Experience with Tandem Pre-Dilution Online Hemodiafiltration and Centrifugal Plasma Exchange in Pretransplant Desensitization for Abo-Incompatible Kidney Transplantation: A Case Report

BACKGROUND

In the use of therapeutic plasma exchange (TPE) as antibody removal therapy for ABO-incompatible (ABOi) kidney transplantation, it is technically possible to perform online hemodiafiltration (OHDF) and TPE simultaneously for patients who are receiving OHDF. In this study, we report tandem therapy of pre-dilution OHDF and centrifugal plasma exchange (cTPE), instead of membrane plasma exchange, which is the mainstay of TPE in Japan.

METHODS

A total of 14 sessions of tandem cTPE and pre-dilution OHDF were performed as preoperative antibody removal therapy for 6 ABOi kidney transplant recipients. cTPE intra-circuit pressure, decreased antibody titer, and adverse events were evaluated. The study was carried out following the ethical standards of the Declaration of Helsinki and Istanbul. Donors were not prisoners or individuals who were coerced or paid.

RESULTS

The tandem therapy was completed safely in 12 of the 14 sessions, with no problems such as pressure upper and lower limit alarms or circuit coagulation. In 2 sessions, the tandem therapy had to be interrupted due to coagulation on the dialysis circuit side. Antibody titers were reduced by a median of 3-fold for both IgG and IgM. There was no acute antibody-associated rejection.

CONCLUSIONS

In preoperative apheresis therapy for ABOi kidney transplantation, tandem therapy of pre-dilution OHDF and cTPE may be a useful treatment option that can be performed safely and results in sufficient reduction of antibody levels.

Is 0.6% Reasonable as the Minimum Requirement of the Graft-to-recipient Weight Ratio Regardless of Lobe Selection in Adult Living-donor Liver Transplantation?

BACKGROUND

Several studies reported favorable outcomes of small-for-size grafts with graft-to-recipient weight ratio (GRWR) <0.8% in living-donor liver transplantation (LDLT). However, their indications should be carefully determined because they must have been indicated for low-risk cases over larger grafts with 0.8% ≤ GRWR. Furthermore, evidence for minimum requirements of GRWR remains inconclusive. We investigated the safety of small-for-size grafts against larger grafts by adjusting for confounding risk factors, and minimum requirement of graft volume in adult LDLT.

METHODS

We enrolled 417 cases of primary adult-to-adult LDLT in our center between 2006 and 2019. The outcomes of small grafts (0.6% ≤ GRWR < 0.8%, n = 113) and large grafts (0.8% ≤ GRWR, n = 289) were mainly compared using a multivariate analysis and Kaplan-Meier estimates.

RESULTS

The multivariate analysis showed that small grafts were not a significant risk factor for overall graft survival (GS). In the Kaplan-Meier analysis, small grafts did not significantly affect overall GS regardless of lobe selection (versus large grafts). However, GRWR < 0.6% was associated with poor overall GS. Although there were no significant differences between the 2 groups, unadjusted Kaplan-Meier curves of small grafts were inferior to those of large grafts in subcohorts with ABO incompatibility, and donor age ≥50 years.

CONCLUSIONS

Similar outcomes were observed for small and large graft use regardless of lobe selection. 0.6% in GRWR was reasonable as the minimum requirement of graft volume in LDLT. However, small grafts should be indicated carefully for high-risk cases.

Creating Options for Difficult-to-match Kidney Transplant Candidates

BACKGROUND

Most transplantation centers recognize a small patient population that unsuccessfully participates in all available, both living and deceased donor, transplantation programs for many years: the difficult-to-match patients. This population consists of highly immunized and/or ABO blood group O or B patients.

METHODS

To improve their chances, Computerized Integration of Alternative Transplantation programs (CIAT) were developed to integrate kidney paired donation, altruistic/unspecified donation, and ABO and HLA desensitization. To compare CIAT with reality, a simulation was performed, including all patients, donors, and pairs who participated in our programs in 2015-2016. Criteria for inclusion as difficult-to-match, selected-highly immunized (sHI) patient were as follows: virtual panel reactive antibody >85% and participating for 2 years in Eurotransplant Acceptable Mismatch program. sHI patients were given priority, and ABO blood group incompatible (ABOi) and/or HLA incompatible (HLAi) matching with donor-specific antigen-mean fluorescence intensity (MFI) <8000 were allowed. For long-waiting blood group O or B patients, ABOi matches were allowed.

RESULTS

In reality, 90 alternative program transplantations were carried out: 73 compatible, 16 ABOi, and 1 both ABOi and HLAi combination. Simulation with CIAT resulted in 95 hypothetical transplantations: 83 compatible (including 1 sHI) and 5 ABOi combinations. Eight sHI patients were matched: 1 compatible, 6 HLAi with donor-specific antigen-MFI <8000 (1 also ABOi), and 1 ABOi match. Six/eight combinations for sHI patients were complement-dependent cytotoxicity cross-match negative.

CONCLUSIONS

CIAT led to 8 times more matches for difficult-to-match sHI patients. This offers them better chances because of a more favorable MFI profile against the new donor. Besides, more ABO compatible matches were found for ABOi couples, while total number of transplantations was not hampered. Prioritizing difficult-to-match patients improves their chances without affecting the chances of regular patients.

Does ABO and RhD matching matter for platelet transfusion?

Platelets express ABO antigens and are collected in plasma, which contains ABO antibodies as would be consistent with the donor ABO group. Platelet ABO antigens that are incompatible with recipient ABO antibodies may have accelerated clearance from circulation and result in lower count increments. ABO antibodies that are passively transferred from donor plasma may result in hemolysis of recipient red blood cells. Although platelets do not express Rh antigens, they contain small numbers of intact red blood cells or fragments, which can lead to alloimmunization in the recipient. Alloimmunization to the RhD antigen may occur when platelets obtained from RhD-positive donors are transfused to RhD-negative recipients. All of these compatibility considerations must be balanced against the available supply, which may be limited due to the 5- to 7-day shelf life of platelets. This articles describes considerations for platelet ABO and RhD selection for platelet transfusions, including the impact of major ABO incompatibility on count increments, the risks of hemolysis associated with minor ABO incompatibility, and the risk of RhD alloimmunization when RhD-negative patients receive platelets obtained from RhD-positive donors.

Role of complement in alloimmunization and hyperhemolysis

PURPOSE OF REVIEW

The purpose of this review is to summarize the role of complement in regulating the removal of a target alloantigen following an incompatible red blood cell (RBC) transfusion, the formation of alloantibodies following RBC alloantigen exposure, and the development of hyperhemolysis in patients with sickle cell disease (SCD).

RECENT FINDINGS

Recent studies demonstrate that complement can accelerate alloantibody-mediated removal of target alloantigens from the RBC surface following incompatible transfusion. Complement also influences alloantigen availability during developing alloimmune responses and serves as a unique mediator of CD4 T-cell-independent alloantibody formation following RBC alloantigen exposure. Finally, alternative complement pathway activation appears to play a key role in the development of acute hemolytic episodes in patients with SCD, providing a potential druggable target to prevent acute complications in patients with this disease.

SUMMARY

Recent studies suggest that complement can regulate a wide variety of processes germane to hematology, from transfusion complications to baseline hemolysis in patients with SCD. As the role of complement in various disease processes becomes more fully understood, the ability to leverage recently developed complement modulating drugs will only continue to enhance providers' ability to favorably intervene in many hematological diseases.

