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Tu1929 Patients With Inflammatory Bowel Disease and Immunosuppressive Treatment Show Cellular Immune Response Towards Microsatellite Instability-Induced Frameshift Mutations
Tu1927
as microsatellite instability (MSI), an accumulation of frameshift-like mutations that change the lengths of DNA regions. These frameshift-like mutations are coding for highly immunogenic antigens known as frameshift peptides (FSPs). Objectives: Here, we aimed to examine the cellular immune response in non-transplanted patients without cancer in order to show the impact of a specific immunosuppression in a chronic inflammatory disease. Material and methods: Frameshift peptide (FSP)-specific T cell responses were measured by enzymelinked immunospot (ELISpot) in the peripheral blood from patients with IBD and immunosuppressive treatment (n = 79). Blood samples of 20 healthy controls were examined additionally. Frequencies of FSP-specific T cells were quantified by determining the number of specific Interferon (IFN)-secreting T cells against FSPs derived from 14 coding microsatellitecontaining candidate genes by taking advantage of a commercially available ELISpot analysis. Results: There were 42 patients (53%) with Crohn`s disease and 37 patients (47%) with ulcerative colitis. Mean age was 43,7 years (range 20-80). T cells isolated from patients with IBD under immunosuppression specifically recognized MSI-induced FSPs in 62 of 79 patients (78,5%) and showed clear reactivity by increased IFN-secretion. This was a striking contrast to 20 healthy controls which did not show significant reactivity. Mean duration of disease was 12,1 years for patients who showed immune response compared to 7,9 years for patients without elevated immune response. 52 of 64 patients (81,2%) with azathioprine therapy showed reactivity. Interestingly, patients without azathioprine therapy also showed an increased immune response in 66,7% (10 of 15 patients). Conclusion: Patients with IBD and immunosuppressive treatment showed an increased immune response in the majority of patients referring to MSI-induced frameshift mutations. Mean duration of disease was longer in patients who showed an increased immune response. If this reactivity is due to a specific immunosuppression or if it is a characteristic sign of patients with IBD remains unclear. Further evaluation of IBD patients without any immunosuppressants will be necessary to answer this question.
AGA Abstracts
A20 (a Ubiquitin Editing E3 Ligase) Inhibits Intestinal Inflammation Hong Song, Zhanju Liu, Ping-Chang Yang Background and aims: Macrophages (Mos)-derived proinflammatory cytokines and nuclear factor-kappa B (NF-kB) play a critical role in the pathogenesis of inflammatory bowel disease (IBD). The ubiquitin E3 ligase A20 (A20) is required in limiting the activation of NF-kB. This study aims to elucidate the role of A20 in regulating the intestinal inflammation. Methods: We collected the colon biopsies from 14 UC, 11 CD and 8 colon polyp patients (using as a non-IBD control). IBD colon biopsy sections were observed by immune staining for A20 expression. A20-deficient and wild Mos were prepared; the cells were adoptively transferred to mice to characterize the role of A20 in limiting the intestinal inflammation. Results: The immune staining results showed that the A20+ Mos were localized in the normal colon mucosa that were significantly less in the IBD colonic mucosa (Numbers of A20+ Mos: 32.2 ± 3.6/mm2 and 16.5 ± 2.4/mm2 in colonic mucosa of control and IBD, respectively; p<0.01). Most Mos in the IBD colon mucosa did not express A20. We next tested the role of TNFa on the expression of A20 in Mos. Bone marrow derived Mos (BMos) were stimulated by a representative microbial product, peptidoglycan (PGN) in culture at graded doses. The expressions of both NF-kB and A20 in BMos were increased in a PGN dose-dependent manner. The addition of TNF-alpha into the culture significantly suppressed the levels of the A20 (reduced 3.5 ± 1.2 folds), but markedly increased the levels of NF-kB (increased 4.8 ± 1.4 folds) in BMos. To confirm the results, the TNFa receptor (TNFaR) gene was knocked down from BMos by RNA interference (RNAi) via transducing with lentiviral vector carrying TNFaR shRNA. Indeed, subsequent exposure to PGN did not alter the levels of A20 and NF-kB in the TNFaR-deficient BMos. The above results indicate that A20 is a repressor of NF-kB in Mos. We then knocked down the A20 gene in BMos by RNAi with lentiviral constructs carrying shRNA of A20. The A20-deficient BMos were stimulated with PGN that resulted in significant increases in TNFa (increased 3.8 ± 1.6 folds) and IL-1beta (increased 5.3 ± 1.8 folds) in the culture supernatants. The control shRNA did not alter the PGN-induced proinflammatory cytokines in BMos. Subsequently, we adoptively transferred the PGN-stimulated A20-deficient Mos (10 million Mos/mouse) to BALB/c mice and then treated with a small dose of TNBS (1.2 mg TNBS/mouse) via published procedures. The mice were sacrificed one week later to examine the colon. The results showed that mice treated with the small dose of TNBS alone did not show detectable signs of colitis while the mice treated with both PGN-stimulated A20-deficient BMos and a small dose of TNBS had severe inflammation in the colon. Conclusions: A20 plays an important role in limiting intestinal inflammation.
