Background: Antibodies to Saccharomyces cerevisiae (ASCA) have been described as specific markers for Crohn disease (CD). The reason for this disease specific generation of antibodies is not clear. Therefore, a family study was performed to evaluate whether the antibody production was due to genetic or environmental factors.
Methods: Seventy-one patients with CD, 25 patients with ulcerative colitis (UC), their 282 first-degree relatives, and 32 spouses were included. As controls, 43 sera from healthy persons and 69 sera from patients with various autoimmune disorders were tested for ASCA by indirect immunofluorescence and ELISA.
Results: ASCA were detected in 68% of the patients with CD and in none of the controls, UC patients included. Forty-eight (25%) first-degree relatives of patients with CD were ASCA-positive. ASCA status of relatives was not related to the fact whether these persons lived in the same household with the patients or not. However, one of the spouses of CD patients (4%) was found to be ASCA-positive and the antibody was also found in 5 (6%) of the relatives of UC patients.
Conclusions: ASCA are specific markers for CD. Since these antibodies are found in 25% of first-degree relatives, the generation of ASCA may be mainly related to genetic influences although environmental factors may also play a certain role.