PDCD1/TNFRSF4 protein level ratio in blood (OBA_2054040) can be described as follows. A compound attribute that is the ratio of amount of programmed cell death protein 1 (human) in blood to amount of tumor necrosis factor receptor superfamily member 4 (human) in blood. Also known as: the ratio of amount of programmed cell death protein 1 (human) in blood to amount of tumor necrosis factor receptor superfamily member 4 (human) in blood.