A compound attribute that is the ratio of amount of junctional adhesion molecule B (human) in blood to amount of tumor necrosis factor receptor superfamily member 21 (human) in blood. The trait is JAM2/TNFRSF21 protein level ratio in blood (OBA_2055496). Also known as: the ratio of amount of junctional adhesion molecule B (human) in blood to amount of tumor necrosis factor receptor superfamily member 21 (human) in blood.