ATP citrate lyase (ACLY)-dependent immunometabolism in mucosal T cells drives experimental colitis in vivo

OBJECTIVE

Mucosal T cells play a major role in inflammatory bowel disease (IBD). However, their immunometabolism during intestinal inflammation is poorly understood. Due to its impact on cellular metabolism and proinflammatory immune cell function, we here focus on the enzyme ATP citrate lyase (ACLY) in mucosal T cell immunometabolism and its relevance for IBD.

DESIGN

ACLY expression and its immunometabolic impact on colitogenic T cell function were analysed in mucosal T cells from patients with IBD and in two experimental colitis models.

RESULTS

ACLY was markedly expressed in colon tissue under steady-state conditions but was significantly downregulated in lamina propria mononuclear cells in experimental dextran sodium sulfate-induced colitis and in CD4+ and to a lesser extent in CD8+ T cells infiltrating the inflamed gut in patients with IBD. ACLY-deficient CD4+ T cells showed an impaired capacity to induce intestinal inflammation in a transfer colitis model as compared with wild-type T cells. Assessment of T cell immunometabolism revealed that ACLY deficiency dampened the production of IBD-relevant cytokines and impaired glycolytic ATP production but enriched metabolites involved in the biosynthesis of phospholipids and phosphatidylcholine. Interestingly, the short-chain fatty acid butyrate was identified as a potent suppressor of ACLY expression in T cells, while IL-36α and resolvin E1 induced ACLY levels. In a translational approach, in vivo administration of the butyrate prodrug tributyrin downregulated mucosal infiltration of ACLYhigh CD4+ T cells and ameliorated chronic colitis.

CONCLUSION

ACLY controls mucosal T cell immunometabolism and experimental colitis. Therapeutic modulation of ACLY expression in T cells emerges as a novel strategy to promote the resolution of intestinal inflammation.

Single-cell RNA sequencing reveals intrahepatic and peripheral immune characteristics related to disease phases in HBV-infected patients

OBJECTIVE

A comprehensive immune landscape for HBV infection is pivotal to achieve HBV cure.

DESIGN

We performed single-cell RNA sequencing of 2 43 000 cells from 46 paired liver and blood samples of 23 individuals, including six immune tolerant, 5 immune active (IA), 3 acute recovery (AR), 3 chronic resolved and 6 HBV-free healthy controls (HCs). Flow cytometry and histological assays were applied in a second HBV cohort for validation.

RESULTS

Both IA and AR were characterised by high levels of intrahepatic exhausted CD8+ T (Tex) cells. In IA, Tex cells were mainly derived from liver-resident GZMK+ effector memory T cells and self-expansion. By contrast, peripheral CX3CR1+ effector T cells and GZMK+ effector memory T cells were the main source of Tex cells in AR. In IA but not AR, significant cell-cell interactions were observed between Tex cells and regulatory CD4+ T cells, as well as between Tex and FCGR3A+ macrophages. Such interactions were potentially mediated through human leukocyte antigen class I molecules together with their receptors CANX and LILRBs, respectively, contributing to the dysfunction of antiviral immune responses. By contrast, CX3CR1+GNLY+ central memory CD8+ T cells were concurrently expanded in both liver and blood of AR, providing a potential surrogate marker for viral resolution. In clinic, intrahepatic Tex cells were positively correlated with serum alanine aminotransferase levels and histological grading scores.

CONCLUSION

Our study dissects the coordinated immune responses for different HBV infection phases and provides a rich resource for fully understanding immunopathogenesis and developing effective therapeutic strategies.

Intratumoural immune signature to identify patients with primary colorectal cancer who do not require follow-up after resection: an observational study

BACKGROUND

Following surgical and adjuvant treatment of primary colorectal cancer, many patients are routinely followed up with axial imaging (most commonly computerised tomography imaging) and blood carcinoembryonic antigen (a tumour marker) testing. Because fewer than one-fifth of patients will relapse, a large number of patients are followed up unnecessarily.

OBJECTIVES

To determine whether or not the intratumoural immune signature could identify a cohort of patients with a relapse rate so low that follow-up is unnecessary.

DESIGN

An observational study based on a secondary tissue collection of the tumours from participants in the FACS (Follow-up After Colorectal Cancer Surgery) trial.

