CTLA4-Ig prevents alloantibody production and BMT rejection in response to platelet transfusions in mice

• Type of Material: Article
• Authors: Christopher R Gilson, Emory University; Seema R Patel, Emory University; James Zimring, Emory University
• Language: English
• Date: 2012-10-01
• Publisher: Wiley: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2012 American Association of Blood Banks.
• Final Published Version (URL): http://dx.doi.org/10.1111/j.1537-2995.2011.03550.x
• Title of Journal or Parent Work: Transfusion
• ISSN: 0041-1132
• Volume: 52
• Issue: 10
• Start Page: 2209
• End Page: 2219
• Grant/Funding Information: This work was funded in part by grants from NHLBI at the National Institutes of Health; grants R01HL092977 and R01HL105613.
• Keywords: AUTOIMMUNE THROMBOCYTOPENIC PURPURA; IMMUNITY; HEMATOPOIETIC-CELL TRANSPLANTATION; IMMUNOSUPPRESSION; PATHWAYS; Life Sciences & Biomedicine; IRRADIATION; KIDNEY-TRANSPLANTATION; INDUCTION; APLASTIC-ANEMIA; Hematology; COSTIMULATORY BLOCKADE; Science & Technology
• Research Categories: Health Sciences, Pathology; Health Sciences, Medicine and Surgery

Abstract

BACKGROUND: Platelet (PLT) transfusions can induce humoral and cellular alloimmunity. HLA antibodies can render patients refractory to subsequent transfusion, and both alloantibodies and cellular alloimmunity can contribute to subsequent bone marrow transplant (BMT) rejection. Currently, there are no approved therapeutic interventions to prevent alloimmunization to PLT transfusions other than leukoreduction. Targeted blockade of T-cell costimulation has shown great promise in inhibiting alloimmunity in the setting of transplantation, but has not been explored in the context of PLT transfusion. STUDY DESIGN AND METHODS: We tested the hypothesis that the costimulatory blockade reagent CTLA4-Ig would prevent alloreactivity against major and minor alloantigens on transfused PLTs. BALB/c (H-2d) mice and C57BL/6 (H-2b) mice were used as PLT donors and transfusion recipients, respectively. Alloantibodies were measured by indirect immunofluorescence using BALB/c PLTs and splenocytes as targets. BMTs were carried out under reduced-intensity conditioning using BALB.B (H-2b) donors and C57BL/6 (H-2b) recipients to model HLA-identical transplants. Experimental groups were given CTLA4-Ig (before or after PLT transfusion) with control groups receiving isotype-matched antibody. RESULTS: CTLA4-Ig abrogated both humoral alloimmunization (H-2d antibodies) and transfusion-induced BMT rejection. Whereas a single dose of CTLA4-Ig at time of transfusion prevented alloimmunization to subsequent PLT transfusions, administration of CTLA4-Ig after initial PLT transfusion was ineffective. Delaying treatment until after PLT transfusion failed to prevent BMT rejection. CONCLUSIONS: These findings demonstrate a novel strategy using an FDA-approved drug that has the potential to prevent the clinical sequelae of alloimmunization to PLT transfusions.