Long-term multicentre study on beta 2-microglobulin removal by PMMA BK membrane.

A long-term multi-centre clinical study was performed, based upon our first identification of beta 2-microglobulin (beta 2-M) amyloid fibrils and optimisation of the pore-size of the polymethylmethacrylate (PMMA) membrane for its removal. To clarify the clinical significance of the newly designed PMMA membrane, BK membrane, having an average pore radius of 70-80 Angströms (7-8 nm), a total of 73 chronic haemodialysis patients from 28 centres, classified into four groups, were studied. Although the plasma beta 2-M decreased in all groups through the continued use of BK membrane, the early introduction of haemodialysis with BK membrane reduced the plasma concentration of this substance more than in the case of the later introduction. Pain index, defined as the total pain score divided by the number of painful joints, decreased significantly over the period of haemodialysis duration with BK membrane. This suggests that the continued use of BK membrane from the early phase of haemodialysis treatment results in the amelioration and/or prevention of joint pains of haemodialysis patients as well as preventing the increase in plasma beta 2-M.