P089 Immune system cell differences between Crohn’s disease and ulcerative colitis patients in remission under anti TNF treatment
S. Notararigo1, J.E. Viñuela Roldán2, A. Quiroga3, J.E. Dominguez-Munoz3, M. Barreiro-de Acosta3
1FIDIS, Laboratory of Gastroenterology, Santiago de Compostela, Spain, 2University Hospital, Immunology Laboratory, Santiago, Spain, 3University Hospital Santiago De Compostela CHUS, Department of Gastroenterology- IBD Unit, Santiago De Compostela, Spain
Background
Inflammatory bowel disease (Crohn’s disease (CD) and ulcerative colitis (UC)) are chronic gastrointestinal disorders of unknown aetiology where the immune system dysregulation is the responsible for immunological imbalance characterised by a relevant production of pro-inflammatory cytokines. The tumour necrosis factor-α (TNF-α) plays a central role in the mucosal inflammation, recruiting and over stimulating other immune system cells like Th1. The aim of this study is to describe CD4+T cells sampled in fresh peripheral blood in IBD patients and in healthy controls (HCs) to estimate the effect of IFX on peripheral immune system cell subtypes.
Methods
A pilot case–control study was performed. Inclusion criteria were IBD patients in clinical remission under maintenance IFX treatment. Remission was defined as a Partial Mayo <2 in UC and a Harvey–Bradshaw <4 in CD. The inflammation patient’s condition was measured by C-reactive protein (CRP) and Calprotectin. After informed consent, blood samples were obtained in IBD patients just before IFX infusions and in HC. Participants were classified in different groups (1) HC, (2) CD and (3) UC. To investigate the immune system cell subtype, PBMCs were isolated from fresh blood in order to characterise: monocyte, dendritic cells (DC), Th1, Th17, Thf and Th1/Th17. Cells were then incubated with specific fluorescent antibodies’ cocktails, then identified with flow cytometry. We spotlight on DC and monocyte, in order to characterise the plasticity of both.
Results
Thirty-two participants were consecutively included 13CD, 9UC, mean age 43, all in remission under IFX maintenance therapy and 10 HC. Mean CRP was 0.08 mg/dl and 99.5 µg/g. Th1 CD4+CXCR3+increased in UC than CD patients, showing a tendency reaching a relative value of 45% vs. 34% of HC, nevertheless the expression of CCR5 maintained normal value in both groups. Th17 CD4+CCR6+CD161+significantly increase in CD and UC groups vs. control, indeed the Th17/Thf CD4+CCR6+CXCR5+showed higher expression in UC patients, as well as the Thf subtype CD4+CXCR5+conduct. Th1/Th17 CD4+CXCR3+CCR6+belonging to Th17 subtype showed a tendency to rise in UC with a relative value of 23% vs. 19% HC. DC did not show difference in Myeloid subtype CD11C+and Precursor CD11C+CD123low. Plasmacytoid CD11C+CD123+increased significantly in UC with a relative value of 6.5%. Monocyte M3 CD14−CD16+ revealed itself to be higher in UC than in CD.
Conclusion
The immune system cell subset is highly modified by the IBD disease type (CD,UC) despite being in remission under IFX therapy. Th1 levels are significantly augmented although their reactivity is not altered by CCR5 detection. Plamacytoid DC cell increases in UC patients if total amount of CD11C+ CD diminishes.