SETTING AND PARTICIPANTS

Formalin-fixed paraffin-embedded tumour tissue was obtained from 550 out of 1202 participants in the FACS trial. Tissue microarrays were constructed and stained for cluster of differentiation (CD)3+ and CD45RO+ T lymphocytes as well as standard haematoxylin and eosin staining, with a view to manual and, subsequently, automated cell counting.

RESULTS

The tissue microarrays were satisfactorily stained for the two immune markers. Manual cell counting proved possible on the arrays, but manually counting the number of cores for the entire study was found to not be feasible; therefore, an attempt was made to use automatic cell counting. Although it is clear that this approach is workable, there were both hardware and software problems; therefore, reliable data could not be obtained within the time frame of the study.

LIMITATIONS

The main limitations were the inability to use machine counting because of problems with both hardware and software, and the loss of critical scientific staff. Findings from this research indicate that this approach will be able to count intratumoural immune cells in the long term, but whether or not the original aim of the project proved possible is not known.

CONCLUSIONS

The project was not successful in its aim because of the failure to achieve a reliable counting system.

FUTURE WORK

Further work is needed to perfect immune cell machine counting and then complete the objectives of this study that are still relevant.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN41458548.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 2. See the NIHR Journals Library website for further project information.

The TRPA1 ion channel is expressed in CD4+ T cells and restrains T-cell-mediated colitis through inhibition of TRPV1

OBJECTIVE

Transient receptor potential ankyrin-1 (TRPA1) and transient receptor potential vanilloid-1 (TRPV1) are calcium (Ca²⁺)-permeable ion channels mostly known as pain receptors in sensory neurons. However, growing evidence suggests their crucial involvement in the pathogenesis of IBD. We explored the possible contribution of TRPA1 and TRPV1 to T-cell-mediated colitis.

DESIGN

We evaluated the role of Trpa1 gene deletion in two models of experimental colitis (ie, interleukin-10 knockout and T-cell-adoptive transfer models). We performed electrophysiological and Ca²⁺ imaging studies to analyse TRPA1 and TRPV1 functions in CD4+ T cells. We used genetic and pharmacological approaches to evaluate TRPV1 contribution to the phenotype of Trpa1^-/- CD4+ T cells. We also analysed TRPA1 and TRPV1 gene expression and TRPA1⁺TRPV1⁺ T cell infiltration in colonic biopsies from patients with IBD.

RESULTS

We identified a protective role for TRPA1 in T-cell-mediated colitis. We demonstrated the functional expression of TRPA1 on the plasma membrane of CD4+ T cells and identified that Trpa1^-/- CD4+ T cells have increased T-cell receptor-induced Ca²⁺ influx, activation profile and differentiation into Th1-effector cells. This phenotype was abrogated upon genetic deletion or pharmacological inhibition of the TRPV1 channel in mouse and human CD4+ T cells. Finally, we found differential regulation of TRPA1 and TRPV1 gene expression as well as increased infiltration of TRPA1⁺TRPV1⁺ T cells in the colon of patients with IBD.

CONCLUSIONS

Our study indicates that TRPA1 inhibits TRPV1 channel activity in CD4+ T cells, and consequently restrains CD4+ T-cell activation and colitogenic responses. These findings may therefore have therapeutic implications for human IBD.

Tumour CD274 (PD-L1) expression and T cells in colorectal cancer

OBJECTIVE

Evidence suggests that CD274 (programmed death-ligand 1, B7-H1) immune checkpoint ligand repress antitumour immunity through its interaction with the PDCD1 (programmed cell death 1, PD-1) receptor of T lymphocytes in various tumours. We hypothesised that tumour CD274 expression levels might be inversely associated with T-cell densities in colorectal carcinoma tissue.

DESIGN

We evaluated tumour CD274 expression by immunohistochemistry in 823 rectal and colon cancer cases within the Nurses' Health Study and Health Professionals Follow-up Study. We conducted multivariable ordinal logistic regression analyses to examine the association of tumour CD274 expression with CD3⁺, CD8⁺, CD45RO (PTPRC)⁺ or FOXP3⁺ cell density in tumour tissue, controlling for potential confounders including tumour status of microsatellite instability (MSI), CpG island methylator phenotype, long interspersed nucleotide element-1 methylation level and KRAS, BRAF and PIK3CA mutations.

