White blood cell (WBC) and lymphocyte (LYM) counts in the blood (6A) and spleen (6B) after irradiation and/or hindlimb unloading (HLU). Mice were euthanized and blood was collected in ethylenediaminetetraacetic acid (EDTA)-coated syringes via inferior vena cava (IVC) at 4 or 30 days post-unloading (11 and 37 days post-irradiation, respectively). Blood and spleens were analyzed via an ABC Vet Automated Hematology Analyzer. Three-Way ANOVA: * = P<0.05, main effect of proton irradiation (IR) or HLU, †=P<0.05, IR x HLU interaction. T =P<0.1, IR x HLU interaction. Post hoc Tukey test: # =p<0.05, TT =P<0.1. Note the strong radiation dependence at 4 days post treatment, but smaller influence of HLU for both WBC and lymphocytes.