Vedolizumab and Ustekinumab Levels in Pregnant Women With Inflammatory Bowel Disease and Infants Exposed In Utero.

BACKGROUND & AIMS: Vedolizumab and ustekinumab pharmacokinetics in pregnancy and the infant after in utero exposure remain incompletely defined. We aim to define the antenatal stability of ustekinumab and vedolizumab levels and the time at which infant drug levels become undetectable. METHODS: This multicenter prospective observational cohort study recruited pregnant or preconception women with inflammatory bowel disease receiving vedolizumab or ustekinumab. Trough drug levels, clinical data, and biochemical data were documented preconception, during each trimester of pregnancy, and postpartum. Maternal and cord blood drug levels were measured at delivery and in infants until undetectable. Infant outcomes were assessed until 2 years of age. RESULTS: A total of 102 participants (vedolizumab, n = 58) were included. The majority of mothers were, and remained, in clinical and biochemical remission. Maternal vedolizumab levels decreased over the course of pregnancy in association with increasing weight, rather than increasing gestation. Maternal ustekinumab levels remained stable. The median time to drug becoming undetectable in the infant was shorter for vedolizumab (11 wk; range, 5-19 wk; n = 32) than ustekinumab (14 wk; range, 9-36 wk; n = 17) and correlated positively with infant delivery level. Thirty-two of 41 (88%) and 17 of 30 (67%) vedolizumab- and ustekinumab-exposed infants had undetectable drug levels by 15 weeks of age, respectively. Pregnancy and infant outcomes were favorable. Twenty infants with undetectable drug levels received the rotavirus vaccine, with no adverse reactions reported. CONCLUSIONS: Maternal vedolizumab levels decreased, whereas ustekinumab levels remained stable over the course of pregnancy. Most vedolizumab- and approximately half of ustekinumab-exposed infants had undetectable drug levels by 15 weeks of age. No concerning maternal or infant safety signals were identified.

Thiopurine metabolite shunting in late pregnancy increases the risk of intrahepatic cholestasis of pregnancy in women with inflammatory bowel disease, and can be managed with split-dosing.

BACKGROUND AND AIMS: The risk of intrahepatic cholestasis of pregnancy (ICP) is increased in thiopurine exposed pregnancies. Thiopurine 'shunting', with a 6-methylmecrcaptopurine (MMP) to 6-thioguanine (TGN) ratio of >11, progresses over pregnancy, and may promote ICP development. We aimed to explore the association between thiopurine exposure and ICP, including the hypothesized impact of thiopurine shunting, and identify risk minimization strategies. METHODS: This prospective multi-centre cohort study compared thiopurine and biologic monotherapy exposed pregnant participants. Disease activity and obstetric outcome data, thiopurine metabolites, bile acids and transaminases were obtained preconception, in each trimester, at delivery, and post-partum. Thiopurine dose management was at the discretion of the treating physician. RESULTS: 131 thiopurine and 147 biologic monotherapy exposed pregnancies were included. MMP/TGN ratio increased from preconception to third trimester (p<0.01), with approximately 25% of participants shunting in pregnancy. Second trimester split-dosing led to a decrease in the median MMP/TGN ratio from 18 (IQR 6-57) to 3 (IQR 2-3.5) at delivery (p=0.04). The risk of ICP was increased in thiopurine exposed pregnancies (6.7% (7/105) vs 0% (0/112), p<0.001), with all ICP cases occurring in the setting of antenatal thiopurine shunting. Thiopurine dose increases (RR 8.10 [95% CI 1.88-34.85] p=0.005) and shunting in third trimester (6.20 [1.21-30.73] p=0.028) and at delivery (14.18 [1.62-123.9] p=0.016) were associated with an increased risk of ICP. CONCLUSIONS: Thiopurine exposure is associated with an increased risk of ICP, particularly following dose increases antenatally and with shunting in late pregnancy. The latter may be effectively managed with split dosing, although further studies are warranted.

Thrombocytosis and Transaminitis in Infants Born to Women With Inflammatory Bowel Disease Is Associated With Exposure to Maternal Inflammation In Utero.