RESULTS

CD274 expression in tumour cells or stromal cells (including immune cells) was detected in 731 (89%) or 44 (5%) cases, respectively. Tumour CD274 expression level correlated inversely with FOXP3⁺ cell density in colorectal cancer tissue (outcome) (p_trend=0.0002). For a unit increase in outcome quartile categories, multivariable OR in the highest (vs lowest) CD274 expression score was 0.22 (95% CI 0.10 to 0.47). Tumour CD274 expression was inversely associated with MSI-high status (p=0.001). CD274 expression was not significantly associated with CD3⁺, CD8⁺ or CD45RO⁺ cell density, pathological lymphocytic reactions or patient survival prognosis.

CONCLUSIONS

Tumour CD274 expression is inversely associated with FOXP3⁺ cell density in colorectal cancer tissue, suggesting a possible influence of CD274-expressing carcinoma cells on regulatory T cells in the tumour microenvironment.

Hepatic overexpression of cAMP-responsive element modulator α induces a regulatory T-cell response in a murine model of chronic liver disease

OBJECTIVE

Th17 cells are a subset of CD4⁺ T-helper cells characterised by interleukin 17 (IL-17) production, a cytokine that plays a crucial role in inflammation-associated diseases. The cyclic AMP-responsive element modulator-α (CREMα) is a central mediator of T-cell pathogenesis, which contributes to increased IL-17 expression in patients with autoimmune disorders. Since an increased Th17 response is associated with a poor prognosis in patients with chronic liver injury, we investigated the relevance of Th17 cells for chronic liver disease (CLD) and hepatocarcinogenesis.

DESIGN

Transgenic mice overexpressing CREMα were crossed with hepatocyte-specific Nemo knockout mice (Nemo^Δhepa) to generate Nemo^Δhepa/CREMα^Tg mice. The impact of CREMα^Tg on CLD progression was examined. Additionally, soft agar colony formation assays, in vitro studies, adoptive transfer of bone marrow-derived cells (BMDCs) and T cells, and gene arrays in T cells were performed.

RESULTS

8-week-old Nemo^Δhepa/CREMα^Tg mice presented significantly decreased transaminase levels, concomitant with reduced numbers of CD11b⁺ dendritic cells and CD8⁺ T cells. CREMα^Tg overexpression in Nemo^Δhepa mice was associated with significantly reduced hepatic fibrogenesis and carcinogenesis at 52 weeks. Interestingly, hepatic stellate cell-derived retinoic acid induced a regulatory T-cell (Treg) phenotype in CREMα^Tg hepatic T cells. Moreover, simultaneous adoptive transfer of BMDCs and T cells from CREMα^Tg into Nemo^Δhepa mice ameliorated markers of liver injury and hepatitis.

CONCLUSIONS

Our results demonstrate that overexpression of CREMα in T cells changes the inflammatory milieu, attenuating initiation and progression of CLD. Unexpectedly, our study indicates that CREMα transgenic T cells shift chronic inflammation in Nemo^Δhepa livers towards a protective Treg response.

Dual role of tumour-infiltrating T helper 17 cells in human colorectal cancer

BACKGROUND

The immune contexture predicts prognosis in human colorectal cancer (CRC). Whereas tumour-infiltrating CD8+ T cells and myeloid CD16+ myeloperoxidase (MPO)+ cells are associated with favourable clinical outcome, interleukin (IL)-17-producing cells have been reported to correlate with severe prognosis. However, their phenotypes and functions continue to be debated.

OBJECTIVE

To investigate clinical relevance, phenotypes and functional features of CRC-infiltrating, IL-17-producing cells.

METHODS

IL-17 staining was performed by immunohistochemistry on a tissue microarray including 1148 CRCs. Phenotypes of IL-17-producing cells were evaluated by flow cytometry on cell suspensions obtained by enzymatic digestion of clinical specimens. Functions of CRC-isolated, IL-17-producing cells were assessed by in vitro and in vivo experiments.

RESULTS

IL-17+ infiltrates were not themselves predictive of an unfavourable clinical outcome, but correlated with infiltration by CD8+ T cells and CD16+ MPO+ neutrophils. Ex vivo analysis showed that tumour-infiltrating IL-17+ cells mostly consist of CD4+ T helper 17 (Th17) cells with multifaceted properties. Indeed, owing to IL-17 secretion, CRC-derived Th17 triggered the release of protumorigenic factors by tumour and tumour-associated stroma. However, on the other hand, they favoured recruitment of beneficial neutrophils through IL-8 secretion and, most importantly, they drove highly cytotoxic CCR5+CCR6+CD8+ T cells into tumour tissue, through CCL5 and CCL20 release. Consistent with these findings, the presence of intraepithelial, but not of stromal Th17 cells, positively correlated with improved survival.

