Excellent long-term outcome of ABO-incompatible living donor kidney transplantation in Japan

Incidence of postoperative cytomegalovirus and BK-polyoma virus infections and graft loss in ABO-incompatible renal transplant recipients: a multicenter retrospective study

OBJECTIVES

The current study aimed to examine the incidence of perioperative infections and graft viability in ABO-compatible and ABO-incompatible renal transplant recipients.

METHODS

We included 643 living donor renal transplant recipients registered in the Michinoku Renal Transplant Network from 1998 to 2021. Patients were divided into the ABO-compatible and ABO-incompatible kidney transplantation groups. We compared the characteristics of the two groups and evaluated the incidence of postoperative viral infections (cytomegalovirus and BK virus), graft loss-free survival, and overall survival between the two groups.

RESULTS

Of 643 patients, 485 (75%) and 158 (25%) were ABO-compatible and ABO-incompatible renal transplant recipients, respectively. Postoperative viral infections, rituximab use, and plasma exchange were significantly more common in ABO-incompatible than in ABO-compatible transplant recipients. However, there were no significant differences in terms of other background characteristics. The ABO-incompatible group was more likely to develop viral infections than the ABO-compatible group. Graft loss-free survival and overall survival did not significantly differ between the two groups. According to the multivariate Cox regression analysis, ABO compatibility was not significantly associated with graft loss-free survival and overall survival.

CONCLUSION

Although the incidence of postoperative viral infections in ABO-incompatible renal transplant recipients increased, there was no significant difference in terms of rejection events, graft loss-free survival, and overall survival.

Non-antigen-specific Immunoadsorption Is a Risk Factor for Severe Postoperative Infections in ABO-Incompatible Kidney Transplant Recipients

ABO-incompatible (ABOi) living kidney transplantation (KTx) is an established procedure to address the demand for kidney transplants with outcomes comparable to ABO-compatible KTx. Desensitization involves the use of immunoadsorption (IA) to eliminate preformed antibodies against the allograft. This monocentric retrospective study compares single-use antigen-selective Glycosorb® ABO columns to reusable non-antigen-specific Immunosorba® immunoglobulin adsorption columns regarding postoperative infectious complications and outcome. It includes all 138 ABOi KTx performed at Freiburg Transplant Center from 2004-2020. We compare 81 patients desensitized using antigen-specific columns (sIA) to 57 patients who received IA using non-antigen-specific columns (nsIA). We describe distribution of infections, mortality and allograft survival in both groups and use Cox proportional hazards regression to test for the association of IA type with severe infections. Desensitization with nsIA tripled the risk of severe postoperative infections (adjusted HR 3.08, 95% CI: 1.3-8.1) compared to sIA. nsIA was associated with significantly more recurring (21.4% vs. 6.2%) and severe infections (28.6% vs. 8.6%), mostly in the form of urosepsis. A significantly higher proportion of patients with sIA suffered from allograft rejection (29.6% vs. 14.0%). However, allograft survival was comparable. nsIA is associated with a two-fold risk of developing a severe postoperative infection after ABOi KTx.

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.

Success rate and safety of living donor kidney transplantation in ABO blood group incompatible relatives: A systematic review and meta-analysis

BACKGROUND

Kidney transplantation is considered an ideal treatment for end-stage renal disease (ESRD) because it provides a longer and better quality of life than dialysis. ABO-incompatible (ABO-I) kidney transplantation relies on two principles: (i) removal of antibodies from a blood group; and (ii) inhibition of reappearance of blood group antibodies by intensifying the induction and maintenance of immunosuppression. This systematic review aimed to analyze the success and safety of ABO-I live-donor kidney transplantation.

METHODS

Databases, including Google Scholar, PubMed, Embase, Web of Science, and Medline were searched. Search duration was from the database establishment to December 2022. A thorough search was performed for relevant studies investigating the success and safety of ABO-I live-donor kidney transplantation. Two investigators independently extracted literature information and assessed the quality of the included studies. Heterogeneity test was performed using Cochrane's Q and chi-squared tests. All statistical analyses were performed using R software (version 4.2.1).

RESULTS

The search for relevant literature in the five electronic databases yielded 1238 articles. Of the 1238 articles, only 15 were included. Meta-analysis of outcomes from five studies showed a survival rate of 0.93 (95% confidence interval [CI]: 0.88 to 0.97, P < 0.001) after ≥3 years, while outcomes from 12 studies revealed a short-term patient survival rate of 0.94 (95% CI: 0.92 to 0.96, P = 0.75). In contrast, long- and short-term graft survival rates were 0.89 (95% CI: 0.75 to 0.96, P < 0.001) and 0.94 (95% CI: 0.90 to 0.97, P < 0.001), respectively. Incidence rates of infectious, surgical, and medical complications were 0.31 (95% CI: 0.22 to 0.41, P < 0.001), 0.12 (95% CI: 0.05 to 0.25, P < 0.001), and 0.38 (95% CI: 0.17 to 0.66, P < 0.001), respectively.

CONCLUSION

Good long- and short-term patient outcomes and graft survival rates were observed after ABO-I kidney transplantation. Similarly, the safety of performing kidney transplantations from living donors with ABO-I blood groups was established by the results of the current meta-analysis. Therefore, ABO-I live-donor kidney transplantations should be encouraged to reduce the time recipients spend on waiting lists and supplement the existing paired-exchange donor program.

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.

Current Status of ABO-incompatible Liver Transplantation

By 2014, strategies to prevent antibody-mediated rejection (AMR) after ABO-incompatible (ABO-I) living donor liver transplantation (LDLT) were established in Japan and expanded primarily to Asia, where LDLT is now the predominant form of LT owing to the scarcity of brain-dead donors. A desensitization protocol consisting of rituximab (375 mg/m 2 ), plasma pheresis, tacrolimus, and mycophenolate mofetil before LDLT, followed by standard immunosuppression, is currently the best option in terms of safety and efficacy. Rituximab administration is now known not to increase the risk of hepatocellular carcinoma recurrence, and the feasibility of rituximab for LDLT for acute liver failure and the need for desensitization before LDLT in children older than 1 y have been documented. Strategies are needed to distinguish patients at high risk of AMR from those at low risk and to adjust immunosuppression to prevent both AMR and infection. Specific single-nucleotide polymorphisms in genes encoding Fcγ receptors affecting the cytotoxicity of rituximab on B cells could be useful for adjusting immunosuppression levels to decrease infectious complications. Immunological accommodation after ABO-I transplantation could be provided by immune factors in both the grafts and recipients.

