Association of amyloid P component with complement proteins in neurologically diseased brain tissue.

Amyloid P component (AP) was detected in a number of lesions in human brain associated with chronic degenerative disease. These lesions included diffuse and consolidated amyloid deposits, cerebral amyloid angiopathy, neurofibrillary tangles, neuropil threads and complement activated oligodendroglia. The staining for AP generally paralleled that for complement proteins C4d and C3d, suggesting that AP may serve as an adjuvant for phagocytosis.