The present invention relates to the use of fibronectin, tenascin, collagens type I, III, VI and/or VIII modified by aldehyde or by glycosylation in ELISA for detection of antibodies in plasma and serum to diagnose atherosclerosis as well as the use of induction of tolerance and active as well as passive immunization against glycosylated or aldehydemodified fibronectin, tenascin, collagen type I, III, VI and/or VIII for prevention and treatment of atherosclerosis.