aetiology
Last reviewed 01/2018
The cause of PSC is uncertain. The most common association is with ulcerative colitis which is found in up to 75% of patients. However, only 3-4% of patients with UC develop PSC.
Other conditions associated with PSC include:
- Crohn's disease
- retroperitoneal fibrosis
- sarcoidosis
- Riedel's thyroiditis
PSC is frequently associated with HLA-B8 and HLA-DR3.
The cellular immune system appears to play a part in primary sclerosing cholangitis. There is a decrease in the total number of circulating T cells, wheras the number of T cells in the portal tracts is increased. The ratio of CD4 to CD8 lymphocytes in the circulation is increased, as are the number and percentage of B cells. It is unknown whether these immunologic abnormalities are primary events or are due to the underlying disease.