M1691 IFN-γ and Lamina Propria Lymphocytes (LPLS) Regulate Sox9 and Gp180 Expression in Fresh...
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AGA Abstracts mucosa from CD patients vs. normal controls, and was lower in involved vs. uninvolved mucosa from CD patients. In contrast, IL-8 mRNA was highest in involved CD mucosa and lowest in mucosa from normal controls. In healthy polarized, epithelial cells we observed a normal baso-apical traffic of pIgR-IgA complexes. In patients with active disease there was complete reversal of the traffic towards the lamina propria. Dense deposits of IgA, pIgR- IgA and CD71-IgA akin to IgA nephropathy were noted. Interestingly one of the patients also developed this condition. The observed defect was only partially corrected in uninvolved segments. Serum IgA levels were significantly elevated in CD patients compared to normal controls. Conclusions: Progressive inflammation in intestinal mucosa from CD patients is correlated with decreased expression of anti-inflammatory factors such as pIgR and increased expression of pro-inflammatory factors such as IL-8. In addition, aberrant traffic of pIgR receptor prevents IgA secretion and promotes antibody complex deposition. Elevated serum IgA in CD could be due to diminished intestinal transport of IgA, and/or enhanced IgA production due to increased access and persistence of luminal antigens into the gut wall. We conclude that dysregulated expression of pIgR and reduced transport of IgA may contribute to the etiology of CD. M1689 Transferred Naive and Regulatory T Cells Are Mandatory for Normal IEC Differentiation in the Colon of RAG1-/- Deficient Mice Stephanie Dahan, Masayuki Fukata, Andrea P. Martin, Paul M. Arnaboldi, Lloyd Mayer INTRODUCTION: Gut lympho-epithelial interactions occur in the epithelial layer and in the sub-epithelial space. We have shown that normal LPL induce IEC differentiation (promoting intestinal alkaline phosphatase (IAP) activity) in T84 cells, and that this was greater with CD LPL. This correlated In Vivo as crypt IECs were positively stained for IAP in CD mucosa. AIM: To determine whether IEC differentiation is regulated by LPLs In Vivo and whether this effect is induced by cytokine or cognate interactions. METHODS: T84 cells were stimulated with TNFα and IFNγ (cytokines expressed in CD mucosa), or seeded on Transwells and co-cultured on the basolatoral side with freshly isolated LPL (Nor or CD). T84 cells were lysed and IAP activity was quantified. CD4+CD45RbHi naive T cells and/or CD4+CD45RblowCD25+ regulatory T cells (Tregs) were isolated from C57BL/6 (WT) spleens and adoptively transferred to RAG1-/- mice. Colonic tissues were stained for IAP activity. RESULTS: In T84 cells co-cultured with Nor or CD LPL on conventional Transwells (without contact between the cell types), the IAP activity was comparable to control. Furthermore neither IFNγ nor TNFα induced IAP activity in these cells. However, when T84 cells were co-cultured with CD but not Nor LPL in inverted Transwells (with contact between the cell populations), IAP activity was significantly increased after 2 days (858+/-753.9 nmol pNP/ mg prot vs. 377+/-69.9, p<0.05). Thus the enhancement of IEC differentiation is due to cognate interactions and is not cytokine driven. To determine whether these findings were relevant In Vivo we studied IEC differentiation in RAG1-/- mice lacking lymphocytes. IAP staining was absent in RAG1-/- colonocytes but normal in small bowel (SB) enterocytes. These data suggest that LPL are involved in IEC differentiation in the colon, but that SB IECs are regulated differently. Transfer of CD45RbHi and Lo T cells induced the expression of IAP in colonocytes at levels comparable to control WT mice. Transfer of CD45RbHi T cells alone resulted in the development of colitis with IAP expression upregulated in both crypt and surface colonocytes in a manner comparable to human CD mucosa. CONCLUSION: Normal IEC differentiation involves both the presence of and contact with LPLs; the absence of lymphocytes impairs this differentiation. Moreover, the WT naive T cell adoptive transfer colitis model promotes the acceleration of IEC differentiation similar to that seen in active CD mucosa. This finding is specific to the CD mucosa and may be regulated by unique lymphoid populations. M1690 