AN IMMUNOHISTOCHEMICAL STUDY OF AMYLOID-P COMPONENT, APOLIPOPROTEIN-EAND UBIQUITIN IN HUMAN AND MURINE AMYLOIDOSES

Amyloid P component (AP) and apolipoprotein E (Apo E), which are known to be minor constituents of amyloid deposits, commonly are associated with almost all types of amyloid deposits. In this study, the distrib ution of AP-, Apo E- and ubiquitin (Ub)-immunoreactivity (IR) in amylo id deposits in the liver and spleen of human systemic amyloidosis (34 autopsy cases: 17 immunoglobulin light chain derived, 17 amyloid A pro tein derived) and experimental murine amyloidosis is examined using an immunohistochemical technique. In human cases, all of the amyloid dep osits examined showed colocalization of AP- and Apo E-IR with individu al amyloid proteins. In experimental amyloidosis, AP-IR of amyloid dep osits in the liver and spleen and Apo E-IR in the liver were seen unif ormly throughout this experiment. In contrast, Apo E-IR in the spleen was not uniform at the phase of amyloid deposition. At 4 weeks and at 16 weeks after casein injection, Apo E-IR was unevenly distributed in amyloid deposits in the perifollicular area; however, from 6 to 12 wee ks it was seen to be uniform. Ubiquitin-IR of amyloid deposits in huma n cases was seen in 22 of 34 livers and in 22 of 33 spleens. In experi mental amyloidosis, Ub-IR of amyloid deposits was demonstrated in the space of Disse in all mice examined, and there appeared to be a gradua l increase in intensity with the amount of amyloid deposition. However , in the spleen, amyloid deposits did not react with anti-Ub antibody in any phase of amyloid induction. These results suggest that Apo E an d Ub are not always associated with the process of amyloid deposition and may appear in a deposit after the deposition.