Outcome of the risk-stratified desensitization protocol in donor-specific antibody-positive living kidney transplant recipients: a retrospective study

Desensitization With Imlifidase for HLA-Incompatible Deceased Donor Kidney Transplantation: A Delphi International Expert Consensus

Highly sensitized (HS) patients in need of kidney transplantation (KTx) typically spend a longer time waiting for compatible kidneys, are unlikely to receive an organ offer, and are at increased risk of antibody-mediated rejection (AMR). Desensitization using imlifidase, which is more rapid and removes total body immunoglobulin G (IgG) to a greater extent than other methods, enables transplantation to occur between HLA-incompatible (HLAi) donor-recipient pairs and allows patients to have greater access to KTx. However, when the project was launched there was limited data and clinical experience with desensitization in general and with imlifidase specifically. Hence, this Delphi methodology was used to reach a consensus from a multi-disciplinary team (MDT) of experts from 15 countries on the management of HS patients undergoing imlifidase HLAi from a deceased donor (DD) KTx. This Delphi consensus provides clinical practice guidance on the use of imlifidase in the end-to-end management of HS patients undergoing an HLAi DD KTx and supports centers in the development of guidelines for the utilization and integration of imlifidase into clinical practice.

Outcomes of Kidney Transplantation in Highly HLA-Sensitized Patients Treated with Intravenous Immuno-Globulin, Plasmapheresis and Rituximab: A Meta-Analysis

(1) Background: We aimed to investigate the outcomes of human leukocyte antigen (HLA)-incompatible transplantation for patients who received desensitization with intravenous immunoglobulins (IVIg), plasmapheresis, and rituximab. (2) Methods: A comprehensive search of multiple electronic databases to identify studies that utilized desensitization was conducted. The random-effects model was used to calculate the pooled rates and the 95% confidence interval (CI). (3) Results: A total of 1517 studies were initially identified. From these, 16 studies met the inclusion criteria, encompassing 459 patients, with a mean age of 45 years, of whom 40.8% were male. CDC crossmatch was positive in 68.3% (95% CI: 43.5-85.8; I2 87%), and 89.4% (95% CI: 53.4-98.4%; I2 89.8%) underwent living-donor transplantation. The 1-year graft survival pooled rate was 88.9% (95% CI: 84.8-92; I2 0%) and the 5-year graft survival rate was 86.1% (95% CI: 81.2-89.9; I2 0%). The 1-year patient survival rate was 94.2% (95% CI: 91-96.3; I2 0%), and the 5-year patient survival rate was 88.9% (95% CI: 83.5-92.7%; I2 7.7%). The rate of antibody-mediated rejection was 37.7% (95% CI: 25-52.3; I2 80.3%), and the rate of acute cell-mediated rejection was 15.1% (95% CI: 9.1-24; I2 55%). (4) Conclusions: Graft and patient survival are favorable in highly sensitized patients who undergo desensitization using IVIg, plasmapheresis, and rituximab for HLA-incompatible transplantation.

Glycolysis Changes in Alloreactive Memory B Cells in Highly Sensitized Kidney Transplant Recipients Undergoing Desensitization Therapy

Despite the growing use of desensitization strategies, hyperimmune patients remain at high risk of antibody-mediated rejection suggesting that, even when donor-specific antibodies (DSA) are effectively depleted, anti-donor specific B cells persist. We included 10 highly sensitized recipients that underwent desensitization with plasmapheresis and B cell depletion prior to kidney transplantation. We quantified changes in DSA (luminex), total B-cell subsets (flow cytometry), anti-donor HLA B cells (fluorospot), and single-cell metabolism in serially collected samples before desensitization, at the time of transplant, and at 6 and 12 months thereafter. Desensitization was associated with a decrease in DSA and total memory B cell and naive B cell percentage, while plasma cells and memory anti-donor HLA circulating B cells persisted up to 12 months after transplant. At 12-month post-transplantation, memory B cells increased their glycolytic capacity, while proliferative KI67+ plasma cells modified their metabolism by increasing fatty acid and amino acid oxidation capacity and decreasing their glucose dependence. Despite effective DSA depletion, anti-donor B cells persist in kidney transplant recipients. Due to the reliance of these cells on glycolysis, glycolysis-targeting therapies might represent a valuable treatment strategy.

