P048 The peripheral pool of gut-homing CD4+beta7+ T-cells and regulatory CD4+FoxP3+ T-cells is maintained in Crohn's disease patients with small bowel inflammation
U. Kopylov*1, A. Lahat2, N. Levhar2, S. Neuman2, D. Yablecovitch2, B. Ungar1, R. Eliakim2, S. Ben-Horin2
1Sheba Medical Center, Gastroenterology, Tel Hashomer, Israel, 2Chaim Sheba Medical Center, Gastroenterology, Ramat Gan, Israel
There are some data suggesting that the peripheral blood pool of gut-homing CD4+beta7+ pool and of T-regulatory cells CD4+is reduced in patients with active IBD, presumably due to enhanced recruitment to the gut. Our aim was to investigate these T-cell subsets in Crohn's disease (CD) patients included in a prospective study evaluating small bowel inflammation by inflammatory markers, MRE and capsule endoscopy.
Patients with known small bowel CD in clinical remission or mild disease (CDAI<220) were prospectively recruited and underwent MRE, followed by a video capsule endoscopy (CE). PBMC were obtained, and FACS analysis of CD4+ and CD8+ gut homing beta7 integrin expressing cells and of expression of the transcription factor FoxP3 were performed.
Fifty three patients were studied. Capsule endoscopy documented no active inflammation and complete mucosal healing in 15 patients, and active inflammation in 38 patients (12 with severe inflammation with a Lewis score above 790, and 26 with milder inflammation and Lewis score of 135-790). The median percentage of CD4+FoxP3+ T-regulatory cells in the peripheral blood of patients with any active small bowel inflammation was not different than in patients with complete mucosal healing (5.3% versus 5.1%, respectively, p=0.8,), and was also similar when only patients with severely active mucosal inflammation (Lewis score>790) were considered. Percentage of CD4+CD45RO+Beta7+ gut-homing memory cells within the total CD4+CD45RO+ pool was also similar between patients with active inflammation and patients with healed mucosa (30.1% vs 30.2%, respectively, p=0.94). Similar Results for beta7 expression were found for the CD8+ T-cell subset.
Contrary to prior reports, when patients are fully evaluated for verified small bowel inflammation by capsule endoscopy, there does not seem to be a mucosal-inflammation induced depletion of the peripheral blood pool of gut-homing memory CD4+CD45RO+beta7+ T-cells, nor of the regulatory CD4+FoxP3+ T-cell subset.
RE, SBH- Equal contribution
The study was sponsored by the Helmsley Charitable Trust.