CAR-T and GvHD: Have We Engineered GvHD Out of Allogeneic CAR‑T Therapy?

Autologous CAR-T has transformed lymphoma therapy, but 40-60% of patients still relapse, and manufacturing is slow/expensive. Allogeneic CAR-T cells (from healthy donors or iPSCs) could overcome these issues. They can avoid patient leukapheresis and reliance on heavily pretreated autologous T cells, reduce the need for bridging therapy, permit advance manufacture, and allow deliberate donor and cell-subset selection. However, they face two main immunologic barriers: (1) GvHD, in which donor T cells' native TCRs may recognize patient tissues as foreign, causing acute/chronic GvHD; and (2) host-versus-graft rejection, in which the patient's immune system may reject the donor cells2. In mismatched stem cell transplant (alloHCT), GvHD occurs in ∼50-80% of cases without intervention3. By analogy, unmodified donor αβ T cells with CARs might similarly attack HLA-mismatched host tissues. Thus, successful allogeneic CAR-T must reduce donor-to-host alloreactivity while managing the distinct host-versus-graft barrier. This focused Perspective asks whether GvHD directed engineering has made clinically significant product-associated GvHD rare.