How is beta2-microglobulin amyloidosis (Abeta2M) diagnosed and treated?

Updated: Nov 12, 2018
  • Author: Robert O Holmes, Jr, DO; Chief Editor: Herbert S Diamond, MD  more...
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Answer

Answer

The precursor protein is a normal beta2 -microglobulin (β2 M), which is the light-chain component of the major histocompatibility complex (MHC). In the clinical setting, β2 M is associated with patients on dialysis and, rarely, patients with renal failure who are not on dialysis.

β2 M is normally catabolized in the kidney after it is displaced from the MHC-I heavy chain in the proximal tubules, but in patients with decreased clearance the serum level of the β2 M can be more than 60 times the normal level. [47] In patients with renal failure, the protein accumulates in the serum, leading to secondary osteoarticular destruction and dialysis-related amyloidosis (DRA). [48] 2 M commonly is associated with deposits in the carpal ligaments, synovium, and bone, resulting in carpal tunnel syndrome, destructive arthropathy, bone cysts, and fractures. Other organs involved include the heart, gastrointestinal tract, liver, lungs, prostate, adrenals, and tongue.

Conventional dialysis membranes do not remove β2 M, but new techniques are now being used to improve hemodialysis β2 M removal. Traut et al reported that patients using polyamide high-flux membranes had lower β2 M concentrations compared with those patients on low-flux dialyzers. [49] They postulated that the difference was mediated by an increase in β2 M mRNA, lower concentrations of β2 M released from the blood cells, and or better β2 M clearance in patients treated with high-flux dialyzers. [49] Yamamoto et al have investigated Lixelle adsorbent columns that remove serum β2 M safely in dialysis patients and significantly improved quality of life, strength, C-reactive protein levels, and β2 M concentration. [50]

Treatment also includes renal transplantation, which may arrest amyloid progression. For details, see Dialysis-Related Beta-2m Amyloidosis.


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