Currents concepts on the immunopathology of amyloidosis.

Amyloidosis is defined as the extracellular accumulation at systemic or organ-specific level of insoluble low molecular weight protein fibrils manifesting a beta pleated sheet configuration and a characteristic staining pattern. Several different types of proteins may lead to this phenomenon, and amyloidosis is defined by the biochemical nature of the protein in the deposits and further classified according to whether the deposits are localized or systemic, acquired or inherited, and by the resulting clinical phenotype. Amyloidosis includes subtypes such as light chain, associated with serum amyloid A protein, heritable and familial forms, dialysis-related disease, and organ-specific conditions. The pathogenesis and clinical features of these clinical and pathological entities will be critically discussed in this review article.