Outcomes Of ABO-incompatible Kidney Transplantation Research Articles

Short-term outcomes of ABO-incompatible kidney transplantation at Cho Ray Hospital

Short-term outcomes of ABO-incompatible kidney transplantation at Cho Ray Hospital

Impact of ABO incompatibility and early antibody-mediated rejection on chronic antibody-mediated rejection in kidney transplant patients.

Early antibody-mediated rejection has been reported to increase chronic antibody-mediated rejection and decrease graft survival in kidney transplantation. However, the impact of early antibody-mediated rejection in ABO-incompatible kidney transplantation remains unclear. We retrospectively analyzed living-donor kidney transplantation patients from two Korean centers. Patients were categorized based on ABO compatibility and early antibody-mediated rejection within 1 year. The primary outcome was chronic antibody-mediated rejection. The secondary outcomes were production of de novo donor-specific antibody and composite kidney outcome, defined as graft loss or a decline in estimated glomerular filtration rate to below 30mL/min/1.73 m2. A total of 1639 patients were analyzed, including 1292 patients who underwent ABO-compatible kidney transplantation and 347 patients who underwent ABO-incompatible kidney transplantation. ABO-incompatible kidney transplantation had a lower risk of de novo donor-specific antibody production (hazard ratio [HR] 0.68, 95% confidence interval [CI] 0.48-0.95) and chronic antibody-mediated rejection (HR 0.33, 95% CI 0.12-0.92) with a comparable risk of the composite kidney outcome (HR 1.06, 95% CI 0.71-1.59) compared to ABO-compatible kidney transplantation. When outcomes of ABO-incompatible kidney transplantation were analyzed according to early antibody-mediated rejection, ABO-incompatible kidney transplantation without antibody-mediated rejection had a lower risk of de novo donor-specific antibody production (HR 0.60, 95% CI 0.41-0.88) and chronic antibody-mediated rejection (HR 0.28, 95% CI 0.09-0.91) than ABO-compatible kidney transplantation without antibody-mediated rejection. However, ABO-incompatible kidney transplantation with antibody-mediated rejection showed a higher risk of de novo donor-specific antibody production and similar risk of chronic antibody-mediated rejection compared to ABO-compatible kidney transplantation without antibody-mediated rejection. ABO-incompatible kidney transplantation showed a lower risk of de novo donor-specific antibody production and chronic antibody-mediated rejection compared to ABO-compatible kidney transplantation; however, early antibody-mediated rejection abrogated these beneficial effects of ABO-incompatible kidney transplantation.

Outcomes of abo-incompatible kidney transplantation: Novel ways of reducing rejection, complications, and cost

AimOur objective was to report the outcomes of ABO-incompatible (ABOi) transplants and seek solutions to pretransplant desensitization, peri and postoperative bleeding events, acute rejection and infection-related mortality. MethodsWe retrospectively analyzed 247 consecutive ABOi kidney transplantations at our center from June 2012 to March 2020. The primary outcomes were patient, graft, and death-censored graft survival over 5 years. ResultsA total of 31 patients received thymoglobulin and 216 patients received basiliximab induction. Patient survival rates with basiliximab induction at 1, 3, and 5 years were 97.8%, 93.5%, and 93.5%, respectively; corresponding graft survival rates were 95.1%, 86.6%, and 85.2%, respectively. Overall, biopsy-proven acute rejection occurred in 11.7% recipients; primarily due to antibody-mediated rejections. Cumulative incidence of graft loss was 7.5% at 5 years and overall incidence of death was 6.07%. ConclusionReplacement of filtered plasma by donor group fresh frozen plasma rather than albumin reduced bleeding, IVIG administration, number of plasmapheresis sessions and the need for filters. Thymoglobulin avoidance decreased acute rejection rates. Rapid reduction and lower doses of prednisolone and MMF reduced infectious complications. These steps can help reduce rejection rates, complications and cost (up to USD 7000) comparable to ABO compatible transplantation in other centers as well.

Optimal dose of rituximab in ABO-incompatible kidney transplantation in patients with low anti-A/B antibody titers: A single-center retrospective cohort study.

