Background 14-day stored RBCs containing an RBC specific transgenic antigen (HOD) induce a recipient pro-inflammatory cytokine storm and are significantly more immunogenic compared to fresh RBCs. Given that recipient mice clear transfused stored RBCs more rapidly than fresh RBCs, we hypothesized that rapid RBC clearance was associated with adverse transfusion outcomes. Study Design and Methods HOD RBCs were treated by two distinct methodologies known to lead to rapid post-transfusion RBC clearance: phenylhydrazine or heat. HOD antigen expression was analyzed on the treated cells prior to transfusion, and RBC recovery, recipient cytokine response, and recipient anti-HOD alloimmunization response were measured post-transfusion. Results Phenylhydrazine and heat treatment each led to near complete RBC clearance in recipients by 24 hours post-transfusion, without significantly altering HOD antigen expression on the transfused RBCs. Recipients of phenylhydrazine or heat-treated RBCs had elevated circulating levels of KC/CXCL-1, MCP-1, and IL-6 following transfusion. Furthermore, phenylhydrazine or heat treated RBCs were significantly more immunogenic than control RBCs, with a mean 25.1-fold enhancement and 10.3 fold enhancement, respectively, of anti-HOD alloimmunization magnitude by flow cytometric crossmatch. Conclusions Three separate insults to RBCs (storage, phenylhydrazine, or heat treatment) result in rapid post-transfusion clearance, with a recipient pro-inflammatory cytokine storm and enhanced alloimmunogenicity. These data are consistent with the hypothesis that rapid clearance of RBCs is causally involved in these outcomes, and suggest that human donor RBCs with favorable post-transfusion clearance profiles may be less immunogenic.