BACKGROUND: Despite reassuring clinical safety data, thrombocytosis, anemia, lymphopenia, and liver function derangements have been observed in infants born to women with inflammatory bowel disease (IBD) treated with thiopurines and biologics. We aimed to define the prevalence, course, associations, and clinical impact of hematological and biochemical abnormalities in such infants. METHODS: This multicenter prospective cohort study assessed clinical, hematologic, and biochemical outcomes of infants exposed to thiopurines or biologics in utero for management of maternal IBD. Liver transaminases, full blood examination, and infant thiopurine metabolites (where exposed) were taken at delivery and 6 weeks of age. Abnormal results were repeated until normalization. Infants were followed clinically by a pediatric gastroenterologist up to 2 years of age. RESULTS: A total of 130 infants were included. Thrombocytosis and elevated alanine transaminase (ALT) were seen in over half of infants up to 6 months of age with no significant clinical impact. Elevated ALT was associated with increasing maternal C-reactive protein in second trimester, while thrombocytosis was associated with increasing maternal C-reactive protein and fecal calprotectin in third trimester. Preceding infection and vaccination were associated with an increased risk of elevated alkaline phosphatase at 3 months. In those exposed to thiopurines, increasing maternal 6-methylmercaptopurine at delivery was associated with increased ALT to 6 months. CONCLUSIONS: Infants born to women with IBD commonly developed thrombocytosis, elevated alkaline phosphatase, and elevated ALT. These findings were associated with exposure to maternal inflammation, elevated 6-methylmercaptopurine at delivery, and infant vaccinations and infections, and had minimal clinical consequence.

Hematological and biochemical abnormalities have been observed in infants born to women with inflammatory bowel disease. This prospective study shows that thrombocytosis and elevated alanine transaminase are common in infants to 6 months of age and are associated with maternal inflammation, rather than with in utero medication exposures.

Colonic cytomegalovirus DNA detection by polymerase chain reaction does not influence outcomes in inflammatory bowel disease and immunosuppressed cohorts.

BACKGROUND AND AIM: Cytomegalovirus (CMV) colitis is associated with negative outcomes in inflammatory bowel disease (IBD) and immunosuppressed cohorts and therefore requires timely recognition for appropriate management. We aimed to evaluate the diagnostic tools for CMV colitis and their associations with clinical outcomes. METHODS: A retrospective cohort study of patients in a metropolitan health service with colonic samples analysed for CMV between 2012 and 2022, stratified into IBD and non-IBD groups, was performed. The main outcome measures were the prevalence of positive and negative results for each CMV test, as well as need for colectomy, use of antiviral and hospital length of stay. RESULTS: Five hundred eighty-two biopsies from 418 patients were included; the median age was 36 years (interquartile range, 24-52 years) and 223 (53.3%) were men. Four hundred sixty-one (79.2%) biopsies were from patients with IBD and 121 (20.8%) were from those without IBD. There were similar proportions of positive CMV histology (IBD 5.9% and non-IBD 7.4%) and tissue CMV polymerase chain reaction (PCR) in the two groups (IBD 5.6% and non-IBD 5.0%), but within each group, results were discordant. Positive CMV histology was significantly associated with need for colectomy in the IBD group, while positive tissue CMV PCR was not. Positive CMV histology, and tissue and serum CMV PCR were all significantly associated with antiviral use. Positive serum CMV PCR was significantly associated with colectomy. CONCLUSIONS: Histopathology remains the most predictive tool in assessing CMV colitis, while qualitative tissue CMV PCR was found to have limited utility. Quantitative serum CMV PCR may be useful but requires further evaluation.