CONCLUSIONS

Our study shows the dual role played by tumour-infiltrating Th17 in CRC, thus advising caution when developing new IL-17/Th17 targeted treatments.

Interaction between tumour-infiltrating B cells and T cells controls the progression of hepatocellular carcinoma

OBJECTIVE

The nature of the tumour-infiltrating leucocytes (TILs) is known to impact clinical outcome in carcinomas, including hepatocellular carcinoma (HCC). However, the role of tumour-infiltrating B cells (TIBs) remains controversial. Here, we investigate the impact of TIBs and their interaction with T cells on HCC patient prognosis.

DESIGN

Tissue samples were obtained from 112 patients with HCC from Singapore, Hong Kong and Zurich and analysed using immunohistochemistry and immunofluorescence. RNA expression of CD19, CD8A, IFNG was analysed using quantitative PCR. The phenotype of freshly isolated TILs was analysed using flow cytometry. A mouse model depleted of mature B cells was used for functional study.

RESULTS

Tumour-infiltrating T cells and B cells were observed in close contact with each other and their densities are correlated with superior survival in patients with HCC. Furthermore, the density of TIBs was correlated with an enhanced expression of granzyme B and IFN-γ, as well as with reduced tumour viability defined by low expression of Ki-67, and an enhanced expression of activated caspase-3 on tumour cells. CD27 and CD40 costimulatory molecules and TILs expressing activation marker CD38 in the tumour were also correlated with patient survival. Mice depleted of mature B cells and transplanted with murine hepatoma cells showed reduced tumour control and decreased local T cell activation, further indicating the important role of B cells.

CONCLUSIONS

The close proximity of tumour-infiltrating T cells and B cells indicates a functional interaction between them that is linked to an enhanced local immune activation and contributes to better prognosis for patients with HCC.

B Cell Depletion Therapy Normalizes Circulating Follicular Th Cells in Primary Sjögren Syndrome

OBJECTIVE

To assess the effect of B cell depletion therapy on effector CD4+ T cell homeostasis and its relation to objective measures of disease activity in patients with primary Sjögren syndrome (pSS).

METHODS

Twenty-four patients with pSS treated with rituximab (RTX) and 24 healthy controls (HC) were included. Frequencies of circulating effector CD4+ T cell subsets were examined by flow cytometry at baseline and 16, 24, 36, and 48 weeks after the first RTX infusion. Th1, Th2, follicular Th (TFH), and Th17 cells were discerned based on surface marker expression patterns. Additionally, intracellular cytokine staining was performed for interferon-γ, interleukin (IL)-4, IL-21, and IL-17 and serum levels of these cytokines were analyzed.

RESULTS

In patients with pSS, frequencies of circulating TFH cells and Th17 cells were increased at baseline compared with HC, whereas frequencies of Th1 and Th2 cells were unchanged. B cell depletion therapy resulted in a pronounced decrease in circulating TFH cells, whereas Th17 cells were only slightly lowered. Frequencies of IL-21-producing and IL-17-producing CD4+ T cells and serum levels of IL-21 and IL-17 were also reduced. Importantly, the decrease in circulating TFH cells was associated with lower systemic disease activity over time, as measured by the European League Against Rheumatism Sjögren's Syndrome Disease Activity Index scores and serum IgG levels.

CONCLUSION

B cell depletion therapy in patients with pSS results in normalization of the elevated levels of circulating TFH cells. This reduction is associated with improved objective clinical disease activity measures. Our observations illustrate the pivotal role of the crosstalk between B cells and TFH cells in the pathogenesis of pSS.

Batf-dependent Th17 cells critically regulate IL-23 driven colitis-associated colon cancer

OBJECTIVES

IBDs have an increased risk for development of colorectal cancer (CRC). Here, we aimed at the characterisation of the functional role of Th17-associated transcription factors in sporadic and colitis-associated colon cancer in vivo.

DESIGN

We used mice deficient or transgenic for the activating protein 1 family member basic leucine zipper transcription factor ATF-like (Batf) to evaluate the role of Th17 cells during sporadic and inflammation-induced colon carcinogenesis. We also studied the expression of Batf and RORγt in patients with IBD and CRC.

