Infection Risk in the First Year After ABO-incompatible Kidney Transplantation: A Nationwide Prospective Cohort Study

A comparative study on outcomes of ABO-incompatible kidney transplants between robot-assisted vs. open surgery-propensity score-matched analysis: a retrospective cohort study

BACKGROUND

Robot-assisted kidney transplantation (RAKT) is increasingly being adopted worldwide. Despite this growing interest, there remains a notable gap in the literature, especially concerning its effectiveness in immunologically high-risk patients compared to conventional open kidney transplantation (OKT). This study investigates the viability and success of RAKT in comparison with OKT, particularly for recipients with ABO incompatibility (ABOi).

METHODS

This retrospective, single-center study included 239 living-donor transplants between October 2020 and February 2023, with 210 patients undergoing ABOi-OKT and 29 undergoing ABOi-RAKT. A composite of biopsy-proven acute rejection (BPAR), graft failure, and the development of de novo donor-specific antibodies was analyzed through univariate and multivariate models. Propensity score matching (PSM) was utilized to ensure a balanced comparison between the two groups. Following PSM, a total of 131 cases in the OKT group and 26 cases in the RAKT group were analyzed.

RESULTS

After PSM, the mean recipient age was 48.56 years for OKT and 47.96 years for RAKT. Both groups had comparable one-year (RAKT: 92.4%, OKT: 93.1%) and two-year BPAR-free survival rates (RAKT: 92.4%, OKT: 91.9%). Mean estimated glomerular filtration rate values were similar at 12 months post-transplant (RAKT: 62.15 ml/min/1.73 m², OKT: 64.53 ml/min/1.73 m²). Operative times were significantly longer for RAKT (291.42 vs. 150.81 min, p < 0.001), while cold ischemic time was also longer for RAKT (119.77 vs. 47.22 min, p < 0.001). Hospital stays were shorter for RAKT (median 6 vs. 8 days, p < 0.001). There was no significant difference in the composite outcome of BPAR, graft failure, and de novo donor-specific antibodies between the two groups (HR 0.858, 95% CI: 0.180-4.096, p = 0.848).

CONCLUSIONS

RAKT is a safe and effective alternative to OKT in ABOi patients, demonstrating similar perioperative outcomes, graft survival rates, and renal function. The application of ropensity score matching analysis strengthens the reliability of these findings, confirming RAKT's viability for high-risk kidney transplant recipients.

TRIAL REGISTRATION

The clinical trial associated with this study was registered on 2024-02-24 with the Clinical Trial Number NCT06287008|| https://www.

CLINICALTRIALS

gov/ ).

Recipient donor sex combinations in solid organ transplantation and impact on clinical outcome: A scoping review

INTRODUCTION

Solid organ transplantation (SOT) is a lifesaving treatment for end-stage organ failure. Although many factors affect the success of organ transplantation, recipient and donor sex are important biological factors influencing transplant outcome. However, the impact of the four possible recipient and donor sex combinations (RDSC) on transplant outcome remains largely unclear.

METHODS

A scoping review was carried out focusing on studies examining the association between RDSC and outcomes (mortality, graft rejection, and infection) after heart, lung, liver, and kidney transplantation. All studies up to February 2023 were included.

RESULTS

Multiple studies published between 1998 and 2022 show that RDSC is an important factor affecting the outcome after organ transplantation. Male recipients of SOT have a higher risk of mortality and graft failure than female recipients. Differences regarding the causes of death are observed. Female recipients on the other hand are more susceptible to infections after SOT.

CONCLUSION

Differences in underlying illnesses as well as age, immunosuppressive therapy and underlying biological mechanisms among male and female SOT recipients affect the post-transplant outcome. However, the precise mechanisms influencing the interaction between RDSC and post-transplant outcome remain largely unclear. A better understanding of how to identify and modulate these factors may improve outcome, which is particularly important in light of the worldwide organ shortage. An analysis for differences of etiology and causes of graft loss or mortality, respectively, is warranted across the RDSC groups.

PRACTITIONER POINTS

Recipient and donor sex combinations affect outcome after solid organ transplantation. While female recipients are more susceptible to infections after solid organ transplantation, they have higher overall survival following SOT, with causes of death differing from male recipients. Sex-differences should be taken into account in the post-transplant management.

A Multicenter Retrospective Cohort Study on Management Protocols and Clinical Outcomes After ABO-incompatible Kidney Transplantation in India

BACKGROUND

There is no robust evidence-based data for ABO-incompatible kidney transplantation (ABOiKT) from emerging countries.

METHODS

Data from 1759 living donor ABOiKT and 33 157 ABO-compatible kidney transplantations (ABOcKT) performed in India between March 5, 2011, and July 2, 2022, were included in this retrospective, multicenter (n = 25) study. The primary outcomes included management protocols, mortality, graft loss, and biopsy-proven acute rejection (BPAR).

RESULTS

Protocol included rituximab 100 (232 [13.18%]), 200 (877 [49.85%]), and 500 mg (569 [32.34%]); immunoadsorption (IA) (145 [8.24%]), IVIG (663 [37.69%]), and no induction 200 (11.37%). Mortality, graft loss, and BPAR were reported in 167 (9.49%), 136 (7.73%), and 228 (12.96%) patients, respectively, over a median follow-up of 36.3 mo. In cox proportional hazard model, mortality was higher with IA (hazard ratio [HR]: 2.53 [1.62-3.97]; P  < 0.001), BPAR (HR: 1.83 [1.25-2.69]; P  = 0.0020), and graft loss (HR: 1.66 [1.05-2.64]; P  = 0.0310); improved graft survival was associated with IVIG (HR: 0.44 [0.26-0.72]; P  = 0.0010); higher BPAR was reported with conventional tube method (HR: 3.22 [1.9-5.46]; P  < 0.0001) and IA use (HR: 2 [1.37-2.92]; P  < 0.0001), whereas lower BPAR was reported in the prepandemic era (HR: 0.61 [0.43-0.88]; P  = 0.008). Primary outcomes were not associated with rituximab dosing or high preconditioning/presurgery anti-A/anti-B titers. Incidence of overall infection 306 (17.39%), cytomegalovirus 66 (3.75%), and BK virus polyoma virus 20 (1.13%) was low. In unmatched univariate analysis, the outcomes between ABOiKT and ABOcKT were comparable.

