Anti Saccharomyces cerevisiae antibodies (ASCA)

General information:

Saccharomyces cerevisiae is a unicellular fungus known as "bread yeast". Antibodies against Saccharomyces cerevisiae of the IgG and IgA class are directed against the oligomannan epitope of mannan (phosphopeptidoanan) on the yeast cell membrane. IgG and IgA antibodies against Saccharomyces cerevisiae are closely associated with Crohn's disease and have a specificity of 95-100%. IgG antibodies against Saccharomyces cerevisiae are found in only 5% of ulcerative colitis patients and IgA antibodies in 7%. The diagnostic sensitivity of the detection of IgG antibodies for the diagnosis of Crohn's disease is 75%, for IgA, 60%. Simultaneous determination of p-ANCA antibody class IgG and IgA, and Saccharomyces Cerevisiae serum increases the specificity of the differential diagnosis of Crohn's disease and ulcerative colitis to 99%. The presence of any class of Saccharomyces Cerevisiae antibodies in serum and the absence of antibodies to neutrophil cytoplasm is 95-100% specific and 50% sensitive for Crohn's disease; the absence of antibodies to Saccharomyces Cerevisiae and the presence of antibodies to neutrophil cytoplasm gives 90-100% specificity and 50-60% sensitivity for the diagnosis of ulcerative colitis.