Diseases that can be treated with plasma exchange or immunosorbent therapy involve many areas such as neurological diseases, autoimmune diseases, renal diseases, hematologic diseases, oncologic diseases, liver diseases, metabolic diseases, connective tissue diseases, and organ transplantation. In renal diseases, such as acute glomerulonephritis, which includes anti-glomerular basement membrane nephropathy and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis involving the kidney, the presence of a large number of anti-glomerular basement membrane antibodies or ANCA in the patient’s blood circulation can rapidly destroy a large number of glomeruli and even invade other important organs of the body, such as the lungs, and the patient’s kidneys can be completely destroyed within a few weeks. The disease is extremely dangerous and the prognosis is very poor. However, if intensive plasma exchange or immunosorbent treatment is given in the early stage of the disease, together with pharmacological treatment, it can save lives and the kidney function of many patients can be basically restored to normal. In thrombotic thrombocytopenic purpura/hemolytic urotoxic syndrome, the presence of a pathogenic substance called Von willebrand factor multimers in the blood and possibly other pathogenic substances such as abnormal anti-endothelial cell antibodies can be life-threatening when the disease involves the central nervous system and the kidneys, and timely and aggressive plasma exchange therapy can often reverse the disease and save the patient’s life. Prompt and aggressive plasma exchange therapy can often reverse the disease and save the patient’s life. Multiple myeloma and light chain disease can cause acute renal failure, and intensive plasma exchange therapy can remove abnormal proteins from the blood to reduce their deposition in the kidneys and improve renal function. Systemic lupus erythematosus (SLE) can also involve various organs throughout the body, including the kidneys and central nervous system, and can be life-threatening in severe cases. Studies have found that plasma exchange or immunosorbency has a therapeutic effect on SLE. Rejection occurs after kidney transplantation because of the destructive effect of the presence of a large number of abnormal antibodies in the patient’s blood on the transplanted kidney. Whether it is a hypersensitive patient with a large number of abnormal antibodies in the body before kidney transplantation or a rejection patient with a large number of abnormal antibodies secondary to transplantation, the use of plasma exchange or immunosorbent to remove the above-mentioned antibodies can avoid the rejection of the transplanted kidney and protect the function of the transplanted kidney. In addition, plasma replacement is also useful in the treatment of certain specific types of glomerulonephritis, such as focal segmental glomerulosclerosis.