Successful ABO and HLA incompatible kidney transplantation in children in the UK

BACKGROUND

There is increasing evidence of good short-term and medium-term outcomes of ABO incompatible (ABOi) and HLA incompatible (HLAi) kidney transplantation with pre-transplant positive crossmatches in paediatric practice. However, there remain concerns regarding the higher risks of infective complications and antibody-mediated rejections. The aim of our study is to show longer-term follow-up on all ABOi and HLAi paediatric kidney transplant recipients (pKTR) in the UK.

METHODS

Questionnaires specifying kidney transplant type, desensitisation requirement and kidney allograft function were sent to 13 paediatric nephrology centres that performed kidney transplantation in children and young people under 18 years of age who received an ABOi and/or HLAi transplant between 1 January 2006 and 31 December 2016. Patient and kidney allograft survival were compared between ABOi, HLAi and ABO/HLA compatible (ABOc/HLAc) groups.

RESULTS

Among 711 living donor kidney transplants performed in the UK, 23 were ABOi and 6 were HLAi. Patient survival was 87%, 100% and 96% in ABOi, HLAi and ABOc/HLAc groups, respectively, at median follow-up of 6.8 (3.6-14.0) years post-transplant. Death-censored kidney allograft survival was 100% in all 3 groups at last follow-up. There were no cases of primary non-function in ABOi or HLAi groups, but 2% in the ABOc/HLAc group. There was one reported case of Epstein-Barr viral-induced post-transplant lymphoproliferative disorder.

CONCLUSION

Longer term follow-up has shown that ABOi and HLAi kidney transplantation are feasible for pKTR where no compatible donors are available, and that minimising desensitisation should be achieved where possible. A higher resolution version of the Graphical abstract is available as Supplementary information.

Hyporesponsiveness against donor's ABO antigens of renal grafts after ABO-incompatible kidney transplantation

BACKGROUND

ABO antigens expressed on the red blood cells (RBCs) are not identical to those expressed on the renal endothelial cells. The isohemagglutinin assay employing the RBCs is the gold standard for evaluating anti-ABO antibody (Ab) levels. However, it remains unclear whether the anti-ABO Abs detected by the isohemagglutinin assay after ABO-incompatible (ABOi) kidney transplantations (KTx) that are not associated with antibody-mediated rejection can bind to renal graft endothelial cells.

METHODS

Ninety plasma samples were collected from patients with stable graft function after ABO-compatible (ABOc) or ABOi KTx. Anti-ABO Ab titers were examined by both the isohemagglutinin assay and the CD31-ABO microarray, which was developed as a mimic of the ABO antigens expressed on the renal endothelial cells.

RESULTS

The antibody titers detected by the isohemagglutinin assay and the CD31-ABO microarray after the ABOc KTx relatively correlated with each other. However, the CD31-ABO microarray results showed low antibody levels against donor blood group antigens after ABOi KTx and did not correlate with the isohemagglutinin assay. In contrast, the antibody levels against non-donor blood group antigens after ABOi KTx were comparable to those after the ABOc KTx. Fourteen patients received graft biopsies, and no antibody-mediated rejection was observed in ABOi KTx recipients, except for two patients who had anti-donor-HLA Abs.

CONCLUSION

The present study suggested that the anti-ABO Abs detected by the isohemagglutinin assay after ABOi KTx with stable graft function were hyporeactive to the ABO antigen of graft renal endothelial cells.

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.

Therapeutic apheresis in kidney diseases: an updated review

Besides conventional medical therapies, therapeutic apheresis has become an important adjunctive or alternative therapeutic option to immunosuppressive agents for primary or secondary kidney diseases and kidney transplantation. The available therapeutic apheresis techniques used in kidney diseases, including plasma exchange, double-filtration plasmapheresis, immunoadsorption, and low-density lipoprotein apheresis. Plasma exchange is still the leading extracorporeal therapy. Recently, growing evidence supports the potential benefits of double-filtration plasmapheresis and immunoadsorption for more specific and effective clearance of pathogenic antibodies with fewer side effects. However, more randomized controlled trials are still needed. Low-density lipoprotein apheresis is also an important supplementary therapy used in patients with recurrent focal segmental glomerulosclerosis. This review collects the latest evidence from recent studies, focuses on the specific advantages and disadvantages of these techniques, and compares the discrepancy among them to determine the optimal therapeutic regimens for certain kidney diseases.

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.

Establishment of a Hyperacute Rejection Model of ABO-Incompatible Renal Transplantation in Nonhuman Primates

The establishment of a hyperacute rejection (HAR) model of ABO-incompatible kidney transplantation (ABOi-KTx) in nonhuman primates is of great significance for the study of the relevant clinical pathophysiological processes and related interventions in ABOi-KTx. In this study, blood group B cynomolgus monkeys were presensitized with synthetic blood group A-antigen conjugated to keyhole limpet hemocyanin (A-KLH) to boost circulating anti-A antibody levels. The serum anti-A antibody levels were measured by flow cytometry using type A human reagent red blood cells (RBCs) or monkey primary renal tubular epithelial cells (RTECs) as target cells. ABOi-KTx was performed in type B monkeys using type A monkeys as donors. After 14 days of A-KLH sensitization, 12 of 16 (75%) type B monkeys had significantly elevated anti-A antibody levels. We found that in order to avoid irregular results in the detection of blood group antibodies by flow cytometry, it was more effective to use RTECs rather than RBCs as target cells. In the absence of presensitization, ABOi-KTx in three monkeys with relatively high levels of natural anti-A antibodies did not produce HAR. However, when four Type B monkeys with significantly increased anti-A antibodies after presensitization were randomly selected as recipients for ABOi-KTx, the allografts in all four monkeys developed HAR with typical pathologic characteristics. Thus, we have successfully established a monkey model of HAR in ABOi-KTx via blood group antigen presensitization, which will be helpful for the further study of rejection, accommodation, and clinical intervention in ABOi-KTx.

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.

Characteristics and Prognosis of Stroke in Living Donor Renal Transplant Recipients

Aims: We aimed to determine the characteristics and vascular outcomes of stroke in renal transplant (RT) recipients and compare them with those in patients on hemodialysis (HD) and those with no renal replacement therapy (RRT).