Tu1930 Cats-1 Study: Immunomonitoring and Clinical Results of Treg Cell Therapy for Crohn's Disease Arnaud Foussat, Pierre Desreumaux, Matthieu Allez, Laurent Beaugerie, Xavier Hebuterne, Yoram Bouhnik, Maria Nachury, Valérie Brun, Agnès Duchange, Nathalie Clerget-Chossat, MIguel Forte, Jean-Frederic Colombel INTRODUCTION: CATS1 study assessed the tolerability and efficacy of Ovasave, an antigenspecific T regulatory (Treg) therapy for patients with Crohn's Disease (CD). Treg cells induce immunomodulating effects through cytokines secretion and cell-cell contact. AIMS & METHODS: CATS1 was an open label, 12-week multicenter, single injection, ascending dose, phase I/II study in 20 patients (4 dose groups of 10e6 cells: 8 pts; 10e7: 3 pts; 10e8: 3 pts; 10e9: 6pts) with CD and active inflammation. Ovasave was produced ex vivo from patients' PBMC (peripheral blood mononuclear cells) exposed to ovalbumin followed by cell cloning, cell expansion and formulation for infusion. Patients were assessed for tolerability and efficacy (CDAI: responder: decrease >=100; in remission: <150; IBDQ and CRP). Patient's peripheral blood was collected before and 1, 3, 8 and 12 weeks after Ovasave administration. Change in peripheral blood immune cell populations was evaluated by flow cytometry. The impact of Ovasave on the proliferative response of patients' PBMC to ovalbumin In Vitro was also evaluated. RESULTS: Mean age was 34.5 and disease duration 12.9 years. CD was predominantly ileo-colic (65%) with a baseline CDAI of 364±81 (n=20) and IBDQ of 114±21 (n=19); 19/20 had previous failure to immuno supressors and anti-TNF and 16 had previous CD related surgery. Ovasave injections were well tolerated with 54 adverse events (15 possibly and 2 definitely related) and 11 serious adverse events (3 possibly related), all recovered. Response was observed in 40% (8/20) patients at weeks 5 and 8. In the best dose group (10e6 cells), response was 75% (6/8) at both time points; remission was 38% (3/8) and 25% (2/8) and the mean CDAI reduction 143.4±105 (p=0.0062) and 131.6.3±65.4 (p=0.002) at weeks 5 and 8 respectively. CRP (mg/l) dropped significantly (p=0.04) in responder (-11.4±6.3) patients versus non-responders (5.2±4.2). Immunomonitoring studies revealed that blood CD16+ pro-inflammatory monocytes, one of the contributors of mucosal inflammation, were selectively decreased 3 weeks after Ovasave administration in the group of responder patients. In this group, the proliferative response of PBMC to ovalbumin In Vitro was abolished 3 weeks after treatment, suggesting a direct suppression of ovalbuminspecific immune response. CONCLUSION: Treg cell therapy is well tolerated and shows a positive dose related efficacy in severe CD patients consistent across multiple assessment methods including mechanistic immunological measurements in patient's blood.
