Comparison of free light chain removal by four blood purification methods.

Renal failure is a frequent complication in patients with multiple myeloma. Immunoglobulin free light chains (FLCs) form casts in the distal tubules, resulting in renal obstruction, and are also directly toxic to proximal renal tubules. Removal of FLCs contributes to renal recovery. High cut-off (HCO) membrane Theralite2100, protein leaking dialyzer PES210Dα, plasma separator Evacure1A20 and β(2) microglobulin adsorption column LixelleS-35 were compared in their FLC removal rate. Dialysis using Theralite2100 or Evacure1A20, diafiltration using PES210Dα and adsorption using LixelleS-35 were performed in an in vitro circuit. The highest removal rate was obtained by Theralite2100 dialysis among the four blood purification methods. Albumin loss was also the greatest in Theralite2100 dialysis. The removal content of FLCs per 1 g albumin loss was better in PES210Dα diafiltration. The removal rate of FLCs by Evacure EC1A-20 dialysis was the third highest. Adsorption of FLCs by the β(2) microglobulin adsorption column Lixelle S-35 was confirmed. In conclusion, Theralite2100 dialysis was the best in removal of FLCs. PES210Dα diafiltration can remove FLCs with smaller loss of albumin.