OR22 Identification and validation of non-HLA antibodies in allograft recipients

Aim Non-HLA antibodies (Ab) are associated with an increased risk of allograft rejection. Currently, only a few non-HLA Ab can be tested in the clinical setting however, many have been reported in the literature. Simultaneously screening allograft recipients for a panel of novel and previously published non-HLA Ab would further elucidate the prevalence of non-HLA Ab, their organ specificity, and their association with allograft rejection. Methods Endothelial cell cross matches (ECXM) were performed using sera obtained at the time of cardiac allograft rejection ( n  = 37) to identify clinically relevant endothelial specific Ab. ECXM+ HLA DSA-sera ( n  = 12) were further evaluated by protoarray analysis of 9000 human proteins (Invitrogen) to identify novel non-HLA Ab targets. Previously published non-HLA Ab and the novel non-HLA Ab targets identified by protoarray were validated in a cohort of cardiac transplant recipients ( n  = 61) using a multiplex bead array (Immucor, Inc.) to detect Ab to over 45 non-HLA Ab targets. Results Thirty-two novel non-HLA Ab targets including 22 membrane proteins and 10 autoantigens were identified with protoarray analysis. Nineteen novel targets and 26 previously published non-HLA Ab were evaluated in a cardiac cohort ( n  = 61). Previously published renal targets including nucleolin (NCL) and peroxisomal trans-2-enoyl-CoA reductase (PECR) Ab and multiple novel targets were increased (Mann-Whitney, p Conclusion Multiple non-HLA Ab are present in organ transplant patients some of which are associated with rejection. A panel to screen many non-HLA Ab simultaneously is beneficial to further elucidate the prevalence and organ specificity of non-HLA Ab in allograft rejection. N. Jiang: Employee; Company/Organization; Immucor, Inc. , I. Balazs: Employee; Company/Organization; Immucor, Inc , E.F. Reed: Grant/Research Support; Company/Organization; Immucor, Inc.