Exogenous expression of SFRP1 in heterozygous APP;PS1 mice (with slowed amyloid plaque build-up compared to the homozygous animal) by lentiviral transduction accelerated amyloid plaque formation, and these were surrounded by an elevated number of CD45-positive activated microglia (which is indicative of gliosis), as well as by lysosomal-marker-enriched dystrophic neurites. This evidence concerns the gene APP and amyloidosis.