The clinical outcomes of ABO-incompatible (ABOi) kidney transplantation have improved with the introduction of desensitization therapy with rituximab. However, rituximab prevents not only antibody-mediated rejection (AMR) but also increases the risk of adverse events, such as infection. For ABOi kidney transplantation in patients with low anti-A/B antibody titers, we previously used a rituximab-free desensitization protocol and then initiated a single dose of 100mg rituximab in 2016. We retrospectively compared the outcomes of ABOi kidney transplantation in patients with low anti-A/B antibody titers before and after the introduction of rituximab. ABOi kidney transplantations (n=142) in patients with low anti-A/B antibody titers between 2007 and 2021 were included. Patients were divided into two groups (with and without rituximab) for desensitization. The primary outcomes were the incidence of acute AMR and infection. Sixty-six patients were desensitized without rituximab (rituximab-free group), and 76 were pretreated with 100mg rituximab (rituximab group) before transplantation. The incidence of acute AMR was significantly lower in the rituximab group than in the rituximab-free group (.0% [0/76] vs. 7.6% [5/66], respectively; p=.047). Post-transplantation anti-A/B antibody titers were also lower in the rituximab group than in the rituximab-free group. There was no significant difference in the incidence of adverse events, including infections, between the two groups. In ABOi kidney transplantation patients with low anti-A/B antibody titers, the desensitization protocol with a single dose of 100mg rituximab was effective in preventing acute AMR without increasing the risk of other adverse events.

Outcome of ABO-Incompatible Kidney Transplantation According to ABO Type of Transfused Plasma: Comparative Analysis Between "Universal" AB and Donor-Type Plasma.

We compared the clinical outcomes of recipients of ABO-incompatible (ABOi) kidney transplantation (KT) according to the blood group of the plasma transfused. We retrospectively analyzed the data of 60 recipients of ABOi-KT with blood type O and A or B donors. Demographic and clinical characteristics were compared between 2 groups of recipients: 1 group received AB plasma regardless of the donor's blood type (n = 30), and the other group received donor-type plasma (n = 30). There were no significant differences between the groups in terms of demographic characteristics. Transfusion of donor-type plasma was noninferior to transfusion of type AB plasma in terms of both rejection-free survival and rejection rate (P = .455, P = .335). There was no significant prognostic difference between the 2 groups. In terms of blood supply and inventory management, we suggest that the blood group of the plasma should match the donor's type.

Outcomes of ABO-Incompatible kidney transplantation with respect to baseline isoagglutinin immunoglobulin G titers: A retrospective observational study

Outcomes of ABO-Incompatible kidney transplantation with respect to baseline isoagglutinin immunoglobulin G titers: A retrospective observational study

Outcomes of Abo-Incompatible Kidney Transplantation: Novel Ways of Reducing Rejection, Complications and Cost

Outcomes of Abo-Incompatible Kidney Transplantation: Novel Ways of Reducing Rejection, Complications and Cost

Long-Term Outcome of ABO-Incompatible Kidney Transplantation in Patients Treated With Low-Dose Rituximab Regimen

BackgroundIntroduction of rituximab in the desensitization protocols for ABO-incompatible (ABOI) kidney transplantation (KTX) has afforded excellent results. However, the acceptability of minimal dosage of rituximab in these protocols remains to be defined. MethodsSixty-three patients who underwent ABOI KTX were included in this study. The desensitization protocol consisted of plasmapheresis, tacrolimus, mycophenolate mofetil, methylprednisolone, intravenous immunoglobulin, basiliximab, and low-dose rituximab (100 mg/body). We evaluated the efficacy, safety, and long-term outcome of this protocol (group R, n = 39) and compared them with those of patients who underwent splenectomy (group S, n = 24). ResultsGraft and patient survival at 10 years after KTX were comparable between the groups (94.4% [group R] vs 95.4% [group S] and 94.6% [group R] vs 95.8% [group S], respectively). The incidence of acute antibody-mediated rejection (AAMR) was similar in the 2 groups (10.2% vs 12.5%). There were no significant differences in the incidence of chronic active antibody-mediated rejection. Of the patients, 7 developed AAMR and 3 of these patients (1 in group R and 2 in group S) lost their grafts. There were no significant differences in the incidence of chronic active antibody-mediated rejection. The incidence of postoperative cytomegalovirus infection in group R was significantly lower than that in group S. Furthermore, the incidence of postoperative late-onset neutropenia was low in group R. ConclusionsA low-dose rituximab regimen for ABOI KTX is acceptable for preventing AAMR with a low incidence of delayed adverse events.

Outcome of ABO-incompatible kidney transplantation depending on the ABO type of transfused plasma: comparative analysis between the universal AB plasma and donor type plasma

Outcome of ABO-incompatible kidney transplantation depending on the ABO type of transfused plasma: comparative analysis between the universal AB plasma and donor type plasma

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.

Clinical significance of isoagglutinin titre with the current desensitization protocol in ABO-incompatible kidney transplantation.

