasma exchange, or selective immunoadsorption column. Tacrolimus and mycophenolate mofetil were initiated at day -7. Induction agents included ATG, ATLG, basiliximab, or no induction. Postoperatively, anti-ABO titers were done daily for 2 weeks.

Results

A total of 202 patients underwent transplantation; of these, 195 patients whose data were for available for 12 months were included in the study. Mean duration of follow-up was 28.9 ± 21.7 months. UTI was the most common source of infection, occurring in almost half (46.1%) of the patients. Antibody-mediated rejection (ABMR; 15%) was common in the first year. Patient survival was 86.6% (169/195) at 1 year. Sepsis was the most common of death in more than two-thirds of the population, including coronavirus disease 2019 (COVID-19)-associated mortality in nine patients (4.6%). Death-censored graft survival was 89.3% (174/195). AMR was the leading cause of graft loss in almost half of the patients.

Conclusion

ABOi should be considered in ESRD patients for whom suitable ABO-compatible donor is not available. Higher rate of rejection and infection are still a major concern.

Protracted COVID-19 pneumonitis early post-ABO incompatible kidney transplantation: Management considerations and the role of whole genome sequencing

We present the case of a recent ABO incompatible kidney transplant recipient with persistent SARS-CoV-2 infection and pneumonitis. Serial whole genome sequencing confirmed intra-host viral evolution, which was used as a surrogate to confirm active viral replication and support re-treatment with antivirals, late in the course of infection. A prolonged course of remdesivir combined with immunosuppression modulation resulted in successful clearance of virus and clinical improvement. The diagnostic process undertaken in this case provides a useful guide for other clinicians when approaching similar patients.

Long-term outcomes following ABO-incompatible living donor liver transplantation for acute liver failure: a single-center experience of over 20 years

PURPOSE

Acute liver failure is a life-threatening condition for which ABO-incompatible living donor liver transplantation (ABOi-LDLT) is sometimes the only life-saving treatment option. We reviewed a single-center experience of adult ABOi-LDLT treatment for acute liver failure (ALF).

METHODS

Preoperative treatment, immune indices (B cell marker, anti-donor blood-type antibody), and postoperative outcomes were compared between ALF and non-ALF groups.

RESULTS

There were 5 and 33 patients in the ALF and non-ALF groups, respectively. The ALF group received higher doses of steroids, underwent more rounds of plasma exchange (PE), and underwent transplantation for ALF with a shorter interval following preoperative rituximab (RTx) administration (median: 2 vs 13 days; P < 0.05) than the non-ALF group. Preoperatively, CD19-positive lymphocytes in the peripheral blood were sufficiently depleted in all of the non-ALF group patients, whereas they were poorly depleted in the ALF group. Postoperatively, neither group suffered anti-donor blood-type antibody titer rebound or antibody-mediated rejection. The ALF group had a comparable 5-year survival rate to the non-ALF group (80.0% vs 77.9%).

CONCLUSIONS

Despite the delayed preoperative administration of RTx, the ALF group showed an uneventful immunological response and acceptable long-term survival rate. Thus, ABOi-LDLT seems a viable treatment option for ALF.

ABO Incompatible Kidney Transplantation Without B-cell Depletion is Associated With Increased Early Acute Rejection: A Single-Center Australian Experience

We performed a single-center retrospective cohort study of 66 consecutive ABO incompatible kidney transplants (ABOiKT) performed without B-cell depleting therapy. Outcomes were compared to an earlier era performed with rituximab (n = 18) and a contemporaneous cohort of ABO compatible live donor transplants (ABOcKT). Acute rejection within 3 months of transplant was significantly more common after rituximab-free ABOiKT compared to ABOiKT with rituximab (OR 8.8, p = 0.04) and ABOcKT (OR 2.9, p = 0.005) in adjusted analyses. Six recipients of rituximab-free ABOiKT experienced refractory antibody mediated rejection requiring splenectomy, and a further two incurred early graft loss with no such episodes amongst ABOiKT with rituximab or ABOcKT cohorts. Patient and graft survival were similar between groups over a median follow-up of 3.1 years. This observational evidence lends strong support to the continued inclusion of rituximab in desensitization protocols for ABOiKT.

Acute hemolytic transfusion reaction following ABO-mismatched platelet transfusion: Two case reports

Acute hemolytic transfusion reaction following ABO-incompatible platelet transfusion: two case reports An ideal platelet transfusion should provide ABO identical platelet concentrate, and cross match compatibility is not routinely performed in the standard practices. However, ABO non identical platelet transfusions are not uncommon with the limited resources and short shelf life of platelet concentrate. Though rare, acute hemolytic transfusion reaction (AHTR) may occur following minor ABO-incompatible platelet transfusion. Here, we report two cases of thrombocytopenic patients (one child and one adult) type as Group B RhD positive and received Group O RhD positive platelet transfusions. Both patients experienced an AHTR evidenced by a drop in hemoglobin level, spherocytosis and small agglutinations on the blood film, and positive direct Coombs test. They were treated symptomatically, recovered and discharged well post-event without any morbidity. No anti-B isohemagglutinins titer were done to confirm the high titer of the antibody in the platelet donors. Our cases highlighted the importance of ABO-compatible platelet transfusion, especially to children and those vigilant groups of patients.

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Assessing the risks of haemolysis as an adverse reaction following the transfusion of ABO incompatible plasma-containing components - A scoping review

Background The limited supply of universal plasma has resulted in transfusion of ABO incompatible plasma to patients. As the need to implement whole blood transfusion in pre-hospitals setting rises, the lowest cut-off for anti-A/anti-B that does not cause haemolysis remains unknown. In this first scoping review, we aimed to determine the lowest ABO titre and volume reported in the literature to cause haemolysis from ABO incompatible plasma transfusions (plasma, platelets, cryoprecipitate, and whole blood). Methods We searched several databases from inception to April 2022, including all study types. Three independent reviewers extracted and reviewed the data. Primary outcome was the anti-A and anti-B titre (measured by IgM or IgG) that resulted in measurable haemolysis following ABO incompatible plasma transfusion. Results We identified 5681 citations, of which 49 studies were eligible, reporting a total of 62 cases (34 adults, 14 children and 14 did not specify age). The methods for antibody measurement and antibody type (IgG or IgM) varied significantly between studies. Component volumes were poorly reported. The most common component responsible for the haemolysis was apheresis platelets followed by pooled platelets and whole blood. Most haemolytic cases reported were due to anti-A. The lowest anti-A titre reported to cause haemolysis (children and adults) was 32 (IgG), while for anti-B it was 512 (IgG and IgM) for adults, 16,384 for paediatrics (IgG and IgM) and 128 (IgM) in cases where the age was not specified. The lowest reported volume associated with haemolysis were 100 ml (adults) and 15 ml (children). Of the 62 15 (24%) died. Conclusion The lowest titre reported to cause haemolysis was an anti-A of 32. ABO mismatch plasma transfusion may be associated with significant mortality. There is a need to agree/standardise methods for ABO titration measurement internationally for plasma components and agree the lowest anti-A/anti-B titre for transfusing ABO mismatched plasma.

