Leukocyte dysfunction and reduced CTLA-4 expression are associated with perianal Crohn's disease.

Although perianal Crohn's disease (PCD) is highly associated with the exacerbated inflammation, the molecular basis and immunological signature that distinguish patients who present a history of perianal lesions are still unclear. This paper aims to define immunological characteristics related to PCD. In this cross-sectional observational study, we enrolled 20 healthy controls and 39 CD patients. Blood samples were obtained for the detection of plasma cytokines and lipopolysaccharides (LPS). Peripheral blood mononuclear cells (PBMCs) were phenotyped by flow cytometry. Leukocytes were stimulated with LPS or anti-CD3/anti-CD28 antibodies. Our results show that CD patients had augmented plasma interleukin (IL)-6 and LPS. However, their PBMC was characterized by decreased IL-6 production, while patients with a history of PCD produced higher IL-6, IL-8, and interferon-γ, along with decreased tumor necrosis factor alpha (TNF). CD patients had augmented FoxP3 and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) regulatory markers, though the PCD subjects presented a significant reduction in CTLA-4 expression. CTLA-4 as well as IL-6 and TNF responses were able to distinguish the PCD patients from those who did not present perianal complications. In conclusion, IL-6, TNF, and CTLA-4 exhibit a distinct expression pattern in CD patients with a history of PCD, regardless of disease activity. These findings clarify some mechanisms involved in the development of the perianal manifestations and may have a great impact on the disease management.

Plasma bile acids in association with Crohn's disease.

BACKGROUND: In addition to facilitating lipid digestions, bile acids (BA) are signalling molecules acting on receptors on immune cells and along the gastrointestinal (GI) tract. The aim of this study was to assess if altered bile acid profiles in plasma are associated with Crohn's disease (CD). METHOD: This cross-sectional study included individuals (aged ≥18 years) referred for colonoscopy at a tertiary centre in Stockholm between 2016 and 2019. All participants received bowel preparation, completed a lifestyle questionnaire and provided blood samples for analysis. During colonoscopy, severity of disease was graded, and biopsies were taken from colonic mucosa. In the current substudy, 88 individuals with CD and 88 age-matched controls were selected for analysis of BA in plasma with ultra performance liquid chromatography (UPLC). Linear regression models were then used to compare mean bile acid concentrations and concentration ratios between CD and controls. RESULTS: Individuals with CD had lower plasma concentrations of the majority of secondary BA compared to controls, in total CD/CC ratio 0.60 (SE 0.12), p = 0.001. The most prominent observations were lower levels of deoxycolic acid derivates and lithocolic acid derivates among participants with CD. Moreover, plasma concentration for secondary BA among participants with active CD was significantly lower compared to those with CD in remission, CD active/CD remission ratio 0.65 (SE 0.11), p < 0.002. CONCLUSION: Crohn's disease may be associated with altered plasma bile acid composition. The significance of colonic bacterial diversity in this context needs to be investigated in further studies.

It is known that Crohn's disease is associated with dysbiosis in the gut microbiota and that primary bile acids are transformed to secondary bile acids by bacterial enzymes in the gut before reabsorbed and transported back to the liver.In this cross-sectional study, Crohn's disease was associated with lower concentrations of secondary bile acids in blood plasmaThe findings should encourage further studies the role of the gut microbiome and bile acid metabolism in development of Crohn's disease and bile acid profile as a biomarker for bowel inflammation.

Exclusive enteral nutrition impacts peripheral blood mononuclear cell profile of children with Crohn's disease.

The immunological effects of exclusive enteral nutrition (EEN) in the treatment of active Crohn's disease (CD) are yet to be unveiled. The present study investigated changes in peripheral blood mononuclear cell profiles in children with active CD following 8-week treatment with EEN. In nine children, EEN significantly decreased the number and frequency of circulating effector memory CD8+ T cells re-expressing CD45RA, with corresponding increases observed in the frequency of circulating central and effector memory CD8+ T cells. These signals were conserved when looking at a subgroup of patients who achieved remission, and another who demonstrated the highest level of compliance to EEN. We speculate that the increases in circulating central and effector memory CD8+ T cells may be related to the extensive microbiome-modifying effects of EEN dampening immune response within the gastrointestinal tract.

Ozanimod Differentially Impacts Circulating Lymphocyte Subsets in Patients with Moderately to Severely Active Crohn's Disease.

