Breast cancer survivors are at an 80% higher risk of dying of cardiovascular disease than women in the general population, with the greatest relative risk occurring nearly a decade after diagnosis.55 Hypertension is an important precursor to cardiovascular disease, and survivors of breast cancer treated with radiation are at increased risk.3 Our group8 has previously shown that lower circulating percentages of naive CD4+ helper T cells and higher percentages of B cells are associated with a 20% higher risk of developing hypertension. Here, CD4 is linked to cardiovascular disorder.