ABO-incompatible granulocyte transfusion: Is ABO subgroup a barrier?

Granulocyte transfusion (GTx) is an efficient and compelling treatment option for patients with neutropenia following hematopoietic stem cell transplant. The donor pool for granulocyte harvest is limited to close friends and family members and the donors accepted are often of the same ABO Rh type. We report a case of ABO-incompatible prophylactic GTx, in a case of acute myeloblastic leukemia. Postcollection processing of the granulocyte product was done to reduce the red blood cell volume to <5 ml, making it safe for transfusion. The transfusion was successful in stabilizing the total leukocyte counts in the patient. The patient was monitored, and there were no adverse reactions posttransfusion.

Outcome of ABO-incompatible kidney transplantation using a modified desensitization protocol without plasmapheresis

OBJECTIVES

Several controversies regarding desensitization strategies for successful ABO-incompatible (ABOi) kidney transplantation still exist. This study aimed to investigate whether pretransplant anti-A/B antibody removal is mandatory in an ABOi kidney transplant recipient with low baseline isoagglutinin titers.

METHODS

We adopted a modified desensitization protocol with two doses of rituximab (RTX, 100 mg/body) without pretransplant antibody removal for ABOi kidney transplant recipients with a titer of ≤1:64 (group A; n = 35) and investigated the feasibility of this protocol by comparing it with the clinical outcomes of patients undergoing standard pretransplant plasmapheresis (group B; n = 21).

RESULTS

There was no significant difference in the rate of antibody-mediated rejection within the first month after transplantation between the two groups (11.4% in group A vs. 2% in group B, p = 0.6019). Moreover, no differences were observed in the short- and long-term graft outcomes between the groups. However, two major critical acute antibody-mediated events occurred in group A; one patient lost the graft due to hyperacute rejection, and the other patient developed thrombotic microangiopathy after surgery. Risk factors predicting these perioperative complications were not identified.

CONCLUSIONS

We conclude that not only B-cell depletion using RTX but also pretransplant antibody removal is still recommended even for patients with low isoagglutinin titers. In addition, a new diagnostic tool is needed for accurate risk stratification.

Choice of ABO Group for Blood Component Transfusion in ABO-Incompatible Solid Organ Transplantation: A Questionnaire Survey in Korea and Guideline Proposal

The number of ABO-incompatible solid organ transplantations (ABOi SOTs) has markedly increased worldwide since the early 2000s. We investigated the choice of ABO group for blood component transfusion in ABOi SOT. We conducted a survey by e-mailing a questionnaire to blood bank specialists at 77 major hospitals in Korea, among whom 34 responded to the survey. In major ABOi SOT, for red blood cells (RBCs), the recipient’s type (70.6%) was the most common choice, followed by group O (29.4%); for platelets, group AB (50.0%) was the most common choice, followed by the donor type (38.2%); for plasma, group AB (55.9%) was the most common choice, followed by the donor type (32.4%). In bidirectional ABOi SOT, for RBCs, the recipient’s type (55.9%) was the most common choice, followed by group O (44.1%); for platelets and plasma, group AB was the most common choice (94.1% and 97.1%, respectively). The policies for transfusion in ABOi SOT were diverse. We suggest a guideline on the choice of ABO group for transfusion in ABOi SOT to secure patient health and enable an efficient use of blood components.

Risk Due to ABO Incompatibility and Donor-Recipient Weight Mismatch in Living Donor Kidney Transplantation: A National Cohort Study

The effect of donor-recipient weight mismatch is not well established in ABO-incompatible living donor kidney transplantation (LDKT). A total of 2584 LDKT patients in the Korean Organ Transplantation Registry were classified into four groups according to the presence or absence of ABO incompatibility and donor-recipient weight mismatch (donor-to-recipient weight ratio (DRWR) < 0.8). In a multivariable Cox analysis, the combination of ABO incompatibility and DRWR incompatibility (n = 124) was an independent risk factor for graft survival (HR = 2.73, 95% CI = 1.11-6.70) and patient survival (HR = 3.55, 95% CI = 1.39-9.04), whereas neither factor alone was a significant risk factor for either outcome. The combination of ABO incompatibility and DRWR incompatibility was not an independent risk factor for biopsy-proven graft rejection (HR = 1.27, 95% CI = 0.88-1.82); however, it was an independent risk factor for pneumonia (HR = 2.94, 95% CI = 1.64-5.57). The mortality rate due to infection was higher among patients with both ABO incompatibility and DRWR incompatibility than among patients with neither factor or with either factor alone. The combination of ABO incompatibility and DRWR incompatibility was an independent risk factor for graft and patient survival after LDKT, whereas neither factor alone significantly affected graft or patient survival. Thus, donor-recipient weight matching should be cautiously considered in LDKT with ABO incompatibility.

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.

Non-simultaneous kidney exchange cycles in resource-restricted countries without non-directed donation - a prospective single-center cohort study

Recent reports suggest that bridge-donor reneging is rare (1.5%) in non-simultaneous kidney exchange chains. However, in developing countries, the non-directed donors who would be needed to initiate chains are unavailable, and furthermore, limited surgical space and resources restrain the feasibility of simultaneous kidney exchange cycles. Therefore, the aim of this study was to evaluate the bridge-donor reneging rate during non-simultaneous kidney exchange cycles (NSKEC) in a prospective single-center cohort study (n = 67). We describe the protocol used to prepare co-registered donor-recipient pairs for non-simultaneous surgeries, in an effort to minimize the reneging rate. In addition, in order to protect any recipients who might be left vulnerable by this arrangement, we proposed the use of standard criteria deceased-donor kidneys to rectify the injustice in the event of any bridge-donor reneging. We report 17 successful NSKEC resulting in 67 living-donor kidney transplants (LDKT) using 23 bridge-donors without donor renege and no intervening pairs became unavailable. We propose that NSKEC could increase LDKT, especially for difficult-to-match sensitized pairs (25 of our 67 pairs) in countries with limited transplantation resources. Our study confirms that NSKEC can be safely performed with careful patient-donor selection and non-anonymous kidney exchanges.

No diffuse intrahepatic biliary stricture after ABO-incompatible adult living donor liver transplantation using tailored rituximab-based desensitization protocol

Background

Rituximab (RTx) desensitization protocol offered good outcome in ABO-incompatible (ABOi) living donor liver transplantation (LDLT). However, diffuse intrahepatic biliary stricture (DIHBS) is still inevitable hurdle. We selectively added postoperative high dose intravenous immunoglobulin (IVIG) and/or simultaneous splenectomy if ABO isoagglutinin titer just before liver transplantation after plasma exchange (PE) was higher than 1/16. Herein, we reported the excellent outcome of ABOi LDLT without DIHBS using tailored desensitization protocol and compared it with that of ABO-compatible (ABOc) LDLT.