CONCLUSIONS

Our largest multicenter study on ABOiKT provides insights into various protocols and management strategies with results comparable to those of ABOcKT.

Impact of Infection-Related Immunosuppressant Reduction on Kidney Transplant Outcomes: A Retrospective Study Considering the Temporal Dynamics of Immunosuppressive Requirements

Immunosuppressant reduction (ISR) is a common treatment for kidney transplant recipients experiencing infections, but its impacts on kidney transplant outcomes remains unclear. This retrospective single-center study included 300 patients who underwent kidney transplantation between January 2017 and April 2020. The post-transplant timeline was divided into four distinct phases: ≤1 month, 2-6 months, 7-12 months, and >12 months. Patients were categorized based on the presence of clinically relevant infections and whether they received ISR. Significant differences were observed in the spectrum of clinically relevant infections across the post-transplant phases. During the ≤1 month phase, primary infections were associated surgical operation, such as urinary tract infections involving Enterococcus spp. and Candida spp. Cytomegalovirus and BK polyomavirus (BKPyV) infections increased during the 2-6 months and 7-12 months periods. Approximately one-third of patients experienced ISR due to infection, with BKPyV infections being the primary causes. Recipients who experienced their first ISR due to infection between 2-6 months and 7-12 months had worse graft survival comparing with patients without any infections. ISR due to infections between 2 and 6 months was associated with a higher risk of rejection. Tailored ISR strategies should be developed according to temporal dynamics of immunosuppressive intensity to prevent rejection.

Advancement in preoperative desensitization therapy for ABO incompatible kidney transplantation recipients

ABO incompatibility has long been considered an absolute contraindication for kidney transplantation. However, with the increasing number of patients with ESRD in recent years, ABO-incompatible kidney transplantation (ABOi-KT) has expanded the types of donors by crossing the blood group barrier through preoperative desensitization therapy. At present, the desensitization protocols consist of removal of preexisting ABO blood group antibody titers and prevention of ABO blood group antibody return. Studies have suggested similar patient and graft survival among ABOi-KT and ABOc-KT recipients. In this review, we will summarize the effective desensitization regimens of ABOi-KT, aiming to explore effective ways to improve the success rate and the long-term survival rate of ABOi-KT recipients.

Updated management for antibody-mediated rejection: opportunity to prolong kidney allograft survival

PURPOSE OF REVIEW

Antibody-mediated rejection (ABMR) is an important barrier to achieve long-term kidney allograft survival. Human leukocyte antibody (HLA)-incompatibility and ABO-incompatibility are the two main mechanisms of ABMR. Nevertheless, the advances in managing ABMR have changed the paradigm for kidney transplantation. This review aimed to emphasize the HLA-incompatibility and ABO-incompatibility kidney transplant and update the management of ABMR.

RECENT FINDINGS

HLA-incompatibility kidney transplantation is a strong risk factor for ABMR. Donor-specific antibody (DSA) is a surrogate biomarker that prevents long-term allograft survival. The standard treatment for ABMR has unfavorable results. New drugs that target the B cell are a promising approach to treat ABMR. In the past, ABO-incompatibility kidney donor was an absolute contraindication but now, it is widely accepted as an alternative organ resource. The advancement of ABO antibody removal and B-cell depletion therapy has been successfully developed. ABO isoagglutination remains the main biomarker for monitoring ABMR during the transplantation process. C4d staining without inflammation of the kidney allograft is the marker for the accommodation process.

SUMMARY

With the shortage of organ donors, transplant experts have expanded the organ resources and learned how to overcome the immunological barriers by using novel biomarkers and developing new treatments that support long-term graft survival.

Evaluating the Potential for ABO-incompatible Islet Transplantation: Expression of ABH Antigens on Human Pancreata, Isolated Islets, and Embryonic Stem Cell-derived Islets

BACKGROUND

ABO-incompatible transplantation has improved accessibility of kidney, heart, and liver transplantation. Pancreatic islet transplantation continues to be ABO-matched, yet ABH antigen expression within isolated human islets or novel human embryonic stem cell (hESC)-derived islets remain uncharacterized.

METHODS

We evaluated ABH glycans within human pancreata, isolated islets, hESC-derived pancreatic progenitors, and the ensuing in vivo mature islets following kidney subcapsular transplantation in rats. Analyses include fluorescence immunohistochemistry and single-cell analysis using flow cytometry.

RESULTS

Within the pancreas, endocrine and ductal cells do not express ABH antigens. Conversely, pancreatic acinar tissues strongly express these antigens. Acinar tissues are present in a substantial portion of cells within islet preparations obtained for clinical transplantation. The hESC-derived pancreatic progenitors and their ensuing in vivo-matured islet-like clusters do not express ABH antigens.

CONCLUSIONS

Clinical pancreatic islet transplantation should remain ABO-matched because of contaminant acinar tissue within islet preparations that express ABH glycans. Alternatively, hESC-derived pancreatic progenitors and the resulting in vivo-matured hESC-derived islets do not express ABH antigens. These findings introduce the potential for ABO-incompatible cell replacement treatment and offer evidence to support scalability of hESC-derived cell therapies in type 1 diabetes.