ABO-Incompatible Kidney Transplantation After Bone Marrow Transplantation: A Case Report

Many studies have been made on ABO-compatible kidney transplants following hematopoietic stem cell transplantation. However, there have been few reports on ABO-incompatible kidney transplantation following hematopoietic stem cell transplantation (HSCT). We report on the case of a successful ABO-incompatible kidney transplantation with high titers after bone marrow transplantation experienced no infectious episodes. The patient was a 38-year-old man with end-stage kidney disease resulting from interstitial nephritis induced by drug toxicity or graft-vs-host disease (GVHD). He had received allogeneic bone marrow transplantation from a human leukocyte antigen-identical unrelated donor to treat chronic myelogenous leukemia. The patient with high anti-B antibody titers (IgM 1:1024 IgG 1:256) received a desensitization protocol consisting of 2 doses of rituximab and 5 courses of plasmapheresis. The patient had prolonged depletion of circulating B cells 2 years after the transplant and was infected with cytomegalovirus viremia, pneumocystis jiroveci pneumonia, and adenovirus urinary tract infection at 2, 3, and 17 months post-transplant, respectively. Currently, at 6 years after his transplant, the patient has had no rejection and is in good clinical condition with only mild renal insufficiency. Our results suggest that ABO-incompatible kidney transplantation may be an effective renal replacement therapy for patients with end-stage kidney disease after HSCT, but desensitization in combination with immunosuppressants could lead to a state of over-immunosuppression, causing various infections.

Examining the Role of Complement in Predicting, Preventing, and Treating Hemolytic Transfusion Reactions

Red blood cell (RBC) transfusion is a critical component of optimal management for a broad range of conditions. Regardless of the indication, pretransfusion testing is required to appropriately match RBC donors and recipients to provide immunologically compatible blood. Although this approach is effective in the vast majority of situations, occasionally, patients will inadvertently receive an incompatible RBC transfusion, which can result in a hemolytic transfusion reaction (HTR). In addition, patients with life-threatening anemia and a complex alloantibody profile, which precludes rapid procurement of compatible RBCs, may also receive incompatible RBCs, placing them at risk for an HTR. Despite the rarity of these clinical situations, when incompatible blood transfusion results in an HTR, the consequences can be devastating. In this review, we will explore the challenges associated with actively preventing and treating acute HTRs following incompatible RBC transfusion. In doing so, we will focus primarily on the role of complement, not only as a key player in HTRs, but also as a potential target for the prevention and treatment of HTRs.

[Isoantibodies, prevalence and risk factors in two hospitals in Mexico]

BACKGROUND

Erythrocyte isoimmunization or alloimmunization is a late complication of transfusion, in which antibodies against erythrocyte antigens other than the ABO system are developed. Its prevalence is variable, groups of patients with low prevalence (2%) and others of high risk with more than 50% have been described. These antibodies can have serious clinical repercussions in transfused patients.

OBJECTIVE

To know the prevalence of erythrocyte isoimmunization, the risk factors for its development and the types of antibodies developed in the user population of two hospitals in Mexico.

METHODS

Retrospective study. The database of the Blood Bank and the Transfusion Service of two hospitals was analyzed for the search of transfused patients who developed isoantibodies from 2012 to 2016, analyzing their background to determine the risk factors, prevalence and type of antibodies.

RESULTS

An isoimmunization prevalence of 0.97% was found in 5 years; the main antibodies found were: anti-E, anti-K, anti-C, anti-Dia, anti-c, anti-D and anti-Fya. The associated risk factors for the development of isoimmunization were: transfusion history, pregnancy and female sex, as a finding it was found that group O is a protective factor.

CONCLUSIONS

Erythrocyte alloimmunization in the population studied corresponded to a low prevalence. The main antibodies found were against Rh, Kell and Diego system antigens, with a different distribution than published in other international series. No previous report was found about the finding on group O as a protective factor for isoimmunization.

Revisiting ABO incompatibility as a risk factor for significant neonatal hyperbilirubinemia

Babies with ABO incompatibility are often advised frequent biochemical screening and prolonged hospital stay. Our primary objective of the study was to compare serum bilirubin levels at 48 h and 96 h of age in neonates with and without ABO incompatibility. Our prospective study included neonates with gestation ≥ 34 weeks, with or without ABO incompatibility (92 in each group). A direct Coombs test was performed on cord blood. The mean serum bilirubin and haematocrit levels in both groups at 48 h and 96 h were comparable. The mean reticulocyte count of babies with ABO incompatibility was, however, significantly higher. Late preterm and term neonates with and without ABO incompatibility have similar bilirubin levels and no increased risk of significant hyperbilirubinemia. Prolonged hospitalisation of these neonates appears to be unnecessary.

Clinical outcomes after ABO-incompatible renal transplantation: a systematic review and meta-analysis

BACKGROUND

ABO-incompatible renal transplantation (ABOi-rTx) is increasingly used to overcome organ shortage. Evidence about its non-inferiority in comparison with ABO-compatible renal transplantation (ABOc-rTx) needs to be analysed at early and late timepoints. We aimed to investigate differences in outcome after ABOi-rTX and ABOc-rTX.

METHODS

We did a systematic review and meta-analysis of observational studies published up until Dec 31, 2017, that reported outcome data (≥1 year of follow-up) after ABOi-rTx and included an ABO-compatible control group, by searching the Cochrane Central Register of Controlled Trials (CENTRAL), Embase Ovid, MEDLINE Ovid, and PubMed. Trials on recipients of ABOi-rTx were assessed, if an ABO-compatible control group was included and if outcome data on at least graft or recipient survival with 1 year or more of follow-up were available. Exclusion criteria included case reports, editorials, reviews and letters, animal studies, meeting papers, studies unable to extract data, non-renal solid organ and bone-marrow transplant studies, and deceased donor ABOc-rTx. Data were extracted from published reports. Primary endpoints were all-cause mortality and graft survival at 1, 3, 5, and more than 8 years after transplantation. In the meta-analysis, we used a fixed-effects model if the I² value was 0, and both a fixed-effects and random-effects model if I² was more than 0. This study is registered with PROSPERO, number CRD42018094550.

FINDINGS

1264 studies were screened and 40 studies including 49 patient groups were identified. 65 063 patients were eligible for analysis, 7098 of whom had undergone ABOi-rTx. Compared with ABOc-rTx, ABOi-rTx was associated with significantly higher 1-year mortality (odds ratio [OR] 2·17 [95% CI 1·63-2·90], p<0·0001; I²=37%), 3 years (OR 1·89 [1·46-2·45], p<0·0001; I²=29%), and 5 years (OR 1·47 [1·08-2·00], p=0·010; I²=68%) following transplantation. Death-censored graft survival was lower with ABOi-rTx than with ABOc-rTx at 1 year (OR 2·52 [1·80-3·54], p<0·0001; I²=61%) and 3 years (OR 1·59 [1·15-2·18], p=0·0040; I²=58%) only. Graft losses were equivalent to that of ABOc-rTx after 5 years and patient survival after 8 years. No publication bias was detected and the results were robust to trial sequential analysis until 5 years after transplantation; thereafter, data became futile or inconclusive.

INTERPRETATION

Despite progress in desensitisation protocols and optimisation of ABOi-rTx procedures, excess mortality and loss of kidney grafts was found compared with ABOc-rTx within the first 3 years after transplantation. Only long-term outcomes after 5 years yielded equivalent survival rates and organ function. Awareness of the increased risks of infection, organ rejection, and bleeding could improve care of patients and promote efforts towards paired kidney exchange programmes.

FUNDING

None.

