CD1B and acute graft versus host disease: Preliminary data from a pilot cohort of patients undergoing allogeneic HCT (5 with acute GVHD and 5 without), suggests that the amount of intracellular XBP-1s is significantly increased in CD1b+, epidermal DCs among skin biopsies from patients with acute GVHD compared to no GVHD controls (Supplemental Figures 8A–C).