The interplay between the microbiota, diet and T regulatory cells in the preservation of the gut barrier in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is becoming more common in the Western world due to changes in diet-related microbial dysbiosis, genetics and lifestyle. Incidences of gut permeability can predate IBD and continued gut barrier disruptions increase the exposure of bacterial antigens to the immune system thereby perpetuating chronic inflammation. Currently, most of the approved IBD therapies target individual pro-inflammatory cytokines and pathways. However, they fail in approximately 50% of patients due to their inability to overcome the redundant pro inflammatory immune responses. There is increasing interest in the therapeutic potential of T regulatory cells (Tregs) in inflammatory conditions due to their widespread capability to dampen inflammation, promote tolerance of intestinal bacteria, facilitate healing of the mucosal barrier and ability to be engineered for more targeted therapy. Intestinal Treg populations are inherently shaped by dietary molecules and gut microbiota-derived metabolites. Thus, understanding how these molecules influence Treg-mediated preservation of the intestinal barrier will provide insights into immune tolerance-mediated mucosal homeostasis. This review comprehensively explores the interplay between diet, gut microbiota, and immune system in influencing the intestinal barrier function to attenuate the progression of colitis.

Evaluation and management of ileal pouch-anal anastamosis (IPAA) complications in pregnancy, and the impacts of an IPAA on fertility.

Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) remains the preferred surgical option for medically refractory ulcerative colitis. Management of individuals with an IPAA prior to and during pregnancy presents challenges that can have serious consequences. Infertility, mechanical obstructive and inflammatory pouch complications are frequently encountered in pregnant women with an IPAA. Mechanical obstructions occur due to a variety of underlying aetiologies, including stricturing disease, adhesions and pouch twists. Conservative management of such obstructions often results in resolution of symptoms without a need for endoscopic or surgical intervention, although endoscopic decompression may be attempted in isolation or as a bridge to definitive surgical intervention. Parenteral nutrition, and early delivery, may also be necessary. Faecal calprotectin and intestinal ultrasound, both of which are accurate in pregnancy, are useful in the setting of suspected inflammatory pouch complications, in some circumstances allowing for avoidance of pouchoscopy. Penicillin-based antimicrobials can be considered first line in pregnancy for the management of pouchitis and pre-pouch ileitis, and biologics can be safely instituted in the setting of refractory disease or suspected Crohn's disease-like inflammation of the pouch or pre-pouch ileum. Pragmatism, clear patient communication and multidisciplinary discussion are essential in approaching pregnant women with complications of an IPAA, particularly given the lack of definitive evidence to guide therapeutic decisions.

The Effect of In Utero Exposure to Maternal Inflammatory Bowel Disease and Immunomodulators on Infant Immune System Development and Function.

Autoimmune and inflammatory disorders, including inflammatory bowel disease (IBD), commonly affect women of childbearing age, warranting the use of immunomodulatory agents at a time where pregnancy may be desired. In utero exposure to pro-inflammatory mediators from maternal IBD, IBD-associated intestinal dysbiosis, and immunomodulatory drug use may impact neonatal immune system development during what is considered to be a critical period, with potential long-lasting impacts on susceptibility to disease. Both the innate and adaptative immune systems of the neonatal differ to that of the adult in terms of both cellular composition and sensitivity to antigenic and innate stimulation. The infant immune system gradually develops to more closely resemble that of the adult. Exposure to maternal inflammation in utero may aberrantly impact this period of infant immune system development, with maternal autoimmune and inflammatory disorders shown to affect the physiologic changes in serum cytokine abundance observed during pregnancy. The maternal and neonatal intestinal microbiome greatly influence infant mucosal and peripheral immune system development, and thereby impact the susceptibility to short-term inflammatory diseases, the adequacy of vaccine response, and later life risk of atopic and inflammatory disorders. Maternal disease, mode of delivery, method of feeding, time of weaning to include solid foods in the diet, and neonatal antibiotic exposure all influence the composition of the infant microbiome, and thereby infant immune system maturation. How exposure to specific immunosuppressive medications in utero alters infant immune cell phenotype and response to stimulation has been explored, but with existing studies limited by the time at which samples are performed, heterogenicity in methods, and small sample size. Furthermore, the impact of more recently introduced biologic agents have not been explored. Evolving knowledge in this field may influence therapeutic preferences for individuals with IBD planning to conceive, particularly if substantive differences in the risk of infant infection and childhood immune disease are identified.

Impact of a pharmacist-led thiopurine monitoring service in outpatients with inflammatory bowel disease.

