Immunoglobulin Induction Therapy in Renal Transplant Recipients: Effects on Immunoglobulin and Regulatory Antibody Levels

Abstract

We have previously shown that high pretransplant regulatory autoantibodies are associated with better kidney graft outcome. To analyze the effect of intravenous immunoglobulin (IVIG) induction therapy on these regulatory antibodies, we performed a prospective randomized study in 50 renal transplant recipients who were randomly assigned to receive 7 × 10 g IVIG or 7 × 10 g IV albumin infusions. Basic immunosuppressive therapy consisted of tacrolimus/azathioprine ( n = 24) and tacrolimus/mycophenolate mofetil ( n = 26), respectively. ELISA was used to assess IgG-/IgA-anti-Fab, -anti-F(ab) 2 and -anti-hinge regulatory antibodies. IVIG induction therapy resulted in upregulation of serum IgG and IgA levels within the first 20 days posttransplant ( P = .001, IgG; P = .04, IgA), so that a significant IgG deficiency was found only in non-IVIG patients (day 10: IgG <6 g/L: 7/25 (28%) non-IVIG versus 0/25 IVIG patients; P = .005). As the IVIG charges contained all of the regulatory antibodies tested, intravenous administration of these antibodies explain the elevated IgG- and IgA-anti-F(ab) 2 antibody levels found in IVIG compared to non-IVIG patients on day 10 ( P = .005 and P = .04, respectively). Our data indicated that IVIG induction prevented severe IgG deficiency in the early posttransplant period but had no impact on severe infectious complications. IVIG induction enhanced immunoregulatory antibody levels early posttransplant, which might provide graft protective effects.