Anti - Saccharomyces cerevisiae ASCA (IgG)

Antibodies to Saccharomyces cerevisiae ASCA (IgG) is a test for the quantitative determination of IgG anti-Saccharomyces cerevisiae antibodies (ASCA) in human serum. These antibodies are directed against mannan in the cell membrane of S. cerevisiae.

Inflammatory bowel disease (IBD) is characterized by idiopathic inflammation of the intestine and is manifested by diarrhea, abdominal pain, rectal bleeding, weight loss, and anemia. The two main manifestations of IBD are Crohn's disease (CD) and ulcerative colitis (UC).

In the late 1980s, Main et al. first described elevated levels of anti-Saccharomyces cerevisiae (ASCA) in the serum of a patient with CD. These antibodies were directed against phosphopeptide mannans found in the cell wall of baker's yeast (Saccharomyces cerevisiae). Both ASCA IgG and IgA are important and should be measured in parallel.

The frequency of ASCA in patients with CD ranges from 50 to 80% for IgG and from 30 to 50% for IgA antibodies. Positive ASCA results are a risk factor for ileum lesions at a young age in patients with CD. Also, ASCA-positive CD patients tend to have a severe course and the need for surgical intervention.

ASCA's ability to predict disease course and response to treatment may allow patients to be categorized into high- and low-risk groups. Patients at high risk may require closer monitoring and treatment.