Methods

Sixty-five cases (14.8%) of ABOi LDLTs were performed among 438 primary adult LDLTs in our center between March 2012 and June 2017. We performed 1-to-2 propensity score matching (PSM) to extract 60 cases of ABOi LDLTs and 120 cases of ABOc LDLTs.

Results

There were no significant differences in clinical characteristics between ABOi and ABOc recipients. There were no significant differences in complications and rejection. There was no DIHBS in both groups. The 1-, 3-, and 5-year overall survival rates were 98.3%, 86.7%, and 82.9% in ABOi group and 96.7%, 86.7%, and 85.4% in ABOc group, respectively (P=0.88). Most common cause of deaths of both groups was hepatocellular recurrence. The 1-, 3-, and 5-year biliary complication (anastomosis leakage or stricture) free survival rates were 81.4%, 69.5%, and 67.5% in ABOi group and 83.0%, 81.3%, and 80.0% in ABOc group, with no significant differences (P=0.11).

Conclusions

RTx-based tailored (optional IVIG + splenectomy) desensitization protocol for ABOi LDLT was feasible and acceptable.

[ABO incompatible living donor kidney transplantation in a center in Córdoba, Argentina]

The ABO incompatible (ABOi) living donor (LD) kidney transplant allows increasing the number of donors and reducing the time on the waiting list. The objectives of this study were to compare graft survival, patient survival, rejection risk factors and complications during the first year p ost-transplantation in patients who received an ABOi LD kidney transplant between 2014 and 2019 in our institution, matched according to sex, age and immunological risk with a control group of ABO compatible (ABOc) LD kidney transplants in the same period. Thirteen patients were included in each group. No significant differences were found between ABOi and ABOc in the incidence of delayed graft function (n = 0 vs. 1), bleeding (0 vs. 0), infections (13 vs. 13), cellular rejection (1 vs. 3) and humoral rejection (4 vs. 3) in the first year after transplantation. The rejection rate in ABOi do not seem to be related to blood incompatibility. No risk factors associated with rejection were found. Overall survival of patients was 100% in both groups, and graft survival was 92.3% in ABOi and 100% in ABOc (p = 1). ABOi kidney transplantation is an adequate feasible option in our environment for those who do not have compatible donors.

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

BACKGROUND AND AIMS

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

Patient outcome and graft outcomes observed with incompatible transplants were not worse than those observed with compatible transplants.

Isoagglutinin removal by plasma centrifugation or filtration (single or double): A prospective study in a single center

INTRODUCTION

ABO-incompatible (ABOi) kidney transplantation, a well-established procedure, has good long-term results provided pretransplant desensitization that includes immunosuppression and apheresis.

OBJECTIVE

To compare, within the first pretransplant apheresis session given to 29 ABOi kidney-transplant candidates, the effect on isoagglutinin titers (both IgG and IgM isotypes) of three modalities: centrifugation therapeutic plasmapheresis (cTP; n = 10), filtration TP (fTP; n = 9), and double-filtration plasmapheresis (DFPP; n = 10).

RESULTS

The three groups were comparable according to baseline demographics. Treated plasma volumes were similar across the three groups, that is, 4111 ± 403 mL (cTP), 3861 ± 282 mL (fTP), and 3699 ± 820 mL (DFPP): that is, 54 ± 7, 53 ± 7, and 53 ± 10 mL/kg respectively. One session of centrifugation or filtration TP reduced IgG anti-A/anti-B isoagglutinin titer by ~4, whereas one DFPP session reduced it by ~2. One session of cTP reduced IgM anti-A isoagglutinin titer by a little less than 4, whereas fTP and DFPP sessions reduced it by ~3. There were no statistical differences across the three groups regarding isoagglutinin rebound (IgG and IgM). However, isoagglutinin IgG rebound was >4 dilutions for anti-B titers compared with ~2 dilutions for anti-A titers. The median decreases in IgG level were -3.9 g/L (DFPP), -5.9 g/L (cTP), and - 6.06 g/L (fTP) (p = ns). Median fibrinogen depletions were ~ 60% (fTP), 64% (DFPP), and 76% (cTP).

CONCLUSIONS

Isoagglutinin depletions within the first apheresis session were similar across cTP, fTP, and DFPP: this was numerically lower for DFPP.

Low rates of anti-recipient isohemagglutinins in ABO incompatible hematopoietic stem cell transplants

INTRODUCTION

Isohemagglutinins occur naturally and form in an 'opposite' (antigen-negative) pattern to a patient's ABO blood type. Patients undergoing minor and bidirectional ABO incompatible hematopoietic stem cell transplantation (HSCT) may demonstrate detectable antibodies against their native blood type. In this study, we sought to characterize the rates of such antibody formation and evaluate the clinical significance of our findings.

MATERIALS AND METHODS

An internal database of HSCT patients at an academic medical center was queried for ABO incompatible transplant patients from 2009-2019. Serum typing results, clinical histories, and laboratory data were compiled and reviewed.

RESULTS

A total of 182 minor and bidirectional ABO incompatible HSCT patients were identified. Anti-recipient isohemagglutinins were found in 9% (16/182) of the HSCT patients. The rate was higher in patients with minor incompatibility (12%: 15/127) versus bidirectional ABO incompatibility (2%: 1/55) (p = 0.04). No anti-recipient isohemagglutinins were identified in umbilical cord HSCT patients (0%: 0/7). Serologic agglutination reactions of recipient isohemagglutinins were overall mostly weak (13/16 weak + to 1+). There was a trend towards a higher rate of acute graft-versus-host-disease in patients with anti-recipient isohemagglutinins compared to those without (75% vs. 53%; p = 0.12), though not statistically significant. Rates of alloimmunization to minor red cell antigens were similar between the two groups. Few patients showed laboratory evidence of hemolysis at 12 months follow up.

DISCUSSION AND CONCLUSIONS

Anti-recipient isohemagglutinins occur at low rates in ABO incompatible HSCT and are significantly more common in minor ABO incompatible transplant compared to bidirectional transplants. Larger cohort studies are needed to better understand the relationship between anti-recipient isohemagglutinins and HSCT outcomes.

Clinical outcome of living donor kidney transplantation across simultaneous ABO and HLA incompatibility: Single center experience of first ten cases

BACKGROUND AND AIMS

Preconditioning using different protocols has been tested to prevent antibody mediated rejection (ABMR) individually for ABO and HLA incompatibility. However, simultaneous presence of both barriers is still less explored. The aim of this study was to report outcomes of institutional desensitization protocol in renal transplant recipients with simultaneous ABO and HLA incompatibility.

