Cross-reactivity studies on bacteria believed to be associated with inflammatory bowel disease (IBD), ankylosing spondylitis (AS) and reactive arthritis (ReA).

Six bacteria believed to be associated with IBD and/or AS and ReA were investigated for antigenic cross-reactivity using an ELISA. Considerable degrees of cross-reactivity were detected and it is suggested that if bacterial antigens are involved aetiologically in the diseases, no specific bacterium is concerned.