BACKGROUND: Thiopurines are effective therapies for inflammatory bowel disease (IBD); however, treatment comes with safety concerns and adverse effects. Knowledge of the impact of pharmacists performing thiopurine monitoring is limited. AIMS: To determine the impact of a pharmacist-led monitoring service in patients with IBD commencing thiopurine therapy managed in the ambulatory care setting. METHODS: Patients commencing thiopurine therapy for IBD pre- and post-introduction of a pharmacist-led monitoring intervention were assessed. Pre-intervention patients received standard of care, while the post-intervention cohort was managed by the pharmacist. Data were acquired via retrospective audit of hospital medical records. The primary end-point was the proportion of patients with documented review for thiopurine adverse effects within the initial 3 weeks. Secondary end-points included achievement of therapeutic drug levels, persistence with thiopurine therapy, IBD-related episodes of care and number of outpatient medical reviews. RESULTS: Pre- and post-intervention cohorts comprised of 37 and 33 patients respectively. Pharmacist intervention increased the proportion of patients with documented monitoring within 3 weeks from 8.1% to 84.8% (P < 0.01). No difference in thiopurine dose optimisation was seen (27% vs 27.3%). Persistence with thiopurine therapy increased from 65.7% to 87.9% (P < 0.03) at 6 months. IBD-related emergency department presentations were not significantly decreased (8.1% vs 3%; P = 0.62). No significant change was observed in hospital admissions (16.2% vs 12.1%; P = 0.74) or outpatient medical reviews. CONCLUSIONS: Pharmacist monitoring of thiopurine therapy initiation in IBD outpatients improves adverse effect monitoring and increases medication persistence.

Preconception, antenatal and postpartum management of inflammatory bowel disease.

BACKGROUND: Inflammatory bowel disease (IBD), comprising ulcerative colitis and Crohn's disease, commonly affects individuals of childbearing age. Pregnancy in women with IBD presents an anxiety-provoking prospect for practitioners and patients alike, with disease flares occurring in between 20% and 55% of patients antenatally. OBJECTIVE: The aim of this review is to provide an overview of antenatal IBD management principles and therapeutic goals, with a specific focus on the role of general practitioners. DISCUSSION: A collaborative approach is favoured in managing pregnancy and IBD. Preconception counselling should be prioritised, with emphasis on the importance of achieving three months of preconception corticosteroid-free remission. Close monitoring of disease activity in pregnancy is crucial, warranting the careful interpretation of both clinical and biochemical parameters. Reassurance regarding the safety of IBD medications in pregnancy and vaginal delivery can be provided in the majority of cases. Specialist support should be sought expeditiously in the setting of disease flare, particularly where symptoms and biochemical parameters are refractory to escalation of 5-aminosalicylates or topical therapies, corticosteroids or biologic agents are required, or an emergent IBD complication is suspected.

Ustekinumab levels in pregnant women with inflammatory bowel disease and infants exposed in utero.

BACKGROUND: Ustekinumab is increasingly used in pregnant women with inflammatory bowel disease (IBD). Existing safety data are reassuring, but the stability of ustekinumab levels in pregnancy, degree of transfer to the infant and time to infant clearance are unknown. METHODS: In this prospective observational study, ustekinumab-exposed women with IBD had trough levels measured in each trimester of pregnancy and at delivery. Infant ustekinumab levels were measured at delivery and ongoing until clearance was achieved. Trough ustekinumab level stability in individuals across pregnancy was compared by Skillings-Mack test. Spearman coefficients were used to correlate maternal and infant delivery levels, and median time to infant ustekinumab clearance was defined. RESULTS: 19 pregnant women receiving ustekinumab were included. There was no difference in ustekinumab levels across pregnancy in those with two or more representative trough levels (P = 0.83, n = 11). Infant delivery ustekinumab levels were higher than maternal levels, with a median infant:maternal ratio of 1.79 (IQR 1.26-3.1). There was a positive correlation between maternal and infant delivery ustekinumab levels (r = 0.75, P = 0.001) and an inverse correlation between the number of days from final antenatal dose and delivery infant ustekinumab level (r = -0.65, P = 0.006). Median time of infant ustekinumab clearance was 9 (range 6-19) weeks (n = 9). CONCLUSION: Ustekinumab drug levels appear stable in pregnancy, with a delivery infant:maternal ratio similar to that of anti-TNFs. Infant ustekinumab clearance was complete by 20 weeks post-partum, however, infants exposed in utero should avoid live vaccination before 12 months of age until further clearance data are obtained.