MATERIALS AND METHODS

This was a retrospective study conducted from October 2015 to December 2018. All patients with a clinical diagnosis of dialysis dependent chronic kidney disease (CKD), who were prospective coexistent HLA and ABO incompatible renal transplant recipients were included in the study. Patients were followed up and graft function and patient survival was assessed at 1 y from the date of transplant.

RESULTS

Median and mode baseline anti-A titers were 64, while median and mode baseline anti-B titers were 256. All recipients were discharged by tenth postoperative day. None of the patients had any bleeding complications. Post transplant infection rate was found to be 20 %. A total of 54 therapeutic plasma exchange (TPE) procedures were performed before transplant and 8 were performed after transplant. Graft survival and patient survival was 100 % at 3, 6, 9, and 12 months. Range and mean follow-up period was 15-42 months and 23 months respectively. Mean glomerular filtration rate (GFR) at 1 y using the CKD-EPI equation was 85.25 ± 13.76 mL/min. Biopsy proven ABMR was observed in one case only which was managed with TPE and immunosuppression.

CONCLUSION

Simultaneous ABO and HLA incompatibility in renal transplant recipients can be managed successfully with adequate preconditioning and careful monitoring.

ABO-incompatible living kidney transplantation

ABO-incompatible living kidney transplantation is nowadays a routine procedure to expand living donor pool. The past decades have seen the evolution of desensitization protocol and immunosuppression regimen. Despite increased bleeding events, infectious complications, and rejection episodes reported in some studies, favorable graft and patient survival rate are now achieved, regardless of various protocols among transplant centers. Several issues such as the usage of rituximab and standardization of blood group antibody titration remain to be settled. The deposition of C4d is no longer the histopathologic hallmark of antibody-mediated rejection, which have inspired innovative strategies of peripheral molecular screening and the improvement of histological diagnosis of AMR (antibody-mediated rejection). The better understanding of the underlying mechanism might facilitate the distinction and therapeutic schemes of AMR.

Impact of ABO-Incompatible Living Donor Kidney Transplantation on Patient Survival

RATIONALE & OBJECTIVE

Compared with recipients of blood group ABO-compatible (ABOc) living donor kidney transplants (LDKTs), recipients of ABO-incompatible (ABOi) LDKTs have higher risk for graft loss, particularly in the first few weeks after transplantation. However, the decision to proceed with ABOi LDKT should be based on a comparison of the alternative: waiting for future ABOc LDKTs (eg, through kidney paired exchange) or for a deceased donor kidney transplant (DDKT). We sought to evaluate the patient survival difference between ABOi LDKTs and waiting for an ABOc LDKT or an ABOc DDKT.

STUDY DESIGN

Retrospective cohort study of adults in the Scientific Registry of Transplant Recipients.

SETTING & PARTICIPANTS

808 ABOi LDKT recipients and 2,423 matched controls from among 245,158 adult first-time kidney-only waitlist registrants who did not receive an ABOi LDKT and who remained on the waitlist or received either an ABOc LDKT or an ABOc DDKT, 2002 to 2017.

EXPOSURE

Receipt of ABOi LDKT.

OUTCOME

Death.

ANALYTICAL APPROACH

We compared mortality among ABOi LDKT recipients versus a weighted matched comparison population using Cox proportional hazards regression and Cox models that accommodated for changing hazard ratios over time.

RESULTS

Compared with matched controls, ABOi LDKT was associated with greater mortality risk in the first 30 days posttransplantation (cumulative survival of 99.0% vs 99.6%) but lower mortality risk beyond 180 days posttransplantation. Patients who received an ABOi LDKT had higher cumulative survival at 5 and 10 years (90.0% and 75.4%, respectively) than similar patients who remained on the waitlist or received an ABOc LDKT or ABOc DDKT (81.9% and 68.4%, respectively).

LIMITATIONS

No measurement of ABO antibody titers in recipients; eligibility of participants for kidney paired donation is unknown.

CONCLUSIONS

Transplant candidates who receive an ABOi LDKT and survive more than 180 days posttransplantation experience a long-term survival benefit compared to remaining on the waitlist to potentially receive an ABOc kidney transplant.

An Automated Method for Direct Antiglobulin Testing and the Resulting Amount of Phototherapy Used at a Large Academic Medical Center

OBJECTIVE

To evaluate how clinical practice was affected by the change in direct antiglobulin testing (DAT) methodologies and subsequent stronger reported DAT results at our large academic medical center.

METHOD

We retrospectively reviewed DAT results of umbilical cord blood from infants with blood type A or B born to mothers with antibody-negative type O blood, based on records kept at the University of Alabama at Birmingham (UAB) Hospital, a 1400-bed academic medical center.

RESULTS

We randomly chose 50 neonates with positive DAT results who had been tested using the tube method and 50 whose testing had used the gel method. Although 86% of results with the tube method were positive microscopically, 52% and 40% of the DAT results with the gel method were 1+ and 2+ positive, respectively. Further, we observed an increase in the number of neonates treated with phototherapy who had been tested using the gel method.

CONCLUSION

We report that DATs performed using the gel method had increased DAT strength compared with tube testing, which led to increased use of phototherapy by our clinical colleagues.

Immunoadsorption in ABO-incompatible kidney transplantation in adult and pediatric patients with follow-up on graft and patient survival: First series from India

BACKGROUND:

There are no published reports on desensitization protocol for ABO-incompatible kidney transplants using Immuno-Adsorption (IA) plasmapheresis from India. IA offers certain advantages including processing of larger plasma volumes, quicker reduction of isoagglutinin titers and no requirement of replacement fluids.

AIMS AND OBJECTIVES:

Authors' center evaluated success of desensitization protocol, and graft/patient outcomes when IA procedures were performed for desensitization in adult and pediatric ABO-incompatible kidney transplant patients.

METHODS:

Patients undergoing ABO-incompatible kidney transplant with use of IA were evaluated at tertiary care center in north India. Patient records for 2-years were collated from hospital information system (HIS) and procedure forms.

RESULTS:

Sixteen IA procedures were performed in five patients who underwent successful ABO-incompatible kidney transplant. Initial isoagglutinin IgG titer ranged from 32-512. Mean number of IA procedures performed to achieve the desired pre-transplant IgG titer ≤8 was 3.2. New IA column was used for each patient (and re-used for the same patient, if needed, after sterilization with Low temperature steam of formaldehyde). Mean plasma volume processed during each IA procedure was 4.5 times. No adverse events were observed during any IA procedure. All patients achieved successful desensitization. All patients continue to do well clinically with mean follow-up period of 8.8 months. Although IA was expensive, it offered advantages like specificity, larger plasma volume processing with desired reduction in titer, no 'replacement fluid' requirements and no adverse events in present case series.

CONCLUSION:

IA plasmapheresis was universally successful in decreasing the ABO-isoagglutinin titers to desired level in all prospective ABO incompatible kidney transplant patients.

