Anti–Saccharomyces cerevisiae antibody
| Antigen isoform | Mannans |
|---|---|
| Antigen source | Saccharomyces cerevisiae |
| Antigen gene | pro |
| Affected organ(s) | Large Intestine |
| Affected tissue(s) | Epithelium |
| Associated disease(s) | Colitis |
Anti-Saccharomyces cerevisiae antibodies (ASCAs) are antibodies against antigens presented by the cell wall of the yeast Saccharomyces cerevisiae. These antibodies are directed against oligomannose sequences α-1,3 Man (α-1,2 Man α-1,2 Man)n (n = 1 or 2). ASCAs and perinuclear antineutrophil cytoplasmic antibodies (pANCAs) are the two most useful and often discriminating biomarkers for colitis. ASCA tends to recognize Crohn's disease more frequently, whereas pANCA tend to recognize ulcerative colitis.
ASCA antibodies react to a yeast protein with mannans, a 200-kDa glycoprotein.