Proteins in serum and cerebrospinal fluid in demented patients with Down's syndrome.

Serum and cerebrospinal fluid (CSF) of 19 Down's syndrome (DS) patients over 35 years old, were examined because of progressive dementia. Immunoglobulins, haptoglobin, transferrin, prealbumin and albumin were quantitated nephelometrically. The results were compared to those obtained for age-matched controls without neurological disease. The concentration of IgG was elevated in the DS serum and CSF, while that of IgA was elevated only in the serum. The level of transferrin was decreased in the DS serum and CSF, and that of albumin in the serum. IgM, haptoglobin and prealbumin concentrations were normal in the DS serum and CSF. No evidence of transudation of proteins into CSF and of their increased intrathecal synthesis was noted. These changes appear not to be associated with the development of dementia in DS.