Methods: In this prospective observational study, 717 patients (mean age, 70.8 years; male, 60.5%) with acute ischemic stroke within one week of onset were consecutively enrolled and followed for one year. The patients were classified into three groups: (1) living donor RT recipients (n=27); (2) patients on maintenance HD before the index stroke (n=39); and (3) those with no history of RRT (n=651). The primary outcome was a composite of major adverse cardiovascular events (MACE).

Results: Diabetic nephropathy was the most common reason for RRT in both RT and HD patients. RT patients were more likely to have embolic stroke of undetermined source (33.3%) than others, whereas HD patients more often had cardioembolism (51.3%). No difference was observed in the MACE risk between the patients in RT and non-RRT groups (annual rate, 11.3% vs. 13.1%; log-rankP=0.82; hazard ratio [95% confidence interval], 0.92 [0.29-2.98]). In contrast, HD patients had a greater risk of MACE than those with no RRT (annual rate, 28.2% vs. 13.1%; log-rankP=0.019; hazard ratio [95% confidence interval], 2.24 [1.16-4.3]).

Conclusions: The underlying etiologies of stroke differed in RT and HD patients. The one-year risk of MACE for stroke patients who had received an RT was lower than that for patients undergoing HD and comparable with that of patients with no RRT.

Novel double-filtration plasmapheresis preserves fibrinogen while removing immunoglobulin-G antibodies before ABO blood type-incompatible kidney transplantation

Background

Removal of anti-blood group antibodies is important for successful ABO-incompatible kidney transplantation (ABOi-KTx). Double-filtration plasmapheresis (DFPP) using albumin solution removes antibodies effectively. However, fibrinogen is largely removed resulting in hemostatic failure. Herein, we designed an altered combination of plasma membranes in DFPP (novel DFPP, nDFPP) to retain more fibrinogen while removing IgG, and assessed its efficacy and safety compared with conventional DFPP (cDFPP).

Methods

Consecutive ABOi-KTx recipients (from 2015 to 2018) were enrolled. For the first membrane, we used Cascadeflo EC-50W in nDFPP and Plasmaflo OP-08W in cDFPP, and Cascadeflo EC-20W as the second membrane in both modalities. Removal rates (RR) of IgG, IgM and fibrinogen per DFPP session, and adverse events were compared with historical control patients who underwent cDFPP before ABOi-KTx, between 2006 and 2015.

Results

nDFPP and cDFPP groups included 12 and 23 cases, respectively. nDFPP was inferior to cDFPP in RR of IgG and IgM. nDFPP was also inferior to cDFPP in the decline in anti-blood group IgG and IgM antibody titers. However, fibrinogen was more preserved in nDFPP compared with cDFPP, indicating that nDFPP has more selective removal properties (median RR of IgG, IgM, and fibrinogen: 62.1%, 15.7% and 37.6%, respectively, in nDFPP; and 74.5%, 85.0% and 76.6%, respectively, in cDFPP). In the comparison of hemostatic function among the patients who had arteriovenous fistula for hemodialysis, prolonged hemostasis (> 20 min) at the cannulation site was significantly less frequently observed in nDFPP group (1 in 9 cases, 9.1%) than in cDFPP group (all 18 cases, 10%, p < 0.0001).

Conclusions

nDFPP preserves fibrinogen while removing anti-blood type IgG antibodies before ABOi-KTx.

ABO-incompatible kidney transplantation in perspective of deceased donor transplantation and induction strategies: a propensity-matched analysis

Kidney transplant candidates are blood group incompatible with roughly one out of three potential living donors. We compared outcomes after ABO‐incompatible (ABOi) kidney transplantation with matched ABO‐compatible (ABOc) living and deceased donor transplantation and analyzed different induction regimens. We performed a retrospective study with propensity matching and compared patient and death‐censored graft survival after ABOi versus ABOc living donor and deceased donor kidney transplantation in a nationwide registry from 2006 till 2019. 296 ABOi were compared with 1184 center and propensity‐matched ABOc living donor and 1184 deceased donor recipients (matching: recipient age, sex, blood group, and PRA). Patient survival was better compared with deceased donor [hazard ratio (HR) for death of HR 0.69 (0.49–0.96)] and non‐significantly different from ABOc living donor recipients [HR 1.28 (0.90–1.81)]. Rate of graft failure was higher compared with ABOc living donor transplantation [HR 2.63 (1.72–4.01)]. Rejection occurred in 47% of 140 rituximab versus 22% of 50 rituximab/basiliximab, and 4% of 92 alemtuzumab‐treated recipients (P < 0.001). ABOi kidney transplantation is superior to deceased donor transplantation. Rejection rate and graft failure are higher compared with matched ABOc living donor transplantation, underscoring the need for further studies into risk stratification and induction therapy [NTR7587, www.trialregister.nl].

Highly individual- and tissue-specific expression of glycoprotein group A and B blood antigens in the human kidney and liver

Background

Currently, research on the quantitative distribution of ABO antigens in different organs and tissues remains limited. We aimed to examine the individual characteristics of blood group glycoprotein A and B antigen expression in human kidneys and livers.

Methods

We obtained human samples, including the renal artery, renal vein, renal tissue, hepatic artery, hepatic vein, portal vein, and hepatic tissue, from 24 deceased organ transplant donors. The expression of the blood group antigens glycoprotein A and B was analysed and compared by Western blotting.

Results

There was no significant difference in the expression between blood group glycoprotein A and B antigens at any of the seven sites (p > 0.05). The expression of both A and B antigens was highest in renal tissue and the portal vein and was lowest in the renal artery. A large difference in glycoprotein antigen expression was observed among various donors or different regions of the same individual. Univariate analysis revealed that glycoprotein A/B antigens were affected by the age and sex of donors and were significantly higher in males and in young people.

Conclusions

Our study found that blood group glycoprotein antigen expression showed certain trends and distinct distribution in the kidney, liver, and vessels among individuals and in different regions of the same individual, which may explain the different clinical outcomes of patients who received ABO-incompatible transplantation.

