Selective removal of the autoantibodies from rheumatoid arthritis patient plasma using protein A carrying affinity cryogels

Rheumatoid arthritis is a chronic, progressive, deabilitating autoimmune disease that occurs in approximately 1% of adults. Rheumatoid arthritis is characterized by chronic polyarthritis and destruction of multiple joints. In this study, IgM-antibody removal from human plasma with supermacroporous poly(hydroxyethyl methacrylate) [PHEMA] cryogel carrying protein A has been evaluated. The PHEMA cryogel was prepared by bulk polymerization which proceeds in an aqueous solution of monomer frozen inside a plastic syringe (cryo-polymerization). After thawing, the PHEMA cryogel contains a continuous matrix having interconnected macropores of 10–200 μm size. Pore volume in the PHEMA cryogel was 71.6%. Protein A molecules were covalently immobilized onto the PHEMA cryogel via cyanogen bromide (CNBr) activation. The PHEMA cryogel was contacted with blood in in vitro system for the determination of blood-compatibility. The supermacroporous structure of the PHEMA cryogel makes it possible to process blood cells without blocking the cryogel column. IgM-antibody adsorption capacity decreased significantly with the increase of the plasma flow-rate. The maximum IgM-antibody adsorption amount was 42.7 mg/g. IgM-antibody molecules could be repeatedly adsorbed and eluted without noticeable loss in the IgM-antibody adsorption amount.