The present invention provides a method of diagnosing the presence or severity of tissue fibrosis in an individual by detecting .alpha.2-macroglobulin (.alpha.2-MG) in a sample from the individual; detecting hyaluronic acid (HA) in a sample from the individual; detecting tissue inhibitor of metalloproteinases-1 (TIMP-1) in a sample from the individual; and diagnosing the presence or severity of tissue fibrosis in the individual based on the presence or level of .alpha.2-MG, HA and TIMP-1.