Immunoadsorption Column Reuse

Enhancing Success in the ABO-Incompatible Kidney Transplantation: A Case Report

Kidney transplantation is the preferred treatment for end-stage renal disease (ESRD); however, ABO incompatibility (ABOi) poses challenges due to increased graft rejection risk. Desensitization strategies, including immunoadsorption (IA), aim to overcome ABOi barriers. The objective of this case report was to present the initial findings and patient outcomes of ABOi kidney transplantation (KT) using two different brands of IA columns (Glycosorb® ABO and SECORIM®-ABO) in reducing isoagglutinin titers to the desired target level. We present a case report of a 51-year-old male with ESRD secondary to diabetic kidney disease who underwent desensitization for ABOi KT, involving rituximab administration followed by IA using Glycosorb® and Vitrosorb SECORIM®-ABO columns and plasmapheresis (PP). Glycosorb® ABO column decreased anti-B titers from an initial level of 1:128/1:128 to 1:64/1:64 (target range ≤1:8); however, the titers rebounded to 1:64 following the fourth session of PP. Subsequent use of Vitrosorb SECORIM®-ABO column achieved target titers of 1:4, enabling successful transplantation with satisfactory graft function. Monitoring included anti-B IgG/IgM titer levels post IA columns, IA column reuse, kidney function, and adverse events. The IA columns were well tolerated. Desensitization using IA columns effectively reduced anti-B titers, facilitating successful ABOi KT.

Chimeric AQP4-based immunosorbent for highly-specific removal of AQP4-IgG from blood

Anti-aquaporin-4 autoantibodies (AQP4-IgG) are implicated in the pathogenesis of neuromyelitis optica spectrum disorders (NMOSD), and their removal from the blood circulation is considered to be an effective method for acute treatment. An ideal extracorporeal AQP4-IgG removal system should have high specificity, which means that it can selectively remove AQP4-IgG without affecting normal immunoglobulins. However, the conventional tryptophan immobilized column lacks sufficient specificity and cannot achieve this goal. In this study, we successfully prepared a fusion protein chimeric AQP4, which consists of the complete antigenic epitopes of human AQP4 and the constant region of scaffold protein DARPin. Chimeric AQP4 was expressed and purified from Escherichia coli, and then immobilized on agarose gel as a ligand for selective capture of AQP4-IgG immunosorbent. The prepared immunosorbent had a theoretical maximum adsorption capacity of 20.48 mg/g gel estimated by Langmuir isotherm. In vitro plasma perfusion tests demonstrated that the chimeric AQP4 coupled adsorbent had remarkable adsorption performance, and could eliminate more than 85 % of AQP4-IgG under the gel-to-plasma ratio of 1:50. Moreover, it exhibited high specificity because other human plasma proteins were not adsorbed in the dynamic adsorption experiment. These results suggest that the chimeric AQP4 coupled immunosorbent can provide a new approach for specific immunoadsorption (IA) treatment of NMOSD.

ABO-Incompatible Renal Transplant: A Single-Center Experience from India

Introduction

In view of ever-increasing end-stage renal disease (ESRD) population but inadequate availability of suitable donors, ABO-incompatible (ABOi) transplantation can be an important void filler. However, at present, ABOi transplantation is limited to a few centers in India and there is a lack of adequate experience and expertise to guide this program to other centers in the country.

Methods

Data of all the ABOi transplants performed from 2012 to 2021 in a tertiary care hospital was retrospectively analyzed. The anti-ABO antibody (IgG) titers (≤1:4) were considered safe before transplantation. Desensitization included rituximab, plasma exchange, or selective immunoadsorption column. Tacrolimus and mycophenolate mofetil were initiated at day -7. Induction agents included ATG, ATLG, basiliximab, or no induction. Postoperatively, anti-ABO titers were done daily for 2 weeks.

Results

A total of 202 patients underwent transplantation; of these, 195 patients whose data were for available for 12 months were included in the study. Mean duration of follow-up was 28.9 ± 21.7 months. UTI was the most common source of infection, occurring in almost half (46.1%) of the patients. Antibody-mediated rejection (ABMR; 15%) was common in the first year. Patient survival was 86.6% (169/195) at 1 year. Sepsis was the most common of death in more than two-thirds of the population, including coronavirus disease 2019 (COVID-19)-associated mortality in nine patients (4.6%). Death-censored graft survival was 89.3% (174/195). AMR was the leading cause of graft loss in almost half of the patients.

Conclusion

ABOi should be considered in ESRD patients for whom suitable ABO-compatible donor is not available. Higher rate of rejection and infection are still a major concern.

Large volume plasmapheresis using a single-use immunoadsorption column: A cost-effective approach for desensitization in ABO-incompatible liver transplant

INTRODUCTION

Liver transplant is a life-saving treatment, but due to the limited availability of suitable liver donors, ABO-incompatible liver transplants (ABOi-LT) are conducted to increase the availability of liver donors. Perioperative desensitization for ABOi-LT is an established strategy to circumvent the risk of graft rejection. A single prolonged session can be performed to achieve the desired titers to avoid using multiple immunoadsorption (IA) columns or off-label reuse of single-use columns. This study retrospectively assessed the effectiveness of a single prolonged plasmapheresis session using IA as a desensitization strategy in live donor liver transplant (LDLT).

MATERIALS AND METHODS

This retrospective observational study conducted at a center for liver diseases in North India on six ABOi-LDLT patients who underwent single prolonged IA sessions in the perioperative period from January 2018 to June 2021.

RESULTS

Median baseline titer in patients was 320 (64, 1024). The median plasma volume adsorbed was 7.5 volumes (4, 8) per procedure, with a mean procedure time of 600 min (310-753). The reduction in titer ranged from 4 log to 7 log reduction per procedure. Two patients developed transient hypotension during the procedure, which was managed successfully. The median duration of pre-transplant hospital stay was 1.5 days (1, 3).

CONCLUSION

Desensitization therapy helps overcome the ABO barrier and decreases the waiting period before a transplant when ABO identical donors are unavailable. A single prolonged IA session reduces the cost of additional IA columns and hospital stay, thus making it a cost-effective approach to desensitization.

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.