Cascade plasmapheresis as a desensitization strategy for patients undergoing ABO incompatible living donor liver transplantation (ABOi LDLT): A single center experience

BACKGROUND AND AIM

The reduction of antibody titres (AT's) to a safe level is essential pre-requisite for patients awaiting ABO-incompatible liver transplantation (ABOi LT). We report our experience of performing cascade plasmapheresis (CP) on 2 different apheresis platforms (COBE Spectra and Spectra Optia) as a desensitization strategy for patients undergoing ABOi LT in our centre.

METHODS

This retrospective observational study was conducted on patients who underwent CP included in the desensitization protocol for ABOi LDLT. CP/conventional TPE was performed (daily/alternate day with daily estimation of AT) until a target titre of ≤ 8 was achieved.

RESULTS

During the study period, 4 patients (mean age 46.7 years; 100% males) underwent desensitization for ABOi LDLT with baseline AT (combined IgM and IgG) ranging from 64 to 512. A total of 15 CP sessions (range 2 - 6) were performed with a median of 3.5 sessions/patient. Desensitization rate was 100%. Only 1 patient underwent conventional TPE in the post-transplant due to rise in AT level to 64 (post-operative day 8). Average post-operative length of stay was 49 days (range 30 - 105). None of the patients experienced any episode of rejection (repeat liver biopsy). On follow up (1 year), 2 patients were alive and doing well, while other 2 patients succumbed during their hospital stay due to sepsis.

CONCLUSION

In our limited experience, the use of CP was safe and effective desensitization strategy for patients undergoing ABOi LDLT.

ABO-incompatible deceased donor pediatric liver transplantation: Novel titer-based management protocol and outcomes

ABO-ILT have re-emerged as an alternate option for select patients awaiting transplant. However, treatment protocols for children undergoing deceased donor ABO-ILT are not standardized. We implemented a novel IS protocol for children undergoing deceased donor ABO-ILT based on pretransplant IH titers. Children with high pretransplant IH titers (≥1:32) underwent an enhanced IS protocol including plasmapheresis, rituximab, IVIG, and mycophenolate, while children with IH titers ≤1:16 received steroids and tacrolimus. We retrospectively assessed our outcomes of ABO-ILT with ABO-compatible recipients of similar age and diagnosis over a 2-year period. Ten children with median age of 8.9 months underwent ABO-ILT, 4 of 10 patients underwent enhanced IS due to high IH titers. Rates of complications (rejection, infections, biliary, and vascular) at both 1 year and up to 3 years post-transplant were comparable between the groups. Patients with ABO-ILT had good graft function with 100% survival at a median follow-up of 3.3 years. In conclusion, IS tailored to pretransplant IH titers in pediatric deceased donor ABO-ILT is feasible and can achieve outcomes similar to ABO-CLT at 1 and 3 years post-transplantation.

Kidney exchange transplantation current status, an update and future perspectives

Kidney exchange transplantation is well established modality to increase living donor kidney transplantation. Reasons for joining kidney exchange programs are ABO blood group incompatibility, immunological incompatibility (positive cross match or donor specific antibody), human leukocyte antigen (HLA) incompatibility (poor HLA matching), chronological incompatibility and financial incompatibility. Kidney exchange transplantation has evolved from the traditional simultaneous anonymous 2-way kidney exchange to more complex ways such as 3-way exchange, 4-way exchange, n-way exchange,compatible pair, non-simultaneous kidney exchange,non-simultaneous extended altruistic donor, never ending altruistic donor, kidney exchange combined with desensitization, kidney exchange combined with ABO incompatible kidney transplantation, acceptable mismatch transplant, use of A2 donor to O patients, living donor-deceased donor list exchange, domino chain, non-anonymous kidney exchange, single center, multicenter, regional, National, International and Global kidney exchange. Here we discuss recent advances in kidney exchanges such as International kidney exchange transplantation in a global environment, three categories of advanced donation program, deceased donors as a source of chain initiating kidneys, donor renege myth or reality, pros and cons of anonymity in developed world and (non-) anonymity in developing world, pros and cons of donor travel vs kidney transport, algorithm for management of incompatible donor-recipient pairs and pros and cons of Global kidney exchange. The participating transplant teams and donor-recipient pairs should make the decision by consensus about kidney donor travel vs kidney transport and anonymity vs non-anonymity in allocation as per local resources and logistics. Future of organ transplantation in resource-limited setting will be liver vs kidney exchange, a legitimate hope or utopia?

ABO incompatible renal transplant: Transfusion medicine perspective

INTRODUCTION:

Our study presents an analysis of the trends of ABO antibody titers and the TPE (Therapeutic Plasma Exchange) procedures required pre and post ABO incompatible renal transplant.

MATERIALS AND METHODS:

Twenty nine patients underwent ABO incompatible renal transplant during the study period. The ABO antibody titers were done using the tube technique and titer reported was the dilution at which 1+ reaction was observed. The baseline titers of anti-A and anti-B antibodies were determined. The titer targeted was ≤8. Patients were subjected to 1 plasma volume exchange with 5% albumin and 2 units of AB group FFP (Fresh Frozen Plasma) in each sitting. TPE procedures post-transplant were decided on the basis of rising antibody titer with/ without graft dysfunction.

RESULTS:

The average number of TPE procedures required was 4-5 procedures/patient in the pretransplant and 2-3/patient in the post-transplant period. An average titer reduction of 1 serial dilution/procedure was noted for Anti-A and 1.1/procedure for Anti-B. Number of procedures required to reach the target titer was not significantly different for Anti-A and Anti-B (P = 0.98). Outcome of the transplant did not differ significantly by reducing titers to a level less than 8 (P = 0.32). The difference in the Anti-A and Anti-B titers at 14th day post-transplant was found to be clinically significant (P = 0.042).

CONCLUSION:

With an average of 4-5 TPE procedures pretransplant and 2-3 TPE procedures post transplants, ABO incompatible renal transplantations can be successfully accomplished.

ABO-Incompatible Kidney Transplantation

ABO-incompatible (ABOi) kidney transplantation has long been considered a contraindication to successful kidney transplantation. During the last 25 years, increasing organ shortage enforced the development of strategies to overcome the ABO antibody barrier. In the meantime, ABOi kidney transplantation has become a routine procedure with death-censored graft survival rates comparable to the rates in compatible transplantations. Desensitization is usually achieved by apheresis and B cell-depleting therapies that are accompanied by powerful immunosuppression. Anti-A/B antibodies are aimed to be below a certain threshold at the time of ABOi kidney transplantation and during the first 2 weeks after surgery. Thereafter, even a rebound of anti-A/B antibodies does not appear to harm the kidney transplant, a phenomenon that is called accommodation, but is poorly understood. There is still concern, however, that infectious complications such as viral disease, Pneumocystis jirovecii pneumonia, and severe urinary tract infections are increased after ABOi transplantations. Recent data from the Collaborative Transplant Study show that during the first year after kidney transplantation, one additional patient death from an infectious complication occurs in 100 ABOi kidney transplant recipients. Herein, we review the recent evidence on ABOi kidney transplantation with a focus on desensitization strategies and respective outcomes.

