Low Dose of IL‐2 Application for Graft‐Versus‐Host Disease Prophylaxis Following Haploidentical Stem Cell Transplantation

Graft-versus-host disease (GVHD) are still key obstacles of haploidentical transplantation. Interleukin-2 (IL-2) could promote natural killer (NK) cells and T-regulatory cells (Tregs) cells expansion in vitro and in vivo. We explored whether low-dose IL-2 administration at an early stage could promote NK cells and Tregs reconstitution and reduce GVHD after haplo-HSCT. This cohort trial included 10 recipients of accepting IL-2 treatment and case-pairing 30 recipients without IL-2 treatment post haplo-HSCT. In contrast to the control group, the 5-year incidence of chronic GVHD (cGVHD) was lower (<i>p</i> = 0.018), and GVHD progression-free survival (GPFS) was better (<i>p</i> = 0.025) in the IL-2 group. Blood NK-cells, Treg cells, conventional T cells (Tcon) cells, and the expression of CD62L+ on Tregs and Tcon cells reconstitution were increased post-IL-2 treatment. NKG2A expression on NK cells increased significantly post-IL-2 treatment. Meanwhile, IL-2 administration shortly increased the plasma levels of IFN-Ƴ, TNF-a, IL-10, and IL-2 in subjects post haplo-HSCT. Relative to the control group, low-dose IL-2 increased NK cell counts and the expression of CD122, DNAM-1, and NKG2D on NK cells post transplantation. Administration of low-dose IL-2 after haplo-HSCT correlated with reduced cGVHD, which should be explored further with randomized trial.