Background Amyloidosis is a progressive cumulative process, in its early stage only a few structures in some organs are affected, and in later stages of the disease increasingly more may be involved (1).
Objectives The aim of this study was to determine the amount of amyloid deposits in various organs of rheumatoid arthritis (RA) patients afflicted with amyloidosis at death.
Methods Systemic AA amyloidosis (AAa) was located in 34 (21.1%) of 161 RA patients.
The existence of amyloid A deposits in various organs was determined histologically. The extent of amyloid A deposition was evaluated by semi-quantitative visual estimation on a 0 to 3 plus scale, based on the number of involved blood vessels and tissue structures per light microscopic field (x40 objective of an Olympus BX51).
Results Amyloid A protein deposition does not begin at the same time in various organs, but subsequently the amount of deposited amyloid A protein is increasing simultaneously in all investigated organs.
The amounts of deposited amyloid A protein are different, but the proportion of deposits in various organs is constant and independent of the stage of amyloidosis (Fig. 1).
Conclusions Amyloid A deposition starts in the most frequently involved structures and organs (1). Amyloid A deposition started earlier in the kidneys and in the heart than in the liver or lungs. The amount of deposited amyloid A varied in various organs, but in later stages of amyloidosis the proportion of deposits did not change; the ratios were constant, independent of the stage of the disease.
The constant relationship between amyloid A deposits in various organs allows an estimate of deposited amyloid in not investigated organs as well. For example, actual amounts of amyloid A in the kidneys may indirectly indicate the extent of amyloid A deposition in the heart, liver, lungs etc. Detection of amyloid deposits in an organ may allow the estimation of amyloid deposits in other organs. This indirect correlation may be of clinical significance.
Bély M, Apáthy Άgnes: Clinical Pathology of rheumatoid arthritis: Cause of death, lethal complications and associated diseases in rheumatoid arthritis. First English edition. Published by Akadémiai Kiadό, Member of Wolters Kluwer Group. Budapest 2012 http://www.akkrt.hu
Disclosure of Interest None declared