A compound attribute that is the ratio of amount of interleukin-15 (human) in blood to amount of interleukin-18-binding protein (human) in blood. The trait is OBA_2054418 (IL15/IL18BP protein level ratio in blood). Also known as: the ratio of amount of interleukin-15 (human) in blood to amount of interleukin-18-binding protein (human) in blood.