Normal human plasma contains a large number of important and useful components, such as various coagulation factors and transfer proteins, etc. In order to remove disease-causing substances during plasma exchange, it is necessary to discard all the plasma containing the above-mentioned useful components and supplement it with a large amount of exogenous plasma. This not only causes waste of plasma, but also has certain hidden dangers. First of all, the source of blood products is currently tight, once the supply is not available, the plasma replacement cannot be carried out; secondly, after the exogenous plasma is frozen, some important components such as clotting factors may be lost to varying degrees, and a large amount of supplemental frozen plasma, even if it is “fresh” frozen plasma, will also have certain hidden dangers; and There is also a risk of contracting blood-borne infections and allergies when supplementing with large amounts of exogenous blood products. If specific removal of specific pathogenic substances from plasma can be achieved, large amounts of plasma can be removed without the need for supplementation, which is not only efficient but also relatively safe. Immunosorbency is one such treatment. It has been found that many diseases are associated with the abnormal production of certain specific antibodies, antigens or circulating immune complexes in the body. Immunosorbent is made by immobilizing a substance with immunosorbent activity on a polymer compound. During immunosorbent treatment, the patient’s blood or separated plasma is drained into an adsorbent column, where the adsorbent specifically binds to disease-causing substances in the blood, thus achieving clearance, while the rest of the blood components are returned to the patient. The specific adsorption principles of immunosorbents include specific antigen-antibody binding reactions, C1q complement-circulating immune complex binding reactions, and protein A immunosorbency. Protein A immunosorbent is currently the most commonly used. Protein A is a protein component isolated from the wall of certain aureus. Each protein A molecule has four immunoglobulin binding regions and can bind to different types of immunoglobulin molecules, with the strongest binding ability to immunoglobulin G. Moreover, the binding of protein A to immunoglobulin G is reversible and can be separated by special eluents. In general, the disease-causing antibody in vivo is immunoglobulin G. Compared with ordinary plasma exchange, immunosorbent columns made of protein A can remove disease-causing antibodies from blood efficiently and safely, and are widely used in the treatment of autoimmune diseases, but they are more expensive.