ABO incompatibility in renal transplantation

ABO blood group incompatibility (ABO-I) was historically considered an absolute contraindication to kidney transplantation due to the significant risk of acute antibody-mediated rejection and early graft loss. Nevertheless, the urge to minimize the gap between the candidates’ number on the waitlist for kidney transplants and the available kidney donors encourage investigation into finding ways to use organs from ABO-I kidney donors, especially in the era of using more potent immunosuppression therapies. This review aims to discuss a general overview of ABO-I kidney transplantation and the different protocols adopted by some transplant centers to meaningfully overcome this barrier.

Effect of Donor and Recipient ABH-Secretor Status on ABO-Incompatible Living Donor Kidney Transplantation

Introduction

ABO blood group antigens within grafts are continuously exposed to anti-A/B antibodies in the serum of recipients after ABO-incompatible (ABOi) kidney transplantation and are instrumental in antibody-mediated rejection. Some individuals secrete soluble blood group antigens into body fluids. In this study, we investigated the effect of donor and recipient secretor status on the outcomes of ABOi kidney transplantation.

Methods

Data of a total of 32 patients with ABOi living donor kidney transplantation were retrospectively collected between 2014 and 2020 in West China Hospital. The genotype and phenotype of both donors and recipients were examined and evaluated with post-transplantation anti-A/B titer changes, graft function, and rejection.

Results

Of the 32 recipients and 32 donors, 23 (71.9%) recipients and 27 (84.4%) donors had secretor genotypes, whereas 9 (28.1%) recipients and 5 (15.6%) donors did not. Anti-A/B titers after ABOi kidney transplantation were not significantly influenced by the secretor status of either donors or recipients. The post-transplantation serum creatinine (Scr) levels and estimated glomerular filtration rate (eGFR) was better in weak- or non-secretor recipients at day 30 (Scr P = 0.047, eGFR P = 0.008), day 90 (Scr P = 0.010, eGFR P = 0.005), and month 9 (eGFR P = 0.008), and recipients from secretor donors had a lower incidence of graft rejection in the first year after ABOi transplantation (P = 0.004).

Conclusions

A weak secretor status phenotype was found in both genotypes, i.e., individuals who secreted soluble antigens as well as those who did not. The recipient ABH-secretor status may have an influence on early posttransplant renal function, and the donor ABH-secretor status might affect the incidence of graft rejection.

Does steroid-free immunosuppression improve the outcome in kidney transplant recipients compared to conventional protocols?

Steroids continue to be the cornerstone of immune suppression since the early days of organ transplantation. Steroids are key component of induction protocols, maintenance therapy and in the treatment of various forms of rejection. Prolonged steroid use resulted in significant side effects on almost all the body organs owing to the presence of steroid receptors in most of the mammalian cells. Kidney allograft recipients had to accept the short and long term complications of steroids because of lack of effective alternatives. This situation changed with the intro-duction of newer and more effective immune suppression agents with a relatively more acceptable side effect profile. As a result, the clinicians have been contemplating if it is the time to abandon the unquestionable reliance on maintenance steroids in modern transplantation practice. This review aims to evaluate the safety and efficacy of various steroid-minimization approaches (steroid avoidance, early steroid withdrawal, and late steroid withdrawal) in kidney transplant recipients. A meticulous electronic search was conducted through the available data resources like SCOPUS, MEDLINE, and Liverpool University library e-resources. Relevant articles obtained through our search were included. A total number of 90 articles were eligible to be included in this review [34 randomised controlled trials (RCT) and 56 articles of other research modalities]. All articles were evaluating the safety and efficacy of various steroid-free approaches in comparison to maintenance steroids. We will cover only the RCT articles in this review. If used in right clinical context, steroid-free protocols proved to be comparable to steroid-based maintenance therapy. The appropriate approach should be tailored individually according to each recipient immuno-logical challenges and clinical condition.

ABO-Incompatible Living-Donor Kidney Transplantation in a Developing Country: A Multicenter Experience in Malaysia

Malaysia has a low deceased-donor donation rate and has not embarked on a paired kidney exchange program; therefore, ABO-incompatible and HLA-incompatible transplantation remain the main contributor to the sustainability of the national kidney transplantation (KT) program. There were 26 cases of ABO-incompatible KTs performed from 2011 to 2018 in 3 major transplant centers, namely, Hospital Kuala Lumpur, University Malaya Medical Centre, and Prince Court Medical Centre. We collected perioperative and follow-up data through June 2019. The desensitization protocol varies and is center specific: the localized Japanese protocol and Swedish protocol with a target anti-A/B isoagglutinin titer of 16 or 32 on the day of transplant. The induction and tacrolimus-based maintenance protocol was nearly identical. The median follow-up time was 62.3 months (interquartile range, 37.0-79.7). Fifteen subjects had the highest predesensitization anti-A/B titer of ≥32 (57.7%). The acute cellular rejection and antibody-mediated rejection incidence were 12.5% (3 cases) and 8.3% (2 cases), respectively. Patient, graft, and death-censored graft survival rates were 96.2%, 92.3%, and 96.0%, respectively, 1 year post-living-donor KT (LDKT) and 96.2%, 87.2%, and 90.7%, respectively, 5 years post-LDKT. Our experience shows that ABO-incompatible LDKT using a suitable desensitization technique could be a safe and feasible choice for LDKT even with varied desensitization regimens for recipients with relatively high baseline isoagglutinin titers.

Characteristics of Immunoglobulin M Type Antibodies of Different Origins from the Immunologic and Clinical Viewpoints and Their Application in Controlling Antibody-Mediated Allograft Rejection

Antibody-mediated allograft rejection (AMR) hinders patient prognosis after organ transplantation. Current studies concerning AMR have mainly focused on the diagnostic value of immunoglobulin G (IgG)-type donor-specific antihuman leukocyte antigen antibodies (DSAs), primarily because of their antigen specificity, whereas the clinical significance of immunoglobulin M (IgM)-type DSAs has not been thoroughly investigated in the context of organ transplantation because of their nonspecificity against antigens. Although consensus regarding the clinical significance and role of IgM antibodies is not clear, as discussed in this review, recent findings strongly suggest that they also have a huge potential in novel diagnostic as well as therapeutic application for the prevention of AMR. Most serum IgM antibodies are known to comprise natural antibodies with low affinity toward antigens, and this is derived from B-1 cells (innate B cells). However, some of the serum IgM-type antibodies reportedly also produced by B-2 cells (conventional B cells). The latter are known to have a high affinity for donor-specific antigens. In this review, we initially discuss how IgM-type antibodies of different origins participate in the pathology of various diseases, directly or through cell surface receptors, complement activation, or cytokine production. Then, we discuss the clinical applicability of B-1 and B-2 cell-derived IgM-type antibodies for controlling AMR with reference to the involvement of IgM antibodies in various pathological conditions.

