Objectives: An increased prevalence of elevated serum anti-Saccharomyces cerevisiae antibody (ASCA) levels in patients with Crohn's disease (CD) has been described. The aim of the present work was to investigate serum ASCA levels during the courses of prednisolone and mesalamine therapy in CD patients.
Methods: Serum samples of 25 patients with active CD were studied for ASCA levels before as well as 2 and 9 wk after initiation of a prednisolone tapering regimen. The influence of mesalamine (4 g o.d.) on serum ASCA levels compared to that of placebo was tested over 1 yr in 38 patients (20 mesalamine and 18 placebo) participating in a postoperative prophylaxis study. Serum IgG and IgA ASCA levels were measured by ELISA. Sera of 91 CD and 40 ulcerative colitis (UC) patients as well as 334 healthy donors were tested for ASCA to recalculate new cut-off values.
Results: For IgG ASCA cut-off values were determined to be 17.0 U and 25.0 U, and for IgA ASCA 9.3 U and 14.0 U. At baseline visit, 73.0% (46/63) of patients displayed serum ASCA positivity. During prednisolone therapy, a decrease in serum IgG and IgA ASCA levels from baseline to wk 2 (p < 0.0001 and p < 0.001, respectively) as well as to wk 9 (p < 0.001 and p = 0.01, respectively) was observed. A trend toward an association of ASCA positivity and steroid responsiveness was calculated (p = 0.07). During mesalamine treatment, no differences in changes of ASCA levels were observed compared to placebo at any time point.
Conclusions: ASCA are stable markers during steroid and mesalamine treatment, highlighting their reliability for use in diagnosis of CD.