Use of IVIg to identify potential miRNA targets for allograft rejection and GvHD therapy

Allograft rejection ( AR ) and graft‐versus‐host disease (Gv HD ) are serious complications following transplantation. Micro‐ RNA s (mi RNA s) have recently been identified as key players in the regulation of these disorders. Because intravenous immunoglobulin ( IVI g) has shown therapeutic potential for the prophylaxis and post‐transplant reduction of AR and Gv HD , we hypothesized that the effect of IVI g could result from the modulation of specific mi RNA expression. To identify such mi RNA , we performed mixed lymphocyte reactions ( MLR s) as an in vitro model of AR and Gv HD , with or without IVI g. We herein show that IVI g strongly inhibits the MLR s. This inhibition is associated with a modulation in the expression of mi RNA s implicated in the regulation of pro‐inflammatory cytokine ( IL ‐2, IL ‐6, IFN ‐γ) and costimulatory molecule ( CD 80) expression. We propose that these identified mi RNA s could represent potential therapeutic targets for the prevention and therapy of AR and Gv HD .