ECCO Topical Review: Refractory Inflammatory Bowel Disease.

Inflammatory bowel disease is a chronic disease with variable degrees of extent, severity, and activity. A proportion of patients will have disease that is refractory to licensed therapies, resulting in significant impairment in quality of life. The treatment of these patients involves a systematic approach by the entire multidisciplinary team, with particular consideration given to medical options including unlicensed therapies, surgical interventions, and dietetic and psychological support. The purpose of this review is to guide clinicians through this process and provide an accurate summary of the available evidence for different strategies.

A Crohn's Disease-associated IL2RA Enhancer Variant Determines the Balance of T Cell Immunity by Regulating Responsiveness to IL-2 Signalling.

BACKGROUND AND AIMS: Differential responsiveness to interleukin [IL]-2 between effector CD4+ T cells [Teff] and regulatory T cells [Treg] is a fundamental mechanism of immunoregulation. The single nucleotide polymorphism [SNP] rs61839660, located within IL2RA [CD25], has been associated with the development of Crohn's disease [CD]. We sought to identify the T cell immune phenotype of IBD patients who carry this SNP. METHODS: Teff and Treg were isolated from individuals homozygous [TT], heterozygous [CT], or wild-type [CC] for the minor allele at rs61839660, and used for phenotyping [flow cytometry, Cytometry Time Of Flight] functional assays or T cell receptor [TCR] sequencing. Phosphorylation of signal transducer and activator of transcription 5 [STAT5] was assessed in response to IL-2, IL-7, and in the presence of basiliximab, a monoclonal antibody directed against CD25. Teff pro-inflammatory cytokine expression levels were assessed by reverse transcription quantitative polymerase chain reaction after IL-2 and/or TCR stimulation. RESULTS: Presence of the minor T allele enhances CD25 expression, leading to increased STAT5 phosphorylation and pro-inflammatory cytokine transcript expression by Teff in response to IL-2 stimulation in vitro. Teff from TT individuals demonstrate a more activated gut homing phenotype. TCR sequencing analysis suggests that TT patients may have a reduced clonal capacity to mount an optimal regulatory T cell response. CONCLUSIONS: rs61839660 regulates the responsiveness of T cells to IL-2 signalling by modulating CD25 expression. As low-dose IL-2 is being trialled as a selective Treg modulator in CD, these findings highlight the potential for adverse effects in patients with this genotype.

Characterization of the pathoimmunology of necrotizing enterocolitis reveals novel therapeutic opportunities.

Necrotizing enterocolitis (NEC) is a severe, currently untreatable intestinal disease that predominantly affects preterm infants and is driven by poorly characterized inflammatory pathways. Here, human and murine NEC intestines exhibit an unexpected predominance of type 3/TH17 polarization. In murine NEC, pro-inflammatory type 3 NKp46-RORγt+Tbet+ innate lymphoid cells (ILC3) are 5-fold increased, whereas ILC1 and protective NKp46+RORγt+ ILC3 are obliterated. Both species exhibit dysregulation of intestinal TLR repertoires, with TLR4 and TLR8 increased, but TLR5-7 and TLR9-12 reduced. Transgenic IL-37 effectively protects mice from intestinal injury and mortality, whilst exogenous IL-37 is only modestly efficacious. Mechanistically, IL-37 favorably modulates immune homeostasis, TLR repertoires and microbial diversity. Moreover, IL-37 and its receptor IL-1R8 are reduced in human NEC epithelia, and IL-37 is lower in blood monocytes from infants with NEC and/or lower birthweight. Our results on NEC pathomechanisms thus implicate type 3 cytokines, TLRs and IL-37 as potential targets for novel NEC therapies.

Resolving intestinal fibrosis through regenerative medicine.