ABO-incompatible (ABOi) kidney transplantation (KT) has become a routine procedure with graft survival rates comparable to those of ABO-compatible KT. However, the clinical significance of the isoagglutinin titre in ABOi KT remains uncertain. Therefore, in this study, we analysed the clinical outcomes of ABOi KT according to the baseline and post-operative isoagglutinin titre. All patients who received ABOi KT between 2009 and 2013 were reviewed and followed up until December 2016. The patients were classified according to baseline (<1:128 or ≥1:128) and post-operative rebound isoagglutinin titre (<1:16 or ≥1:16), and the clinical outcomes of KT were compared. Patients with a high baseline isoagglutinin titre showed a poor titre reduction rate (1.48 ± 0.41 vs 1.32 ± 0.34, P = 0.008), and more patients experienced titre rebound ≥1:16 after KT (15.0% vs 35.8%, P = 0.002). The occurrence of both T-cell-mediated rejection and antibody-mediated rejection did not show a significant difference (P = 0.805 and 0.714, respectively). The rate of rejection-free survival was not different among groups (P = 0.680, log-rank test). Furthermore, the rate of death-censored graft survival was not different among groups (P = 0.701, log-rank test). Urinary tract infection was the most frequently reported infectious complication overall. The incidence of urinary tract infection, pneumonia and viral infections (BK virus and cytomegalovirus) was not different among groups. In conclusion, high baseline isoagglutinin titre was associated with a high rebound isoagglutinin titre, low titre reduction rates and more sessions of plasmapheresis. However, the isoagglutinin titre may not be as important as it was in the past in ABOi KT if appropriate desensitization is performed.

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.

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

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

ABO-incompatible kidney transplantation as a renal replacement therapy-A single low-volume center experience in Japan.

IntroductionLiving donor kidney transplantation is preferable to deceased donor transplantation due to its superior long-term patient and graft survivals. However, ABO blood group incompatibility is a major barrier to living donor kidney transplantation. ABO-incompatible kidney transplantation has been performed in Japan since the late 1980’s, but it is still globally uncommon. The objective of this study is to compare the clinical outcomes of ABO-incompatible kidney transplantation (ABO-IKT) with that of ABO-compatible kidney transplantation (ABO-CKT) at an institution where only about two kidney transplants are performed a month on average.DesignA single center propensity score-matched cohort study.Patients and methodsWe retrospectively collected and analyzed the data of 240 patients with end-stage kidney disease (ESKD) who underwent living donor kidney transplantation at Osaka City University Hospital from January 1999 to December 2016, of which 66 patients were ABO-IKT. The remaining 174 patients who underwent ABO-CKT were studied as the control group, and the clinical outcomes of ABO-IKT and ABO-CKT recipients were compared based on propensity score matching.ResultsAfter propensity score matching, there were no significant differences in both patient survival and death-censored graft survival rates between the ABO-IKT and ABO-CKT groups. Moreover, there were no significant differences in estimated glomerular filtration rate as well as frequency of acute cellular rejection, antibody-mediated rejection, infectious adverse events, malignancies, and post-operative bleeding between the two groups.ConclusionCurrently, ABO-IKT may be an acceptable treatment for patients with ESKD even at a low-volume transplant center.

Desensitization with the Use of an Antibody Removal–Free Protocol in ABO-Incompatible Kidney Transplant Recipients with a Low Anti-A/B Antibody Titer

BackgroundDesensitization for ABO-incompatible (ABOi) kidney transplantation mainly comprises removal of antibodies with the use of apheresis and suppression of antibody (Ab) production with the use of rituximab. This study aimed to estimate the outcomes of ABOi kidney transplantation with the use of an Ab removal–free protocol to avoid complications associated with apheresis. MethodsA total of 32 de novo consecutive adults who underwent ABOi living-donor kidney transplantation were retrospectively evaluated. Our protocol for ABOi recipients was stratified and fixed according to the anti-A/B Ab titer at baseline before desensitization. Desensitization was performed before transplantation with 0–4 sessions of plasmapheresis or double-filtration plasmapheresis and 1–2 administrations of rituximab at 100 mg/body. Graft outcomes, anti-A/B Ab titer, and plasma fibrinogen level were compared between the Ab removal (n = 21) and Ab removal–free (n = 11) groups. ResultsBetween the Ab removal and Ab removal–free groups, the graft loss rate (4.8% vs 0.0%; P = 1.0), acute rejection rate (19.0% vs 0.0%; P = .14), and serum creatinine level (1.74 vs 1.40 mg/dL, P = .53) were similar. The anti-A/B Ab titer was maintained at a low level until postoperative month 12 in both groups. The plasma fibrinogen level on the operation day was significantly lower in the Ab removal group than in the Ab removal–free group (163.4 vs 250.2 mg/dL; P < .001). ConclusionsDesensitization with the use of an antibody removal–free protocol for ABOi kidney transplant recipients with a low anti-A/B Ab titer can maintain excellent graft outcomes and avoid postoperative bleeding risk.