BACKGROUND: Ozanimod showed efficacy and safety in the phase 2 STEPSTONE study conducted in patients with moderately to severely active Crohn's disease. AIMS: This analysis assessed the effects of ozanimod on circulating lymphocytes in Crohn's disease. METHODS: Patients received ozanimod 0.92 mg for 12 weeks. Lymphocyte subtypes were evaluated using multicolor flow analysis on blood samples collected before treatment and on Week 12. Absolute lymphocyte count changes were analyzed by Wilcoxon signed rank tests. Disease activity changes and efficacy outcomes were evaluated at Week 12, and associations with lymphocyte subtype levels were assessed using Spearman's correlation and logistic regression. RESULTS: Reductions in median total T, Th, and cytotoxic T cells occurred at Week 12 (45.4%-76.8%), with reductions in most subtypes of 47.5% to 91.3% (P < 0.001). CD8+ terminally differentiated effector memory cells were largely unaffected (median change, - 19%; P = 0.44). Reductions in median total B cells occurred at Week 12 (76.7%), with reductions in subtypes of 71.4% to 81.7% (P < 0.001). Natural killer and monocyte cell counts were unchanged. Greater baseline levels and changes in nonswitched memory B cells were significantly associated with clinical, endoscopic, and histologic efficacy (P < 0.05, all comparisons). CONCLUSIONS: Ozanimod reduced circulating levels of all B-cell and most T-cell subsets but not monocytes or natural killer cells. Key subsets relevant to immune surveillance were not reduced, supporting the low risk of infection and malignancy with ozanimod in chronic inflammatory diseases. Levels of nonswitched memory B cells were associated with efficacy, providing a potential marker for ozanimod response. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02531113, EudraCT: 2015-002025-19.

Correlation Between Serum and Fecal Biomarkers and Patient-Reported Outcomes in Patients with Crohn's Disease and Ulcerative Colitis.

BACKGROUND: Patient-reported outcomes (PROs), such as the short CD activity index (sCDAI) and partial Mayo Score (PMS), are used to define clinical remission in IBD, but may not represent the true degree of inflammation and endoscopy is invasive. Non-invasive testing options include c-reactive protein (CRP) and fecal calprotectin (FCP). AIM: The aim of this study was to assess the degree of correlation of non-invasive biomarkers with PROs and the impact other clinical variables can have on their levels. METHODS: We reviewed data collected from the prospective cohort, Study of a Prospective Adult Research Cohort with IBD (SPARC-IBD), comprised of over 3000 patients from 17 tertiary referral centers. Demographic and clinical variables were analyzed by disease type, disease severity was based on PROs, and baseline CRP and FCP were measured. For comparative analysis, we performed Fisher's exact test and Welch's t test, where p < 0.05 was significant. RESULTS: 1547 patients were included; 63% had CD, 56% were female, with an average disease duration of 13.6 years. CRP and FCP were associated with symptom severity in inflammatory CD. CRP was useful to differentiate symptoms across different disease locations in CD, whereas FCP was associated with symptom severity in Crohn's colitis only. For UC, FCP was able to distinguish symptom severity better in distal UC, whereas in extensive or pancolitis, it was useful only to distinguish severe symptoms from other categories of symptom severity. CONCLUSION: PROs correlate with CRP and FCP; however, disease location and phenotype impact their ability to distinguish symptom severity.

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OBJECTIVES: To explore the value of different endoscopic scoring methods in assessing disease activity in pediatric Crohn's disease (CD). METHODS: A total of 70 children diagnosed with CD at the Children's Hospital of Chongqing Medical University from January 2018 to January 2023 were included. Clinical disease activity was assessed using the Pediatric Crohn's Disease Activity Index (PCDAI), while different endoscopic scores were assigned based on endoscopic findings. Spearman rank correlation analysis was used to evaluate the correlation between each endoscopic scoring method and PCDAI as well as laboratory indicators. Kappa test was used to assess the consistency between colonoscopy/capsule endoscopy scoring methods and PCDAI in determining CD activity. Receiver operating characteristic curve analysis was performed to assess the diagnostic efficacy of laboratory indicators in predicting endoscopic activity. RESULTS: The PCDAI score showed a moderate positive correlation with the scores of Crohn's Disease Endoscopic Index of Severity (CDEIS) (rs=0.696, P<0.01), Simple Endoscopic Score for Crohn's Disease (SES-CD) (rs=0.680, P<0.01), Lewis Score (rs=0.540, P<0.01), and Capsule Endoscopy-Crohn's Disease Index (CE-CD) (rs=0.502, P<0.01). The consistency between all endoscopic scoring methods and PCDAI in determining CD activity was poor (Kappa=0.069-0.226). Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), hematocrit (HCT), and serum albumin (ALB) levels showed a moderate correlation with the PCDAI score and the scores of colonoscopy scoring methods (CDEIS and SES-CD) (|rs|=0.581-0.725, P<0.01), but a weak correlation with the scores of capsule scoring methods (P<0.05). ESR and CRP had higher area under the curve (AUC) values in predicting disease activity based on PCDAI, CDEIS, SES-CD, and Lewis Score compared to HCT and ALB (P<0.05). CONCLUSIONS: CDEIS, SES-CD, Lewis Score, and CE-CD can be used to evaluate disease activity in pediatric CD, but they do not fully correspond with disease activity assessed by PCDAI. Elevated levels of ESR and CRP can predict clinical and endoscopic disease activity in children with CD.

