HS mimetic increases serum HS levels and increases CD8 T-cell proliferation in allo-HSCT recipients. BALB/c recipient of B10.D2 allo-BM + LC were treated with subcutaneous injections of the HS mimetic PG545 (20 mg/kg in PBS), or PBS control once weekly, beginning 1 day before allo-HSCT. (A) Serum HS levels were determined by ELISA on the indicated days after transplant; n = 2-4 samples each (*P < .05). (B) BrdU uptake by CD8 T cells 6 days after allo-HSCT. Average and SEM are plotted; n = 3 per group (*P < .05). (C) Survival analysis of allo-BM + LC+PG545 (n = 10) compared with allo-BM + LC + PBS (n = 10).