Red Cell Alloantibodies in Thalassaemia Patients Who Received Ten or More Units of Transfusion

Thalassaemia patients are the highest consumers of blood. Recurrent exposure to allogenic red cell antigen puts this population at increased risk of alloimmunization. This causes delayed hemolytic transfusion reactions. So transfusion requirement increases. But no data regarding alloimmunization was available in Bangladesh. Aim of this study was to estimate the prevalence of alloimmunization and to find out the potential factors associated with its development. This analytical cross sectional study was done by enrolling 97 patients, received at least 10 units transfusions, through convenient sampling. Indirect and direct antiglobulin tests were done to detect immunization by spin tube technique keeping an autocontrol and carried out in the Department of Haematology & Department of Transfusion Medicine, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from March 2016 to March 2017. Polyclonal anti-AHG reagent was used. A total 21 patients developed alloimmunization (21.6%) and 4 patients (4.1%) developed autoimmunization. Age, gender, splenectomy and number of transfusion are shown significant risk factors for alloimmunization. Data from this study demonstrate that the RBC alloimmunization is significantly high in our country. So, pretransfusion antibody screening needs to be initiated in order to ensure safe transfusion and RBC phenotyping should be started before starting first transfusion to prevent alloimmunization.

Long-term Outcomes of ABO-incompatible Pediatric Living Donor Liver Transplantation

BACKGROUND

ABO-incompatible (ABOi) living donor liver transplantation (LDLT) has been performed to compensate for donor shortage. To date, few studies have reported detailed B-cell desensitization protocols and long-term outcomes of ABOi pediatric LDLT.

METHODS

Twenty-nine pediatric ABOi LDLT recipients were retrospectively analyzed. We compared the clinical outcomes between ABOi (n = 29) and non-ABOi (n = 131) pediatric LDLT recipients. Furthermore, we evaluated the safety and efficacy of our rituximab-based regimen for ABOi pediatric LDLT (2 ≤ age < 18; n = 10).

RESULTS

There were no significant differences in the incidence of infection, vascular complications, biliary complications, and acute cellular rejection between ABOi and non-ABOi groups. The cumulative graft survival rate at 1, 3, and 5 years for non-ABOi group were 92.1%, 87.0%, and 86.1%, and those for ABOi group were 82.8%, 82.8%, and 78.2%, respectively. Rituximab-based desensitization protocol could be performed safely, and reduced CD19+ lymphocyte counts effectively. Although rituximab-treated ABOi group showed comparable clinical outcomes and graft survival rate, 2 patients developed antibody-mediated rejection.

CONCLUSIONS

ABOi LDLT is a feasible option for pediatric end-stage liver disease patients. However, it should be noted that current desensitization protocol does not completely prevent the onset of antibody-mediated rejection in several cases.

VDJ Gene Usage of B Cell Receptors in Peripheral Blood of ABO-incompatible Kidney Transplantation Patients

INTRODUCTION

B cell subtypes and immunoglobulin variable (V), diversity (D), joining (J) gene segment usage of B cell receptors in ABO-incompatible (ABOi) kidney transplantation (KT) in comparison to ABO-compatible KT have not been studied. The aims of this study were to analyze the VDJ gene segment usages of B cell receptors in peripheral blood of ABOi KT recipients.

METHODS

Eighteen ABOi KT patients with accommodation (ABOiA), 10 ABO-compatible stable KT patients (ABOcS), and 10 ABOi KT patients with biopsy-proven acute antibody-mediated rejection (ABOiR) at day 10 after transplantation were selected. Complete transcriptomes of their peripheral blood samples were sequenced and analyzed through RNA sequencing.

RESULTS

By family, immunoglobulin heavy chain variable 3 (IGHV3), immunoglobulin light kappa chain variable 1 (IGKV1), immunoglobulin light lambda chain variable 2 (IGLV2), and immunoglobulin light lambda chain joining 3 (IGLJ3) gene segments were most frequently used in all groups, and their usage was not statistically different among the three groups except for IGHV3 and IGKV1. IGKV1 was more frequently used in the ABOiA group than in the ABOcS group. According to individual gene segments, IGHV3-7, IGHV3-15, IGHV4-59, IGKV3-11, IGLV1-44, IGLV2-14, IGLV4-69, and IGLV7-46 were more frequently used in the ABOcS group than other groups, and IGKV3-7 was more frequently used in the ABOiR group than other groups. IGLV5-52 and IGLV7-43 were more frequently used in the ABOiA group than in ABOcS group.

CONCLUSIONS

Our findings suggest that RNA sequencing transcriptomic analyses of peripheral blood can provide information on the VDJ gene usage of B cell receptors and the mechanisms of accommodation and immune reaction in ABOi KT.

The Onus for Altruism in Kidney Transplantation

Ideally, all programs performing living donor kidney transplantation should educate patients on all contemporary exchange options. They should be strongly encouraged to participate in multicenter exchange, or at least refer those with a willing yet incompatible donor to a center that does, and to preferentially allocate altruistic donor kidneys towards chain initiation.

Outcome of ABO-incompatible adult living-donor liver transplantation for patients with hepatocellular carcinoma

BACKGROUND & AIMS

Living-donor liver transplantation (LDLT) can simultaneously cure hepatocellular carcinoma (HCC) and underlying liver cirrhosis, improving long-term results in patients with HCC. ABO-incompatible LDLT could expand the living-donor pool, reduce waiting times for deceased-donor liver transplantation, and improve long-term survival for some patients with HCC.

METHODS

We retrospectively reviewed the medical records of patients undergoing LDLT for HCC from November 2008 to December 2015 at a single institution in Korea. In total, 165 patients underwent ABO-incompatible and 753 patients underwent ABO-compatible LDLT for HCC. ABO-incompatible recipients underwent desensitization to overcome the ABO blood group barrier, including pretransplant plasma exchange and rituximab administration (300-375 mg/m² /body surface area).

RESULTS

We performed 1:1 propensity score matching and included 165 patients in each group. 82.4% of ABO-incompatible and 83.0% of -compatible LDLT groups had HCC within conventional Milan criteria, respectively, and 92.1% and 92.7% of patients in each group had a Child-Pugh score of A or B. ABO-incompatible and -compatible LDLT groups were followed up for 48.0 and 48.7 months, respectively, with both groups showing comparable recurrence-free survival rates (hazard ratio [HR] 1.14; 95% CI 0.68-1.90; p = 0.630) and overall patient-survival outcomes (HR 1.10; 95% CI 0.60-2.00; p = 0.763).

CONCLUSIONS

These findings suggested that ABO-incompatible liver transplantation is a feasible option for patients with HCC, especially for those with compensated cirrhosis with HCC within conventional Milan criteria.

LAY SUMMARY

Despite hypothetical immunological concerns that the desensitization protocol for breaking through the ABO blood group barrier might have a negative impact on the recurrence of hepatocellular carcinoma, our experience demonstrated no significant differences in the long-term overall survival and recurrence-free survival rates between patients receiving ABO-compatible or ABO-incompatible liver transplantation. In conclusion, results from our institution indicated that ABO-incompatible living-donor liver transplantation constitutes a potentially feasible option for patients with hepatocellular carcinoma, especially those with compensated cirrhosis with hepatocellular carcinoma within conventional Milan criteria.

A comparison of desensitization methods: Rituximab with/without plasmapheresis in ABO-incompatible living donor liver transplantation

BACKGROUND

Plasmapheresis is a desensitization method used prior to ABO-incompatible (ABO-I) living donor liver transplantation. However, studies on its usefulness in the rituximab era are lacking.

METHODS

Fifty-six adult patients underwent ABO-I living donor liver transplantation between January 2012 and October 2015. A single dose of rituximab (300 mg/m²) was administered 2 weeks before surgery with plasmapheresis in all patients until February 2014 (RP group, n = 26). Patients were administered rituximab only, without plasmapheresis between March 2014 and October 2015 (RO group, n = 30).