Effect of ABO incompatibility on T-cell flow cytometry cross-match results prior to living donor kidney transplantation

BACKGROUND

Due to its high sensitivity, the flow cytometry cross-match (FCXM) has been described as valuable tool for identifying an optimal donor. We here focused on the impact of ABO incompatibility on FCXM results.

METHODS

We analyzed 29 ABO incompatible and 89 ABO compatible donor-recipient pairs (73 and 175 datasets, respectively) prior to living donor kidney transplantation. In all patients, lymphocytotoxic cross-matches for B and T cells were negative.

RESULTS

Recipients with blood group O (A to O and B to O) displayed significantly (P < 0.05) higher T-FCXM results than those with blood group A and B (A to B, B to A and AB to A), respectively. Donor-specific T-FCXM responses (ΔMFI values) were significantly higher (P < 0.05) in ABO incompatible vs. compatible pairs (ABO incompatible recipients with blood group O: 32 ± 6; with blood group A: 19 ± 7; with blood group B: 7 ± 4; recipients with ABO compatibility: 3 ± 2, respectively, data represent mean ± SEM). Consistent with the T-FCXM results donor-specific isohemagglutinins (IgG titers) were significantly higher in recipients with blood group O vs. A, both prior to rituximab treatment and plasmapheresis/immune adsorption (P = 0.004) and immediately prior to transplantation, i.e., after rituximab and antibody-depleting therapies (P = 0.04).

CONCLUSIONS

ABO incompatibility was associated with higher T-FCXM responses, especially in recipients with blood group O. This finding has major impact on the interpretation of flow cross-match results. Current cut-off values need to be reassessed in the ABO incompatible setting. © 2016 International Clinical Cytometry Society.

Efficacy of single, extended and goal directed immunoadsorption in ABO incompatible living related donor liver transplantation

BACKGROUND

Liver transplantation is one of the solid organs most commonly being transplanted across the world. The indications, affordability and accessibility have grown manifold. To increase the donor pool, inclusion of ABO incompatible liver donors is being considered. To enhance the graft functioning and survival, immunoadsorption apheresis to reduce the ABO hemagglutination titres are on the rise.

CASE REPORT

We report three cases ABO incompatible liver transplantation with immunoadsorption protocol. The patients were in poor general condition with Child-Turcotte-Pugh (CTP) class 'C' and there were no suitable ABO compatible grafts at the time. For all three cases, immunosuppressive protocol consisted of induction with Rituximab, followed by tacrolimus, mycophenolate mofetil and corticosteroids. The third patient received basiliximab for induction, in addition to the above protocol. First 2 patients received 1 immunoadsorption (IA) session with Glycosorb ABO® system (Glycorex AB, Sweden), pre-operatively. The third patient received 2 IA sessions pre-operatively. Baseline IgM plus IgG titres were 1024; 64 and 1024 for anti-B, anti-A and anti-B for patient 1, 2 and 3 respectively. Target pre-operative antibody titre was ≤16. Average post-operative length of stay was 17.3 days. There were no acute rejection. None of them, required any post-operative plasma exchange.

CONCLUSION

Immunoadsorption is effective in reducing hemagglutination titres in recipients of ABO incompatible donor liver.

Successful ABO-Incompatible Renal Transplantation: Blood Group A1B Donor Into A2B Recipient With Anti-A1 Isoagglutinins

OBJECTIVES

Transplantation of the blood group A2B in a recipient was successfully performed in the setting of receiving a deceased donor kidney from an "incompatible" A1B donor.

METHODS

The donor and recipient were both typed for ABO blood group, including ABO genotyping. The donor and recipient were tested for ABO, non-ABO, and human leukocyte antigen (HLA) antibodies. The donor and recipient were typed for HLA antigens, including T- and B-flow cytometry crossmatch tests.

RESULTS

The recipient's RBCs were negative with A1 lectin, and immunoglobulin G anti-A1 was demonstrated in the recipient's plasma. The donor-recipient pair was a four-antigen HLA mismatch, but final T- and B-flow cytometry crossmatch tests were compatible. The transplant procedure was uneventful; the patient experienced immediate graft function with no episodes of rejection or readmissions more than 2 years later.

CONCLUSIONS

It may be safe to transplant across the A1/A2 blood group AB mismatch barrier in the setting of low titer anti-A1 isoagglutinins without the need for pretransplant desensitization even if the antibody produced reacts with anti-human globulin.

An update on ABO incompatible hematopoietic progenitor cell transplantation

Hematopoietic progenitor cell (HPC) transplantation has long been established as the optimal treatment for many hematologic malignancies. In the setting of allogenic HLA matched HPC transplantation, greater than 50% of unrelated donors and 30% of related donors demonstrate some degree of ABO incompatibility (ABOi), which is classified in one of three ways: major, minor, or bidirectional. Major ABOi refers to the presence of recipient isoagglutinins against the donor's A and/or B antigen. Minor ABOi occurs when the HPC product contains the isoagglutinins targeting the recipient's A and/or B antigen. Bidirectional refers to the presence of both major and minor ABOi. Major adverse events associated with ABOi HPC transplantation includes acute and delayed hemolysis, pure red cell aplasia, and delayed engraftment. ABOi HPC transplantation poses a unique challenge to the clinical transplantation unit, the HPC processing lab, and the transfusion medicine service. Therefore, it is essential that these services actively communicate with one another to ensure patient safety. This review will attempt to globally address the challenges related to ABOi HPC transplantation, with an increased focus on aspects related to the laboratory and transfusion medicine services.

Different sensitivity of rituximab-treatment to B-cells between ABO-incompatible kidney and liver transplantation

A desensitization protocol with rituximab is currently widely used for kidney transplantation (KT) and liver transplantation (LT) across the ABO blood group-incompatible (ABO-I) barrier. However, it remains to be elucidated whether rituximab is equally effective for B-cell and T-cell immune responses in both KT and LT recipients. To clarify these effects of rituximab, we enrolled 46 KT and 77 LT recipients in this study. The proportion of peripheral blood B-cells was determined at the perioperative period. T-cell responses to allostimulation were evaluated by a mixed lymphocyte reaction (MLR) assay. One week after rituximab administration, peripheral B-cells became undetectable in ABO-I KT recipients but remained detectable in some of the ABO-I LT recipients; B-cells were undetectable in both groups by week 2. B-cells remained below the detection limit throughout the first year in the ABO-I KT recipients, whereas they reappeared in the periphery after 6months in the ABO-I LT recipients. There were no significant differences in alloreactive T-cell responses based on MLR analyses between ABO-I and ABO-compatible groups. This study indicates that rituximab has differing B-cell sensitivity between KT and LT recipients and a minimal effect on the alloreactive T-cell responses in KT and LT recipients.

