Elevated de novo Donor Specific Antibody after Alemtuzumab Induction in Renal Transplant Recipients

Introduction: Recent data suggests an association between de novo DSA and alemtuzumab induction, believed to result in an above average annual incidence of 3-4% in renal transplantation (RTX). 

Objectives: This study aims to investigate the association between de novo DSA and alemtuzumab in RTX at our center.

Study Design: A single center retrospective analysis of RTX recipients that received a single dose of alemtuzumab (30 mg).

Methods: We collected DSA of 16 RTX recipients that received a single dose of alemtuzumab during 2010-2015. DSA was determined by solid phase single antigen bead testing pre-transplant and at 1 month, 6 month and yearly after RTX.

Results: Sixteen RTX patients received alemtuzumab during the study period. The majority (68%) received early steroid withdrawal. Average follow up time was 814 days (342-1290 days).  A quarter (4/16) of patients developed de novo DSA after alemtuzumab with average time to de novo DSA of 387 days (± 135 days). Donor and recipient characteristics appear in Table 1 (not included in abstract). In patients with de novo DSA, 75% (3/4) had class I only, 25% (1/4) had class II only, and no patients had both class I and II.  The average sum MFI of de novo DSA was 3600 (312-6943).  Rejection preceded development of DSA in 25% (1/4) patients.  Development of de novo DSA triggered a kidney biopsy in 75% (3/4) of patients; 100% (3/3) of these demonstrated rejection and 50% (2/4) received treatment.  There was no difference between groups in kidney function defined as average creatinine and proteinuria) at last follow up. 

Conclusions: Alemtuzumab induction was associated with a significant increase in development of de novo DSA. More study is needed to characterize the mechanism and risk factors associated with development of de novo DSA post RTX and its effect on long-term kidney allograft survival.