Accordingly, there was a significant decrease in IFN-γ, one of proinflammatory cytokine that is produced by lymphoid cells such as Th1 CD4+ T Cells, cytotoxic CD8α+ T cells, NK cells, and innate lymphoid cells (ILC) (19), and most importantly alloreactive T cells during GVHD (29), but not in TNFα, a major cytokine produced mostly by monocyte lineage immune cells such as macrophages (8). This evidence concerns the gene CD8A and graft versus host disease.