ABO-incompatible renal transplantation in developing world - crossing the immunological (and mental) barrier

ABO incompatibility has been considered as an important immunological barrier for renal transplantation. With the advent of effective preconditioning protocols, it is now possible to do renal transplants across ABO barrier. We hereby present a single center retrospective analysis of all consecutive ABOi renal transplants performed from November 2011 to August 2014. Preconditioning protocol consisted of rituximab, plasmapheresis and intravenous immunoglobulin (IVIG) and maintenance immunosuppression consisted of tacrolimus, mycophenolate sodium, and prednisolone. The outcome of these ABOi transplants was compared with all other consecutive ABO-compatible (ABOc) renal transplants performed during same time. Twenty ABOi renal transplants were performed during the study period. Anti-blood group antibody titer varied from 1:2 to 1:512. Patient and graft survival was comparable between ABOi and ABOc groups. Biopsy proven acute rejection rate was 15% in ABOi group, which was similar to ABOc group (16.29%). There were no antibody-mediated rejections in ABOi group. The infection rate was also comparable. We conclude that the short-term outcome of ABOi and ABOc transplants is comparable. ABOi transplants should be promoted in developing countries to expand the donor pool.

Invasive gastric mucormycosis and cytomegalovirus infection in an ABO incompatible renal transplant recipient

Opportunistic infections are common in immunocompromised patients, such as solid organ transplant recipients. Both fungal and viral infections in posttransplant period increase morbidity and mortality. Cytomegalovirus (CMV) remains one of the most important pathogens. CMV disease may manifest as a nonspecific febrile syndrome or tissue-invasive infections. Zygomycosis is a rare infection, usually presents in rhino-cerebral, pulmonary and disseminated forms; gastrointestinal (GI) tract being a rare site of involvement. Newer techniques for early diagnosis and efficient therapies are essential for a better outcome of the disease; however, mortality rate remains high despite aggressive therapy. We report a renal transplant recipient, who developed gastric mucormycosis along with tissue invasive CMV disease, within 4 weeks of renal transplant and was diagnosed on the basis of upper GI endoscopy and gastric biopsy. The patient succumbed to the infection in spite of gastrectomy, antifungal and antiviral therapy.

Modern approaches to incompatible kidney transplantation

The presence of human-leukocyte antigen (HLA)-antibodies and blood group incompatibility remain a large barrier to kidney transplantation leading to increased morbidity and mortality on the transplant waiting list. Over the last decade a number of new approaches were developed to overcome these barriers. Intravenous immunoglobulin (IVIG) remains the backbone of HLA desensitization therapy and has been shown in a prospective, randomized, placebo controlled trial to improve transplantation rates. Excellent outcomes with the addition of rituximab (anti-B cell) to IVIG based desensitization have been achieved. There is limited experience with bortezomib (anti-plasma cell) and eculizumab (complement inhibition) for desensitization. However, these agents may be good adjuncts for patients who are broadly sensitized with strong, complement-fixing HLA antibodies. Excellent short and long-term outcomes have been achieved in ABO incompatible transplantation with the combination of antibody removal, B cell depletion, and pre-transplant immunosuppression. Kidney paired donation has emerged as a reasonable alternative for programs who cannot provide desensitization or in conjunction with desensitization. Future therapies directed toward cytokines that alter B cell proliferation are under investigation.

Bortezomib in ABO-incompatible kidney transplant desensitization: a case report

Positive B cell crossmatch accompanied by high levels of pre-transplant human leukocyte antigen donor-specific antibodies are associated with adverse graft outcomes in kidney transplant recipients. Targeting plasma cells, the main antibody producing cells, with the proteasome inhibitor bortezomib may be a promising desensitization strategy. We report using a combination of bortezomib and plasmapheresis to desensitize a highly sensitized kidney transplant recipient for an ABO-incompatible living donor kidney transplant. The flow cytometric B cell crossmatch was positive on presentation. After treatment, the anti-A titres fell from 1:64 to 1:4, and a negative B flow cytometric crossmatch was achieved prior to transplantation. The combined approach of bortezomib to abrogate antibody production at the plasma cell level, followed by plasmapheresis and low-dose intravenous immunoglobulin to remove in-circulation alloantibodies, has proven to be effective in our case. Bortezomib may play a role in highly sensitized renal transplants.

Automated point-of-care testing for ABO agglutination test: proof of concept and validation

BACKGROUND AND OBJECTIVES

ABO-incompatible red blood cell transfusions still represent an important hazard in transfusion medicine. Therefore, some countries have introduced a systematic bedside ABO agglutination test checking that the right blood is given to the right patient. However, this strategy requires an extremely time-consuming learning programme and relies on a subjective interpretation of ABO test cards agglutination. We developed a prototype of a fully automated device performing the bedside agglutination test that could be completed by reading of a barcoded wristband. This POCT checks the ABO compatibility between the patient and the blood bag.

MATERIALS AND METHODS

Proof of concept and analytical validation of the prototype has been completed on 451 blood samples: 238 donor packed red blood cells, 137 consecutive unselected patients for whom a blood group determination had been ordered and on 76 patient samples selected with pathology that could possibly interfere with or impair performances of the assay.

RESULTS

We observed 100% concordance for ABO blood groups between the POCT and the laboratory instrument.

CONCLUSION

These preliminary results demonstrate the feasibility of ABO determination with a simple POCT device eliminating manipulation and subjective interpretation responsible for transfusion errors. This device should be linked to the blood bank system allowing all cross-check of the results.

One-year protocol biopsies from ABO-incompatible renal allografts compared with a matched cohort of ABO-compatible allografts

Introduction

Early acute antibody-mediated rejection (ABMR) occurs more frequently in ABO-incompatible (ABOi) than in ABO-compatible (ABOc) kidney transplantation. This could lead to increased inflammation/scarring in the ABOi grafts. Protocol biopsy data in ABOi kidney recipients are scarce.

Methods

A single-center retrospective matched cohort study was conducted. Eighty adult living donor (LD) renal transplant recipients without HLA donor-specific antibodies (DSA) transplanted between 2009 and 2012 were included; 20 ABOi and 60 ABOc controls matched for donor age and transplantation year. Protocol biopsies at one yr were scored according to the Banff classification. Three sums of scores were constructed: tubulointerstitial inflammation (t + i = 0 vs. >0), microvascular inflammation (g + ptc = 0 vs. >0), scarring/hyalinosis (ci + ct + cv + ah ≤ 1 vs. >1. Scores and presence of subclinical rejection (SCR) at one yr were compared.

