Full chimaeric CAR.CIK from patients engrafted after allogeneic haematopoietic cell transplant: Feasibility, anti‐leukaemic potential and alloreactivity across major human leukocyte antigen barriers

Cytokine‐induced killer lymphocytes (CIK) are a promising alternative to conventional donor lymphocyte infusion (DLI), following allogeneic haematopoietic cell transplantation (HCT), due to their intrinsic anti‐tumour activity and reduced risk of graft‐versus‐host disease (GVHD). We explored the feasibility, anti‐leukaemic activity and alloreactive risk of CIK generated from full‐donor chimaeric (fc) patients and genetically redirected by a chimeric antigen receptor (CAR) (fcCAR.CIK) against the leukaemic target CD44v6. fcCAR.CIK were successfully ex‐vivo expanded from leukaemic patients in complete remission after HCT confirming their intense preclinical anti‐leukaemic activity without enhancing the alloreactivity across human leukocyte antigen (HLA) barriers. Our study provides translational bases to support clinical studies with fcCAR.CIK, a sort of biological bridge between the autologous and allogeneic sources, as alternative DLI following HCT.