For allogeneic CAR T cells to be used in the clinic there would need to be further genetic modification, for instance knockout of the endogenous T-cell receptor (TCR) and CD52 genes to prevent graft-versus-host disease and allow the use of an anti-CD52 antibody as part of lymphodepletion to prevent CAR T-cell rejection, respectively (28). This evidence concerns the gene CD52 and graft versus host disease.