[Behavior of beta 2-microglobulin in patients undergoing blood purification]

The Behavior of beta 2-microglobulin (beta 2m) in various modes of blood purification was studied. Serum beta 2m concentration was 26.1 +/- 9.9 mg/L in 39 patients on maintained hemodialysis (HD) and 20.6 +/- 5.3 mg/L in 26 patients on CAPD. In both groups, beta 2m was significantly higher than normal (P less than 0.01) and it was positively correlated with the duration of dialysis. However, patients surviving more than three years would show lower beta 2m in the CAPD group than those in the HD group. The mean value of beta 2m clearance was 108 mg during hemofiltration (HF) with polyamide membrane and 38.5 +/- 14.4 mg daily in CAPD. Not only very little. beta 2m could be removed on HD but a rise of beta 2m was observed after the procedure, even if it was corrected for hemoconcentration. A negative correlation was found between delta beta 2m and delta osmolality after HD (r = 0.58, P less than 0.05), but delta beta 2m would be decreasing if a cuprophan membrane dialyzer was reused for HD, and the result was the same if using the same membrane in isolated ultrafiltration (P less than 0.01 in all). These results suggested that the rise of beta 2m during HD with cellulose membrane may be due to increased release of beta 2m owing to the poor biocompatibility of the membrane as well as the generation of beta 2m on account of reduced plasma osmolality.