Intestinal Inflammation Up-Regulates the Expression of the G Protein-Coupled Receptor P2Y2 At the Transcriptional Level Émilie Degagné, Djordje Grbic, Andrée-Anne Dupuis, Fernand-Pierre Gendron Aim: Intestinal inflammation results in the up-regulation of the P2Y 2 nucleotide receptor (P2Y 2 R) expression in the colon of both DSS treated mice and in patients having Crohn disease and ulcerative colitis. However, the exact molecular mechanisms regulating the expression of the P2Y 2 R are not known. Hypothesis: Under inflammatory conditions, the transcriptional regulation of the P2Y 2 R is controlled by transcription factors C/EBPs and NFκB/p65. Methods: Proximal region of the human P2Y 2 R promoter was cloned into a pGL4.10-Luc vector (pGL4/P2Y 2 ). Caco-2/15 cells were co-transfected with the pGL4/P2Y 2 construction or with deletion mutants generated by restriction enzyme digestions and with the transcription factors C/EBPs or NFκB/p65. The interactions were determined by luciferase assays and identification of C/EBPs and NFκB/p65 potential binding sites determined by ChIP assays. Colitis was induced in mice with 5% DSS in water for 7 days. The colonic tissues were extracted and PCR assays were performed to evaluate the presence of P2Y 2 R. Tissue samples were also parafilm-embedded and immunofluorescence was performed for the detection of P2Y 2 R, C/EBPs and NFκB expression pattern. Results: We demonstrated that P2Y 2 R expression was up regulated in colitic mice. We established that the transcription factors C/EBPs and NFκB/p65 can bind to the promoter region of P2Y 2 and transactivated the luciferase gene. We also demonstrated, In Vivo by ChIP assays, that these transcription factors can bind to specific region of the P2Y 2 R proximal promoter. Conclusion: These results showed that inflammation up-regulates the expression of the P2Y 2 R and that the expression of this gene is regulated at the transcriptional level by C/EBPs and NFκB. This work was supported by the CCFC and the FRSQ scholarship program to FP Gendron. A-398 AGA Abstracts M1691 IFN-γ and Lamina Propria Lymphocytes (LPLS) Regulate Sox9 and Gp180 Expression in Fresh Intestinal Epithelial Cells (IECs) Giulia Roda, Alessandra Caponi, Andrea Belluzzi, Laura Mezzanotte, Sara Cameli, Michele Grazia, Giampaolo Ugolini, Giancarlo Rosati, Isacco Montroni, Lloyd Mayer, Aldo Roda, Enrico Roda Backgroud and aims: Our previous work suggested a role for the transcription factor SOX9 in IEC differentiation and its correlation with the expression of carcinoembryonic antigen family members (CEA). The interaction between IECs and LPLs is regulated by CEA members (gp180) and CD1d molecules expressed on IECs. Defects in gp180 expression by IECs, as seen in Inflammatory Bowel Disease (IBD), results in the loss of activation of CD8+ regulatory T cells. We have previously demonstrated a role for IFN-γ in the regulation of SOX9 in intestinal cell lines. The aim of the current study was to determine whether IFN- γ or LPLs regulate expression of SOX9 and gp180 in fresh IECs isolated from normal controls and IBD patients. Methods: Surgical specimens and biopsies were used as a source of IECs and LPLs. IECs, from 5 normal (cancer), 4 ulcerative colitis (UC) and 5 Crohn's disease (CD) (both active and inactive disease), were isolated by enzymatic digestion. Primary cells were either used for protein extraction (for SOX9 and gp180) or for stimulation with either IFN- γ, normal, UC or CD LPLs or supernatants derived from LPLs. These were further tested by immunohistochemistry and immunofluorescence to localize SOX9 expression. Results: In normal IECs, SOX9 expression decreases in the presence of IFN-γ (20-50 ng/ml) after 1 hour. In contrast, in CD and UC IECs, SOX9 was reduced in presence of lower concentrations of IFN-γ (10 ng/ml) at 1h. The expression of gp180 was similar. Furthermore there was a significant decrease in SOX9 and gp180 in the presence of LPLs or LPL supernatants. By immunofluorescence and immunohistochemistry, SOX9 localized to the nucleus and was reduced in the cytoplasm in the presence of IFN-γ. Conclusion: Both LPLs and IFN-γ downregulate SOX9 expression in IECs, with IECs derived from IBD patients being more sensitive to the effects of IFN-γ. The loss of CEA expression seen in IBD IECs does not relate to SOX9 expression as the