Tu1928 TNF-α-Induced Down-Regulation of CDx2 Suppresses Mep1a Expression in Colitis: A Potential Pathogenetic Key Factor in IBD Mehmet Coskun, Anders Krüger Olsen, Thomas L. Holm, Peter H. Kvist, Lene Riis, Jørgen Olsen, Jesper Troelsen, Ole H. Nielsen Background: High levels of pro-inflammatory cytokines in inflamed intestinal tissues are linked to the pathogenesis of Crohn's disease (CD) and ulcerative colitis (UC). The transcription factor CDX2 plays a crucial role in the differentiation of intestinal epithelial cells and regulates several inflammatory bowel disease (IBD) susceptibility genes, including MEP1A. Although previous studies have indicated a decreased expression of protective MEP1A in IBD, the underlying molecular mechanisms remain unknown. Aims: To investigate the expression of CDX2 and MEP1A in colitis; to assess if they are regulated by tumor necrosis factor-α (TNF-α), and finally to reveal if CDX2 is involved in a TNF-α-induced downregulation of MEP1A. Methods: Expression of CDX2 and MEP1A was investigated in active UC (n=6), quiescent UC (n=8), healthy controls (n=8) as well as in a murine experimental colitis model using dextran sodium sulphate (DSS) (n=24). The disease activity of all UC patients were prior to a colonoscopy graded in accordance with the Mayo score: A score ≤ 2 as quiescent, and > 2 as active disease. The DSS colitis model was graded according to the disease activity index (DAI) score. CDX2 protein expression and its localization was investigated by immunoblotting and by standard immunohistochemical procedures. CDX2 and MEP1A regulation was examined in TNF-α-treated Caco-2 cells by quantitative reversetranscription polymerase chain reaction (RT-PCR) and with reporter gene assays, and the effect of anti-TNF-α treatment was assessed using infliximab at a pharmacological relevant dosage (100 μg/ml). Finally, In Vivo CDX2-DNA interactions were investigated by chromatin immunoprecipitation. Results: CDX2 and MEP1A expression significantly declined during inflammation in active UC patients as well as DSS-induced colitis. TNF-α treatment of Caco2 cells significantly diminished the CDX2 and MEP1A mRNA levels (p<0.001), respectively, a decrease which, however, was counteracted by infliximab treatment. In line with these results, reporter gene assays showed significantly reduced CDX2 and MEP1A transcriptional activity upon TNF-α stimulation (p<0.05), respectively. Finally, we found that TNF-α treatment impaired the ability of CDX2 to interact and activate its own as well as the MEP1A expression (p<0.05). Conclusions: This study suggests that a TNF-α-mediated downregulation of CDX2 might be related to a suppressed expression and activity of MEP1A during inflammation. The present results indicate that a dysfunctional CDX2 expression could be a key factor involved in the pathogenesis of UC.
Tu1931 The Influence of Vitamin a on the Intestinal Permeability and a Release of Cytokines From Human In Vitro-Differentiated Macrophages and Dendritic Cells Kacper A. Wojtal, Harald Kropshofer, Lutz Mueller, Lutz Wolfram, Stephan R. Vavricka, Gerhard Rogler Background & Aims: Vitamin A and retinoids are a group of biologically active compounds, which play various roles in the healthy and pathological conditions. They are essential for cell growth, vision and the immune system. Retinoids inflict their biologic activity via retinoic acid receptors (RARs), which bind to retinoic acid response element (RARE) and induce transcription. The aim of this study was to evaluate the potential role of vitamine A and its derivatives on the intestinal permeability and immune response. Methods: All-trans- (ATRA), 13-cis- (isotretinoin) and 4-oxo-13-cis-retinoic acid (human metabolite of isotretinoin) were used at different concentrations (0.01-5μg/ml) for all stimulation experiments. Human intestinal cell line Caco2 was grown and stimulated on the transwells. The effect of retinoids on the intestinal permeability was assessed by diffusion of FITC-dextran (10kDa) across monolayers. Human monocytes were isolated from peripheral mononuclear cells obtained from healthy donors using the monocyte isolation kit (negative selection). From monocytes In Vitro-differentiated macrophages (ivMACs) were generated using teflon bags and In Vitrodifferentiated dendritic cells (ivDCs) by stimulation with IL-4 and GM-CSF. Additionally, in order to confirm findings monocytic/ macrophage cell line THP-1 was used. To measure pro- and anti-inflammatory responses cell supernatant was analyzed by multikine ELISA.
