Impaired Peripheral Th1 CD4+T Cell Response to Escherichia coli Proteins in Patients with Crohn's Disease and Ankylosing Spondylitis

To clarify the impact of T cell responses towards enteric antigens for chronic intestinal inflammation, we determined T helper 1 reactivity towards conserved Escherichia coli proteins in patients with Crohn's disease (CD) and healthy individuals and patients with ankylosing spondylitis (AS), who also often show microscopic inflammatory lesions within the gut or even develop overt inflammatory bowel disease. We determined the frequency of IFN gamma+CD40L+ cells/CD4+ T cells after stimulation of whole blood with pools of E. coli proteins. The E. coli-specific Th1 response was significantly reduced in CD patients and to a lower extent also in AS patients. E. coli is a target for polyclonal Th1 responses in healthy individuals. The impairment of these responses in CD and AS patients might be due to recruitment of enterobacteria-specific Th1 cells to the gut or might reflect inadequate priming of adaptive immune response.