regulation is distinct. M1692 A New Role of Co-Inhibitory Molecule B7-H1 for Induction of Oral Tolerance Sung Yeun Yang, Jae Hwan Kim, Su Kyoung Kwon, Sang Hoon Seol, Tae Hee Kim, In Hak Choi B7-homolog 1 (B7-H1, CD274), a member of B7 co-signaling molecule family, is believed to play dual actions as a co-stimulator enhancing T cell receptor (TCR)-mediated responses and as a co-inhibitor suppressing T cell immunity. In this study, we examined the role of B7-H1 In Vivo for the induction of oral tolerance using hydrodynamic injection of B7-H1- expressing plasmid into oral tolerance-induced mice or B7-H1-expressing allogeneic cell line for oral administration. In Vivo study showed that B7-H1 significantly reduced delayed- type hypersensitivity (DTH) responses in oral tolerance-induced mice as evidenced by the finding that ear swelling of oral tolerance-induced mice injected with B7-H1.hFc-expressing plasmid compared to control plasmid-injected mice. We also found that proliferation of sensitized T cells in mixed lymphocyte reactions (MLR) was decreased in oral tolerance- induced mice given B7-H1.hFc plasmid more than in mice given control plasmid. The similar results were obtained from the mice, in which oral tolerance was induced by direct oral administration of B7-H1-expressing allogeneic DC2.4 cell line. To further understand the underlying mechanisms by which B7-H1 exerts more efficient oral tolerance In Vivo, we investigated the cytokine profiles from MLR and frequency of regulatory T cells (Treg) In Vivo. Cytokine analysis showed that B7-H1 decreased Th1 and Th2 cytokines such as IFN-gamma, TNF-alpha, IL-5, not IL-2 and IL-4. In addition, B7-H1 augmented the frequency of CD4+CD25+FoxP3+ T cells in spleen and mesenteric lymph node cells In Vivo. However, there were no significant differences in cell frequencies of NKT cell, myeloid suppressor cells, and PD-1-expressing CD4/CD8+ T cells. In conclusion, in oral tolerance-induced mice, B7-H1 synergistically inhibits DTH responses and suppresses allospecific T cell responses and Th1 and Th2 cytokine production. In addition, B7-H1 generated more CD4+CD25+FoxP3+ Treg cells In Vivo of oral tolerance-induced mice. These findings suggest that B7-H1 might be of great value for improving the therapeutic efficacy of oral tolerance, and therefore benefit the treatment of allograft rejection in human. M1693 Expression of the Tight Junction Molecule Claudin-18 Is Increased in Patients with Ulcerative Colitis Gerd Bouma, Antoon Zwiers, Chris J. Mulder, Georg Kraal Introduction: We have recently shown that resistance in the C57Bl/6 strain or susceptibility in the SJL/J strain to trinitrobenzene sulfonic acid (TNBS) inducible colitis, resides on two loci on the mouse genome, Tnbs1 on chromosome 9 and Tnbs2 on chromosome 11 (Bouma et al. Gastroenterol 2002;123:554). In a subsequent study we applied micro-array technology to identify possible candidate genes in the Tnbs loci. This led to the identification of Claudin- 18 on chromosome 9 as a plausible candidate gene in conferring resistance or susceptibility in TNBS induced colitis. Claudins belong to the integral membrane proteins of the tight junction (TJ), a structure that seals off the intercellular space between adjacent epithelial cells and regulates passive diffusion of solutes and macromolecules to the underlying lamina propria. These observations in a mouse model prompted us to study the expression of Claudin 18 in human inflammatory bowel disease. Methods: Colonic biopsies from 13 patients with ulcerative colitis and 13 healthy individuals undergoing surveillance endoscopy were taken and RNA isolated. PCRs were performed using the SYBR green method in an ABI 7900HT sequence detection system and GAPDH served as the endogenous reference gene. Results: The relative expression of Claudin-18 compared to GAPDH in control indi- viduals ranged from 0.2 to 1.2 in the control group. In contrast a marked upregulation was seen in patients with ulcerative colitis. Three patients had an expression comparable to controls, whereas 10 patients showed a marked upregulation of Claudin 18 (median 12.2, range 2.2 to 345; P < 0.0005). Expression was not related to the histological severity of the
Transcript of M1691 IFN-γ and Lamina Propria Lymphocytes (LPLS) Regulate Sox9 and Gp180 Expression in Fresh...