Outcomes of ABO-incompatible kidney transplantation in older patients: a national cohort study

BACKGROUND

Outcomes of ABO-incompatible living donor kidney transplantation (ABOi LDKT) in older individuals have not been established.

METHODS

This multicentric observational study, using data from the Korean Organ Transplantation Registry database, included 634 older patients (≥60 years) undergoing kidney transplantation. We compared clinical outcomes of ABOi LDKT (n = 80) with those of ABO-compatible LDKT (ABOc LDKT, n = 222) and deceased donor kidney transplantation (DDKT, n = 332) in older patients.

RESULTS

Death-censored graft survival was similar between the three groups (P = 0.141). Patient survival after ABOi LDKT was similar to that after ABOc LDKT (P = 0.489) but higher than that after DDKT (P = 0.038). In multivariable analysis, ABOi LDKT was not risk factor (hazard ratio [HR] 1.73, 95% confidence interval [CI] 0.29-10.38, P = 0.548), while DDKT was significant risk factor (HR 3.49, 95% CI 1.01-12.23, P = 0.049) for patient survival. Although ABOi LDKT showed higher biopsy-proven acute rejection than ABOc LDKT, the difference was not significant after adjustment with covariates. However, ABOi LDKT was significant risk factor for infection (HR 1.66, 95% CI 1.12-2.45, P = 0.012).

CONCLUSIONS

In older patients, ABOi LDKT was not inferior to ABOc LDKT and was superior to DDKT for patient survival. ABOi LDKT can be recommended for older patients, rather than waiting for DDKT.

The impact of country reimbursement programmes on living kidney donations

INTRODUCTION

Living-donor kidney transplantation is the gold standard treatment for patients with end-stage kidney disease. However, potential donors ubiquitously face financial as well as logistical barriers. To remove these disincentives from living kidney donations, the governments of 23 countries have implemented reimbursement programmes that shift the burdens of non-medical costs from donors to the governments or private entities. However, scientific evidence for the effectiveness of these programmes is scarce. The present study investigates whether these reimbursement programmes designed to ease the financial and logistical barriers succeeded in increasing the number of living kidney donations at the country level. The study examined within-country variations in the timing of such reimbursement programmes.

METHOD

The study applied the difference-in-difference (two-way panel fixed-effect) technique on the Poisson distribution to estimate the effects of these reimbursement programmes on a 17 year long (2000-2016) dataset covering 109 countries where living donor kidney transplants were performed.

RESULTS

The results indicated that reimbursement programmes have a statistically significant positive effect. Overall, the model predicted that reimbursement programmes increased country-level donation numbers by a factor of 1.12-1.16.

CONCLUSION

Reimbursement programmes may be an effective approach to alleviate the kidney shortage worldwide. Further analysis is warranted on the type of reimbursement programmes and the ethical dimension of each type of such programmes.

Current protocols and outcomes of ABO-incompatible kidney transplantation

One of the principal obstacles in transplantation from living donors is that approximately 30% are immunologically incompatible because of the presence in the recipient of antibodies directed against the human leukocyte antigen system of the donor or because of the incompatibility of the ABO system. The aim of this review is to describe the more recent data from the literature on the different protocols used and the clinical outcomes of ABO-incompatible kidney transplantation. Two different strategies are used to overcome these barriers: desensitization of the recipient to remove the antibodies and to prevent their rebound after transplantation and the exchange of organs between two or more pairs. The largest part of this review is dedicated to describing the techniques of desensitization. Even if the first reports of successful renal transplantation between ABO-incompatible pairs have been published by 1980, the number of ABO-incompatible transplants increased substantially in this century because of our improved knowledge of the immune system and the availability of new drugs. Rituximab has substantially replaced splenectomy. The technique of apheresis has improved and more recently a tailored desensitization proved to be the more efficient strategy avoiding an excess of immunosuppression with the related side effects. Recent reports document outcomes for such transplantation similar to the outcomes of standard transplantation.

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.

A case of successful late steroid withdrawal after ABO-incompatible kidney transplantation

Few data exist regarding steroid withdrawal in ABO-incompatible (ABO-i) kidney transplantation (KT). Here, we report a case of steroid withdrawal after ABO-i KT. A 46-year-old man diagnosed with Henoch-Schonlein purpura received ABO-i KT from his 42-year-old sister. The recipient and donor blood types were O and AB, respectively. His preoperative ABO antibody titers were anti-A of 1:16 and anti-B of 1:8 in isoagglutinin test. HLA mismatch was 0 and he received a single 325 mg/m² dose of intravenous (IV) rituximab 4 weeks before KT. Three sessions of plasma exchange were undertaken before KT and low-dose IV immunoglobulin of 0.1 g/kg was administered after plasma exchange. On the day of the operation, ABO antibody titer decreased to anti-A of 1:4 and anti-B of 1:2. Renal function remained stable after KT. The patient wished to stop steroid treatment despite the risk of rejection after withdrawal. Steroid tapering was initiated at 20 months and accomplished at 26 months after KT. At that time, serum creatinine level was 1.13 mg/dL, and anti-A and anti-B titers were 1:8 and 1:2, respectively. No issues were observed after steroid withdrawal. At 48 months after KT, serum creatinine level was 1.21 mg/dL, and anti-A and anti-B antibody titers were 1:32 and 1:2, respectively. Steroid withdrawal in ABO-i KT might be considered in immunologically low-risk patients.

Outcome of ABO Blood Type-Incompatible Living-Related Donor Kidney Transplantation Under a Contemporary Immunosuppression Strategy in Japan

BACKGROUND

Because of the serious donor shortage in Japan, there is an increasing need for ABO blood type-incompatible kidney transplantation (ABOi-KT) in living-related donor kidney transplantation. We evaluated the outcomes of ABOi-KT performed at our hospitals using a contemporary immunosuppression strategy with low-dose rituximab.

PATIENTS AND METHODS

Between June 2006 and April 2019, 107 patients underwent living-related donor kidney transplantation at our hospitals. The patients were divided into ABO-compatible (ABOc) and ABOi groups. The basic immunosuppression regimen differed between the 2 groups in the use of low-dose rituximab and therapeutic apheresis in the ABOi group. We compared graft survival, patient survival, rejection, viral infection, and posttransplant renal function between the 2 groups.

