A compound attribute that is the ratio of amount of butyrophilin subfamily 2 member A1 (human) in blood to amount of leukocyte immunoglobulin-like receptor subfamily B member 4 (human) in blood. The trait is OBA_2053170 (BTN2A1/LILRB4 protein level ratio in blood). Also known as: the ratio of amount of butyrophilin subfamily 2 member A1 (human) in blood to amount of leukocyte immunoglobulin-like receptor subfamily B member 4 (human) in blood.