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smucosa from CD patients vs. normal controls, and was lower in involved vs. uninvolvedmucosa from CD patients. In contrast, IL-8 mRNA was highest in involved CD mucosa andlowest in mucosa from normal controls. In healthy polarized, epithelial cells we observeda normal baso-apical traffic of pIgR-IgA complexes. In patients with active disease there wascomplete reversal of the traffic towards the lamina propria. Dense deposits of IgA, pIgR-IgA and CD71-IgA akin to IgA nephropathy were noted. Interestingly one of the patientsalso developed this condition. The observed defect was only partially corrected in uninvolvedsegments. Serum IgA levels were significantly elevated in CD patients compared to normalcontrols. Conclusions: Progressive inflammation in intestinal mucosa from CD patients iscorrelated with decreased expression of anti-inflammatory factors such as pIgR and increasedexpression of pro-inflammatory factors such as IL-8. In addition, aberrant traffic of pIgRreceptor prevents IgA secretion and promotes antibody complex deposition. Elevated serumIgA in CD could be due to diminished intestinal transport of IgA, and/or enhanced IgAproduction due to increased access and persistence of luminal antigens into the gut wall.We conclude that dysregulated expression of pIgR and reduced transport of IgA maycontribute to the etiology of CD.
M1689
Transferred Naive and Regulatory T Cells Are Mandatory for Normal IECDifferentiation in the Colon of RAG1-/- Deficient MiceStephanie Dahan, Masayuki Fukata, Andrea P. Martin, Paul M. Arnaboldi, Lloyd Mayer
INTRODUCTION: Gut lympho-epithelial interactions occur in the epithelial layer and in thesub-epithelial space. We have shown that normal LPL induce IEC differentiation (promotingintestinal alkaline phosphatase (IAP) activity) in T84 cells, and that this was greater withCD LPL. This correlated In Vivo as crypt IECs were positively stained for IAP in CD mucosa.AIM: To determine whether IEC differentiation is regulated by LPLs In Vivo and whetherthis effect is induced by cytokine or cognate interactions. METHODS: T84 cells werestimulated with TNFα and IFNγ (cytokines expressed in CD mucosa), or seeded on Transwellsand co-cultured on the basolatoral side with freshly isolated LPL (Nor or CD). T84 cellswere lysed and IAP activity was quantified. CD4+CD45RbHi naive T cells and/orCD4+CD45RblowCD25+ regulatory T cells (Tregs) were isolated from C57BL/6 (WT) spleensand adoptively transferred to RAG1-/- mice. Colonic tissues were stained for IAP activity.RESULTS: In T84 cells co-cultured with Nor or CD LPL on conventional Transwells (withoutcontact between the cell types), the IAP activity was comparable to control. Furthermoreneither IFNγ nor TNFα induced IAP activity in these cells. However, when T84 cells wereco-cultured with CD but not Nor LPL in inverted Transwells (with contact between the cellpopulations), IAP activity was significantly increased after 2 days (858+/-753.9 nmol pNP/mg prot vs. 377+/-69.9, p<0.05). Thus the enhancement of IEC differentiation is due tocognate interactions and is not cytokine driven. To determine whether these findings wererelevant In Vivo we studied IEC differentiation in RAG1-/- mice lacking lymphocytes. IAPstaining was absent in RAG1-/- colonocytes but normal in small bowel (SB) enterocytes.These data suggest that LPL are involved in IEC differentiation in the colon, but that SBIECs are regulated differently. Transfer of CD45RbHi and Lo T cells induced the expressionof IAP in colonocytes at levels comparable to control WT mice. Transfer of CD45RbHi Tcells alone resulted in the development of colitis with IAP expression upregulated in bothcrypt and surface colonocytes in a manner comparable to human CD mucosa. CONCLUSION:Normal IEC differentiation involves both the presence of and contact with LPLs; the absenceof lymphocytes impairs this differentiation. Moreover, the WT naive T cell adoptive transfercolitis model promotes the acceleration of IEC differentiation similar to that seen in activeCD mucosa. This finding is specific to the CD mucosa and may be regulated by uniquelymphoid populations.
