Introduction Crohn’s disease (CD) is characterised by an exaggerated immune response to mucosal antigen. Dendritic cells (DC) are the primary antigen presenting cells and may promote either tolerogenic or inflammatory T cell responses to mucosal antigens. We characterised homing marker profile and ongoing cytokine production of circulating DC subsets from patients with Crohn’s disease. Methods DC within peripheral blood mononuclear cells from adults with active luminal Crohn’s or from healthy controls (HC) were characterised using flow cytometry. DC were identified as HLA-DR + and negative for markers of other cell lineages (CD3, CD14, CD16, CD19, CD34). Myeloid DC (mDC, CD11c + CD123 − ) and plasmacytoid DC (pDC, CD11c − CD123 + ) were assessed for phenotype (maturation status, homing markers and pattern recognition receptors) and on-going cytokine production by surface and intracellular staining, respectively. Results In patients with Crohn’s (n = 16), a greater proportion of myeloid DC expressed a gut-homing profile (CLA − β7 + , p = 0.0022) compared to controls (n = 10) where most myeloid DC were not tissue-specific (CLA + β7 + , p = 0.0014, Fig C). In Crohn’s and controls, myeloid DC were largely gut-homing (CLA − β7 + , p = 0.003) whilst plasmacytoid DC were strongly skin (CLA + β7 − ) and lymph node (CCR7 + ) homing (p Conclusion The increased myeloid DC expression of gut homing phenotype markers and production of TNFα in Crohn’s compared with controls highlights the central role that DC play in the pathogenesis of Crohn’s disease. Differences between homing markers on myeloid DC (gut homing) and plasmacytoid DC (skin homing) suggest that they may have different roles in different manifestations of Crohn’s, with myeloid DC being central to gut inflammation whilst plasmacytoid DC might be involved in cutaneous Crohn’s disease and the skin sequelae of anti-TNFα therapy. Disclosure of Interest None Declared

Introduction Dendritic cells (DC) can determine whether the mucosal immune system mounts an inflammatory or regulatory response to antigen and may contribute to the pathogenesis of Crohn’s disease. Vitamin D down-regulates DC inflammatory responses and could prove beneficial as a treatment adjunct in Crohn’s. This study assessed the effect of high dose parenteral vitamin D treatment on circulating DC phenotype and function in patients with active luminal Crohn’s receiving anti-TNFα therapy. Methods Peripheral blood mononuclear cells were isolated from 13 patients with active luminal Crohn’s and suboptimal vitamin D levels prior to and 6 weeks after starting anti-TNFα (infliximab) therapy. Patients with low vitamin D (<50nmol/L) were also given a single high dose of parenteral vitamin D (300,000 international units 1,25(OH)2 vitamin D3). Flow cytometry was used to identify total DC, (HLA-DR+ cells negative for markers of other cell lineages (CD3, CD14, CD16, CD19 & CD34)). DC were further subtyped as myeloid (mDC, CD11c+CD123−). Expression of phenotypic markers (including maturation and homing markers and pattern recognition receptors) and on-going DC cytokine production during 4 hours’ culture were assessed. Results Production of TNFα by myeloid DC was significantly reduced (p = 0.016 Fig C) in those patients who received vitamin D alongside anti-TNFα therapy; without vitamin D treatment, TNFα production by myeloid DC did not decrease significantly after anti-TNFα therapy (p = 0.96 Fig B). There was a significant negative correlation between change in vitamin D level and change in TNFα production by myeloid DC (p = 0.025, correlation coefficient =0.68 Fig D). An increase of serum 25(OH)vitamin D greater than 20 nmol/m was associated with a decrease in myeloid DC TNFα production. Anti-TNFα therapy alone induced a significant upregulation of the skin homing marker cutaneous lymphocyte antigen (CLA) on myeloid DC (p = 0.0055), an effect which was not seen in patients receiving adjunctive vitamin D.Abstract PWE-023 Figure 1 A&B TNFα production by mDC before and after treatment with anti-TNFα therapy in: patients who did not (A) and patients who did (B) receive vitamin D. (C) Correlation of change in vitamin D level and decrease in TNFα production by mDC Conclusion High doses of parenteral vitamin D in patients with Crohn’s promotes anti-TNFα down-regulation of circulating myeloid DC production of TNFα which may influence the subsequent interaction of DC and T cells. TNFα promotes a TH-1/ TH-17 response characteristic of Crohn’s inflammation; thus the ability of vitamin D to further block TNFα production may promote a more regulatory T cell response and improve outcomes when used as an adjunct to anti-TNFα therapy. The down-regulation of skin homing marker CLA by vitamin D may be clinically useful in those patients suffering cutaneous sequelae of anti-TNFα therapy. Disclosure of Interest None Declared