The medical cost and outcome of desensitization protocol in kidney transplantation recipients with high immunological risks

BACKGROUND

Kidney transplantation is a well-established alternative in renal replacement therapy. Compared with hemodialysis, low-immunological-risk kidney transplantation can reduce the medical treatment costs associated with end-stage renal disease. However, there are few reports on whether high-immunological-risk kidney transplantation reduces the financial burden on governments. We investigated the medical costs of high-immunological-risk kidney transplantation in comparison with the cost of hemodialysis in Japan.

METHODS

We compared the medical costs of high-immunological-risk kidney transplantation with those of hemodialysis. 15 patients who underwent crossmatch-positive and/or donor-specific antibody-positive kidney transplantations between 2020 and 2021 were enrolled in this study. The patients received intravenous immunoglobulin, plasmapheresis, and rituximab as desensitizing therapy.

RESULTS

Acute antibody-mediated rejection was detected in nine (60%) recipients, while there were no indications of graft function deterioration during the follow-up. For each patient, the transplant hospitalization cost was 38 428 ± 8789 USD. However, the cumulative costs were 59 758 ± 10 006 USD and 79 781 ± 16 366 USD, at 12 and 24 months, respectively. Compared with hemodialysis (34 286 USD per year), high-immunological-risk kidney transplantation tends to be expensive in the first year, but the cost is likely to be lower than that of hemodialysis after 3 years.

CONCLUSIONS

Although kidney transplantation is initially expensive compared with hemodialysis, the medical cost becomes advantageous after 3 years even in kidney transplant recipients with high immunological risk.

A bibliometric and knowledge-map analysis of antibody-mediated rejection in kidney transplantation

OBJECTIVES

Antibody-mediated rejection (AMR) is a large obstacle to the long-term survival of allograft kidneys. It is urgent to find novel strategies for its prevention and treatment. Bibliometric analysis is helpful in understanding the directions of one field. Hence, this study aims to analyze the state and emerging trends of AMR in kidney transplantation.

METHODS

Literature on AMR in kidney transplantation from 1999 to 2022 was collected from the Web of Science Core Collection. HistCite (version 12.03.17), CiteSpace (version 6.2.R2), Bibliometrix 4.1.0 Package from R language, and Gephi (https://gephi.org) were applied to the bibliometric analysis of the annual publications, leading countries/regions, core journals, references, keywords, and trend topics.

RESULTS

A total of 2522 articles related to AMR in kidney transplantation were included in the analysis and the annual publications increased year by year. There were 10874 authors from 118 institutions located in 70 countries/regions contributing to AMR studies, and the United States took the leading position in both articles and citation scores. Halloran PF from Canada made the most contribution to AMR in kidney transplantation. The top 3 productive journals, American Journal of Transplantation, Transplantation, and Transplantation Proceedings, were associated with transplantation. Moreover, the recent trend topics mainly focused on transplant outcomes, survival, and clinical research.

CONCLUSIONS

North American and European countries/regions played central roles in AMR of kidney transplantation. Importantly, the prognosis of AMR is the hotspot in the future. Noninvasive strategies like plasma and urine dd-cfDNA may be the most potential direction in the AMR field.

A modified perioperative regimen for deceased donor kidney transplantation in presensitized recipients without prior desensitization therapy

Background

Renal transplantation in HLA-presensitized recipients entails an increased risk of antibody-mediated rejection (AMR) and graft loss. There is currently no accepted standard treatment protocol that can help transplant surgeons safely perform deceased donor (DD) kidney transplantation in presensitized patients without pretransplant desensitization.

Methods

Fifty-one panel-reactive antibody (PRA)-positive recipients and 62 PRA-negative retransplant recipients (control) who received DD renal transplantation were included. Patients in the presensitized group (donor-specific antibody [DSA]-positive, n=25; DSA-negative, n=26) without desensitization received a modified perioperative treatment starting on day 0 or -1 with rituximab, thymoglobulin, and low daily doses of intravenous immunoglobulin (IVIG, 10-20 g/d, for 14 days). Plasmapheresis was performed once before surgery in DSA-positive recipients.

Results

The median follow-up time was 51 months in the presensitized group and 41 months in the control group. The incidence of early acute rejection (AR) and AMR (including mixed rejection) was 35.3% and 13.7% in the presensitized group, respectively, significantly higher than in the control group (14.5% and 1.6%, respectively). Within the presensitized group, the DSA-positive subgroup had more AMR than the DSA-negative subgroup (24.0% vs. 3.8%), but the incidence of T cell-mediated rejection was comparable (20.0% vs. 23.4%). In the presensitized group, all rejections were successfully reversed, and graft function remained stable during follow-up. The 1-year and 3-year survival rates of the grafts and recipients in this group were 98.0%.

