#2917 Desensitization techniques in ABO-incompatible renal transplantation: efficacy and analysis of complications
Authors: González Silvia Vega , Jara Michele Toledo , Esteban Rafael Alvarez , Val Miguel Hueso , Urquia Ronny Isaac Rodriguez , Ramos Maria Quero , Coloma Ana , Manonelles Anna , Couceiro Carlos , Rama Inés , Garrit Josep Maria Cruzado , Sandoval Diego 
Published: May 2024

Abstract

Background and Aims
Living donor transplantation is the best optimal choice for the vast majority of patients with terminal renal insufficiency. However, it is limited by the AB0/ HLA incompatibility between donor and receptor. The resolution of this inconvenient relies on desensitization of isoagglutinins (anti-AB0 immunoglobulins depletion); thus transplantation could be performed safely. For desensitization there are two techniques: specific adsorption (S) and non-specific (NS) techniques, including centrifugal therapeutic plasma exchange (cTPE) and membrane-based therapeutic plasma exchange (mTPE).
The aims are to evaluate the efficacy of apheresis techniques: specific versus non-specific, and identify their complications. Secondary objectives include analyzing the acute rejection rate (RR), graft survival, and complications of each technique.

Method
A retrospective cohort study was conducted on AB0-incompatible living donor transplantation patients at our center (Bellvitge's Hospital) from 2014 to 2022. All patients (except 1) received rituximab and induction treatment by Thymoglobulin or Basiliximab, followed by maintenance treatment (Steroids, Mycophenolate, and calcineurin inhibitors). During follow-up, protocol renal biopsies (RB) were taken at one month and between 3-6 months post-transplantation. Complications were defined as significant haematological alterations, bleeding, or major infections requiring hospitalization.
According to the technique used, two cohorts were identified: specific (Glycosorb®/Vitrosorb® columns) and non-specific: mTPE (prismaflex TPE2000) and cTPE (Spectra/Optia®). Both were anticoagulated with heparin or citrate randomly. An expert nurse supervised the technique. To calculate the efficacy we considered the percentual reduction of isoagglutinins in the first session. T-student test was used to calculate the percentage of complication and compare the results.

Results
A total of 50 patients were selected with a mean age (MA) of 49.5 ± 11.8. Four of these did not require apheresis due to lower title isoagglutinins (&lt;1/8). Each cohort included 23 patients: specific with MA 49.5 vs non-specific 48.4, with a mean isoagglutinin titles in specific of 61.65 vs non-specific 11.8 (p = 0.05). Isoagglutinin clearance were higher in specific techniques with 73% vs 59% non-specific (p &lt; 0.03). Due to the dispersion in the number of sessions, results are expressed with the median (4 sessions in specific vs 3 non-specific).
Total renal graft survival rate is 93.4%. At one month, it was diagnosed by biopsy an acute renal rejection rate of 16.7% in non-specific vs 18.2% specific (p &gt; 0.05). Considering complications, they are higher with non-specific 41.7% vs specific 18% (p &lt; 0.05). Regarding infectious issues, there are no differences in cytomegalovirus or polyomavirus infections, but there are differences in urinary infections observing in non-specific 79.2% vs specific 63% (p &lt; 0.05).

Conclusion
Specific techniques are more effective in reducing isoagglutinins, show a lower rate of complications and post-transplant infections, providing greater benefit to the patient.