Introduction Dendritic cells (DC) act as a bridge between the innate and adaptive immune system, sensing and presenting antigen to lymphocytes and mounting either a tolerogenic or inflammatory response. They are able to imprint homing capacity on T-cells, directing them into specific tissues. Abnormal DC function contributes to the pathogenesis of Crohn’s disease and thus DC represent a potential therapeutic target. In this study we have investigated the effect of anti-TNFα therapy on circulating DC of patients with Crohn’s disease. Methods We recruited 13 consecutive patients with active luminal Crohn’s due to start anti-TNFα therapy. Clinical parameters including the Harvey-Bradshaw index, C-reactive protein and faecal calprotectin were measured. Peripheral blood mononuclear cells were isolated from each patient immediately before and six weeks after commencing anti-TNFα therapy. At both time points flow cytometry was performed to assess DC phenotype and function. We also analysed subsets of DC: myeloid (mDC, CD11c + CD123 − ) and plasmacytoid (pDC, CD11c − CD123 + ). Expression of phenotypic markers (including maturation and homing markers and pattern recognition receptors) and intra-cellular on-going DC cytokine production were determined. Results Treatment with anti-TNFα resulted in an alteration of the phenotype of mDC in Crohn’s disease. The gut homing phenotype of mDC in Crohn’s disease was down-regulated with anti-TNFα (CLA − β7 + p = 0.0056 Fig A) whilst the non-tissue specific phenotype (CLA + β7 + p = 0.0026 Fig not shown) and skin homing phenotype were up-regulated (CLA + β7 − p = 0.0055 Fig B). Production of TNFα and IL-6 by mDC and pDC respectively, shown to be increased in Crohn’s disease, was significantly reduced by anti-TNFα therapy (p = 0.033 and p = 0.014 Fig C and Fig D respectively). Production of IL-10 was increased following therapy (p = 0.051). There were no changes in IL-12, IL-23 and IFN-α production. Significant improvements in clinical markers were observed following treatment. Conclusion The reversal of inflammatory DC phenotype and function by anti-TNFα further highlights the potential role this antigen presenting cell may play in the pathogenesis of Crohn’s disease. DC are a promising therapeutic target in Crohn’s because they can be modulated to express a non-gut homing phenotype and direct T cells away from the gut and promote tolerogenic effects. The increase in skin homing DC following anti-TNFα treatment may explain the high rate of skin complications. The reduction in gut homing DC may offer an explanation for reduced treatment success with vedolizumab (α4β7 blocker) after previous anti-TNFα therapy (reduction of vedolizumab treatment target). Disclosure of Interest None Declared

The term breast-milk jaundice was used in a previously reported (wong and wood) claim of a high indicence of jaundice in breast-fed infants whose mothers previously had taken the oral contraceptive pills. This study selected 120 newborns from 1968-1971 clinically jaundiced during the first 10 days of life having serum bilirubin over 10 mcg/100 ml but without low birth weight illness or positive direct Coombs test. Mothers were questioned on use of oral contraceptives: 82 replied and 82 control mothers were also questioned. The results showed 15 mothers of jaundiced breast-fed babies used the pill; 9 mothers of jaundiced bottle-fed babies used the pill; 23 mothers of jaundiced breast-fed babies had not used the pill. In comparison 8 mothers of nonjaundiced breast-fed babies used the pill; 12 mothers of nonjaundiced bottle-fed babies used the pill; and 25 mothers of nonjaundiced breast-fed babies had not used the pill. These differences were not significant by the chi-square test.

Summary.— The treatment of psoriasis with methotrexate carries a low but definite risk of producing histological abnormalities in the liver. Forty-two patients treated for 3 to 80 months were found to have more histological abnormalities than 25 untreated patients with equally severe psoriasis. Of the treated patients, 3 had cirrhosis, all of whom were heavy drinkers, and 12 had fibrosis. None of the untreated patients had cirrhosis, but 4 had fibrosis. Only the cirrhotic patients showed clinical evidence of hepatic inpairment. The incidence of histological abnormality increased with increasing cumulative dosage of methotrexate, but patients on weekly therapy had less abnormality than those on daily oral therapy. Fourteen of the 25 untreated patients were given the drug subsequently, once weekly for a mean period of 23 months. Very few additional histological abnormalities have developed. In patients with socially and physically crippling psoriasis where methotrexate would be used, the risk of significant hepatic damage is low enough to be acceptable, providing supervision is thorough.