Conclusion

With a modified IVIG-based perioperative regimen, excellent intermediate-term graft and recipient survival outcomes can be achieved in presensitized patients who received DD kidney transplantation without prior desensitization.

Virtual crossmatching and epitope analysis in kidney transplantation: What the physician involved in kidney transplantation should know?

Solid-phase single antigen bead (SAB) assay for detection of anti-human leukocyte antigen (HLA) antibodies and high-resolution HLA typing have enabled tremendous progress in virtual crossmatch (VXM) technology in recent years. However, misinterpretation of the SAB assay may result in detrimental consequences after kidney transplantation. Meanwhile, epitope analysis could be an effective method to estimate immunizing eplets, which may provide ancillary information for better understanding of the SAB assay. To perform epitope analysis appropriately, it is necessary to understand the basic principles related to histocompatibility testing and the characteristics of the SAB assay. Therefore, knowledge of the properties and limitations of the SAB assay is critical. In this review, we aim to describe the fundamental concepts regarding immunobiological assessment, including HLA, anti-HLA antibodies, and SAB assay, and explain epitope analysis using examples.

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.

Influence of a low-dose tacrolimus protocol on the appearance of de novo donor-specific antibodies during 7 years of follow-up after renal transplantation

BACKGROUND

Tacrolimus (TAC) is a key immunosuppressant drug for kidney transplantation (KTx). However, the optimal serum trough level of TAC for good long-term outcomes remains unclear. This study aimed to investigate the relationship between the maintenance TAC trough level and the appearance of de novo donor-specific anti-human leukocyte antigen (HLA) antibodies (dnDSAs).

METHODS

A total of 584 KTx recipients were enrolled in this study, of whom 164 developed dnDSAs during the follow-up period and 420 did not.

RESULTS

We found no significant relationship between TAC trough level during the follow-up period and dnDSA incidence. Patients who developed dnDSAs had a significantly greater number of HLA-A/B/DR mismatches (3.4 ± 1.3 versus 2.8 ± 1.5; P < 0.001), were more likely to have preformed DSAs (48.2% versus 27.1%; P < 0.001) and showed poor allograft outcome.

CONCLUSIONS

There was no clear relationship between TAC trough level and dnDSA incidence for KTx recipients whose TAC trough levels were kept within the narrow range of 4-6 ng/mL during the immunosuppression maintenance period.

Desensitization Regimen Consisting of High-Dose Intravenous Immunoglobulin, Plasmapheresis, and Rituximab (an Anti-CD20 Antibody), Without Eculizumab and/or Bortezomib, in 41 Highly Sensitized Kidney Transplant Recipients

OBJECTIVES

Antibody-mediated rejection in patients with positive crossmatches can be severe and result in sudden onset of oliguria, leading to graft loss. In an attempt to prevent posttransplant oliguria, we adopted a preoperative desensitization protocol involving the use of high-dose intravenous immunoglobulin/plasmapheresis and the anti-CD20 antibody, rituximab, in 41 transplant recipients with positive crossmatch test results.

MATERIALS AND METHODS

We retrospectively examined the clinical courses of the 41 kidney transplant recipients, paying special attention to renal graft function, urine volume, and changes in the titers of donor-specific antibodies.

RESULTS

Four grafts were lost during an average of 4.5-year follow-up. Average graft function was excellent, with a serum creatinine level of 1.3 ± 0.4 mg/dL. Sufficient urine output, with no oliguria or anuria, was achieved postoperatively in 40 of the 41 patients. However, among the 34 patients who underwent graft biopsies, the biopsies revealed acute antibody-mediated rejection in 21 patients (62%), and chronic antibodymediated rejection in 10 patients (30%).

CONCLUSIONS

The high-dose intravenous immunoglobulin treatment included in our desensitization protocol was shown to be safe and effective for achieving successful transplant outcomes and allowed the avoidance of more aggressive B-cell-targeted treatments, such as C5 inhibitors and/or proteosome inhibitors, for preventing posttransplant oliguria and anuria.

Serum creatinine level at 1-month posttransplant can independently predict long-term graft survival and functional status

Background

After the year 2000, kidney transplants with high immunologic risk and deceased donors increased rapidly in Korea. At the same time, the medical community developed special pretransplant and early posttransplantation management protocols. Our team evaluated the effect of early graft stabilization on long-term graft survival and functional status using databases from a high-volume kidney transplantation center.

