Selective Adsorption of Immunoglobulin G and Immunoglobulin M from Plasma without Adsorption of Fibrinogen by Using Thienyl Amino Acids as Ligands

In vitro adsorption of plasma proteins such as immunoglobulin (Ig)-G and IgM without the removal of albumin and fibrinogen forms the basis of the field of therapeutic immunoadsorption. In the present study, we investigated the activities of adsorbents with thienyl amino acids, tryptophan, or phenylalanine as ligands. IgG adsorption by an adsorbent with a thienyl amino acid ligand was lower than that by an adsorbent with a tryptophan ligand but higher than that by an adsorbent with a phenylalanine ligand. On the other hand, IgM adsorption by an adsorbent with a thienyl amino acid ligand was higher than that by adsorbents with tryptophan and phenylalanine ligands. The adsorption of fibrinogen onto the adsorbent with a thienyl amino acid ligand was far lesser than its adsorption onto the adsorbents with tryptophan and phenylalanine ligands. Adsorbents with thienyl amino acid ligands may therefore be useful for removing antibodies produced in autoimmune diseases. Further in vitro biocompatibility studies, in vivo animal studies, and clinical trials are required to confirm these results.