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.

The First North American Experience Using Glycosorb Immunoadsorption Columns for Blood Group-Incompatible Kidney Transplantation

Background:

Blood group incompatibility (ABOi) is the most common barrier to living donor kidney transplantation. Options for such recipients include kidney paired donation (KPD) or desensitization methodology to reduce blood antibody response.

Objective:

The objective of this study is to report on the first North America experience in ABOi living donor kidney transplantation using Glycosorb ABO immunoadsorption columns.

Design:

Retrospective observational cohort study.

Setting:

Renal transplant program at St. Michael’s Hospital, Unity Health Toronto, University of Toronto.

Patients:

Twenty-six ABOi living donor transplants from August 2011 through February 2020 were undertaken at our center.

Measurements:

Renal allograft and patient survival postdesensitization for ABOi living donor transplants and isohemagglutinin titer reduction.

Methods:

Preoperative immunosuppressive regimen consisted of a single dose of Rituximab 375 mg/m² IV on day −28; tacrolimus, mycophenolic acid, and prednisone to start on day −7. Immunoadsorption treatments with Glycosorb A or B columns were performed on day −7 through day −1 based on anti-A or anti-B titers on Spectra Optia Apheresis System. Immunosuppression included basiliximab, solumedrol followed by oral prednisone, once-daily tacrolimus, and mycophenolic acid. The mean follow-up was 53 months (3-96 months).

Results:

A total of 26 individuals underwent an attempt at desensitization of whom 24 patients underwent immediate transplant. One patient had a rebound in titers and subsequently was transplanted from a blood group compatible living donor. A second patient had an unrelated medical issue and desensitization was discontinued. Five-year patient survival was 96% and death censored allograft survival was 92%. Posttransplant anti-A or anti-B titers were monitored daily for the first 7 days posttransplant and every 2 days from days 7 to 14. There were no acute rejections seen in this cohort of transplant recipients.

Limitations:

As our protocol was first initiated as proof of concept, a few recipients had low initial isohemagglutinin titers. This may have contributed to improved clinical outcomes.

Conclusions:

ABO column immunoadsorption with specific columns is a safe and effective method for ABOi living donor kidney transplantation, and an option when KPD is less than ideal.

Trial not registered as this was a retrospective cohort review.

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

BACKGROUND:

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

AIMS AND OBJECTIVES:

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

METHODS:

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

RESULTS:

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

CONCLUSION:

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

Regulatory B cells and advances in transplantation

The effects of B cell subsets with regulatory activity on the immune response to an allograft have evoked increasing interest. Here, we summarize the function and signaling of regulatory B cells (Bregs) and their potential effects on transplantation. These cells are able to suppress the immune system directly via ligand-receptor interactions and indirectly by secretion of immunosuppressive cytokines, particularly IL-10. In experimental animal models, the extensively studied IL-10-producing B cells have shown unique therapeutic advantages in the transplant field. In addition, adoptive transfer of B cell subsets with regulatory activity may reveal a new approach to prolonging allograft survival. Recent clinical observations on currently available therapies targeting B cells have revealed that Bregs play an important role in immune tolerance and that these cells are expected to become a new target of immunotherapy for transplant-related diseases.

Outcomes Following ABO-Incompatible Kidney Transplantation Performed After Desensitization by Nonantigen-Specific Immunoadsorption

BACKGROUND

For desensitization of ABO-incompatible kidney transplant recipients we recently proposed nonantigen-specific immunoadsorption (IA) and rituximab.

METHODS

We now compared clinical outcomes of 34 ABO-incompatible living-donor kidney recipients who were transplanted using this protocol with that of 68 matched ABO-compatible patients. In addition, we analyzed efficacy and cost of nonantigen-specific as compared to blood group antigen-specific IA.

RESULTS

Before desensitization, the median isoagglutinin titer of 34 ABO-incompatible patients was 1:64 (Coombs technique). Patients received a median of 7 preoperative IA treatments. Twenty-four patients had a median of 2 additional plasmapheresis treatments to reach the preoperative target isoagglutinin titer of 1:8 or less. After a median postoperative follow-up of 22 months, overall graft survival in the ABO-incompatible group was not significantly different from that in ABO-compatible patients (log-rank P = 0.20), whereas patient survival tended to be lower (log-rank P = 0.05). The incidence of rejection episodes was 15% in both groups. The ABO-incompatible kidney recipients had a higher incidence of BK virus replication (P = 0.04) and nephropathy (P = 0.01) and showed more often colonization with multidrug resistant bacteria (P = 0.02). In comparison to blood group antigen-specific IA, nonantigen-specific IA showed equal efficacy but was associated with reduction in cost.

