Amyloid deposition is a disease that disrupts cellular and organ function due to the deposition of amyloid (amyloid) in the interstitial spaces of extracellular tissues throughout the body. The etiologic mechanisms may vary in different biochemical types of amyloidosis, secondary to impaired metabolism of protein precursors, while hereditary amyloidosis presents with different proteins. The specific factors are listed below. Physicochemical factors (25%) In animal experiments, bacterial toxins such as Escherichia coli endotoxin, as well as antitoxins, serum, nucleic acids, plasma globulins, methacholine, colloidal sulfur, thiouracil, mucopolysaccharides and γ-rays are available to create models of amyloidosis, although the most commonly used is casein, which is given to rabbits as a subcutaneous injection of 10% casein 5 ml twice a week for 3 months to amyloidosis occurs. Immune factors (20%) Amyloid deposits are often associated with chronic or recurrent infections or inflammatory diseases such as tuberculosis, leprosy, syphilis, etc., but the incidence varies greatly from country to country and region to region, it has been reported that about 3/4 (150/200) of secondary amyloidosis is caused by tuberculosis in India and very rarely in North America. Other diseases such as chronic osteomyelitis, burns, paraplegia with decubitus ulcers, chronic pyelonephritis, schistosomiasis, cystic fibrosis, etc. are also more often complicated by this disease, chronic purulent skin infections caused by subcutaneous injection of heroin (diacetylmorphine), as well as reports of secondary amyloidosis associated with human immunodeficiency virus infection, all of which support the idea that amyloid is the result of an antigen-antibody reaction. In addition, amyloidosis is also seen in patients with some autoimmune diseases, most commonly rheumatoid arthritis, and it has been reported that after 10 years of follow-up in 1000 patients with rheumatoid arthritis 3.1% of 1000 patients with rheumatoid arthritis died due to complications of amyloidosis after 10 years of follow-up; followed by ankylosing spondylitis, systemic lupus erythematosus, progressive sclerosis, Still’s disease, psoriatic arthritis, Reiter’s syndrome, polyarteritis nodosa, Schelgren’s syndrome (dry syndrome), Behcet’s disease, ulcerative colitis, Crohn’s disease and Wipple’s disease. Some scholars believe that amyloid is a physiological substance, which exists in trace amounts in normal people and increases with age. Once T-cell function is reduced and B-cell function is hyperactive, amyloid is produced in excess and can lead to pathological changes; or B-cell function is defective and produces abnormal light chains, which are easily deposited in tissues due to their low solubility, causing amyloidosis. The importance of T-cell function in the pathogenesis is illustrated by the shortened induction time of amyloidosis in cases of developmental insufficiency. Genetic factors (15%) Clinically, amyloidosis is commonly associated with certain genetic disorders such as familial Mediterranean fever, familial amyloid polyneuropathy, familial amyloid cardiomyopathy, central nervous system disorders such as Alzheimer’s disease, Down syndrome and hereditary cerebral hemorrhagic amyloidosis, and thus amyloidosis is thought to have some relationship with genetics. Tumors (5%) A number of patients with malignant tumors are often complicated by amyloidosis, such as Hodgkin’s disease, malignant lymphoma, immunoblast lymphadenopathy, heavy chain disease, and cancers of the rectum, lung, liver, kidney and esophagus can occur secondary to amyloidosis. Other factors (5%): Excessive increase in AH protein due to long-term hemodialysis can also be associated with secondary amyloidosis.