RESULTS

Of 107 recipients, 37 (35%) underwent ABOi-KT. The 5-year graft survival rates in the ABOc and ABOi group were 91% and 100%, respectively. The Kaplan-Meier analyses showed no difference in graft survival (P = .168) or patient survival (P = .873) between the groups. Biopsy-proven rejection in the ABOc and ABOi groups was observed in 13 (19%) and 7 (19%) patients, respectively (P = .965), and viral infection was observed in 21 (30%) and 10 (27%) patients (P = .747), respectively. Renal function by estimated glomerular filtration rate from 1 week to 5 years after transplantation was similar in both groups.

CONCLUSIONS

The outcomes of ABOi-KT with low-dose rituximab were comparable with those of ABOc-KT at our hospitals. ABOi-KT with proper immunosuppression may be an option to help resolve the severe donor shortage in Japan.

Splenectomy for ABO-Incompatible Kidney Transplantation and Very Late-Onset Cytomegalovirus Disease

INTRODUCTION

Splenectomy had been previously performed in ABO-incompatible kidney transplantation to reduce the B cell pool. However, studies have shown that patients undergoing splenectomy may have a lifelong susceptibility to infection and mortality. Splenectomy may affect the incidence of cytomegalovirus (CMV) disease even at a very late stage after transplantation in ABO-incompatible recipients.

PATIENTS AND METHODS

Seven patients received their graft from an ABO-incompatible living donor at our institution and underwent splenectomy for B cell reduction. Among them, 3 recipients experienced very late-onset CMV disease approximately 10 years after their transplant and were enrolled in this study.

RESULTS

Very late-onset CMV disease occurred at 9 years and 9 months, 15 years, and 13 years and 5 months after transplantation, respectively. Two recipients suffered from CMV retinitis, while one experienced colitis. The age of the patients at onset of CMV disease was 69 years, 42 years, and 71 years, respectively.

CONCLUSION

This may be the first report on very late-onset CMV disease after splenectomy in ABO-incompatible kidney transplantation. We should be aware that these recipients can experience very late-onset CMV disease even approximately 10 years after their transplant.

Outcomes of Renal Transplant Recipients after Percutaneous Coronary Intervention

Renal transplantation (RT) can improve life expectancy in hemodialysis (HD) patients. However, little is known about the outcomes of renal transplant recipients after percutaneous coronary intervention (PCI). This study aimed to elucidate the effect of RT on clinical outcomes after PCI. Renal transplant recipients who underwent PCI from 2002 to 2017 were enrolled. To evaluate the effectiveness of RT, we retrospectively reviewed HD patients who underwent PCI. Propensity-score matching was performed using logistic regression to control for differences in baseline characteristics. The primary outcome was the incidence of major adverse cardiac events. After propensity matching, patients were classified into the RT (n = 50) group and HD (n = 50) group. Kaplan-Meier analysis revealed that the incidence of major adverse cardiac events was significantly lower in the RT group than in the HD group (p < 0.0001). Moreover, RT was associated with a lower risk for all-cause death (odds ratio 0.04; 95% confidence interval 0.002 to 0.03; p = 0.0054) and target vessel revascularization (OR 0.27; 95% CI 0.07 to 0.79; p = 0.015). RT may improve clinical outcomes after PCI, and it is encouraged for HD patients to increase life expectancy and reduce the occurrence of adverse events after PCI. Further research would be warranted to support this finding.

ABO-incompatible pediatric kidney transplantation without antibody removal

BACKGROUND

Because of the severe shortage of suitable deceased donors, ABO-incompatible living donor kidney transplantation (ABOi LDKT) is performed even in pediatric recipients in Japan. We performed pediatric ABOi LDKT using rituximab without anti-A/B antibody removal.

METHODS

Thirteen pediatric recipients (mean age 7.4, range 3.4-15.7, four females) whose baseline anti-A/B IgG titers were ≤ × 64 underwent ABOi LDKT without antibody removal and splenectomy between July 2013 and April 2017 at Toho University. Mycophenolate mofetil (MMF) was initiated on day - 10. Rituximab (100 mg) was administered twice. Basiliximab and triple maintenance immunosuppression (calcineurin inhibitor, MMF, and steroids) were administered. Protocol biopsy was performed at 3 months and 1 year after transplantation. We retrospectively compared the clinical outcomes between these recipients and 37 children (mean age 9.0, range 2.6-18.9, 15 female) who underwent ABO-compatible (ABOc) LDKT during the same period.

RESULTS

The mean follow-up periods of ABOi and ABOc groups were 31.9 ± 13.5 and 28.8 ± 14.4 months, respectively. In the ABOi group, no clinical acute rejection (AR) was noted and subclinical AR was observed in four patients without evidence of acute antibody-mediated rejection. In the ABOc group, clinical and subclinical AR developed in 3 and 10 patients, respectively. No significant difference was identified for the mean eGFR between the ABOi and ABOc groups (98.3 ± 48.8 vs. 86.9 ± 39.4, P = 0.452 at 3 months; 78.2 ± 21.2 vs. 79.7 ± 21.3, at 1 year, P = 0.830). Death-censored graft survival at follow-up was 100% in the ABOi group and 94.6% in the ABOc group. Patient survival during the follow-up period in both the groups was 100%. Late-onset neutropenia (LON) requiring granulocyte colony-stimulating factor occurred more frequently in the ABOi group than in the ABOc group (4 vs. 0 patients) (P < 0.001).

CONCLUSIONS

Pre- and post-transplantation antibody removal is not a prerequisite for successful pediatric ABOi LDKT, at least in patients with a low anti-A/B IgG antibody titer. However, LON caused by rituximab should be monitored.