M1690
Intestinal Inflammation Up-Regulates the Expression of the G Protein-CoupledReceptor P2Y2 At the Transcriptional LevelÉmilie Degagné, Djordje Grbic, Andrée-Anne Dupuis, Fernand-Pierre Gendron
Aim: Intestinal inflammation results in the up-regulation of the P2Y2 nucleotide receptor(P2Y2R) expression in the colon of both DSS treated mice and in patients having Crohndisease and ulcerative colitis. However, the exact molecular mechanisms regulating theexpression of the P2Y2R are not known. Hypothesis: Under inflammatory conditions, thetranscriptional regulation of the P2Y2R is controlled by transcription factors C/EBPs andNFκB/p65. Methods: Proximal region of the human P2Y2R promoter was cloned into apGL4.10-Luc vector (pGL4/P2Y2). Caco-2/15 cells were co-transfected with the pGL4/P2Y2
construction or with deletion mutants generated by restriction enzyme digestions and withthe transcription factors C/EBPs or NFκB/p65. The interactions were determined by luciferaseassays and identification of C/EBPs and NFκB/p65 potential binding sites determined byChIP assays. Colitis was induced in mice with 5% DSS in water for 7 days. The colonictissues were extracted and PCR assays were performed to evaluate the presence of P2Y2R.Tissue samples were also parafilm-embedded and immunofluorescence was performed forthe detection of P2Y2R, C/EBPs and NFκB expression pattern. Results: We demonstratedthat P2Y2R expression was up regulated in colitic mice. We established that the transcriptionfactors C/EBPs and NFκB/p65 can bind to the promoter region of P2Y2 and transactivatedthe luciferase gene. We also demonstrated, In Vivo by ChIP assays, that these transcriptionfactors can bind to specific region of the P2Y2R proximal promoter. Conclusion: Theseresults showed that inflammation up-regulates the expression of the P2Y2R and that theexpression of this gene is regulated at the transcriptional level by C/EBPs and NFκB. Thiswork was supported by the CCFC and the FRSQ scholarship program to FP Gendron.
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M1691
IFN-γ and Lamina Propria Lymphocytes (LPLS) Regulate Sox9 and Gp180Expression in Fresh Intestinal Epithelial Cells (IECs)Giulia Roda, Alessandra Caponi, Andrea Belluzzi, Laura Mezzanotte, Sara Cameli, MicheleGrazia, Giampaolo Ugolini, Giancarlo Rosati, Isacco Montroni, Lloyd Mayer, Aldo Roda,Enrico Roda
Backgroud and aims: Our previous work suggested a role for the transcription factor SOX9in IEC differentiation and its correlation with the expression of carcinoembryonic antigenfamily members (CEA). The interaction between IECs and LPLs is regulated by CEA members(gp180) and CD1d molecules expressed on IECs. Defects in gp180 expression by IECs, asseen in Inflammatory Bowel Disease (IBD), results in the loss of activation of CD8+ regulatoryT cells. We have previously demonstrated a role for IFN-γ in the regulation of SOX9 inintestinal cell lines. The aim of the current study was to determine whether IFN- γ or LPLsregulate expression of SOX9 and gp180 in fresh IECs isolated from normal controls andIBD patients. Methods: Surgical specimens and biopsies were used as a source of IECs andLPLs. IECs, from 5 normal (cancer), 4 ulcerative colitis (UC) and 5 Crohn's disease (CD)(both active and inactive disease), were isolated by enzymatic digestion. Primary cells wereeither used for protein extraction (for SOX9 and gp180) or for stimulation with either IFN-γ, normal, UC or CD LPLs or supernatants derived from LPLs. These were further testedby immunohistochemistry and immunofluorescence to localize SOX9 expression. Results:In normal IECs, SOX9 expression decreases in the presence of IFN-γ (20-50 ng/ml) after 1hour. In contrast, in CD and UC IECs, SOX9 was reduced in presence of lower concentrationsof IFN-γ (10 ng/ml) at 1h. The expression of gp180 was similar. Furthermore there was asignificant decrease in SOX9 and gp180 in the presence of LPLs or LPL supernatants. Byimmunofluorescence and immunohistochemistry, SOX9 localized to the nucleus and wasreduced in the cytoplasm in the presence of IFN-γ. Conclusion: Both LPLs and IFN-γdownregulate SOX9 expression in IECs, with IECs derived from IBD patients being moresensitive to the effects of IFN-γ. The loss of CEA expression seen in IBD IECs does notrelate to SOX9 expression as the regulation is distinct.