Exhaustion of CD39-Expressing CD8+ T Cells in Crohn's Disease Is Linked to Clinical Outcome.

BACKGROUND & AIMS: Exhaustion of CD8 T cells has been suggested to inform different clinical outcomes in Crohn's disease, but detailed analyses are lacking. This study aimed to identify the role of exhaustion on a single-cell level and identify relevant CD8 T cell populations in Crohn's disease. METHODS: Blood and intestinal tissue from 58 patients with Crohn's disease (active disease or remission) were assessed for CD8 T cell expression of exhaustion markers and their cytokine profile by highly multiplexed flow and mass cytometry. Key disease-associated subsets were sorted and analyzed by RNA sequencing. CD39 inhibition assays were performed in vitro. RESULTS: Activated CD39+ and CD39+PD-1+ CD8 T cell subsets expressing multiple exhaustion markers were enriched at low frequency in active Crohn's disease. Their cytokine production capacity was inversely linked to the Harvey-Bradshaw Index. Subset-level protein and transcriptome profiling revealed co-existence of effector and exhaustion programs in CD39+ and CD39+ PD-1+CD8 T cells, with CD39+ cells likely originating from the intestine. CD39 enzymatic activity controlled T cell cytokine production. Importantly, transcriptional exhaustion signatures were enriched in remission in CD39-expressing subsets with up-regulation of TOX. Subset-level transcriptomics revealed a CD39-related gene module that is associated with the clinical course. CONCLUSIONS: These data showed a role for the exhaustion of peripheral CD39-expressing CD8 T cell subsets in Crohn's disease. Their low frequency illustrated the utility of single-cell cytometry methods for identification of relevant immune populations. Importantly, the link of their exhaustion status to the clinical activity and their specific gene signatures have implications for exhaustion-based personalized medicine approaches.

Integrative Analysis of the Inflammatory Bowel Disease Serum Metabolome Improves Our Understanding of Genetic Etiology and Points to Novel Putative Therapeutic Targets.

BACKGROUND & AIMS: Polygenic and environmental factors are underlying causes of inflammatory bowel disease (IBD). We hypothesized that integration of the genetic loci controlling a metabolite's abundance, with known IBD genetic susceptibility loci, may help resolve metabolic drivers of IBD. METHODS: We measured the levels of 1300 metabolites in the serum of 484 patients with ulcerative colitis (UC) and 464 patients with Crohn's disease (CD) and 365 controls. Differential metabolite abundance was determined for disease status, subtype, clinical and endoscopic disease activity, as well as IBD phenotype including disease behavior, location, and extent. To inform on the genetic basis underlying metabolic diversity, we integrated metabolite and genomic data. Genetic colocalization and Mendelian randomization analyses were performed using known IBD risk loci to explore whether any metabolite was causally associated with IBD. RESULTS: We found 173 genetically controlled metabolites (metabolite quantitative trait loci, 9 novel) within 63 non-overlapping loci (7 novel). Furthermore, several metabolites significantly associated with IBD disease status and activity as defined using clinical and endoscopic indexes. This constitutes a resource for biomarker discovery and IBD biology insights. Using this resource, we show that a novel metabolite quantitative trait locus for serum butyrate levels containing ACADS was not supported as causal for IBD; replicate the association of serum omega-6 containing lipids with the fatty acid desaturase 1/2 locus and identify these metabolites as causal for CD through Mendelian randomization; and validate a novel association of serum plasmalogen and TMEM229B, which was predicted as causal for CD. CONCLUSIONS: An exploratory analysis combining genetics and unbiased serum metabolome surveys can reveal novel biomarkers of disease activity and potential mediators of pathology in IBD.

The use of calgranulin-C (S100A12) and fecal zonulin as possible non-invasive markers in children with inflammatory bowel disease: a clinical study.

