CCR5 and graft versus host disease: Published studies show that CCR5 not only participates in the pathogenesis of AIDS, atherosclerosis, rheumatoid arthritis, graft rejection, and neurodegenerative diseases but also plays an important role in the development and progression of acute graft‐versus‐host disease (GVHD) following allogeneic hematopoietic cell transplantation (AHCT).1, 2, 10, 11, 12, 13