RESULTS

The 6-, 12- and 18-month overall survival rates were 92.3%, 80.8% and 76.9% in the RP group and 96.6%, 85.4% and 85.4% in the RO group, respectively (P = 0.574). When the initial isoagglutinin titers < 16, neither group showed a rebound rise of isoagglutinin titers. For patients with initial isoagglutinin titers ≥ 16, the rebound rise of isoagglutinin titers was more prominent in the RP group. There was no difference in time-dependent changes in B cell subpopulations and ABO-I-related complications.

CONCLUSIONS

Sufficient desensitization for ABO-I living donor liver transplantation can be achieved using rituximab alone. This desensitization strategy does not affect the isoagglutinin titers, ABO-I-related complications and patient survival.

Incomplete Antibodies May Reduce ABO Cross-Match Incompatibility: A Pilot Study

OBJECTIVE

Any erythrocyte transfusion among humans having type A or B blood groups is impossible due to antibodies causing fatal transfusion complications. A cross-match test is performed to prevent immune transfusion complications before transfusion. Our hypothesis is that the fragment antibody (Fab) part of the antibody (incomplete antibody) may be used to prevent an immune stimulus related to the complete antibody. Therefore, we designed a pilot study to evaluate the effectiveness of these incomplete antibodies using cross-match tests.

MATERIALS AND METHODS

Pepsin enzyme and staphylococcal protein A columns were used to cut anti-A and anti-B monoclonal antibodies and purify their Fab (2) fragments, respectively. An Rh-positive erythrocyte suspension with purified anti-A Fab (2) solution and B Rh-positive erythrocyte suspension with purified anti-B Fab (2) solution were combined correspondingly. Cross-match tests were performed by tube and gel centrifugation methods. The agglutination levels due to the anti-A and anti-B Fab (2) antibodies and their effects on the agglutination normally observed with complete antibodies were then measured.

RESULTS

No agglutination for the purified incomplete anti-A Fab (2) with A Rh+ erythrocyte and anti-B Fab (2) with B Rh+ erythrocyte combinations was observed in the tube cross-match tests. These agglutination levels were 1+ in two wells in the gel centrifugation cross-match tests. Fab (2)-treated erythrocytes were also resistant to the agglutination that normally occurs with complete antibodies.

CONCLUSION

We determined that the Fab (2) fragments of antibodies may not only be used to obtain a mild or negative reaction when compared to complete antibodies, but they might also be used for decreasing ABO incompatibility. Incomplete antibodies might be a therapeutic option in autoimmune hemolytic anemia and they may also be used in solid organ or hematopoietic stem cell transplantation. Therefore, we have planned an in vivo study to prove these in vitro findings.

Outcomes after liver transplantation in accordance with ABO compatibility: A systematic review and meta-analysis

AIM

To evaluate the differences in outcomes between ABO-incompatible (ABO-I) liver transplantation (LT) and ABO-compatible (ABO-C) LT.

METHODS

A systematic review and meta-analysis were performed by searching eligible articles published before No-vember 28, 2016 on MEDLINE (PubMed), EMBASE, and Cochrane databases. The primary endpoints were graft survival, patient survival, and ABO-I-related complications.

RESULTS

Twenty-one retrospective observational studies with a total of 8247 patients were included in this meta-analysis. Pooled results of patient survival for ABO-I LT were comparable to those for ABO-C LT. However, ABO-I LT showed a poorer graft survival than ABO-C LT (1-year: OR = 0.66, 95%CI: 0.57-0.76, P < 0.001; 3-year: OR = 0.74, 95% CI 0.64-0.85, P < 0.001; 5-yearr: OR =0.75, 95%CI: 0.66-0.86, P < 0.001). Furthermore, ABO-I LT was associated with more incidences of antibody-mediated rejection (OR = 74.21, 95%CI: 16.32- 337.45, P < 0.001), chronic rejection (OR =2.28, 95%CI: 1.00-5.22, P = 0.05), cytomegalovirus infection (OR = 2.64, 95%CI: 1.63-4.29, P < 0.001), overall biliary complication (OR = 1.52, 95%CI: 1.01-2.28, P = 0.04), and hepatic artery complication (OR = 4.17, 95%CI: 2.26-7.67, P < 0.001) than ABO-C LT. In subgroup analyses, ABO-I LT and ABO-C LT showed a comparable graft survival in pediatric patients and those using rituximab, and ABO-I LT showed an increased acute cellular rejection in cases involving deceased donor grafts.

CONCLUSION

Although patient survival in ABO-I LT was comparable to that in ABO-C LT, ABO-I LT was inferior to ABO-C LT in graft survival and several complications. Graft survival of ABO-I LT could be comparable to that of ABO-C LT in pediatric patients and those using rituximab.

Effects of Neutralization by Soluble ABH Antigens Produced by Transplanted Kidneys From ABO-Incompatible Secretor Donors

BACKGROUND

Grafts survive despite blood group antigens on the transplant being continuously exposed to antibodies in the blood of recipients in ABO-incompatible kidney transplantation (ABOi KT), owing to the mechanism of accommodation. We analyzed the immunodynamics of soluble ABH antigens in allografts from secretor donors and the influence of such immunodynamics on accommodation and subsequent graft survival in ABOi KT.

METHODS

The genotype of a known human β-galactoside α-1,2-fucosyltransferase gene (FUT2), which determines soluble ABH antigen secretor status, was established in 32 donors for ABOi KT at the Severance Hospital, from June 2010 to July 2015. Clinical outcomes of recipients, such as anti-A/B antibody titer change, renal function, and graft survival, were evaluated.

RESULTS

Twenty-five donors were secretors (78.1%), and seven were nonsecretors (21.9%). The frequency of anti-A/B IgG or IgM antibody titer elevation or reduction post-transplantation was not significantly related to donor secretor status. However, IgM titer was rapidly reduced in recipients transplanted from nonsecretor donors (P=0.01), which could be explained by the lack of absorption effect of soluble antigens, enhancing the binding of antibodies to antigens in the allografts. Interestingly, soluble ABH antigens did not affect rejection-free graft survival, which may be due to the nature of β-galactoside α-1,2-fucosyltransferase.

CONCLUSIONS

Soluble ABH antigens produced by transplanted kidneys from secretor donors played a role in inducing accommodation within three months of KT through neutralization; however, major graft outcomes were not affected.

Titres of alloantibodies against A and B blood types in non-pedigree domestic cats in Turkey: Assessing the transfusion reaction risk

The severity of a transfusion reaction depends on alloantibody titres within the recipients' blood. Determination of an agglutination titre of naturally occurring alloantibody may help to assess the risk of transfusion reactions following an unmatched transfusion in a cat population. In this group of 312 cats 227 had blood type A, 78 had blood type B, and seven had type AB blood. All type B cats tested showed gross evidence of agglutinating anti-A antibody with plasma titres ranging from 2 to 256. Among the 227 type A domestic cats tested for plasma anti-B alloantibody titres, 70% had gross agglutination with titres ranging from 2 to 16, while 17.6% had microscopic agglutination. The remaining 12.4% of the type A cats were negative for both gross and microscopic agglutination. Based on agglutinating titres, the relative risk of a transfusion reaction when type A or AB blood was given to a type B cat was 6.4% with acute severe reaction, acute mild reactions in 85.9% and premature red cell destruction in 7.7%. On the other hand, transfusion of type AB blood or type B blood to type A cats carries a potential risk of acute mild transfusion reaction in 4.4% and premature red cell destruction in 83.3%. Transfusion of type A or B blood to type AB cats results in no apparent clinical transfusion reactions.