Calgranulin-C (S100A12) and zonulin are considered markers of intestinal inflammation. Our aim was to evaluate fecal S100A12 (f-S100A12) and fecal zonulin (f-zonulin) in children with inflammatory bowel disease (IBD), compared to fecal calprotectin (FC) and serum inflammatory markers. We enrolled children with a previous diagnosis of Crohn's disease (CD) and ulcerative colitis (UC). F-S100A12, f-zonulin, and FC were determined by enzyme-linked immunosorbent assay (ELISA). Endoscopic examination was considered in the patients who underwent ileocolonoscopy within 2 weeks from the enrollment. One hundred seventeen children, 39.3% with CD and 60.7% with UC were enrolled. In both CD and UC, there was a significant direct correlation between FC and f-S100A12 levels. In children with CD and UC, both FC and f-S100A12 correlated with markers of serum inflammation. We found difference in FC and f-S100A12 levels between patients in clinical relapse and remission (FC: mean 1027 ± 818 mcg/ml vs 580 ± 695 mcg/ml respectively, p = 0.028; f-S100A12: mean 66.4 ± 48.2 mcg/ml vs 42.7 ± 40 mcg/ml, respectively p = 0.02). Moreover, we found difference in FC between children with endoscopic inflammation and remission (mean 825 ± 779 mcg/ml vs 473.3 ± 492 mcg/ml, respectively p = 0.048), as well as for f-S100A12 (53 ± 43 mcg/ml vs mean 31 ± 33 mcg/ml vs, respectively p = 0.019). No significant results were found for f-zonulin. CONCLUSION: Our data suggest that f-S100A12 and FC are both useful non-invasive biomarkers in the management of pediatric IBD in follow up and in monitoring endoscopic and clinical relapse. WHAT IS KNOWN: • Fecal calprotectin (FC), fecal S100A12 (f- S100A12), and fecal zonulin represent potential noninvasive markers of gut inflammation. • Since S100A12 is predominantly expressed by granulocytes, high levels of f-S100A12 should be more specific for inflammation than FC. WHAT IS NEW: • FC and f-S100A12 were correlated to each other and despite the lack of correlation with disease location, they were associated with endoscopic inflammation and clinical relapse in children with IBD. • No significant correlations were found between f-zonulin and the inflammatory parameters.

A Randomized Trial Comparing the Specific Carbohydrate Diet to a Mediterranean Diet in Adults With Crohn's Disease.

BACKGROUND & AIMS: This study compared the effectiveness of the Specific Carbohydrate Diet (SCD) to the Mediterranean diet (MD) as treatment for Crohn's disease (CD) with mild to moderate symptoms. METHODS: Adult patients with CD and with mild-to-moderate symptoms were randomly assigned 1:1 to consume the MD or SCD for 12 weeks. For the first 6 weeks, participants received prepared meals and snacks according to their assigned diet. After 6 weeks, participants were instructed to follow the diet independently. The primary outcome was symptomatic remission at week 6. Key secondary outcomes at week 6 included fecal calprotectin (FC) response (FC <250 µg/g and reduction by >50% among those with baseline FC >250 µg/g) and C-reactive protein (CRP) response (high-sensitivity CRP <5 mg/L and >50% reduction from baseline among those with high-sensitivity CRP >5 mg/L). RESULTS: The study randomized 194 patients, and 191 were included in the efficacy analyses. The percentage of participants who achieved symptomatic remission at week 6 was not superior with the SCD (SCD, 46.5%; MD, 43.5%; P = .77). FC response was achieved in 8 of 23 participants (34.8%) with the SCD and in 4 of 13 participants (30.8%) with the MD (P = .83). CRP response was achieved in 2 of 37 participants (5.4%) with the SCD and in 1 of 28 participants (3.6%) with the MD (P = .68). CONCLUSIONS: The SCD was not superior to the MD to achieve symptomatic remission, FC response, and CRP response. CRP response was uncommon. Given these results, the greater ease of following the MD and other health benefits associated with the MD, the MD may be preferred to the SCD for most patients with CD with mild to moderate symptoms. ClinicalTrials.gov Identifier: NCT03058679.

Anti-Microbial Antibody Response is Associated With Future Onset of Crohn's Disease Independent of Biomarkers of Altered Gut Barrier Function, Subclinical Inflammation, and Genetic Risk.

