Neuropathological hallmarks of Alzheimer's disease (AD) are amyloid plaques and neurofibrillary tangles, containing betaA(42) peptide and tau protein, respectively. Amyloid plaques contain also glycosaminoglycans (GAGs). Whereas cerebrospinal fluid (CSF) levels of betaA(42) peptide and tau protein have been demonstrated as potential markers of Alzheimer's disease (AD), no data are available for GAGs. We determined (Elisa) tau and betaA(42) CSF levels, as well as serum antibodies to GAGs in 9 AD patients, and the values were analyzed in relation to age and severity of the disease. Beta-A42 and tau CSF levels were significantly reduced and increased, respectively, in AD patients when compared to controls, but they did not correlate with the severity of the disease. Despite their role in amyloidogenesis, we did not find evidence for the use of GAGs as diagnostic marker of AD.