Understanding red blood cell alloimmunization triggers

Blood group alloimmunization is "triggered" when a person lacking a particular antigen is exposed to this antigen during transfusion or pregnancy. Although exposure to an antigen is necessary for alloimmunization to occur, it is not alone sufficient. Blood group antigens are diverse in structure, function, and immunogenicity. In addition to red blood cells (RBCs), a recipient of an RBC transfusion is exposed to donor plasma, white blood cells, and platelets; the potential contribution of these elements to RBC alloimmunization remains unclear. Much attention in recent years has been placed on recipient factors that influence RBC alloantibody responses. Danger signals, identified in murine and human studies alike as being risk factors for alloimmunization, may be quite diverse in nature. In addition to exogenous or condition-associated inflammation, autoimmunity is also a risk factor for alloantibody formation. Triggers for alloimmunization in pregnancy are not well-understood beyond the presence of a fetal/maternal bleed. Studies using animal models of pregnancy-induced RBC alloimmunization may provide insight in this regard. A better understanding of alloimmunization triggers and signatures of "responders" and "nonresponders" is needed for prevention strategies to be optimized. A common goal of such strategies is increased transfusion safety and improved pregnancy outcomes.

Cellular immune responses in red blood cell alloimmunization

In excess of 340 blood group antigens have now been described that vary between individuals. Thus, any unit of blood that is nonautologous represents a significant dose of alloantigen. Most blood group antigens are proteins, which differ by a single amino acid between donors and recipients. Approximately 1 out of every 70 individuals are transfused each year (in the United States alone), which leads to antibody responses to red blood cell (RBC) alloantigens in some transfusion recipients. When alloantibodies are formed, in many cases, RBCs expressing the antigen in question can no longer be safely transfused. However, despite chronic transfusion, only 3% to 10% of recipients (in general) mount an alloantibody response. In some disease states, rates of alloimmunization are much higher (eg, sickle cell disease). For patients who become alloimmunized to multiple antigens, ongoing transfusion therapy becomes increasingly difficult or, in some cases, impossible. While alloantibodies are the ultimate immune effector of humoral alloimmunization, the cellular underpinnings of the immune system that lead to ultimate alloantibody production are complex, including antigen consumption, antigen processing, antigen presentation, T-cell biology, and B-cell biology. Moreover, these cellular processes differ to some extent with regard to transfused RBCs as compared with other better-studied immune barriers (eg, infectious disease, vaccines, and solid organ transplantation). The current work focuses on illustrating the current paradigm of humoral immunity, with a specific focus on particulars of RBC alloimmunization and recent advances in the understanding thereof.

ABO blood group incompatible renal transplantation in New Zealand: a report of the first 20 cases

AIM

To report on the first 20 ABO blood group incompatible (ABOi) renal transplants performed in New Zealand.

METHOD

Prospective short-term data and retrospective longer-term follow-up data was collected on the first 20 such transplants between March 2008 and April 2015.

RESULTS

Patient and graft survival was excellent at 95% at 12 months and final follow-up (11-85 months; median 31 months). Three serious infections were noted in this time period, one of which resulted in patient death (pneumococcal pneumonia). There were no episodes of anti-ABO blood group antibody mediated rejection. Only one patient was not able to achieve appropriate antibody reduction prior to the planned transplant.

CONCLUSION

ABOi transplantation is a safe and successful treatment option for patients with end stage renal failure who cannot access an ABO compatible live donor.

Outcome after Desensitization in HLA or ABO-Incompatible Kidney Transplant Recipients: A Single Center Experience

BACKGROUND

The shortage of deceased donors led to an increase of living donor kidney (LDK) transplantations performed in the presence of donor-specific antibodies (DSA) or ABO incompatibility (ABOi) using various desensitization protocols.

METHODS

We herein analyzed 26 ABOi and 8 Luminex positive DSA patients who were successfully desensitized by anti-CD20, antigen-specific immunoadsorption and/or plasmapheresis to receive an LDK transplant. Twenty LDK recipients with non-donor-specific HLA-antibodies (low risk) and 32 without anti-HLA antibodies (no risk) served as control groups.

RESULTS

1-year graft survival rate and renal function was similar in all 4 groups (creatinine: 1.63 ± 0.5 vs 1.78 ± 0.6 vs 1.64 ± 0.5 vs 1.6 ± 0.3 mg/dl in ABOi, DSA, low risk and no risk group). The incidence of acute T-cell mediated rejections did not differ between the 4 groups (15% vs 12, 5% vs 15% vs 22% in ABOi, DSA, low risk and no risk), while antibody-mediated rejections were only found in the DSA (25%) and ABOi (7.5%) groups. Incidence of BK nephropathy (BKVN) was significantly more frequent after desensitization as compared to controls (5/34 vs 0/52, p = 0.03).

CONCLUSION

We demonstrate favorable short-term allograft outcome in LDK transplant recipients after desensitization. However, the desensitization was associated with an increased risk of BKVN.

Helicobacter cinaedi bacteremia with cellulitis after ABO-incompatible living-donor liver transplantation: Case report

Helicobacter cinaedi (H. cinaedi), a Gram-negative spiral-shaped bacterium, is an enterohepatic non-Helicobacter pylori Helicobacter species. We report the first case of H. cinaedi bacteremia with cellulitis after liver transplantation. A 48-year-old male, who had been a dog breeder for 15 years, underwent ABO-incompatible living-donor liver transplantation for hepatitis C virus-induced decompensated cirrhosis using an anti-hepatitis B core antibody-positive graft. The patient was preoperatively administered rituximab and underwent plasma exchange twice to overcome blood type incompatibility. After discharge, he had been doing well with immunosuppression therapy comprising cyclosporine, mycophenolate mofetil, and steroid according to the ABO-incompatible protocol of our institution. However, 7 mo after transplantation, he was admitted to our hospital with a diagnosis of recurrent cellulitis on the left lower extremity, and H. cinaedi was detected by both blood culture and polymerase chain reaction analysis. Antibiotics improved his symptoms, and he was discharged at day 30 after admission. Clinicians should be more aware of H. cinaedi in immunocompromised patients, such as ABO-incompatible transplant recipients.

[Renal transplantation from ABO incompatible donors]

ABC-incompatible (ABOi) living donor renal transplantation is being developed since the 80s, and may provide a significant source of organs. Blood group A and B antigens are expressed not only on red blood cells but also on renal vascular endothelial and renal epithelial membranes. Each individual has preformed natural antibodies against his/ her absent A and/or B antigens. These antibodies may directly damage the ABOi allograft and cause its diffuse thrombosis and primary non-function. ABOi allogratf recipients are conditioned with one dose of rituximab (as a "pharmacological splenectomy") and oral immunosuppressive treatment is introduced several days pre-operatively. Anti A/B titers are lowered by plasmapheresis or specific immunoadsorption. Close follow-up is mandatory in the first two weeks after transplantation, due to higher acute humoral rejection risk, until reaching an "accommodation" state. Thereafter, graft and patient survivals are the same as those of ABO compatible renal transplantations.

Efficacy and safety of tandem hemodialysis and immunoadsorption to desensitize kidney transplant candidates

OBJECTIVES

We conducted a desensitization program in our center in patients undergoing kidney transplant for end-stage renal disease. These patients had a living-donor either ABO incompatible and/or human-leukocyte antigen-incompatible. The safety and efficacy of this program were evaluated.

MATERIALS AND METHODS

A pretransplant desensitization program relies on immunosuppressants and apheresis to remove detrimental antibodies. We chose immunoadsorption as the apheresis technique, and coupled this with hemodialysis in a tandem procedure.