Crohn's Disease and Ulcerative Colitis, known collectively as Inflammatory Bowel Disease (IBD), are lifelong gastrointestinal disorders that commonly present at a young age and are increasing in incidence and prevalence. Fibrosis is a common and incurable complication of IBD. When fibrotic complications occur, patients often have to undergo disfiguring surgery. Thus, research has focused on regenerative therapies as a means to prevent and treat established fibrosis. Both cell and non-cell therapies (exosomes) have anti-fibrotic and anti-inflammatory properties. This review discusses these emerging therapeutics and their potential to treat intestinal fibrosis.

Correction of Defective T-Regulatory Cells From Patients With Crohn's Disease by Ex Vivo Ligation of Retinoic Acid Receptor-α.

BACKGROUND & AIMS: Crohn's disease (CD) is characterized by an imbalance of effector and regulatory T cells in the intestinal mucosa. The efficacy of anti-adhesion therapies led us to investigate whether impaired trafficking of T-regulatory (Treg) cells contributes to the pathogenesis of CD. We also investigated whether proper function could be restored to Treg cells by ex vivo expansion in the presence of factors that activate their regulatory activities. METHODS: We measured levels of the integrin α4ß7 on Treg cells isolated from peripheral blood or lamina propria of patients with CD and healthy individuals (controls). Treg cells were expanded ex vivo and incubated with rapamycin with or without agonists of the retinoic acid receptor-α (RARA), and their gene expression profiles were analyzed. We also studied the cells in cytokine challenge, suppression, and flow chamber assays and in SCID mice with human intestinal xenografts. RESULTS: We found that Treg cells from patients with CD express lower levels of the integrin α4ß7 than Treg cells from control patients. The pathway that regulates the expression of integrin subunit α is induced by retinoic acid (RA). Treg cells from patients with CD incubated with rapamycin and an agonist of RARA (RAR568) expressed high levels of integrin α4ß7, as well as CD62L and FOXP3, compared with cells incubated with rapamycin or rapamycin and all-trans retinoic acid. These Treg cells had increased suppressive activities in assays and migrated under conditions of shear flow; they did not produce inflammatory cytokines, and RAR568 had no effect on cell stability or lineage commitment. Fluorescently labeled Treg cells incubated with RAR568 were significantly more likely to traffic to intestinal xenografts than Treg cells expanded in control medium. CONCLUSIONS: Treg cells from patients with CD express lower levels of the integrin α4ß7 than Treg cells from control patients. Incubation of patients' ex vivo expanded Treg cells with rapamycin and an RARA agonist induced expression of α4ß7 and had suppressive and migratory activities in culture and in intestinal xenografts in mice. These cells might be developed for treatment of CD. ClinicalTrials.gov, Number: NCT03185000.

Vedolizumab: early experience and medium-term outcomes from two UK tertiary IBD centres.

OBJECTIVE: To gain an understanding of the efficacy of vedolizumab in a 'real-world' setting. DESIGN: Retrospective cohort study using prospectively maintained clinical records. SETTING: Two UK tertiary inflammatory bowel disease (IBD) centres. PATIENTS: Patients with IBD commenced on vedolizumab at Guy's & St Thomas' and King's College Hospitals during November 2014-November 2015. INTERVENTION: Vedolizumab, a monoclonal antibody to α-4 ß-7 integrins that selectively inhibit leucocyte migration into the gut. MAIN OUTCOME MEASURES: Clinical disease activity was assessed at baseline, weeks 14 and 30 using Harvey-Bradshaw Index (HBI) for Crohn's disease (CD) and Simple Clinical Colitis Activity Index (SCCAI) for ulcerative colitis (UC). Response was defined as HBI or SCCAI reduction ≥3. Remission was defined as HBI <5 or SCCAI <3. Continuous data are summarised as medians, followed by range. RESULTS: Fifty patients were included: 27 CD, 20 UC and 3 IBD-U (included in the UC group for analysis). At baseline visit, the median HBI was 8 (1-16) and SCCAI was 6 (0-15). At week 14, these values had fallen to 5 (0-15) (p=0.117) and 4 (0-10) (p=0.005), respectively. Additionally, week 30 data were available for 19 patients (9 CD, 10 UC). The clinical disease activity scores at that point were HBI 2 (0-7) (p=0.039) and SCCAI 2 (0-10) (p=0.023). At baseline, 37 (74%) of the 50 patients had clinically active disease. Of the patients with active disease, 22 (59%) responded and 14 (38%) achieved remission at week 14. CONCLUSIONS: Our early experience with vedolizumab demonstrates a clear benefit in terms of disease control as well as a steroid-sparing effect in a cohort, which included patients with complex and previously refractory disease.