Successful launch of an ABO-incompatible kidney transplantation program to overcome the shortage of compatible living donors: experience at a single center .

ABO-incompatible (ABOi) kidney transplantation (KT) is being increasingly performed to overcome donor shortages. However, debate persists regarding the post-transplant outcomes of ABOi KT vs. that of ABO-compatible (ABOc) KT. A total 454 recipients who underwent living-donor KT (LDKT) between June 2010 and July 2014 at Severance Hospital (Seoul) were retrospectively reviewed. 100 ABOi and 354 ABOc KTs were compared. Recipients with a pretransplant positive crossmatch to their donors, pretransplant donor-specific anti-HLA antibody (DSA), or high panel reactive antibody (PRA ≥50%) were excluded from both the ABOi and ABOc KT groups. Finally, the authors compared the transplant outcomes of 95 of these ABOi KTs and 121 ABOc KTs performed over the same period. No significant difference in incidence of biopsy-proven acute rejection was observed between the ABOi and ABOc KT groups (p=0.230), and group glomerular filtration rate of ABOi KT was comparable to that of ABOc KT (p>0.05 at all time points). 3-year death-censored graft survival rates were similar (96.8 vs. 96.6%, respectively; p=0.801). However, the incidences of postoperative bleeding, cytomegalovirus infection, fungal infection, and serious infection rates were significantly higher after ABOi KT. In this study, graft renal function and survival after ABOi KT were excellent, and the incidence of acute rejection was similar to that of ABOc KT. However, efforts are needed to reduce hemorrhagic and infectious complications after ABOi KT. ABOi KT can be a good strategy to overcome ABO antibody barriers and relieve donor shortage. .

Risk factors for postoperative bleeding in ABO-incompatible kidney transplantation.

The outcome of ABO-incompatible kidney transplantation (ABOi KT) has improved and is now comparable to that of ABO-compatible kidney transplantation (ABOc KT). However, ABOi KT may be associated with a higher risk of postoperative bleeding than ABOc KT. Seventy patients with ABOi KT were divided into a bleeding group (n=9) and non-bleeding group (n=61). General, immunologic, and hematological characteristics were compared to identify the risk factors for postoperative bleeding. Pre-emptive transplantation and a high pre-transplant blood urea nitrogen level were more common in the bleeding group (p=0.0176 and 0.023, respectively). A high anti-ABO antibody titer after plasmapheresis (median, ≥16; p=0.0226), a low platelet count of ≤100000/mm(3) after plasmapheresis (p=0.0289), a prolonged activated partial thromboplastin time (p=0.0073), and impaired platelet function (p=0.0274) were associated with an increased risk of bleeding after ABOi KT. Postoperative bleeding after ABOi KT was difficult to control and increased the risk of immediate graft loss (p=0.015). Our results suggest that changes in coagulability associated with uremia and plasmapheresis may increase the risk of bleeding after ABOi KT.

ABO-Incompatible Kidney Transplantation Outcomes: A Single Center Experience.

Background In recent years, ABO-incompatible kidney donor protocols have been developed, allowing more patients access to kidneys from a living donor. However, it is still unclear what the long-term outcomes of ABO-incompatible kidney transplantation are. Methods We conducted a single center case control study comparing 10 ABO-incompatible (ABO-i) kidney transplantations to 40 ABO-compatible (ABO-c) kidney transplantations. Controls were matched by gender, age and follow-up period. ABO-i recipients were treated with a single dose of rituximab four weeks before transplantation and started triple immunosuppressive treatment (prednisone, mycophenolate mofetil and tacrolimus) two weeks before transplantation. All ABO-incompatible recipients received IVIG preoperatively. Immunoadsorption was conducted at least four times preoperatively, with additional sessions being performed if the target anti donor blood type IgG ≤ 1:8 had not been reached. Postoperatively, 3 immunoadsorptions were conducted. Results ABO-i and ABO-c patients were followed for a median period of 2,25 vs. 2,5 years respectively. There was no significant difference in patient and graft survival. Kidney function (as measured by creatinin clearance, MDRD and proteinuria) was also not significantly different, although there was a trend toward a lower kidney function in ABO-i patients. ABO-i patients had more biopsy-proven rejection episodes (50% in ABO-i vs. 15% in ABO-c, p=0,018) for which they received additional immunosuppressive treatment. This resulted in significantly more infections (1,7 infections per ABO-i patient vs. 0,9 infections per ABO-c patient, p=0,045). The number of days in the hospital in the first year post-transplantation was also higher in the ABO-i group (24 vs. 15,5 median days). In linear regression analysis, higher baseline anti donor blood type IgG were predictive of a lower kidney function during follow-up. Conclusion ABO-i transplantations can be performed successfully, without a significant difference in patient and graft survival after a median follow-up of 2,25 years. However, patients are at increased risk of rejections and infections. Patients with high anti donor blood type IgG are not suitable candidates for ABO-i kidney transplantation.

