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AA Amyloidosis (Inflammatory)
Amyloid A (AA) amyloidosis is the most common form of systemic amyloidosis worldwide. It is characterized by extracellular tissue deposition of fibrils that are composed of fragments of serum amyloid A (SAA) protein, a major acute-phase reactant protein, produced mainly by liver cells (hepatocytes). It occurs in the course of a chronic inflammatory disease of either infectious or noninfectious origin, hereditary periodic fevers, and with certain neoplasms such as Hodgkin disease and renal cell carcinoma.[1]
Glomerular amyloidosis usually causes protein in the urine. Amyloidosis is sometimes inherited in Chinese Shar-Peis [2].
There are several types of amyloid, and the classification of amyloidosis is based on which amyloid protein is involved. Amyloid is now classified chemically. The amyloidoses are referred to with a capital A (for amyloid) followed by an abbreviation for the fibril protein. Twenty-three different fibril proteins are described in human amyloidosis with variable clinical features. In all forms of amyloidosis, the cell secretes the precursor protein in a soluble form that becomes insoluble at some tissue site, compromising organ function. In humans, some of the conditions associated with AA include the following:
- Rheumatoid arthritis
- Juvenile chronic arthritis
- Ankylosing spondylitis
- Psoriasis and psoriatic arthritis
- Adult Still disease and Behcet syndrome
- Familial Mediterranean fever
- Crohn disease
- Leprosy
- Osteomyelitis
- Tuberculosis
- Chronic bronchiectasis
- Castleman disease
- Hodgkin disease
- Renal cell carcinoma
- Carcinoma of the gut, lung, or urogenital tract
AA is the most common systemic amyloidosis; it was formerly termed secondary amyloidosis. [3]
Deposists of AA amyloid can result from chronic inflammatory diseases, chronic bacterial infections, and cancer.
References
1. Mohammed Mubashir Ahmed, MD. Amyloidosis, AA (Inflammatory)
2. Cynthia M. Khan, BA, MA and Scott Line, DVM, PdD, Dipl ACVB. The Merck/Merial Manual for Pet Health Home Edition. Whitehouse Station, NJ: Merck & Co., Inc., 2007: 294, 307
3. Bruce A Baethge, MD. "Amyloidosis, Overview." eMedicine, August 11, 2006.
Go Pets America recommends seeking the advice of your local veterinarian for the most appropriate vaccination program and for the diagnosis and treatment of your pet's health problems. For vaccination requirements please contact your state and local licensing authorities.
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