Tu1929 Patients With Inflammatory Bowel Disease and Immunosuppressive Treatment Show Cellular Immune Response Towards Microsatellite Instability-Induced Frameshift Mutations Florian Kuehn, Ernst Klar, Anja Bliemeister, Michael Linnebacher Introduction: An immunosuppressive treatment after organ transplantation is an acknowledged risk factor for several malignant diseases such as lymphoma, skin cancer and acute myeloid leukaemia. Specified evaluation showed that a thiopurine treatment of human cells In Vitro selects variants with a defective DNA mismatch repair system (MMR). Inactivation of MMR leads to an increased spontaneous mutation rate. This mutator effect is observed
AGA Abstracts
S-880
as microsatellite instability (MSI), an accumulation of frameshift-like mutations that change the lengths of DNA regions. These frameshift-like mutations are coding for highly immunogenic antigens known as frameshift peptides (FSPs). Objectives: Here, we aimed to examine the cellular immune response in non-transplanted patients without cancer in order to show the impact of a specific immunosuppression in a chronic inflammatory disease. Material and methods: Frameshift peptide (FSP)-specific T cell responses were measured by enzymelinked immunospot (ELISpot) in the peripheral blood from patients with IBD and immunosuppressive treatment (n = 79). Blood samples of 20 healthy controls were examined additionally. Frequencies of FSP-specific T cells were quantified by determining the number of specific Interferon (IFN)-secreting T cells against FSPs derived from 14 coding microsatellitecontaining candidate genes by taking advantage of a commercially available ELISpot analysis. Results: There were 42 patients (53%) with Crohn`s disease and 37 patients (47%) with ulcerative colitis. Mean age was 43,7 years (range 20-80). T cells isolated from patients with IBD under immunosuppression specifically recognized MSI-induced FSPs in 62 of 79 patients (78,5%) and showed clear reactivity by increased IFN-secretion. This was a striking contrast to 20 healthy controls which did not show significant reactivity. Mean duration of disease was 12,1 years for patients who showed immune response compared to 7,9 years for patients without elevated immune response. 52 of 64 patients (81,2%) with azathioprine therapy showed reactivity. Interestingly, patients without azathioprine therapy also showed an increased immune response in 66,7% (10 of 15 patients). Conclusion: Patients with IBD and immunosuppressive treatment showed an increased immune response in the majority of patients referring to MSI-induced frameshift mutations. Mean duration of disease was longer in patients who showed an increased immune response. If this reactivity is due to a specific immunosuppression or if it is a characteristic sign of patients with IBD remains unclear. Further evaluation of IBD patients without any immunosuppressants will be necessary to answer this question.
AGA Abstracts
A20 (a Ubiquitin Editing E3 Ligase) Inhibits Intestinal Inflammation Hong Song, Zhanju Liu, Ping-Chang Yang Background and aims: Macrophages (Mos)-derived proinflammatory cytokines and nuclear factor-kappa B (NF-kB) play a critical role in the pathogenesis of inflammatory bowel disease (IBD). The ubiquitin E3 ligase A20 (A20) is required in limiting the activation of NF-kB. This study aims to elucidate the role of A20 in regulating the intestinal inflammation. Methods: We collected the colon biopsies from 14 UC, 11 CD and 8 colon polyp patients (using as a non-IBD control). IBD colon biopsy sections were observed by immune staining for A20 expression. A20-deficient and wild Mos were prepared; the cells were adoptively transferred to mice to characterize the role of A20 in limiting the intestinal inflammation. Results: The immune staining results showed that the A20+ Mos were localized in the normal colon mucosa that were significantly less in the IBD colonic mucosa (Numbers of A20+ Mos: 32.2 ± 3.6/mm2 and 16.5 ± 2.4/mm2 in colonic mucosa of control and IBD, respectively; p<0.01). Most Mos in the IBD colon mucosa did not express A20. We next tested the role of TNFa on the expression of A20 in Mos. Bone marrow derived Mos (BMos) were stimulated by a representative microbial product, peptidoglycan (PGN) in culture at graded doses. The expressions of both NF-kB and A20 in BMos were increased in a PGN dose-dependent manner. The addition of TNF-alpha into the culture significantly suppressed the levels of the A20 (reduced 3.5 ± 1.2 folds), but markedly increased the levels of NF-kB (increased 4.8 ± 1.4 folds) in BMos. To confirm the results, the TNFa receptor (TNFaR) gene was knocked down from BMos by RNA interference (RNAi) via transducing with lentiviral vector carrying TNFaR shRNA. Indeed, subsequent exposure to PGN did not alter the levels of A20 and NF-kB in the TNFaR-deficient BMos. The above results indicate that A20 is a repressor of NF-kB in Mos. We then knocked down the A20 gene in BMos by RNAi with lentiviral constructs carrying shRNA of A20. The A20-deficient BMos were stimulated with PGN that resulted in significant increases in TNFa (increased 3.8 ± 1.6 folds) and IL-1beta (increased 5.3 ± 1.8 folds) in the culture supernatants. The control shRNA did not alter the PGN-induced proinflammatory cytokines in BMos. Subsequently, we adoptively transferred the PGN-stimulated A20-deficient Mos (10 million Mos/mouse) to BALB/c mice and then treated with a small dose of TNBS (1.2 mg TNBS/mouse) via published procedures. The mice were sacrificed one week later to examine the colon. The results showed that mice treated with the small dose of TNBS alone did not show detectable signs of colitis while the mice treated with both PGN-stimulated A20-deficient BMos and a small dose of TNBS had severe inflammation in the colon. Conclusions: A20 plays an important role in limiting intestinal inflammation.