Genetic variants alter T-bet binding and gene expression in mucosal inflammatory disease.

The polarization of CD4+ T cells into distinct T helper cell lineages is essential for protective immunity against infection, but aberrant T cell polarization can cause autoimmunity. The transcription factor T-bet (TBX21) specifies the Th1 lineage and represses alternative T cell fates. Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) that may be causative for autoimmune diseases. The majority of these polymorphisms are located within non-coding distal regulatory elements. It is considered that these genetic variants contribute to disease by altering the binding of regulatory proteins and thus gene expression, but whether these variants alter the binding of lineage-specifying transcription factors has not been determined. Here, we show that SNPs associated with the mucosal inflammatory diseases Crohn's disease, ulcerative colitis (UC) and celiac disease, but not rheumatoid arthritis or psoriasis, are enriched at T-bet binding sites. Furthermore, we identify disease-associated variants that alter T-bet binding in vitro and in vivo. ChIP-seq for T-bet in individuals heterozygous for the celiac disease-associated SNPs rs1465321 and rs2058622 and the IBD-associated SNPs rs1551398 and rs1551399, reveals decreased binding to the minor disease-associated alleles. Furthermore, we show that rs1465321 is an expression quantitative trait locus (eQTL) for the neighboring gene IL18RAP, with decreased T-bet binding associated with decreased expression of this gene. These results suggest that genetic polymorphisms may predispose individuals to mucosal autoimmune disease through alterations in T-bet binding. Other disease-associated variants may similarly act by modulating the binding of lineage-specifying transcription factors in a tissue-selective and disease-specific manner.

Developing in vitro expanded CD45RA+ regulatory T cells as an adoptive cell therapy for Crohn's disease.

BACKGROUND AND AIM: Thymus-derived regulatory T cells (Tregs) mediate dominant peripheral tolerance and treat experimental colitis. Tregs can be expanded from patient blood and were safely used in recent phase 1 studies in graft versus host disease and type 1 diabetes. Treg cell therapy is also conceptually attractive for Crohn's disease (CD). However, barriers exist to this approach. The stability of Tregs expanded from Crohn's blood is unknown. The potential for adoptively transferred Tregs to express interleukin-17 and exacerbate Crohn's lesions is of concern. Mucosal T cells are resistant to Treg-mediated suppression in active CD. The capacity for expanded Tregs to home to gut and lymphoid tissue is unknown. METHODS: To define the optimum population for Treg cell therapy in CD, CD4(+)CD25(+)CD127(lo)CD45RA(+) and CD4(+)CD25(+)CD127(lo)CD45RA(-) Treg subsets were isolated from patients' blood and expanded in vitro using a workflow that can be readily transferred to a good manufacturing practice background. RESULTS: Tregs can be expanded from the blood of patients with CD to potential target dose within 22-24 days. Expanded CD45RA(+) Tregs have an epigenetically stable FOXP3 locus and do not convert to a Th17 phenotype in vitro, in contrast to CD45RA(-) Tregs. CD45RA(+) Tregs highly express α4ß7 integrin, CD62L and CC motif receptor 7 (CCR7). CD45RA(+) Tregs also home to human small bowel in a C.B-17 severe combined immune deficiency (SCID) xenotransplant model. Importantly, in vitro expansion enhances the suppressive ability of CD45RA(+) Tregs. These cells also suppress activation of lamina propria and mesenteric lymph node lymphocytes isolated from inflamed Crohn's mucosa. CONCLUSIONS: CD4(+)CD25(+)CD127(lo)CD45RA(+) Tregs may be the most appropriate population from which to expand Tregs for autologous Treg therapy for CD, paving the way for future clinical trials.