BACKGROUND AND AIMS: Altered host immune reactivity to microbial antigens is hypothesized to trigger the onset of Crohn's disease (CD). We aimed to assess whether increased serum anti-microbial antibody response in asymptomatic first-degree relatives (FDRs) of CD patients is an independent risk factor for future CD development. METHODS: We measured host serum antibody response to 6 microbial antigens at enrollment (Prometheus enzyme-linked immunosorbent assay test: anti-Saccharomyces cerevisiae antibodies immunoglobulin A/immunoglobulin G, anti-OmpC, anti-A4-Fla2, anti-FlaX, anti-CBir1) and derived the sum of positive antibodies (AS). We used samples at enrollment of prospectively followed healthy FDRs from a nested case-control cohort of the Crohn's and Colitis Canada Genetics Environment Microbial Project. Those who later developed CD (n = 77) were matched 1:4 by age, sex, follow-up duration, and geographic location with control FDRs remaining healthy (n = 307). To address our research aims, we fitted a multivariable conditional logistic regression model and performed causal mediation analysis. RESULTS: High baseline AS (≥2) (43% of cases, 11% of controls) was associated with higher risk of developing CD (adjusted odds ratio, 6.5; 95% confidence interval, 3.4-12.7; P < .001). Importantly, this association remained significant when adjusted for markers of gut barrier function, fecal calprotectin, C-reactive protein, and CD-polygenic risk score, and in subjects recruited more than 3 years before diagnosis. Causal mediation analysis showed that the effect of high AS on future CD development is partially mediated (42%) via preclinical gut inflammation. CONCLUSIONS: Our results suggest that increased anti-microbial antibody responses are associated with risk of future development of CD, independent of biomarkers of abnormal gut barrier function, subclinical inflammation, and CD-related genetic risks. This suggests that anti-microbial antibody responses are an early predisease event in the development of CD.

Human Microbiota Flagellins Drive Adaptive Immune Responses in Crohn's Disease.

BACKGROUND AND AIMS: Crohn's disease and ulcerative colitis are characterized by dysregulated adaptive immune responses to the microbiota in genetically susceptible individuals, but the specificity of these responses remains largely undefined. Therefore, we developed a microbiota antigen microarray to characterize microbial antibody reactivity, particularly to human-derived microbiota flagellins, in inflammatory bowel disease. METHODS: Sera from healthy volunteers (n = 87) at the University of Alabama at Birmingham and from patients recruited from the Kirklin Clinic of University of Alabama at Birmingham Hospital, including patients with Crohn's disease (n = 152) and ulcerative colitis (n = 170), were individually probed against microbiota bacterial flagellins of both mouse and human origin and analyzed for IgG and IgA antibody responses. Circulating flagellin-reactive T effector (CD4+CD154+) and T regulatory (CD4+CD137+) cells were isolated and evaluated in selected patients. Resulting adaptive immune responses were compared with corresponding clinical data to determine relevancy to disease behavior. RESULTS: We show that patients with IBD express selective patterns of antibody reactivity to microbiota flagellins. Patients with Crohn's disease, but not patients with ulcerative colitis, display augmented serum IgG to human ileal-localized Lachnospiraceae flagellins, with a subset of patients having high responses to more than 10 flagellins. Elevated responses to CBir1, a mouse Lachnospiraceae flagellin used clinically to diagnose CD, correlated with multi-Lachnospiraceae flagellin reactivity. In this subset of patients with CD, multi-flagellin reactivity was associated with elevated flagellin-specific CD154+CD45RA- T memory cells, a reduced ratio of flagellin-reactive CD4+ T regulatory to T effector cells, and a high frequency of disease complications. CONCLUSIONS: Patients with Crohn's disease display strong adaptive immune response to human-derived Lachnospiraceae flagellins, which may be targeted for prognosis and future personalized therapies.

Endocrine disruption in Crohn's disease: Bisphenol A enhances systemic inflammatory response in patients with gut barrier translocation of dysbiotic microbiota products.

The relevance of environmental triggers in Crohn's disease remains poorly explored, despite the well-known association between industrialization and disease onset/progression. We have aimed at evaluating the influence of endocrine disrupting chemicals in CD patients. We performed a prospective observational study on consecutive patients diagnosed of CD. Serum levels of endocrine disruptors, short-chain fatty acids, tryptophan and cytokines were measured. Bacterial-DNA and serum endotoxin levels were also evaluated. Gene expression of ER-α, ER-ß and GPER was measured in PBMCs. All patients were genotyped for NOD2 and ATG16L1 polymorphisms. A series of 200 CD patients (140 in remission, 60 with active disease) was included in the study. Bisphenol A was significantly higher in patients with active disease versus remission and in colonic versus ileal disease. GPER was significantly increased in active patients and correlated with BPA levels. BPA was significantly increased in patients with bacterial-DNA and correlated with serum endotoxin levels, (r = 0.417; P = .003). Serum butyrate and tryptophan levels were significantly lower in patients with bacterial-DNA and an inverse relationship was present between them and BPA levels (r = -0.491; P = .001) (r = -0.611; P = .001). Serum BPA levels correlated with IL-23 (r = 0.807; P = .001) and IL-17A (r = 0.743; P = .001). The multivariate analysis revealed an independent significant contribution of BPA and bacterial-DNA to serum levels of IL-23 and IL-17A. In conclusion, bisphenol A significantly affects systemic inflammatory response in CD patients with gut barrier disruption and dysbiotic microbiota secretory products in blood. These results provide evidence of an endocrine disruptor playing an actual pathogenic role on CD.