M1692
A New Role of Co-Inhibitory Molecule B7-H1 for Induction of Oral ToleranceSung Yeun Yang, Jae Hwan Kim, Su Kyoung Kwon, Sang Hoon Seol, Tae Hee Kim, InHak Choi
B7-homolog 1 (B7-H1, CD274), a member of B7 co-signaling molecule family, is believedto play dual actions as a co-stimulator enhancing T cell receptor (TCR)-mediated responsesand as a co-inhibitor suppressing T cell immunity. In this study, we examined the role ofB7-H1 In Vivo for the induction of oral tolerance using hydrodynamic injection of B7-H1-expressing plasmid into oral tolerance-induced mice or B7-H1-expressing allogeneic cellline for oral administration. In Vivo study showed that B7-H1 significantly reduced delayed-type hypersensitivity (DTH) responses in oral tolerance-induced mice as evidenced by thefinding that ear swelling of oral tolerance-induced mice injected with B7-H1.hFc-expressingplasmid compared to control plasmid-injected mice. We also found that proliferation ofsensitized T cells in mixed lymphocyte reactions (MLR) was decreased in oral tolerance-induced mice given B7-H1.hFc plasmid more than in mice given control plasmid. Thesimilar results were obtained from the mice, in which oral tolerance was induced by directoral administration of B7-H1-expressing allogeneic DC2.4 cell line. To further understandthe underlying mechanisms by which B7-H1 exerts more efficient oral tolerance In Vivo,we investigated the cytokine profiles from MLR and frequency of regulatory T cells (Treg)In Vivo. Cytokine analysis showed that B7-H1 decreased Th1 and Th2 cytokines such asIFN-gamma, TNF-alpha, IL-5, not IL-2 and IL-4. In addition, B7-H1 augmented the frequencyof CD4+CD25+FoxP3+ T cells in spleen and mesenteric lymph node cells In Vivo. However,there were no significant differences in cell frequencies of NKT cell, myeloid suppressorcells, and PD-1-expressing CD4/CD8+ T cells. In conclusion, in oral tolerance-induced mice,B7-H1 synergistically inhibits DTH responses and suppresses allospecific T cell responsesand Th1 and Th2 cytokine production. In addit ion, B7-H1 generated moreCD4+CD25+FoxP3+ Treg cells In Vivo of oral tolerance-induced mice. These findings suggestthat B7-H1 might be of great value for improving the therapeutic efficacy of oral tolerance,and therefore benefit the treatment of allograft rejection in human.
M1693
Expression of the Tight Junction Molecule Claudin-18 Is Increased in Patientswith Ulcerative ColitisGerd Bouma, Antoon Zwiers, Chris J. Mulder, Georg Kraal
Introduction: We have recently shown that resistance in the C57Bl/6 strain or susceptibilityin the SJL/J strain to trinitrobenzene sulfonic acid (TNBS) inducible colitis, resides on twoloci on the mouse genome, Tnbs1 on chromosome 9 and Tnbs2 on chromosome 11 (Boumaet al. Gastroenterol 2002;123:554). In a subsequent study we applied micro-array technologyto identify possible candidate genes in the Tnbs loci. This led to the identification of Claudin-18 on chromosome 9 as a plausible candidate gene in conferring resistance or susceptibilityin TNBS induced colitis. Claudins belong to the integral membrane proteins of the tightjunction (TJ), a structure that seals off the intercellular space between adjacent epithelialcells and regulates passive diffusion of solutes and macromolecules to the underlying laminapropria. These observations in a mouse model prompted us to study the expression ofClaudin 18 in human inflammatory bowel disease. Methods: Colonic biopsies from 13patients with ulcerative colitis and 13 healthy individuals undergoing surveillance endoscopywere taken and RNA isolated. PCRs were performed using the SYBR green method in anABI 7900HT sequence detection system and GAPDH served as the endogenous referencegene. Results: The relative expression of Claudin-18 compared to GAPDH in control indi-viduals ranged from 0.2 to 1.2 in the control group. In contrast a marked upregulation wasseen in patients with ulcerative colitis. Three patients had an expression comparable tocontrols, whereas 10 patients showed a marked upregulation of Claudin 18 (median 12.2,range 2.2 to 345; P < 0.0005). Expression was not related to the histological severity of the
