TRAC and graft versus host disease: CRISPR/Cas9 has also been used to disrupt the TRAC and B2M genes to generate ‘universal’ allogeneic CAR T cells that knock out the endogenous TCR and HLA class-1 molecules, respectively (Kebriaei et al., 2016; Magnani et al., 2020), thereby limiting graft-versus-host-disease (GVHD) and immune rejection by T cells in patients.