Effect of Ramadan intermittent fasting on inflammatory markers, disease severity, depression, and quality of life in patients with inflammatory bowel diseases: A prospective cohort study.

BACKGROUND: Intermittent fasting (IF) during the month of Ramadan is part of the religious rituals of Muslims. The effect of intermittent fasting on disease activity in inflammatory bowel diseases (IBD) is still unknown. This is the first study to assess the effect of IF during Ramadan on inflammatory markers in patients diagnosed with IBD. The effects on clinical disease activity, quality of life, and levels of depression were also assessed. METHODS: Patients diagnosed with ulcerative colitis (UC) or Crohn's disease (CD) who intended to observe Ramadan fasting were recruited. The following were assessed immediately before and at the end of Ramadan: Serum CRP and stool calprotectin, partial Mayo score, Harvey Bradshaw index (HBI), Simple IBD questionnaire (SIBDQ), and Hamilton depression scale questionnaire. RESULTS: 80 patients diagnosed with IBD were recruited (60 UC, 20 CD). Serum CRP and stool calprotectin did not show a significant change before vs after fasting (median CRP 0.53 vs 0.50, P value = 0.27, Calprotectin 163 vs 218 respectively, P value = 0.62). The partial Mayo score showed a significant rise after fasting (median 1 before vs 1 after fasting, mean: 1.79 vs 2.33 respectively, P value = 0.02). Harvey-Bradshaw index did not show a significant change after fasting (median 4 vs 5, P value = 0.4). Multiple linear regression revealed that older age and a higher baseline calprotectin were associated with a higher change in Mayo score after fasting (P value = 0.02 and P value = 0.01, respectively). No significant change was detected in SIBDQ or Hamilton depression scale scores. CONCLUSIONS: In patients diagnosed with UC, IF during Ramadan was associated with worsening of clinical parameters, the effect was more pronounced in older patients and those with higher baseline calprotectin levels. However, IF during Ramadan was not associated with an adverse effect on objective inflammatory markers (CRP and calprotectin).

IgA Triggers Cell Death of Neutrophils When Primed by Inflammatory Mediators.

IVIG preparations consisting of pooled IgG are increasingly used for the treatment of autoimmune diseases. IVIG is known to regulate the viability of immune cells, including neutrophils. We report that plasma-derived IgA efficiently triggers death of neutrophils primed by cytokines or TLR agonists. IgA-mediated programmed neutrophil death was PI3K-, p38 MAPK-, and JNK-dependent and evoked anti-inflammatory cytokines in macrophage cocultures. Neutrophils from patients with acute Crohn's disease, rheumatoid arthritis, or sepsis were susceptible to both IgA- and IVIG-mediated death. In contrast to IVIG, IgA did not promote cell death of quiescent neutrophils. Our findings suggest that plasma-derived IgA might provide a therapeutic option for the treatment of neutrophil-associated inflammatory disorders.

A Serological Biomarker of Laminin Gamma 1 Chain Degradation Reflects Altered Basement Membrane Remodeling in Crohn's Disease and DSS Colitis.

BACKGROUND: The laminin gamma 1 chain (LMγ1) is abundant along the crypt-villus axis in the intestinal basement membrane. AIMS: We investigated whether a serological biomarker of laminin degradation was associated with disease activity in patients with Crohn's disease (CD) and in rats with dextran sulfate sodium (DSS)-induced colitis. METHODS: Serum samples from CD patients (n = 43), healthy subjects (n = 19), and Sprague Dawley rats receiving 5-6% DSS water for five days and regular drinking water for 11 days were included in this study. The LG1M biomarker, a neo-epitope degradation fragment of the LMγ1 chain generated by matrix metalloproteinases-9 (MMP-9), was measured in serum to estimate the level of laminin degradation. RESULTS: Serum LG1M was elevated in CD patients with active and inactive disease compared to healthy subjects (p < 0.0001). LG1M distinguished CD patients from healthy subjects, with an area under the curve (AUC) of 0.81 (p < 0.0001). Serum LG1M was decreased in DSS rats compared to controls 2 days after DSS withdrawal, and increased upon reversal of the disease. CONCLUSIONS: Increased serum LG1M in active and inactive CD patients supports the evidence of altered LM expression in both inflamed and non-inflamed tissue. Moreover, lower LG1M levels in the early healing phase of DSS-induced colitis may reflect ongoing mucosal repair.