RESULTS

We report on the efficacy of this new method in 120 procedures performed in 20 patients (14 ABO incompatible, 6 ABO incompatible/human leukocyte antigen-incompatible). The tandem procedure was well tolerated, and saved time compared with conducting sequential immunoadsorption and hemodialysis (6 h vs 10 h). The tandem procedure was associated with significantly decreased isoagglutinin titers and donor-specific alloantibodies (assessed by mean fluorescence intensity). Dialysance was effective (183, 102-264). The biochemical and hematologic parameters were similar to those observed after a conventional hemodialysis session, with the exception of protidemia; this might be related to some degree of albumin loss during the immunoadsoprtion procedure. The posttransplant events included 1) one ABO incompatible / human leukocyte antigenincompatible patient with vein thrombosis and ultimate kidney loss; 2) two patients with steroidsensitive cellular acute rejection; and 3) two patients with acute antibody-mediated rejection, which was successfully treated with apheresis and steroid pulses, plus rituximab in one and eculizumab in the other.

CONCLUSIONS

We conclude that the tandem immunoadsorption-hemodialysis procedure is efficient at desensitizing patients with end-stage renal disease who are candidates for a living ABO incompatible and/or human leukocyte antigenincompatible donor-kidney transplant.

Passenger lymphocyte syndrome in ABO and Rhesus D minor mismatched liver and kidney transplantation: A prospective analysis

The increasing demand for solid organs has necessitated the use of ABO and Rhesus (Rh) D minor mismatched transplants. The passenger lymphocyte syndrome (PLS) occurs when donor lymphocytes produce antibodies that react with host red blood cell (RBC) antigens and result in hemolysis. Our aim was to evaluate prospectively the role of PLS in post transplant anemia and hemolysis in ABO and RhD minor mismatched recipients of liver and kidney grafts and to study the association of PLS with donor lymphocyte microchimerism. We examined 11 liver and 10 kidney recipients at Day +15 for anemia, markers of hemolysis, direct antiglobulin test and eluates, and serum RBC antibodies. Microchimerism was determined in peripheral blood lymphocytes by genotyping of simple sequence length polymorphisms encoding short tandem repeats. Immune hemolytic anemia and anti-recipient RBC antibodies were observed in 2 out of 11 liver (18.2%) and 2 out of 10 kidney (20%) transplants. RBC antibody specificity reflected the donor to recipient transplant, with anti-blood group B antibodies identified in 2 cases of O to B and 1 case of A to AB transplants while anti-D antibodies were detected in 1 case of RhD-negative to RhD-positive transplant. Donor microchimerism was found in only 1 patient. In conclusion, passenger lymphocyte mediated hemolysis is frequent in minor mismatched liver and kidney transplantation. Recognizing PLS as a potential cause of post transplant anemia may allow for early diagnosis and management to decrease the morbidity and mortality in some patients.

Trends in ABO-incompatible kidney transplantation

The ABO-incompatible living-donor kidney transplantation was developed in Japan in 1989. Currently, most transplant physicians and surgeons have noted that outcomes are unexpectedly excellent, and no hyperacute rejections have been reported since 2001. In the registry of the Japanese ABO-Incompatible Kidney Transplantation Committee, the data of 2434 ABO-incompatible living-donor kidney transplants were collected from 120 Japanese kidney transplant centers. Overall patient and graft survival rates were 97% and 94% at 1 year, 93% and 86% at 5 years, 90% and 71% at 10 years, and 73% and 52% at 20 years. The patient survival and graft rates in 2001 to 2012 were 93% and 81%, which were significantly better than 83% and 55% reported in 1989 to 2000. The addition of novel immunosuppressive treatments has improved results. Azathioprine has been replaced by mycophenolate mofetil since 2000 to 2001, and basiliximab and rituximab were introduced in 2002 and 2004. The titer of antidonor blood group antibody before transplantation was not correlated with graft survival in 2001 to 2012. De novo antibodies against vascular endothelium of peritubular and glomerular capillaries seemed to be more important than natural antibodies against red blood cells. Therefore, recipients with antidonor blood group antibody titers < 1:128 did not require antibody-removal procedures such as plasmapheresis or immunoadsorption. In particular, children (regard less of their peritoneal dialysis status) do not need to be catheterized for plasmapheresis or immunoadsorption. It is better to avoid the risks of catheterization and antibody removal procedures in children with end-stage renal failure.

Transfusion-related adverse events in the Platelet Dose study

BACKGROUND

How platelet (PLT) product characteristics such as dose, source (whole blood derived [WBD] vs. apheresis), storage duration, and ABO matching status affect the risks of transfusion-related adverse events (TRAEs) is unclear. Similarly, more information is needed to define how recipient characteristics affect the frequency of TRAEs after PLT transfusion.

STUDY DESIGN AND METHODS

In the multicenter Platelet Dose ("PLADO") study, pediatric and adult hematology-oncology patients with hypoproliferative thrombocytopenia were randomized to receive low-dose (LD), medium-dose (MD), or high-dose (HD) PLT prophylaxis for a pretransfusion PLT count of not more than 10 × 10(9) /L. All PLT units (apheresis or WBD) were leukoreduced. Post hoc analyses of PLADO data were performed using multipredictor models.

RESULTS

A total of 5034 PLT transfusions to 1102 patients were analyzed. A TRAE occurred with 501 PLT transfusions (10.0%). The most common TRAEs were fever (6.6% of transfusions), allergic or hypersensitivity reactions (1.9%), and sinus tachycardia (1.8%). Patients assigned HD PLTs were more likely than LD or MD patients to experience any TRAE (odds ratio for HD vs. MD, 1.50; 95% confidence interval, 1.10-2.05; three-group comparison p = 0.02). PLT source and ABO matching status were not significantly related to overall TRAE risk. Compared to a patient's first PLT transfusion, subsequent PLT transfusions were less likely to have a TRAE reported, primarily due to a lower risk of allergic or hypersensitivity reactions.

CONCLUSION

The most important PLT unit characteristic associated with TRAEs was PLT dose per transfusion. HD PLTs may increase the risk of TRAEs, and LD PLTs may reduce the risk.

Impact of recipient ABH secretor status on outcome in minor ABO-incompatible hematopoietic stem cell transplantation

BACKGROUND

The impact of ABO incompatibility on hematopoietic stem cell transplantation (HSCT) outcome is controversial. As ABH substances are expressed on tissues and secreted in body fluids, they could drive an immune response in minor ABO-incompatible HSCT. The aim of the study was to investigate the prognostic role of the recipients' ABH secretor status.

STUDY DESIGN AND METHODS

Patients who underwent minor ABO-incompatible HSCT were included. Secretor status was determined either serologically or by molecular genetics.

RESULTS

Between March 1996 and June 2012, a total of 176 patients received minor ABO-incompatible HSCT and 150 (85%) were secretors. Incidence and severity of acute graft-versus-host disease (GVHD) and chronic GVHD did not differ between secretors and nonsecretors (cumulative incidences ± standard errors: acute GVHD on Day 100, 41 ± 11 and 46 ± 5%, p = 0.59; chronic GVHD at 2 years, 52 ± 13 and 56 ± 5%, p = 0.62, for secretors and nonsecretors, respectively). Additionally, nonrelapse mortality (NRM) and overall survival (OS) were similar in the two groups (2-year NRM, 27 ± 9 and 23 ± 3%, p = 0.45; 4-year OS, 64 ± 10 and 55 ± 4%, p = 0.28, for secretors and nonsecretors, respectively).

CONCLUSION

The recipients' ABH secretor status in minor ABO-incompatible HSCT has no prognostic impact on major transplant outcomes.

