Interleukin-2 receptor antibody does not reduce rejection risk in low immunological risk or tacrolimus-treated intermediate immunological risk renal transplant recipients

Abstract

The use of interleukin-2 receptor antibody (IL-2Ra) induction has been associated with reduced rejection rates in renal transplant recipients. However, the effect of IL-2Ra induction on graft and patient outcomes in renal transplant recipients with differing immunological risk remains unclear. Using Australia and New Zealand Dialysis and Transplant Registry, renal transplant recipients in Australia between 1995 and 2005 were included. Recipients were stratified into low immunological risk (primary grafts with < or = 2 human leucocyte antigen (HLA)-mismatches and panel-reactive antibody (PRA) < 10%) or intermediate immunological risk (subsequent grafts or >2 HLA-mismatches or PRA > 25%) recipients. Recipients receiving T-cell depletive induction therapy or steroid and/or calcineurin-free inhibitor regimens were excluded. Outcomes analysed included the presence of rejection at 6 months, estimated glomerular filtration rate at 1 and 5 years, graft and patient survival. 218 of 1220 (18%) low-risk and 883 of 3204 (28%) intermediate-risk recipients received IL-2Ra. In intermediate-risk recipients, IL-2Ra induction was associated with a 26% reduction in the incidence of acute rejection; but this benefit was restricted only to recipients initiated on cyclosporine-based immunosuppressive regimens. In contrast, the use of IL-2Ra in low-risk recipients was not associated with reduced rejection risk. There was no association between IL-2Ra induction and other graft or patient outcomes in both low- and intermediate-risk recipients. This registry analysis suggests that IL-2Ra induction may be associated with a reduction in rejection risk in cyclosporine-treated intermediate immunological risk recipients, but not in low-risk renal transplant recipients.