Methods

We included 1,895 kidney transplant patients from a total of 1,976 performed between 2005 and 2018. Early graft failure within 1 month (n=9), loss to follow-up (n=2), pediatric recipient or donor (n=37), and combined organ transplantation (n=33) cases were excluded. We grouped the cases at 1-month posttransplantation by serum creatinine quantiles (1.0 mg%, 1.23 mg%, and 1.52 mg%).

Results

After an average of 95 months of follow-up (maximum 189 months), the high-serum creatinine group (4th quantile) showed significantly poorer graft survival than other groups (1st to 3rd quantile) (P<0.05). In multiple Cox regression analysis, a high serum creatinine level (4th quantile) at 1-month posttransplant is an independent risk factor for graft failure with a hazard ratio of 1.799 (P=0.013). The quantile group by serum creatinine shows a persistent, significant difference of functional graft status (glomerular filtration rate by Modification of Diet in Renal Disease method) among quantile groups beyond ten years posttransplant.

Conclusions

Serum creatinine level at 1-month posttransplant is a strong independent predictor of graft survival and functional graft status beyond ten years posttransplant.

Transplant outcomes in positive complement-dependent cytotoxicity- versus flow cytometry-crossmatch kidney transplant recipients after successful desensitization: a retrospective study

BACKGROUND

Despite the obvious survival benefit compared to that among waitlist patients, outcomes of positive crossmatch kidney transplantation (KT) are generally inferior to those of human leukocyte antigen (HLA)-compatible KT. This study aimed to compare the outcomes of positive complement-dependent cytotoxicity (CDC) crossmatch (CDC + FC+) and positive flow cytometric crossmatch (CDC-FC+) with those of HLA-compatible KT (CDC-FC-) after successful desensitization.

METHODS

We retrospectively analyzed 330 eligible patients who underwent KTs between June 2011 and August 2017: CDC-FC- (n = 274), CDC-FC+ (n = 39), and CDC + FC+ (n = 17). Desensitization protocol targeting donor-specific antibody (DSA) involved plasmapheresis, intravenous immunoglobulin (IVIG), and rituximab with/without bortezomib for positive-crossmatch KT.

RESULTS

Death-censored graft survival and patient survival were not different among the three groups. The median estimated glomerular filtration rate was significantly lower in the CDC + FC+ group than in the compatible group at 6 months (P < 0.001) and 2 years (P = 0.020). Biopsy-proven rejection within 1 year of CDC-FC-, CDC-FC+, and CDC + FC+ were 15.3, 28.2, and 47.0%, respectively. Urinary tract infections (P < 0.001), Pneumocystis jirovecii pneumonia (P < 0.001), and cytomegalovirus viremia (P < 0.001) were more frequent in CDC-FC+ and CDC + FC+ than in CDC-FC-.

CONCLUSIONS

This study showed that similar graft and patient survival was achieved in CDC-FC+ and CDC + FC+ KT compared with CDC-FC- through DSA-targeted desensitization despite the higher incidence of rejection and infection than that in compatible KT.

Prognostic value of C3d-fixing, preformed donor-specific antibodies in crossmatch-positive living kidney transplantation

The occurrence of acute antibody-mediated rejection (ABMR) is higher in flow cytometric crossmatch (FCXM)-positive patients despite desensitization. Accumulating evidence suggests a correlation between the complement-binding ability of donor-specific antibodies (DSAs) and the risk of ABMR. Here, we investigated the correlation between complement C3d-fixing ability of preformed DSA and ABMR risk, the efficacy of a desensitization protocol for patients with C3d-fixing DSA, and the risk of ABMR in 21 DSA- and FCXM-positive patients. We retrospectively analyzed the C3d-fixing ability and mean fluorescence intensity (MFI) of preformed DSA before and after desensitization. Six patients had non-C3d-fixing DSA and 15 had C3d-fixing DSA. The presence of C3d-fixing DSA before desensitization was correlated with the incidence of acute ABMR within 1 year after transplantation (p = .04) and chronic ABMR (p = .03). Moreover, the MFI of preformed DSA differed between responder and non-responder C3d-fixing DSA after desensitization (p < .0001). The C3d-fixing ability of preformed DSA with low MFI disappeared after desensitization. These results indicate that measuring DSA C3d-fixing ability may identify patients with a high risk of ABMR, especially before desensitization. CLINICAL TRIAL NOTATION: UMIN Clinical Trials Registry (UMIN-CTR) number: UMIN000033449.