Atkins et al. (2008) showed grade 3 or greater toxicity on the BCT arm in 95% of patients. By the fourth cycle of therapy, only 57% of patients were able to receive a full dose of IL-2 due to side effects, thus compromising the potential effectiveness of the drug regimen. Toxicities included leukopenias, hypotension, and metabolic dysfunction (Atkins et al., 2008). Eton et al. Here, IL2 is linked to Decreased total leukocyte count.