T cell reconstitution after lymphocyte depletion features a different pattern of inhibitory receptor expression in ABO- versus HLA-incompatible kidney transplant recipients

Chronic antigen stimulation can lead to immune exhaustion (a state of T cell dysfunction). Several phenotypical signatures of T cell exhaustion have been described in various pathological situations, characterized by aberrant expression of multiple inhibitory receptors (IR). This signature has been barely studied in the context of allogenic organ transplantation. We undertook a cross-sectional analysis of the expression of IR [CD244, CD279, T cell immunoreceptor with immunoglobulin (Ig) and immunoreceptor tyrosine-based inhibition motif (ITIM) domains (TIGIT) and CD57] and their correlation with cytokine-producing functions in T cells reconstituting after lymphocyte depletion in patients transplanted from living donors, with preformed donor-specific antibodies. After ABO incompatible transplantation, T cells progressively acquired a phenotype similar to healthy donors and the expression of several IR marked cells with increased functions, with the exception of TIGIT, which was associated with decreased cytokine production. In stark contrast, T cell reconstitution in patients with anti-human leukocyte antigen (HLA) antibodies was characterized with an increased co-expression of IR by T cells, and specifically by an increased expression of TIGIT. Furthermore, expression of these receptors was no longer directly correlated to cytokine production. These results suggest that T cell alloreactivity in HLA-incompatible kidney transplantation drives an aberrant T cell reconstitution with respect to IR profile, which could have an impact on the transplantation outcome.

Excellent outcome after desensitization in high immunologic risk kidney transplantation

Introduction

HLA-incompatible (HLAi) and ABO-incompatible (ABOi) kidney transplantation (KT) has been on the increase over the last decade. However, there are wide variations in outcomes from these procedures. In this study we evaluated the graft and patient outcomes in incompatible KT and non-sensitized KT.

Methods

Patients who underwent KT between January 2012 and April 2018 were enrolled and reviewed. We divided kidney transplant recipients (KTRs) into five groups as follows: HLAi (n = 50); ABOi (n = 65); HLAi+ABOi (n = 5); control (n = 428); and living-donor control (LD control, n = 218). We compared the risk of rejection, graft function, graft survival, and patient survival between incompatible KTRs and control/LD control KTRs.

Results

Although the incidence of active antibody-mediated rejection in HLAi group tends to be higher than in control and LD control groups (6.0% vs. 2.8%, P = 0.20; 6.0% vs. 3.7%, P = 0.44, respectively), the rejection-free survival, graft survival, and patient survival were not significantly different from those of the control and LD control groups in all three incompatible KT groups (all P>0.05). Graft function during the study period was also not different between incompatible KTRs and control/LD control groups (both P>0.05). Using Cox regression analysis, neither HLAi nor ABOi were risk factors for graft failure. Some infectious diseases such as urinary tract infection and cytomegalovirus infection were more common in the HLAi group than in the control/LD control group (both P<0.05), but only one infection-related death occurred in HLAi KTRs. Infection risks were similar in the ABOi and HLAi+ABOi groups compared to controls.

Conclusion

Our results showed favorable outcomes for incompatible KT after desensitization. Although desensitization therapy for incompatible KT has improved access to transplantation for KT candidates with high immunological risk, more clinical data are clearly needed.

Latest insights on ABO-incompatible living-donor renal transplantation

This review summarizes the latest insights on ABO‐incompatible living‐donor renal transplantation. Desensitization protocols and clinical outcomes were investigated, and a comparison was made with kidney‐paired donation, which is not permitted in Japan for ethical reasons. Although renal transplantation is greatly beneficial for most patients with end‐stage kidney disease, many of these patients must remain on dialysis therapy for extended periods due to the scarcity of organs from deceased donors. ABO blood type incompatibility was once believed to be a contraindication to renal transplantation due to the increased risk for antibody‐mediated rejection and early graft loss attributable to isoagglutinins. Recently, pretransplant desensitization strategies, such as removal of isoagglutinins and antibody‐producing cells, have achieved successful outcomes, although it remains unclear whether graft survival and patient morbidity are equivalent to those for ABO‐compatible renal transplantation. The present review suggested that ABO‐incompatible living‐donor renal transplantation might be a favorable radical renal replacement therapy for patients with end‐stage kidney disease.

Association between response to rituximab and antibody-mediated rejection in ABO-incompatible living kidney transplantation

OBJECTIVES

To examine the association of response to rituximab and the incidence of antibody-mediated rejection in preconditioning of rituximab and plasma exchange without post-transplant plasmapheresis in patients undergoing ABO-incompatible living kidney transplantation.

METHODS

A total of 115 patients who underwent ABO-incompatible living kidney transplantation at Tokyo Women's Medical University Hospital, Tokyo, Japan, were divided into two groups based on the response to rituximab: good response (n = 75) or poor response (n = 40). The rituximab good response and poor response patients were defined as patients whose CD19⁺ cells were non-detected (0%) and detected on the day of transplantation (2-5 days, median 3 days, after rituximab administration), respectively.

RESULTS

Rituximab response and anti-A/B blood antibody titer after plasmapheresis were significant risk factors for antibody-mediated rejection (P = 0.036, 0.045, respectively). The occurrence of antibody-mediated rejection was higher in the poor response group than in the good response group (22.5% vs 8.0%; P = 0.028). The 14-day, 3-month and 1-year cumulative incidence of antibody-mediated rejection was 2.7%, 5.3% and 8.0% in the good response group, and 17.5%, 20.0% and 22.5% in the poor response group after ABO-incompatible living kidney transplantation. The patient survival was not significantly different between the two groups. However, graft survival 1 month after transplantation was lower in the poor response group. There is no significant difference in graft function and in the incidence of complications, including infection, after transplantation between the two groups.

CONCLUSIONS

Antibody-mediated rejection after ABO-incompatible living kidney transplantation was significantly associated with the response to rituximab in our preconditioning protocol.

Outcomes, complications, and economic impact of ABO-incompatible living kidney transplantation: A single-center Japanese cohort study

ABO-incompatible kidney transplantation (ABO-ILKT) has been reported to have a higher rate of early complications and higher medical costs than ABO-compatible kidney transplantation (ABO-CLKT). We aimed to compare the clinical outcomes, complications, and medical costs between ABO-ILKTs and ABO-CLKTs at 2 years post-transplantation. We included 65 ABO-ILKTs and 94 ABO-CLKTs in this retrospective analysis. The patient survival, graft survival, rejection incidence, and graft function were similar between ABO-CLKT and ABO-ILKT. The hospitalization costs for ABO-CLKT and ABO-ILKT were 26 544 ± 4168 USD and 34 906 ± 18 732 USD, respectively (P = 0.0001). Total 2-year medical costs were 77 117 ± 15 609 USD and 85 325 ± 33 997 USD for ABO-CLKT and ABO-ILKT, respectively, indicating that the medical costs of ABO-ILKT recipients were non-significantly higher than those of ABO-CLKT recipients at 2 years post-transplantation (P = 0.0866). ABO-ILKT and ABO-CLKT recipients showed similar infectious adverse events and complications. In conclusion, medical cost at 2 years post-transplantation, including transplant hospitalization cost, and the frequency of early complications were not significantly higher in the ABO-ILKT group than in the ABO-CLKT group. ABO-ILKT is an acceptable treatment for patients with ESRD and is comparable to ABO-CLKT not only in terms of outcomes but also in terms of medical cost.

