ALZ-50 staining of enteric neurons in Down syndrome in infants and children.

Abstract

The monoclonal antibody ALZ-50, known to stain degenerating cerebral neurons in Alzheimer disease (AD), demonstrates a protein, A668, that is a modified form of the normal microtubule-associated protein, tau (1 -5). Because of the high incidence of an AD-like dementia in patients with Down syndrome (DS) who reach the age of 35-40 years (6-9), Wolozin et al. (10) studied ALZ-50 staining of temporal lobe neurons of 17 patients with DS aged from 16 fetal weeks to 62 years, finding ALZ-50 staining of these neurons in DS from ages 9 months to 6 years and from 29 to 62 years, whereas in control patients such staining was found from 34 to 36 fetal weeks to age 6 years but not in adults aged 28 to 91 years. These workers proposed that the protein demonstrable by ALZ-50 is developmentally regulated, with its expression reappearing during the third or fourth decade in patients with, but not in those without, DS. Although involvement of olfactory neurons in AD has been reported (1 1, 12), as has the occurrence in bowel wall of amyloid 0protein, a major component of the senile plaques found in the central neurons system in AD (13), we have found no reports on whether the neurons of the enteric nervous system show staining with ALZ-50 in DS or in non-DS infants and children. We have stained 5-pm sections from paraffin blocks of formalin-fixed tissues from various levels of the gastrointestinal tract of 13 DS patients, from 20 weeks of gestational age to 14 years, with biotinylated mouse monoclonal ALZ-50 antibody by a previously described avidin-biotin-horseradish peroxSupported in part by a grant from the Alzheimer Disease Consortium of the Universities of Southern