Researchers sought to investigate whether anti-saccharomyces cerevisiae antibodies (ASCA), a yeast and marker for Crohn's disease, are present in spondyloarthropathies (SpA) and in the subgroups of ankylosing spondylitis (AS), undifferentiated SpA, and psoriatic arthritis (PsA). They compared the study's SpA data to data from "healthy" (non-arthritic) people and those with rheumatoid arthritis (RA). ASCA antibodies, which can include antibodies of both the IgG and IgA classes, have shown to have a high specificity for Crohn's disease. And Crohn's disease associated with spondylitis is one of the SpA's. Results were published in a recent issue of the Annals of the Rheumatic Diseases.

ASCA IgA and IgG levels were measured in 26 patients with Crohn's disease, 108 patients with SpA (43 with AS, 20 with undifferentiated SpA, 45 with PsA), 56 people with RA, and 45 healthy controls. Gut biopsy samples were available in 18 AS and 10 undifferentiated PsA patients, and these samples were screened for the presence of inflammation.

Researchers I. E. A. Hoffman and colleagues from the Ghent University Hospital in Ghent, Belgium found the following:

• Both ASCA IgA and IgG levels were raised in Crohn's disease compared with healthy controls and patients with RA.
• ASCA IgA levels were higher in SpA than in both healthy and RA controls.
• >ASCA IgA levels were raised in AS and undifferentiated SpA, but not in PsA.
• No significant differences in ASCA IgA levels were noted between patients with SpA with and without history of gut inflammation.