Beta-2-microglobulin in hemodiafiltered children: long-term efficiency follow-up

Data of beta 2-microglobulin (beta 2M) levels are not well known in hemodialyzed children. We analyzed 28 children, all maintained on thrice weekly hemodiafiltration (HDF) with highly permeable membrane (mean age 8 years 7 months, mean time on dialysis 32 months). beta 2M is significantly elevated: 34 + 8.5 mg/l without differences for sex but correlated to residual urinary volume. The kinetics of beta 2M removal during HDF with different dialysis membranes (polysulfone, polyacrylonitrile), and with the same membrane (polysulfone) used in diffusive (hemodialysis), in convective (hemofiltration) and in diffusive and convective (HDF) modes reveals that polysulfone membranes in HDF mode allow the greatest beta 2M serum level drop over dialysis session time (-60 +/- 12%). Five children, anuric, mean time on dialysis 75 months (65-94), chronically on thrice weekly (3 x 3 h) HDF with first polyacrylonitrile then polysulfone membranes are investigated regarding beta 2M levels and amyloidosis risks. Despite the high removal rate of beta 2M with these dialytic modes, beta 2M serum levels do not decrease during this five-year study. High beta 2M serum extraction seems to be compensated by high beta 2M cell generation. Further investigation is necessary for the explanation of the presumed high beta 2M generation rate in the HDF with polysulfone membranes before recommendation of safe long-term use of such highly permeable membranes for prevention of amyloidosis risks in dialytic patients.