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.

Long-term peritoneal dialysis followed by kidney transplantation for Takayasu arteritis: a case report

Background

Takayasu arteritis (TA) is a chronic vasculitis of unknown etiology that primarily affects large vessels. Although renal involvement is frequent in TA, patients with TA undergoing renal replacement therapy, especially long-term peritoneal dialysis (PD) and kidney transplantation (KTx), are rarely reported. We herein present the case of an elderly patient with TA treated by PD for more than 5 years and underwent KTx thereafter.

Case presentation

A 69-year-old female diagnosed with TA at the age of 19 was treated by PD for seven and a half years for end-stage renal disease due to TA. Dialysate-to-plasma ratio of creatinine, which was well maintained during this period, reflected the efficacy of long-term PD. However, her residual renal function declined; she developed malnutrition, inflammation, and atherosclerosis syndrome and underwent living-related KTx from her husband. Due to the total occlusion of the external iliac arteries with compensatory development of the internal iliac arteries, the right internal iliac artery was used as the anastomosis site. After KTx, the patient developed chronic active antibody-mediated rejection; however, the graft function was maintained throughout the follow-up period. Despite severe aortic calcification and intermittent claudication in the legs, her condition did not worsen, and the blood flow of the graft was preserved.

Conclusions

The current case illustrating the success of long-term PD and living-related KTx in maintaining kidney function in an elderly patient with TA is the first to demonstrate the potential of PD and KTx as feasible options for renal replacement therapy in TA accompanied by severe cardiac involvement.

Pilot Experience with ABO-Incompatible Kidney Transplantation as a Second Transplant

BACKGROUND

Despite advances in immunosuppressant medications, improvement in long-term survival for kidney transplant recipients has been more difficult to achieve. In fact, the number of patients with failing grafts who must either return to dialysis or undergo a second transplant is increasing. Second transplantation is associated with reduced mortality rates compared to remaining on dialysis after an initial graft loss. Nowadays, excellent ABO-incompatible kidney transplant outcomes have been achieved. However, there have been no reports on ABO-incompatible kidney transplantation as a second transplant.

PATIENTS AND METHODS

Three patients who received their graft from an ABO-incompatible living donor at our institution as a second transplant were enrolled in this study. We focused on immunosuppressive therapy for second ABO-incompatible kidney transplantation, donor-specific antibody status before the second transplant, patient and graft survivals, and complications.

RESULTS

All 3 patients successfully underwent ABO-incompatible kidney transplantation as a second transplant with a follow-up period of 141, 39, and 24 months. Patient and graft survival rates were 100%.

CONCLUSIONS

ABO-incompatible kidney transplantation may be an acceptable treatment for patients who need a second renal replacement therapy after their initial graft failure.

Current protocols and outcomes of ABO-incompatible kidney transplantation based on a single-center experience

ABO-incompatible living kidney transplantation (ABO-ILKT) is an effective option for increasing living kidney transplant opportunities. ABO-ILKT has been conducted in our institution since 1989 to widen the indication for living kidney transplantation. ABO-ILKT is considered to require extra treatment, and it has increased risks compared with ABO-compatible living kidney transplantation (ABO-CLKT). In the past two decades, some protocols have removed anti-blood-type antibodies to prevent the production of antibodies. Additionally, we have made considerable changes to our ABO-ILKT protocol as new immunosuppressive agents have been developed. Consequently, increased immunosuppression and immunological understanding have helped shape recent desensitization protocols. Herein, we review the history, therapeutic strategy, pathology, and future directions of ABO-ILKT. Our standard immunosuppressive regimen and desensitization protocol for ABO-ILKT recipients consist of low doses of tacrolimus (TAC), mycophenolate mofetil (MMF), and rituximab; several sessions of double filtration plasmapheresis; and basiliximab induction. We do not use thymoglobulin induction, intravenous immunoglobulin, or prophylactic post-transplant plasmapheresis. Recently, ABO-ILKT has been recognized as a useful alternative therapy for end-stage kidney disease with ABO-incompatibility, and its outcome is comparable to that of ABO-CLKT.

Successful Third Kidney Transplant After Desensitization for Combined Human Leucocyte Antigen (HLA) and ABO Incompatibility: A Case Report and Review of Literature

BACKGROUND In the present era, kidney transplantation across immunological barriers (ABO incompatibility and human leucocyte antigen (HLA) incompatibility) is a successful strategy to provide transplantation to immunologically high-risk patients. The safety and outcome of crossing both ABO and HLA barriers simultaneously in a retransplantation scenario is rarely reported from the developing world. CASE REPORT A 30-year-old female underwent a third living donor kidney transplantation. Her previous 2 transplants being lost to chronic allograft nephropathy. The transplantation was done across a simultaneous blood group as well as HLA incompatibility. The donor was the mother who was blood group B, with the recipient being blood group O. The complement dependent cytotoxicity crossmatch of the pair was negative but the flow cross match for T as well as B lymphocytes was positive. The mean fluorescence intensity value for class I antigens was 6951 and that for class 2 antigens was 7534. The patient underwent a desensitization procedure including rituximab, plasmapheresis and intravenous immunoglobulin pre-transplantation. The pre-transplantation isohemaglutunin titer was <1: 8 and the donor specific antibody against class 1 antigens was <2200 and <770 against class 2 antigens. Induction was done with anti-thymocyte globulin in the dose of 3 mg/kg in 2 divided doses. The patient is maintained on triple immunosuppression with tacrolimus, prednisolone and mycophenolate mofetil. After a follow-up period of 5 months, she maintains a good graft function with serum creatinine of 1.01 mg/dL. CONCLUSIONS With the advances in the desensitizing procedures in the developing world, kidney transplantation across a combined HLA and ABO incompatible barrier can be offered to these highly sensitized patients, even in case of retransplantation.