CONCLUSIONS

Clinical outcomes of ABO-incompatible patients desensitized with a nonantigen-specific IA device and rituximab do not differ from that of matched ABO-compatible patients although a trend toward reduced patient survival was noted. Special attention must be paid to the higher incidence of BK virus infection in recipients of ABO-incompatible grafts.

Current progress in ABO-incompatible kidney transplantation

ABO-incompatible kidney transplantation (ABOi KT) was introduced to expand the donor pool and minimize shortage of kidneys for transplantation. Because improved outcomes of ABOi KT were reported in Japan in the early 2000s, the number of ABOi KTs has been increasing worldwide. In addition, a better understanding of immune pathogenesis and subsequent aggressive immunosuppression has helped to make effective desensitization protocols. Current strategies of ABOi KT consist of pretransplant antibody removal using plasmapheresis or immunoadsorption to prevent hyperacute rejection and potent maintenance immunosuppression, such as tacrolimus and mycophenolate mofetil, to inhibit antibody-mediated rejection. Recent outcomes of ABOi KT are comparable with ABO-compatible KT. However, there are still many problems to be resolved. Very high anti-ABO antibody producers are difficult to desensitize. In addition, ABOi KT is associated with an increased risk of infection and possibly malignancy due to aggressive immunosuppression. Optimization of desensitization and patient-tailored immunosuppression protocols are needed to achieve better outcomes of ABOi KT. This review provides an overview of the history, immune mechanism, immunosuppressive protocol, outcomes, current obstacles, and future perspectives in ABOi KT.

An update on ABO-incompatible kidney transplantation

ABO-incompatible kidney transplantation is nowadays a well-established procedure to expand living donor transplantation to blood group incompatible donor/recipient constellations. In the last two decades, transplantation protocols evolved to more specific isohaemagglutinin elimination techniques and established competent antirejection protection protocols without the need of splenectomy. ABOi kidney transplantation associated accommodation despite isohaemagglutinin reappearance, C4d positivity of peritubular capillaries as well as the increased incidence of bleeding complications is currently under intense investigation. However, most recent data show excellent graft survival rates equivalent to ABO-compatible kidney transplantation outcome.

ABO-incompatible kidney transplantation using regenerative selective immunoglobulin adsorption

BACKGROUND

ABO-incompatible (ABOi) kidney transplantation is an established procedure relying on the removal of donor-specific isoagglutinine antibodies as part of the recipient preconditioning. At present, current protocols using immunoadsorption apply a single-use selective carbohydrate isoagglutinine adsorber. A regenerative and selective immunoglobulin immunoadsorption could be an alternative but has not been reported for ABOi transplantation.

METHODS

Eight patients were treated with the commonly used isoagglutinine carbohydrate epitope adsorber and seven with a regenerative polyclonal sheep anti-immunoglobulin adsorber as part of the preconditioning for ABOi kidney transplantation. An IgG-isoagglutinine titer of less or equal 1:4 qualified for transplantation. Treatment safety, efficiency, length of desensitization, number of postoperative immunoadsorptions, and allograft outcome were retrospectively compared.

RESULTS

With the use of the immunoglobulin adsorber the median initial isoagglutinine IgG titers of 1:64 (range 1:32-1:256) were lowered to the target of 1:4 preoperatively with a mean of 6.2 immunoadsorptions (range 5-11). Mean IgG/IgM titer step reduction per IA was 1.98/1.21 for (range 0-4/0-4) and mean titer step rebound 1.31/0.82 (range 0-4/0-3), respectively. The number of immunoadsorptions and length of desensitization was not different from the use of the specific isoagglutinine adsorbers. After transplantation, no rejection occurred and only one postoperative immunoadsorption was necessary. No adverse events in relation to immunoadsorption were observed. Graft function was comparable to the isoagglutinine adsorber group.

CONCLUSION

These data suggest that ABOi kidney transplantation can be performed safely and effectively with a selective regenerative immunoglobulin immunoadsorber.

Effect of Apheresis for ABO and HLA Desensitization on Anti-Measles Antibody Titers in Renal Transplantation

Desensitization strategies for ABO-incompatible renal transplants with plasma exchange (PE) or specific immunoadsorption (IA) decrease immunoglobulin levels. After recent measles outbreak and decreasing vaccination rates, we studied the impact of apheresis on anti-measles antibodies. Anti-measles antibodies were measured before desensitization, before transplantation and during followup in 12 patients with ABO incompatibility (2x PE only, 8x IA only, and 2x IA and PE) and 3 patients with donor-specific HLA antibodies (all PE). Patients received rituximab, IVIG, and standard immunosuppressive therapy. All patients had detectable anti-measles antibodies before desensitization (mean 3238 mU/l, range 560–8100). After 3–6 PE sessions, titers decreased significantly to 1710 mU/l (P < 0.05), in one patient to nondetectable values, while IA only maintained protective titers. After a median followup of 64 days, anti-measles antibodies returned to baseline in all patients. Immunity against measles was temporarily reduced by apheresis but remained detectable in most patients at time of transplantation. Desensitization maintains long-term protective immunity against measles.