Tu1930 Cats-1 Study: Immunomonitoring and Clinical Results of Treg Cell Therapy for Crohn's Disease Arnaud Foussat, Pierre Desreumaux, Matthieu Allez, Laurent Beaugerie, Xavier Hebuterne, Yoram Bouhnik, Maria Nachury, Valérie Brun, Agnès Duchange, Nathalie Clerget-Chossat, MIguel Forte, Jean-Frederic Colombel INTRODUCTION: CATS1 study assessed the tolerability and efficacy of Ovasave, an antigenspecific T regulatory (Treg) therapy for patients with Crohn's Disease (CD). Treg cells induce immunomodulating effects through cytokines secretion and cell-cell contact. AIMS & METHODS: CATS1 was an open label, 12-week multicenter, single injection, ascending dose, phase I/II study in 20 patients (4 dose groups of 10e6 cells: 8 pts; 10e7: 3 pts; 10e8: 3 pts; 10e9: 6pts) with CD and active inflammation. Ovasave was produced ex vivo from patients' PBMC (peripheral blood mononuclear cells) exposed to ovalbumin followed by cell cloning, cell expansion and formulation for infusion. Patients were assessed for tolerability and efficacy (CDAI: responder: decrease >=100; in remission: <150; IBDQ and CRP). Patient's peripheral blood was collected before and 1, 3, 8 and 12 weeks after Ovasave administration. Change in peripheral blood immune cell populations was evaluated by flow cytometry. The impact of Ovasave on the proliferative response of patients' PBMC to ovalbumin In Vitro was also evaluated. RESULTS: Mean age was 34.5 and disease duration 12.9 years. CD was predominantly ileo-colic (65%) with a baseline CDAI of 364±81 (n=20) and IBDQ of 114±21 (n=19); 19/20 had previous failure to immuno supressors and anti-TNF and 16 had previous CD related surgery. Ovasave injections were well tolerated with 54 adverse events (15 possibly and 2 definitely related) and 11 serious adverse events (3 possibly related), all recovered. Response was observed in 40% (8/20) patients at weeks 5 and 8. In the best dose group (10e6 cells), response was 75% (6/8) at both time points; remission was 38% (3/8) and 25% (2/8) and the mean CDAI reduction 143.4±105 (p=0.0062) and 131.6.3±65.4 (p=0.002) at weeks 5 and 8 respectively. CRP (mg/l) dropped significantly (p=0.04) in responder (-11.4±6.3) patients versus non-responders (5.2±4.2). Immunomonitoring studies revealed that blood CD16+ pro-inflammatory monocytes, one of the contributors of mucosal inflammation, were selectively decreased 3 weeks after Ovasave administration in the group of responder patients. In this group, the proliferative response of PBMC to ovalbumin In Vitro was abolished 3 weeks after treatment, suggesting a direct suppression of ovalbuminspecific immune response. CONCLUSION: Treg cell therapy is well tolerated and shows a positive dose related efficacy in severe CD patients consistent across multiple assessment methods including mechanistic immunological measurements in patient's blood.