Results

Protocol biopsy findings at one yr in the ABOi vs. ABOc matched control group were not statistically different: (t + i) > 0, 30% vs. 20%; (g + ptc) > 0, 5% vs. 8%; (ci + ct + cv + ah) > 1, 85% vs. 60%, respectively. No transplant glomerulopathy occurred. SCR rate at one yr was 30% vs. 18%, subclinical ABMR 5% vs. 7% (all with de novo HLA DSA).

Conclusion

One-year protocol biopsies of ABOi and ABOc LD recipients do not differ in chronic changes, inflammation, or SCRs.

Kinetics of B, T, NK lymphocytes and isoagglutinin titers in ABO incompatible living donor liver transplantation using rituximab and basiliximab

BACKGROUND

The kinetics of isoagglutinin titers and lymphocyte subpopulations including B, T, and natural killer (NK) cells after ABO incompatible (ABO-I) living donor liver transplantation (LDLT) have not been evaluated.

METHODS

From January 2012 to July 2013, consecutive ABO-I LDLT patients were enrolled at the National Cancer Center. Our desensitizing protocol included rituximab, plasma exchanges, basiliximab, and intravenous immune globulin without splenectomy.

RESULTS

Twenty patients (14 males, 6 females) underwent ABO-I LDLT due to HCC (n=15) or liver cirrhosis (n=5). There was no hyperacute and antibody-mediated rejection. The isoagglutinin titers were effectively lowered less than 1:16 before operation. CD 19+ B cells were rapidly eliminated after rituximab and suppressed during 6months postoperatively. CD3+ and CD4+ T cells were elevated higher than CD8+ T cells. CD4/CD8 ratio was increased during first 1month postoperatively and decreased thereafter. CD16+CD56+ NK cells were lowered and restored after 4months of LDLT. Among 15 patients with HCC, 5 patients (33.3%) experienced early tumor recurrence (1/8 within Milan and 4/7 beyond Milan).

CONCLUSIONS

Our protocol showed effective results in preventing antibody-mediated rejection and suppressing B lymphocytes. Application to advanced hepatocellular carcinoma should be considered due to decreased natural immunity after ABO-I LDLT.

Successful unintentional ABO-incompatible renal transplantation: Blood group A1B donor into an A2B recipient

OBJECTIVES

To report a successful unintentional transplantation of a deceased donor kidney from an "incompatible" A1B donor into a recipient who was blood group A2B with unsuspected preformed anti-A1 antibodies.

METHODS

The donor and recipient were both typed for ABO antigens. The recipient was tested for ABO and non-ABO antibodies. The recipient was typed for HLA class I and class II antigens, including HLA antibody screen. The T-and B-flow cytometry crossmatch test was performed using standard protocol.

RESULTS

The donor-recipient pair was a complete six-antigen human leukocyte antigen mismatch, but final T- and B-flow cytometry cross-match tests were compatible. The recipient was a 65-year-old woman with a medical history of end-stage renal disease secondary to diabetic nephropathy who underwent kidney transplantation from a 46-year-old brain-dead standard criteria donor. The recipient's RBCs were negative with A1 lectin, and the recipient was thus typed as an A2 subgroup. Anti-A1 could be demonstrated in the recipient's plasma. The donor's RBCs were positive with A1 lectin, thereby conferring an A1 blood type.

CONCLUSIONS

It is safe to transplant across the A1/A2 blood group barrier provided that the preformed antibodies are not reactive at 37°C and with anti-human globulin.

ABO incompatible renal transplants: Good or bad?

ABO incompatible kidney transplantation (ABOi-KT) was previously considered to be an absolute contraindication for patients with end-stage kidney disease (ESKD) due to hyperacute rejection related to blood type barrier. Since the first successful series of ABOi-KT was reported, ABOi-KT is performed increasingly all over the world. ABOi-KT has led to an expanded donor pool and reduced the number of patients with ESKD awaiting deceased kidney transplantation (KT). Intensified immunosuppression and immunological understanding has helped to shape current desensitization protocols. Consequently, in recent years, ABOi-KT outcome is comparable to ABO compatible KT (ABOc-KT). However, many questions still remain unanswered. In ABOi-KT, there is an additional residual immunological risk that may lead to allograft damage, despite using current diverse but usually intensified immunosuppressive protocols at the expense of increasing risk of infection and possibly malignancy. Notably, in ABOi-KT, desensitization and antibody reduction therapies have increased the cost of KT. Reassuringly, there has been an evolution in ABOi-KT leading to a simplification of protocols over the last decade. This review provides an overview of the history, outcome, protocol, advantages and disadvantages in ABOi-KT, and focuses on whether ABOi-KT should be recommended as a therapeutic option of KT in the future.

Risk factors for mortality or delisting of patients from the pediatric heart transplant waiting list

OBJECTIVE

Current literature assessing factors associated with outcomes of patients waiting for pediatric heart transplants has focused on survival to transplant and mortality. Our aim was to determine risk factors associated with the outcomes of delisting, transplant, or death while waiting.

METHODS

In this single-center, retrospective study of patients listed for heart transplants, competing risk analysis was used to model survival from listing to 4 competing outcomes (transplant, death, delisting for clinical deterioration, delisting for clinical improvement or surgical intervention).

RESULTS

There were 308 listing episodes in 280 patients. In competing risk analysis, 11% remained listed at 6 months (transplant 62%, dead 13%, delisted worse 6%, delisted improved 8%). Extracorporeal membrane oxygenation and ventricular assist devices were associated both with higher probability of transplant (hazard ratio [HR], 2.8; P < .001) and delisting for clinical deterioration (HR, 2.7; P = .06). Younger age at listing and complex congenital heart disease were shared risk factors for mortality (HR, 1.07; P = .05; HR, 2.9; P = .003) and delisting because of clinical deterioration (HR, 1.17; P = .01; HR, 2.8; P = .02). Younger age at listing and fetal listing were associated with delisting for clinical improvement or surgical intervention (HR, 1.13; P = .01; HR, 2.9; P = .02).

CONCLUSIONS

Overall survival to transplant depends on risk factors including age at listing, cardiac diagnosis, and mechanical circulatory support. Knowledge of risk factors for death and delisting for clinical deterioration or improvement can assist patient selection and timing of transplant listing.

Thrombotic thrombocytopenic purpura secondary to ABO group incompatible blood transfusion in a patient after cardiac surgery

The triggers of secondary thrombotic thrombopcytopenic purpura (TTP) include drug toxicity, radiation and high-dose chemotherapy, angioinvasive infections, surgery and acute graft versus host disease. TTP secondary to surgery have been reported in a number of cases. Most of the cases have been occurred after open heart surgery. Extensive endothelial damage is held responsible as the initiating mechanism in postoperative TTP cases. However, there is no report of secondary TTP describing development owing to ABO incompatible blood transfusion. Here, we describe a patient who developed TTP after transfusion of ABO incompatible blood during hospitalization for bypass surgery. We also propose a hypothesis which may account for the possible underlying mechanism.