A compound attribute that is the ratio of amount of histidine--tRNA ligase, cytoplasmic (human) in blood to amount of LRP chaperone MESD (human) in blood. The trait is HARS1/MESD protein level ratio in blood (Ontology of Biological Attributes entry OBA_2053131). Also known as: the ratio of amount of histidine--tRNA ligase, cytoplasmic (human) in blood to amount of LRP chaperone MESD (human) in blood.