Assessment of the stability of an immunoadsorbent for the extracorporeal removal of beta-2-microglobulin from blood

Background: Dialysis-related amyloidosis (DRA) is a devastating and costly condition that affects patients with end stage kidney disease. A key feature of DRA is the formation of amyloid fibrils, consisting primarily of β₂-microglobulin. Except for kidney transplantation, conventional kidney replacement therapies, which are based on nonspecific mechanisms, do not adequately address β₂-microglobulin removal. An antihuman β₂-microglobulin single-chain variable region antibody fragment (scFv) was developed to confer specificity to β₂-microglobulin removal during hemodialysis. Methods: The scFv was immobilized onto agarose and characterized for β₂m binding capacity, thermal stability at 37°C, regeneration capacity, storage conditions, and sterility. Results: The β₂-microglobulin binding capacity was 1.3 mg/ ml scFv gel. The immunoadsorbent is thermally stable, can be regenerated, stored short-term in 20% ethanol, lyophilized for long-term storage, and withstand process conditions similar to that of a patient's hemodialysis therapy. Conclusions: The results support further investigation of immobilized scFvs as a novel tool to remove β₂-microglobulin from blood.