Rapidity of clinical response to adalimumab and improvement of quality of life in luminal Crohn's disease: RAPIDA study.

OBJECTIVE: No studies evaluating the rapidity of response to biological therapies are available for Crohn's disease (CD). The aim of this study was to evaluate rapidity of onset of clinical response and impact on quality of life (QoL) of adalimumab therapy in adult anti-TNF-naïve patients with moderately-to-severely active CD. PATIENTS AND METHODS: RAPIDA was an open-label, single-arm, prospective, multicenter clinical trial. Adult patients with moderately-to-severely active luminal CD, anti-TNF-naïve, and unresponsive to conventional therapy were treated with adalimumab. Clinical disease activity, QoL and inflammatory biomarkers were measured at day 4, and weeks 1, 2, 4, and 12 after treatment initiation. RESULTS: Eighty-six patients were included in the intention-to-treat (ITT) analyses. Clinical disease activity was reduced from a median of 9.0 points to 6.0 points at day 4. Clinical response (≥ 3-point reduction in the Harvey-Bradshaw Index, HBI) was achieved by 61.6% (d4) and 75.6% (w1) of patients in the ITT population (median 2.5 days) and with non-responder imputation (NRI), by 55.8% and 53.4%, respectively. The proportion of patients in clinical remission (HBI<5) at weeks 2 and 4 in the ITT population was 54.7% and 62.8%, respectively (median 7.0 days), and 38.4% and 45.3% in the NRI population. All QoL scores significantly improved and inflammatory biomarkers significantly decreased from day 4 onwards (p<0.0001). CONCLUSION: Rapid clinical response and remission, improvement in QoL and fatigue, and a reduction of inflammatory biomarkers were achieved with adalimumab as early as day 4 in adult anti-TNF-naïve patients with moderately-to-severely active CD.

HLA-DQA1*05 Carriage Associated With Development of Anti-Drug Antibodies to Infliximab and Adalimumab in Patients With Crohn's Disease.

BACKGROUND & AIMS: Anti-tumor necrosis factor (anti-TNF) therapies are the most widely used biologic drugs for treating immune-mediated diseases, but repeated administration can induce the formation of anti-drug antibodies. The ability to identify patients at increased risk for development of anti-drug antibodies would facilitate selection of therapy and use of preventative strategies. METHODS: We performed a genome-wide association study to identify variants associated with time to development of anti-drug antibodies in a discovery cohort of 1240 biologic-naïve patients with Crohn's disease starting infliximab or adalimumab therapy. Immunogenicity was defined as an anti-drug antibody titer ≥10 AU/mL using a drug-tolerant enzyme-linked immunosorbent assay. Significant association signals were confirmed in a replication cohort of 178 patients with inflammatory bowel disease. RESULTS: The HLA-DQA1*05 allele, carried by approximately 40% of Europeans, significantly increased the rate of immunogenicity (hazard ratio [HR], 1.90; 95% confidence interval [CI], 1.60-2.25; P = 5.88 × 10-13). The highest rates of immunogenicity, 92% at 1 year, were observed in patients treated with infliximab monotherapy who carried HLA-DQA1*05; conversely the lowest rates of immunogenicity, 10% at 1 year, were observed in patients treated with adalimumab combination therapy who did not carry HLA-DQA1*05. We confirmed this finding in the replication cohort (HR, 2.00; 95% CI, 1.35-2.98; P = 6.60 × 10-4). This association was consistent for patients treated with adalimumab (HR, 1.89; 95% CI, 1.32-2.70) or infliximab (HR, 1.92; 95% CI, 1.57-2.33), and for patients treated with anti-TNF therapy alone (HR, 1.75; 95% CI, 1.37-2.22) or in combination with an immunomodulator (HR, 2.01; 95% CI, 1.57-2.58). CONCLUSIONS: In an observational study, we found a genome-wide significant association between HLA-DQA1*05 and the development of antibodies against anti-TNF agents. A randomized controlled biomarker trial is required to determine whether pretreatment testing for HLA-DQA1*05 improves patient outcomes by helping physicians select anti-TNF and combination therapies. ClinicalTrials.gov ID: NCT03088449.

