Patients
PBMC of CD patients with small intestinal manifestation and UC patients with either active disease (defined by Harvey Bradshaw Index (HBI)) or remission (defined by HBI; pMayo) 13,14 were analyzed. Additionally, CeD patients on a GFD for at least one year, newly diagnosed active CeD patients still exposed to gluten (aCeD), or GFD-refractory CeD patients (Refr) were included. Moreover, healthy first-degree relatives (FDR) on a regular diet without symptoms were included. The diagnosis of CeD was based on the presence of tTG antibodies in the serum and characteristic histopathological features in duodenal biopsies (Marsh score >1). Refractory celiac disease diagnosis was based on the presence of a Marsh III enteropathy and clinical malabsorption in spite of consumption of a gluten-free diet for at least one year. Clonality analysis as done by PCR of the CDR3 region of the TCR was performed. Detection of a clonal T-cell population and aberrant lymphocytes by immune phenotyping of duodenal tissue allowed for diagnosis of Refr. type II. All other Refr. cases were diagnosed as RCD type I15. HLA-DQ status could not be determined for IBD patients and controls. As additional non-intestinal inflammatory control group PBMC from rheumatoid arthritis (RA) patients were analyzed.