[Beta 2-microglobulin and dialysis-related amyloidosis]

Dialysis-related amyloidosis is a common complication encountered in patients receiving chronic hemodialysis. beta 2-microglobulin(beta 2-m) constitutes the causative protein of amyloidosis, and its deposition in tissues has been proven to be a primary cause of the onset. However, many other risk factors are also associated including (1) prolonged duration of dialysis, (2) advanced age, (3) dialysate of low purity, and (4) the use of a dialysis membrane with poor biocompatibility. Recently we confirmed that apolipoprotein E is a risk factor for the onset of carpal tunnel syndrome associated with dialysis-related amyloidosis. Dialysis using high-flux membranes and the clinical application of a column that selectively adsorbs beta 2-m are currently being assessed interms of the ability to remove as much beta 2-m from the blood as possible. Drug therapy may also be useful at present in symptomatic treatment; a low dose of adrenocorticosteroids has recently been demonstrated as extremely effective for joint pain associated with beta 2-m amyloid deposits. The long-term use of drugs, however, carries a risk of side effects. As a therapeutic approach to dialysis-related amyloidosis, high-flux dialysis membranes permitting the elimination of beta 2-m with satisfactory biocompatibility have been developed and positive clinical effects have been observed both in the retrospective and prospective studies in the use of high-flux membranes together with a decrease in the serum beta 2-m level. However, there is no evidence yet of the long term reduction of amyloid deposits when the elimination of beta 2-m is maintained using a high-flux membrane.