Outcome Comparison of ABO-Incompatible Kidney Transplantation With Low-Dose Rituximab and ABO-Compatible Kidney Transplantation: A Single-Center Experience

BackgroundThe development of immunosuppressive techniques has helped overcome the ABO incompatibility barrier. However, the outcomes of ABO-incompatible (ABOi) kidney transplantation remain a controversial issue with the advent of the anti-CD20 chimeric antibody rituximab. Herein, we report the outcomes of ABOi kidney transplantation with low-dose rituximab. Patients and MethodsBetween June 2006 and April 2013, 42 patients underwent living-related kidney transplantation at our hospital. The patients were divided into 2 groups: ABO-compatible (ABOc; n = 29) and ABOi kidney transplants using low-dose rituximab (100 mg/m2) without splenectomy (n = 13). The basic immunosuppression regimen (calcineurin inhibitor [CNI], mycophenolate mofetil [MMF], and steroids) was the same for both groups, except for the use of rituximab and therapeutic apheresis in the ABOi group. We compared post-transplantation renal function, incidents of virus infection, episodes of rejection, and graft survival between the 2 groups. ResultsIn our hospital, 30% of recipients received ABOi kidney transplants. The estimated glomerular filtration rate (eGFR) did not differ between the groups. Rejection episodes confirmed by biopsy in the ABOc and ABOi groups were 8 (28%) and 4 (31%) patients (P = .833), acute antibody-mediated rejection was observed in 1 (3.5%) and 2 (15%) patients (P = .165), and virus infection was observed in 14 (48%) and 3 (23%) patients (P = .252), respectively. The 5-year patient survival rate was 100% in both groups, and the 5-year graft survival rates were 95% for ABOc and 100% for ABOi transplants (P = .527). ConclusionsThese results suggest that the outcomes of ABOi kidney transplantation with low-dose rituximab are similar to those of ABOc kidney transplantation. Further study is necessary to address the efficacy and safety of ABOi kidney transplantation.

ABO-incompatible kidney transplantation in elderly patients over 60 years of age

IntroductionPatients aged 60 years and older represent the fastest-growing population with end-stage renal disease worldwide, and the need for a kidney transplant among this population is increasing. Due to the severe shortage of deceased donors in Japan, ABO-incompatible living donor kidney transplantation has been performed since the late 1980s. Excellent long-term outcomes have been achieved, and the rates of graft survival in these patients are currently similar to those in recipients of ABO-compatible grafts. However, the outcomes of ABO-incompatible kidney transplantation in elderly patients over 60 years of age have not been well studied yet.Patients and methodsWe studied 4 elderly kidney transplant patients who received their grafts from ABO-incompatible living donors at our institution between December 2006 and December 2011, focusing on the immunosuppressive protocols, complications and graft survivals. The mean observation period was 21.5 months (range, 8 months to 62 months). Our immunosuppressive protocols were as follows: to remove the anti-A/B antibodies, the patients underwent 4–8 sessions of double-filtration plasmapheresis and/or plasma exchange prior to kidney transplantation until the anti-A/B titers were less than 1:16. For the patients with low anti-A/B titers (<1:512), the immunosuppressive protocol consisted of a single dose of rituximab (150 mg/m2). The patients with high anti-A/B antibody titers (≥1:512) underwent splenectomy and received 2 doses of rituximab. The pretransplant immunosuppressive protocol included B-lymphocyte suppression with 4 weeks of mycophenolate mofetil (0.5 g/day for low-titer protocol and 1 g/day for high-titer protocol).ResultsAll 4 patients underwent successful transplantation. At the end of follow-up, their mean serum creatinine was 1.18 mg/dl. No patient experienced antibody-mediated rejection or acute cellular rejection. Late-onset neutropenia occurred in two cases. Two cases experienced cytomegalovirus reactivation by cytomegalovirus antigenemia. In one patient, diffuse hemorrhage required surgical intervention. However, there were no severe complications.ConclusionsAlthough a careful evaluation of patients is needed, ABO-incompatible kidney transplantation may become a viable treatment option for elderly patients with end-stage renal disease.