The suppression of GVHD by i35-exosomes also correlates with increase of alloreactive T cells expressing checkpoint inhibitors (PD-1, CTLA-4, LAG-3) that promote T cell exhaustion/anergy and significant decrease of cytokines that produce cytokine storms associated with pathological responses observed in GVHD. This evidence concerns the gene CTLA4 and graft versus host disease.