Single-Cell Analyses of Colon and Blood Reveal Distinct Immune Cell Signatures of Ulcerative Colitis and Crohn's Disease.

BACKGROUND & AIMS: Studies are needed to determine the mechanisms of mucosal dysregulation in patients with inflammatory bowel diseases (IBDs) and differences in inflammatory responses of patients with ulcerative colitis (UC) vs Crohn's disease (CD). We used mass cytometry (CyTOF) to characterize and compare immune cell populations in the mucosa and blood from patients with IBD and without IBD (controls) at single-cell resolution. METHODS: We performed CyTOF analysis of colonic mucosa samples (n = 87) and peripheral blood mononuclear cells (n = 85) from patients with active or inactive UC or CD and controls. We also performed single-cell RNA sequencing, flow cytometry, and RNA in situ hybridization analyses to validate key findings. We used random forest modeling to identify differences in signatures across subject groups. RESULTS: Compared with controls, colonic mucosa samples from patients with IBD had increased abundances of HLA-DR+CD38+ T cells, including T-regulatory cells that produce inflammatory cytokines; CXCR3+ plasmablasts; and IL1B+ macrophages and monocytes. Colonic mucosa samples from patients with UC were characterized by expansion of IL17A+ CD161+ effector memory T cells and IL17A+ T-regulatory cells; expansion of HLA-DR+CD56+ granulocytes; and reductions in type 3 innate lymphoid cells. Mucosal samples from patients with active CD were characterized by IL1B+HLA-DR+CD38+ T cells, IL1B+TNF+IFNG+ naïve B cells, IL1B+ dendritic cells (DCs), and IL1B+ plasmacytoid DCs. Peripheral blood mononuclear cells from patients with active CD differed from those of active UC in that the peripheral blood mononuclear cells from patients with CD had increased IL1B+ T-regulatory cells, IL1B+ DCs and IL1B+ plasmacytoid DCs, IL1B+ monocytes, and fewer group 1 innate lymphoid cells. Random forest modeling differentiated active UC from active CD in colonic mucosa and blood samples; top discriminating features included many of the cellular populations identified above. CONCLUSIONS: We used single-cell technologies to identify immune cell populations specific to mucosa and blood samples from patients with active or inactive CD and UC and controls. This information might be used to develop therapies that target specific cell populations in patients with different types of IBD.

Association Between Inflammatory Bowel Diseases and Celiac Disease: A Systematic Review and Meta-Analysis.

BACKGROUND & AIMS: There is controversy over the association between celiac disease (CeD) and inflammatory bowel diseases (IBD). We performed a systematic review and meta-analysis to assess evidence for an association between CeD and IBD. METHODS: We searched databases including MEDLINE, EMBASE, CENTRAL, Web of Science, CINAHL, DARE, and SIGLE through June 25, 2019 for studies assessing the risk of CeD in patients with IBD, and IBD in patients with CeD, compared with controls of any type. We used the Newcastle-Ottawa Scale to evaluate the risk of bias and GRADE to assess the certainty of the evidence. RESULTS: We identified 9791 studies and included 65 studies in our analysis. Moderate certainty evidence found an increased risk of CeD in patients with IBD vs controls (risk ratio [RR] 3.96; 95% confidence interval [CI] 2.23-7.02) and increased risk of IBD in patients with CeD vs controls (RR 9.88; 95% CI 4.03-24.21). There was low-certainty evidence for the risk of anti-Saccharomyces antibodies, a serologic marker of IBD, in patients with CeD vs controls (RR 6.22; 95% CI 2.44-15.84). There was low-certainty evidence for no difference in risk of HLA-DQ2 or DQ8 in patients with IBD vs controls (RR 1.04; 95% CI 0.42-2.56), and very low-certainty evidence for an increased risk of anti-tissue transglutaminase in patients with IBD vs controls (RR 1.52; 95% CI 0.52-4.40). Patients with IBD had a slight decrease in risk of anti-endomysial antibodies vs controls (RR 0.70; 95% CI 0.18-2.74), but these results are uncertain. CONCLUSIONS: In a systematic review and meta-analysis, we found an increased risk of IBD in patients with CeD and increased risk of CeD in patients with IBD, compared with other patient populations. High-quality prospective cohort studies are needed to assess the risk of CeD-specific and IBD-specific biomarkers in patients with IBD and CeD.