Increase of infectious complications in ABO-incompatible kidney transplant recipients--a single centre experience

BACKGROUND

Due to the shortage of deceased donors ABO-incompatible (ABOi) living kidney transplantation has become a popular alternative to deceased kidney transplantation. In recent years, recipient desensitization with a combination of anti-CD20 treatment (rituximab), antigen-specific immunoadsorptions (IA) and intravenous immunoglobulin (IVIG), led to promising short-term and intermediate-term results. However, little is known about the impact of this intensified desensitization protocol on the risk of surgical and infectious complications.

METHODS

We retrospectively analysed 21 consecutive recipients who underwent ABOi renal transplantation. Pre-transplant desensitization included administration of rituximab (375 mg/m(2)), mycophenolate mofetil (MMF), tacrolimus and prednisolone 4 weeks prior of scheduled transplantation as well as IA and IVIG. Forty-seven patients who underwent ABO-compatible (ABOc) renal transplantation served as the control group. Medical records and electronic databases were reviewed for patient and graft survival, renal function, rate of rejections, viral and bacterial infections as well as for surgical complications (SCs) post-transplantation.

RESULTS

All patients showed an immediate graft function. During a mean follow-up of 15.7 ± 8.3 months (interquartile range 11.9) patient survival was 95 and 98% in the ABOi and ABOc group, respectively. Allograft survival and function, as assessed by serum creatinine levels and calculated glomerular filtration rate at 1 year, did not differ between ABOi and ABOc recipients. Furthermore, the rate of biopsy-proven acute rejections was comparable between the two groups. However, there was a trend towards more SCs within the ABOi group (29 versus 11%, non-significant). In addition, the rate of viral infections including cytomegalovirus, Herpes simplex virus, Varicella zoster virus and polyoma virus was significantly increased among the ABOi recipients (50 versus 21%; P = 0.038) despite comparable tacrolimus trough levels and MMF and steroid doses.

CONCLUSIONS

Our results, in line with the extended experience of other groups, demonstrate favourable short-term allograft survival and function after ABOi renal transplantation after desensitization with antigen-specific IA, IVIG and rituximab. However, the intensified desensitization was associated with an increased risk of infectious complications. This observation prompted us to briefly escalate the desensitization protocol in ABOi kidney recipients in our centre.

Exchange living donor liver transplantation to overcome ABO incompatibility in adult patients

ABO incompatibility is the most common cause of donor rejection during the initial screening of adult patients with end-stage liver disease for living donor liver transplantation (LDLT). A paired donor exchange program was initiated to cope with this problem without ABO-incompatible LDLT. We present our results from the first 6 years of this exchange adult LDLT program. Between July 2003 and June 2009, 1351 adult LDLT procedures, including 16 donor exchanges and 7 ABO-incompatible LDLT procedures, were performed at our institution. Initial donor-recipient ABO incompatibilities included 6 A to B incompatibilities, 6 B to A incompatibilities, 1 A to O incompatibility, 1 A+O (dual graft) to B incompatibility, 1 O to AB incompatibility, and 1 O to A incompatibility. Fourteen matches (87.5%) were ABO-incompatible, but 2 (12.5%) were initially ABO-compatible. All ABO-incompatible donors were directly related to their recipients, but 2 compatible donors were each undirected and unrelated directed. After donor reassignment through paired exchange (n = 7) or domino pairing (n = 1), the donor-recipient ABO status changed to A to A in 6, B to B in 6, O to O in 1, A to AB in 1, A+O to A in 1, and O to B in 1, and this made all matches ABO-identical (n = 13) or ABO-compatible (n = 3). Two pairs of LDLT operations were performed simultaneously on an elective basis in 12 and on an emergency basis in 4. All donors recovered uneventfully. Fifteen of the 16 recipients survived, but 1 died after 54 days. In conclusion, an exchange donor program for adult LDLT appears to be a feasible modality for overcoming donor-recipient ABO incompatibility.

[Extending the donor pool in renal transplantation]

The number of patients on the renal transplant waiting list has remained constantly high. In this article we highlight two strategies to extend the donor pool and focus on AB0 incompatible and cross-over renal transplantation. Increased immunologic knowledge and improved therapeutic management have facilitated successful AB0 incompatible renal transplantation with very good long-term results. However, this method has only been applied in very few German transplant centers and should be explored further. The term cross-over transplantation implies the exchange of organs between two otherwise incompatible couples enabling compatible transplantation in both couples. The German transplantation law allows only living transplantation in emotionally related couples. However, in specific cases of close interpersonal relationships cross-over transplantation between two couples is acceptable.