CD19 and B-cell chronic lymphocytic leukemia: Specifically, an exploratory, non-randomised, pilot study (n = 10 exercise group versus n = 6 control group) of supervised (in-person) exercise training combining high-intensity interval (walking) training (HIIT) and resistance training for 12 weeks reported that the absolute change in blood CD5+CD19+ B-CLL cells over time was 21.4% less in the exercise group compared with the control group.