Clinical outcomes of ABO-incompatible kidney transplant with rituximab and double-filtration plasmapheresis

OBJECTIVES

The best treatment for end-stage renal disease is kidney transplant, but the shortage of donor organs has caused long waiting times for an appropriate organ allograft. The use of ABO-incompatible kidney transplant can be a valuable option to expand the donor pool. The purpose of the present study was to evaluate 13 patients who had successful ABO-incompatible kidney transplant with double-filtration plasmapheresis and rituximab.

MATERIALS AND METHODS

From January 2011 to August 2012, there were 13 patients who had ABO-incompatible kidney transplant. Antibody titers were monitored during preconditioning and after transplant. Preconditioning protocol included rituximab, mycophenolate mofetil, tacrolimus, corticosteroids, double-filtration plasmapheresis, and intravenous immunoglobulin.

RESULTS

There were no episodes of acute T-cell or antibody-mediated rejection. There were no surgical complications except postoperative bleeding in 1 patient. Mean serum creatinine at 2 weeks after transplant was 71 ± 18 μmol/L (0.8 ± 0.2 mg/dL). At mean follow-up 267 days (range, 1-19 mo), there was no graft loss or patient death.

CONCLUSIONS

The ABO-incompatible kidney transplants were successful after the preconditioning protocol that included double-filtration plasmapheresis and rituximab. The use of ABO-incompatible kidney transplant may increase the availability of kidney transplant and avoid or shorten dialysis. Future multicenter studies are justified to develop a standardized preconditioning protocol.

Notorious anti-Jk3 in a pregnant woman

This is a case study of a 23-year-old pregnant Polynesian woman with anti-Jk3 identified in her plasma during her third visit to a hospital. This patient, with a history of mild anemia due to beta-thalassemia minor and two known transfusion of packed red cells came to an emergency room complaining of severe abdominal cramps. Her hemoglobin during her second hospital visit was 7.5 g/dL and her antibody screen was negative. Two units of crossmatch compatible packed cells were transfused with no adverse reaction and she was discharged. Four days post transfusion, she returned to the hospital complaining of back pain and fatigue and she was running a fever (101 degrees F). Her antibody screen was positive, direct antiglobulin testing was also positive and the eluate showed pan-agglutination with a red cell panel. Anti-Jk3 was identified in her plasma by the Red Cross and a delayed transfusion reaction was suspected. As a result, Kidd null crossmatch compatible units were obtained from relatives. The patient was successfully transfused and was discharged with a hemoglobin of 10.1 g/dL. The fetus appeared to be unaffected by the antibody. This case reiterates the hard-to-identify characteristics of Kidd antibodies and highlights the need for medical laboratory personnel to be informed on the prevalence of the Kidd null phenotype among various populations. Educating ethnic populations with rare phenotypes and organizing targeted blood drives may increase inventories of these rare blood phenotypes.

Hemolytic disease of the fetus and newborn with late-onset anemia due to anti-M: a case report and review of the Japanese literature

Hemolytic disease of the fetus and newborn (HDFN) attributed to M/N-incompatibility varies from asymptomatic to lethally hydropic. Case reports are rare, and the clinical significance of anti-M is not completely understood. A challenging case of HDFN due to anti-M prompted an investigation of the Japanese literature, in order to characterize the clinical spectrum of M/N-incompatibility pregnancies in Japan and report results to English-language readers. Japanese reports of HDFN attributed to M/N incompatibility were compiled. Abstracted data include maternal antibody titers at delivery, fetal direct antiglobulin test, hemoglobin, total bilirubin, reticulocyte count at birth, and therapeutic interventions. We investigated characteristics of HDFN due to M/N-incompatible pregnancies in Japan after encountering a case of severe HDFN along with late-onset anemia in an infant born to a woman carrying IgG anti-M with a titer of 1. In total, thirty-three babies with HDFN due to anti-M and one due to anti-N have been reported in Japan since 1975. The median maternal antibody titer was 64 at delivery and was 16 or less in 10 of 34 women (29%). Five of 34 babies (15%) were stillborn or died as neonates. Twenty-one of 29 survivors (72%) had severe hemolytic anemia and/or hydrops fetalis. The reticulocyte count of neonates with anemia stayed below the reference interval. Sixteen (55%) developed late-onset anemia and 14 (48%) were transfused with M-negative RBCs. Significant positive correlation (P < .05) between the hemoglobin value and the reticulocyte count within 4 days of birth was obtained in 16 babies with anti-M HDFN. In the Japanese population, 21 of 34 cases of M/N-incompatible HDFN (72%) have manifested as severe hemolytic anemia and/or hydrops fetalis. Low reticulocyte count in neonates with late-onset anemia is consistent with suppressed erythropoiesis due to anti-M.

Discrepancy of B cell frequency between periphery and spleen after rituximab treatment in ABO-incompatible liver transplantation

ABO-incompatible living-donor liver transplantation (ABO-LDLT) is generally more difficult to perform than ABO-incompatible kidney transplantation. Despite introduction of rituximab, ABO-LDLT in non-responders is a still difficult issue. A 23-year-old woman with primary sclerosing cholangitis underwent LDLT. The recipient's blood type was 0(+) and the donor's was B(+). Rituximab was infused twice on preoperative day (POD) 14 and 7. Plasma exchange (PE) was performed on PODs 5, 3, 2, and 1. However, repeated PE failed to decrease the anti-B antibody titer. On the other hand, preoperative esophagogastroscopy revealed esophageal varices with red color sign. Therefore, simultaneous liver transplantation and Hassab operation were performed. The donor left lobe of the liver was orthotopically transplanted into the recipient following Hassab operation. Flow cytometry on the day of surgery showed that the frequencies of B cells (CD20+) and memory B cells (CD20+/CD27+) in the peripheral blood were 0.9% and 0.3%, respectively; flow cytometry of cells recovered from the spleen revealed that the frequencies of B cells and memory B cells were 2.5% and 2.4%, respectively. Acute cellular rejection occurred on POD 15, and was treated by steroid pulse therapy, leading to a decrease in the anti-B antibody titer. The liver was functioning well on POD 390 (AST 19, ALT 34). In non-responders to ABO-LDLT, anti-donor blood type antibody-producing cells remains in the spleen after the conventional preoperative regimen. Splenectomy is an option for ABO-LDLT non-responders.

[Time course of morphological changes in humoral renal allograft rejection in ABO incompatibility between donor and recipient]

One hundred and five biopsy specimens taken in different periods after 34 ABO-incompatible mismatched related kidney transplantations were examined to establish the patterns of humoral activity from the morphological changes and expression of C4d deposits in the peritubular capillaries. Severe reversible forms of acute humoral rejection (AHR) (2 patients) and minimal morphological manifestations (13 patients) were observed in the biopsy specimens taken as long as 2 months later in Group 1 (C4d+). In the early period, the minimal manifestations of AHR did not cause organ dysfunction; but in the late period, 5 of them developed chronic humoral rejection in persistent humoral activity; 4 grafts were removed 531,720, 1019, and 1252 days later. Group 2 (C4d-) (n = 19) showed no graft losses or significant chronic changes; the late minimal manifestations of AHR had no impact on the duration of organ function in 3 recipients. The timely detection of early humoral activity and minimal manifestations of AHR is needed for the measures taken to reduce a risk for late function loss of the grafted organ.