Tu1928 TNF-α-Induced Down-Regulation of CDx2 Suppresses Mep1a Expression in Colitis: A Potential Pathogenetic Key Factor in IBD Mehmet Coskun, Anders Krüger Olsen, Thomas L. Holm, Peter H. Kvist, Lene Riis, Jørgen Olsen, Jesper Troelsen, Ole H. Nielsen Background: High levels of pro-inflammatory cytokines in inflamed intestinal tissues are linked to the pathogenesis of Crohn's disease (CD) and ulcerative colitis (UC). The transcription factor CDX2 plays a crucial role in the differentiation of intestinal epithelial cells and regulates several inflammatory bowel disease (IBD) susceptibility genes, including MEP1A. Although previous studies have indicated a decreased expression of protective MEP1A in IBD, the underlying molecular mechanisms remain unknown. Aims: To investigate the expression of CDX2 and MEP1A in colitis; to assess if they are regulated by tumor necrosis factor-α (TNF-α), and finally to reveal if CDX2 is involved in a TNF-α-induced downregulation of MEP1A. Methods: Expression of CDX2 and MEP1A was investigated in active UC (n=6), quiescent UC (n=8), healthy controls (n=8) as well as in a murine experimental colitis model using dextran sodium sulphate (DSS) (n=24). The disease activity of all UC patients were prior to a colonoscopy graded in accordance with the Mayo score: A score ≤ 2 as quiescent, and > 2 as active disease. The DSS colitis model was graded according to the disease activity index (DAI) score. CDX2 protein expression and its localization was investigated by immunoblotting and by standard immunohistochemical procedures. CDX2 and MEP1A regulation was examined in TNF-α-treated Caco-2 cells by quantitative reversetranscription polymerase chain reaction (RT-PCR) and with reporter gene assays, and the effect of anti-TNF-α treatment was assessed using infliximab at a pharmacological relevant dosage (100 μg/ml). Finally, In Vivo CDX2-DNA interactions were investigated by chromatin immunoprecipitation. Results: CDX2 and MEP1A expression significantly declined during inflammation in active UC patients as well as DSS-induced colitis. TNF-α treatment of Caco2 cells significantly diminished the CDX2 and MEP1A mRNA levels (p<0.001), respectively, a decrease which, however, was counteracted by infliximab treatment. In line with these results, reporter gene assays showed significantly reduced CDX2 and MEP1A transcriptional activity upon TNF-α stimulation (p<0.05), respectively. Finally, we found that TNF-α treatment impaired the ability of CDX2 to interact and activate its own as well as the MEP1A expression (p<0.05). Conclusions: This study suggests that a TNF-α-mediated downregulation of CDX2 might be related to a suppressed expression and activity of MEP1A during inflammation. The present results indicate that a dysfunctional CDX2 expression could be a key factor involved in the pathogenesis of UC.
Tu1931 The Influence of Vitamin a on the Intestinal Permeability and a Release of Cytokines From Human In Vitro-Differentiated Macrophages and Dendritic Cells Kacper A. Wojtal, Harald Kropshofer, Lutz Mueller, Lutz Wolfram, Stephan R. Vavricka, Gerhard Rogler Background & Aims: Vitamin A and retinoids are a group of biologically active compounds, which play various roles in the healthy and pathological conditions. They are essential for cell growth, vision and the immune system. Retinoids inflict their biologic activity via retinoic acid receptors (RARs), which bind to retinoic acid response element (RARE) and induce transcription. The aim of this study was to evaluate the potential role of vitamine A and its derivatives on the intestinal permeability and immune response. Methods: All-trans- (ATRA), 13-cis- (isotretinoin) and 4-oxo-13-cis-retinoic acid (human metabolite of isotretinoin) were used at different concentrations (0.01-5μg/ml) for all stimulation experiments. Human intestinal cell line Caco2 was grown and stimulated on the transwells. The effect of retinoids on the intestinal permeability was assessed by diffusion of FITC-dextran (10kDa) across monolayers. Human monocytes were isolated from peripheral mononuclear cells obtained from healthy donors using the monocyte isolation kit (negative selection). From monocytes In Vitro-differentiated macrophages (ivMACs) were generated using teflon bags and In Vitrodifferentiated dendritic cells (ivDCs) by stimulation with IL-4 and GM-CSF. Additionally, in order to confirm findings monocytic/ macrophage cell line THP-1 was used. To measure pro- and anti-inflammatory responses cell supernatant was analyzed by multikine ELISA.
Tu1929 Patients With Inflammatory Bowel Disease and Immunosuppressive Treatment Show Cellular Immune Response Towards Microsatellite Instability-Induced Frameshift Mutations Florian Kuehn, Ernst Klar, Anja Bliemeister, Michael Linnebacher Introduction: An immunosuppressive treatment after organ transplantation is an acknowledged risk factor for several malignant diseases such as lymphoma, skin cancer and acute myeloid leukaemia. Specified evaluation showed that a thiopurine treatment of human cells In Vitro selects variants with a defective DNA mismatch repair system (MMR). Inactivation of MMR leads to an increased spontaneous mutation rate. This mutator effect is observed
AGA Abstracts
S-880