There is evidence that cytotoxic T lymphocytes (T cells) participate in controlling tumor growth and that they can be harnessed to use the body's immune system to treat cancer. One study investigated the use of a T cell‑engaging antibody, blinatumomab, to recruit T cells to control tumor growth. Given are the T cell counts ( 1000 per microliter) at baseline (beginning of the study) and after 20 days on blinatumomab for six subjects in the study. The difference, after 20 days minus baseline, is the response variable.