Maximising living donation with paediatric blood-group-incompatible renal transplantation

Long-term outcomes for paediatric renal transplant recipients have improved over the last 20 years, with better patient and renal allograft survival. As paediatric renal transplantation programmes have increased over this timeframe, living donation has become the favoured modality for renal replacement therapy and is advocated pre-emptively in as many cases as possible. However, one of the main barriers historically to living donation has been ABO blood-group incompatibility, with the result that patients were listed to be on call for a deceased donor renal transplant. The clinical scenario has now changed so that donors and recipients for renal transplantation can be worked up and listed for paired exchange and/or living-related ABO blood-group-incompatible renal transplantation (ABOi). There is extensive data in adult practice, and increasing evidence in paediatric practice that the short- and medium-term outcomes for both patient and renal allograft survival for ABOi is equivalent to that of blood-group-compatible renal transplantation.

[ABO-incompatible kidney transplantion]

The widespread worldwide implementation of ABO-incompatible kidney transplantation (ABOi KT) programs have increased the chances of gaining access to kidney transplantation. In Italy the practice of ABOi KT has somewhat lagged behind that practiced in many other European Countries. Even though some Italian Transplant Centers have recently started ABOi KT programs, most of them appear still reluctant in adopting this procedure. In this paper, nephrologists from two different Italian Transplant Centers express their contrasting point of view concerning specific issues related to ABOi KT. The first issue concerns the safety and efficacy of ABOi KT and how it compares with HLA-incompatible kidney transplantation. The second concerns to what extent does ABOi KT be adopted, whenever a paired kidney exchange program is available. The third issue regards the indications or contraindications of ABOi KT in specific patient categories. The last issue is about the economical sustainability of ABOi KT programs nowadays. The different point of views of the discussants are summarized in the context of the most recent available evidence.

[Clinical and serological analyses of 70 erythrocyte allo-antibodies to MNS blood group system]

OBJECTIVE

To explore the occurrence and clinical significance of erythrocyte allo-antibodies to MNS blood group system among hospitalized patients in China.

METHODS

The specificity and clinical features of erythrocyte allo-antibodies detected from August 2009 to July 2012 were retrospectively analyzed.

RESULTS

A total of 187 erythrocyte allo-antibodies were detected from 66 042 hospitalized patients (0.28%) among which 70 (37.4%) were specific to MNS blood group system. Antibody frequencies were as follows: anti-M, 18.2%; anti-Mi(a), 18.2%; anti-S, 1.1%. Anti-Mi(a) was more frequent among transfused patients (16/34 vs 5/34, P = 0.004), and tended to be accompanied by other allo-antibodies.

CONCLUSIONS

Antibodies to MNS blood group system are second only to Rh system as the most common erythrocyte allo-antibodies in China. And anti-Mi(a) is an important transfusion-related allo-antibody among the patients of southern ancestry.

Severe hepatic necrosis of unknown causes following ABO-incompatible liver transplantation

Emergency ABO-incompatible (ABO-I) liver transplantations (LTx) have been performed increasingly to treat severe liver failure. Herein, we report a case of severe hepatic necrosis after ABO-I LTx. A 53-year-old man with blood group O was diagnosed as having severe hepatitis B and acute-on-chronic liver failure, and underwent an emergency liver transplantation implanting a blood-group-B liver from a cardiac-death donor. A routine anti-rejection, anti-infection and anti-virus therapy was given after operation. On post-operative day (POD) 16, the recipient had fever and erythra. Laboratory and radiographic examinations suggested a severe hepatic necrosis of unknown causes. The patient was managed with a 10-d methylprednisolone pulse therapy. He was discharged on POD 35 with stable condition, and no recurrent disease was found during the follow-up.

Alloimmunization of patients by blood units harboring distinct DEL variants

The alloimmunization potential of many RHD variants is unknown, and it can be explored by lookback and traceback studies. Hema-Quebec (HQ) investigated the RHD status of 3980 D- repeat blood donors. Thirteen were found to be RHD positive: 4 RHD*1p, and 1 RHD*487delACAG, which show a Dphenotype;and 1 RHD*885T and 7 RHD*(93-94insT) causing a DEL phenotype when C antigen is present. Look back studies were done to verify the alloimmunization potential of these eight DEL donors. Coincidentally, Canadian Blood Services (CBS)performed a trace back study by investigating the RHD status of donors after aD- recipient developed anti-Dafter transfusion of two D- red blood cell (RBC) units. Donor genotyping was done either manually (HQ) or using the Progenika Bloodchip platform(CBS). Donations were traced through computer records. Letters were sent to hospital blood bank physicians to verify the presence of anti-Din recipients and to donors to request repeat samples.A total of 118 RBC units were transfused, 82 to D- recipients.Anti-D was found in three patients transfused with RHD*(93-94insT) DEL red blood cells. One donor presenting the same DEL variant was involved in the trace back study. Even without strong evidence clearly demonstrating the alloimmunization potential of DEL variants, whenever HQ or CBS identifies a donor harboring a DEL phenotype, his or her D status will be changed from DtoD+ to protect against the potential alloimmunization risk.

[Kidney allotransplantation from the AB0-incompatible donors]

The experience of 28 kidney allotransplantations from the AB0-incompatible donors was analyzed. The comparative group consisted of 38 patients, who received the AB0-compatible organ. The results were assessed using the following parameters: renal function, morphology of the biopsy samples of the transplanted kidney and actuary survival of the recipients with functioning transplants in both groups. The comparative analysis showed no significant difference between the two groups, giving the right to consider the kidney allotransplantation from the AB0-incompatible donors safe and effective.

ABO-incompatible kidney transplantation: long-term outcomes

In the past 20 years, over 2,000 cases of ABO-incompatible living kidney transplantation (ABO-ILKT) have been performed in Japan, expanding the donor pool and overcoming the serious shortage of organ donors. Overall long-term outcomes (>20 years) have been excellent and almost identical to the outcomes of ABO-compatible living kidney transplantation (ABO-CLKT). In the last decade, ABO-ILKT has become accepted as a therapeutic alternative for end-stage renal failure. Recently, approximately 30% of all living donor kidney transplantations in Japan have been ABO-ILKT. In the 1990s, desensitization included preoperative plasmapheresis, splenectomy, and heavy immunosuppression that caused surgical and medical stress on patients and a higher cost than that needed for ABO-CLKT for the preoperative conditioning. However, since 2000, rituximab has replaced splenectomy making ABO-ILKT much easier. It is also less stressful for patients. In the last decade, outcomes have improved significantly and 5- and 10-year graft survival have reached 95% and 90%, respectively-identical to, or even better than outcomes of ABO-CLKT. Our current preconditioning includes plasmapheresis 0-2 times, rituximab injection, and regular immunosuppression. Neither intravenous immunoglobulin nor prophylactic plasmapheresis is used after transplantation. ABO-ILKT is a standard option for kidney transplantation requiring minimal preconditioning and regular immunosuppression after transplantation. It now provides an excellent long-term (>20 years) outcome.

Incompatible kidney transplantation: a brief overview of the past, present and future

Live kidney donor transplantation across immunological barriers, either blood group or positive crossmatch [ABO- and human leucocyte antigens (HLA)-incompatible kidney transplantation, respectively], is now practised widely across many transplant centres. This provides transplantation opportunities to patients that hitherto would have been deemed contra-indicated and would subsequently have waited indefinitely for a suitably matched kidney. Protocols have evolved with time as experience has grown and now a variety of desensitization strategies are currently practised to overcome such immunological barriers. In addition, desensitization protocols are complemented by kidney paired donation exchange schemes and therefore incompatible patients now have strategies to either confront or bypass immunological barriers, respectively. As the field expands it is clear that non-transplant clinicians will be exposed to incompatible kidney transplant recipients outside of experienced centres. It is therefore timely to review the evolution of practice that have led to current desensitization modalities, contrast protocols and outcomes of current regimens and speculate on future direction of incompatible kidney transplantation.