beta 2-Microglobulin amyloidosis. A systemic amyloid disease affecting primarily synovium and bone in long-term dialysis patients.

A number of rheumatic disorders occur in patients on long-term hemodialysis treatment. In recent years a clinical syndrome comprising carpal tunnel syndrome, destructive arthropathy, and cystic bone lesions has been recognized in these patients. Congo-red staining and microscopy in polarized light reveal a high frequency of amyloid in the affected tissues. Amino acid sequence data of the isolated major amyloid fibril protein show its identity with beta 2-microglobulin. beta 2-microglobulin amyloid has a predilection for synovial tissues and bone, but visceral deposits may also occur indicating the systemic nature of the disease. The clinicopathological features, pathogenesis, and diagnosis of beta 2-microglobulin amyloidosis are reviewed, and the therapeutic and prophylactic measures discussed. The identification of beta 2-microglobulin as an amyloidogenic protein has in an important way contributed to the understanding of the mechanisms of amyloidogenesis in general and emphasized the complexity of amyloid disease and the diversity of proteins capable of forming congophilic fibrillar deposits in human tissues.