RESULTS

Batf but not retinoic acid-related orphan receptor γt(RORγt) expression was significantly increased together with interleukin (IL) 23 expression in UC but not in Crohn's disease (CD) tissue samples. In CRC also Batf but not RORγt expression was increased and its expression correlated with the IL-23 and IL-23 receptor (IL-23R) expression. Finally, Batf but not RORγt was coexpressed with IL-17a, IL-23R and IL-6 within CRC-infiltrating CD4(+) T cells. Functional studies in mice revealed that Batf-dependent T cells are crucial regulators of sporadic and inflammation-induced CRC. Colitis-associated Batf(-/-) tumours lacked IL-17a(+)IL-23R(+)IL-6(+)CD4(+) T cells, hence displaying characteristics reminiscent of human CRC-infiltrating CD4(+) T cells. Strikingly, Batf(-/-) tumours contained low IL-23 but high IL-17a expression levels. Tumour formation and intratumoral IL-23 expression could be restored by administration of Hyper-IL-6 consisting of IL-6 and soluble IL-6 receptor.

CONCLUSIONS

Batf-dependent IL-23R(+)IL-6(+)CD4(+) Th17 cells critically control IL-23 driven colitis-associated tumour formation and the progression of sporadic colon tumours. Batf-dependent IL-23R(+) T cells represent a potential future therapeutic target limiting CRC progression.

miR-10a inhibits dendritic cell activation and Th1/Th17 cell immune responses in IBD

OBJECTIVE

Although both innate and adaptive responses to microbiota have been implicated in the pathogenesis of IBD, it is still largely unknown how they are regulated during intestinal inflammation. In this report, we investigated the role of microRNA (miR)-10a, a small, non-coding RNA, in the regulation of innate and adaptive responses to microbiota in IBD.

METHODS

miR-10a expression was analysed in the inflamed mucosa of IBD patients treated with or without antitumour necrosis factor (anti-TNF) monoclonal antibodies (mAb) (infliximab) by qRT-PCR. Human monocyte-derived dendritic cells (DC) and IBD CD4+ T cells were transfected with miR-10a precursor to define their effect on the function of DC and CD4+ T cells.

RESULTS

The expression of miR-10a was markedly decreased, while NOD2 and interleukin (IL)-12/IL-23p40 were significantly increased, in the inflamed mucosa of IBD patients compared with those in healthy controls. Commensal bacteria, TNF and interferon-γ inhibited human DC miR-10a expression in vitro. Anti-TNF mAb treatment significantly promoted miR-10a expression, whereas it markedly inhibited NOD2 and IL-12/IL-23p40 in the inflamed mucosa. We further identified NOD2, in addition to IL-12/IL-23p40, as a target of miR-10a. The ectopic expression of the miR-10a precursor inhibited IL-12/IL-23p40 and NOD2 in DC. Moreover, miR-10a was found to markedly suppress IBD T helper (Th)1 and Th17 cell responses.

CONCLUSIONS

Our data indicate that miR-10a is decreased in the inflamed mucosa of IBD and downregulates mucosal inflammatory response through inhibition of IL-12/IL-23p40 and NOD2 expression, and blockade of Th1/Th17 cell immune responses. Thus, miR-10a could play a role in the pathogenesis and progression of IBD.

Bone marrow Th17 TNFα cells induce osteoclast differentiation, and link bone destruction to IBD

OBJECTIVE

Under both physiological and pathological conditions, bone volume is determined by the rate of bone formation by osteoblasts and bone resorption by osteoclasts. Excessive bone loss is a common complication of human IBD whose mechanisms are not yet completely understood. Despite the role of activated CD4(+) T cells in inflammatory bone loss, the nature of the T cell subsets involved in this process in vivo remains unknown. The aim of the present study was to identify the CD4(+) T cell subsets involved in the process of osteoclastogenesis in vivo, as well as their mechanism of action.

DESIGN

CD4(+) T cells were studied in IL10-/- mice and Rag1-/- mice adoptively transferred with naive CD4(+)CD45RB(high) T cells, representing two well-characterised animal models of IBD and in patients with Crohn's disease. They were phenotypically and functionally characterised by flow cytometric and gene expression analysis, as well as in in vitro cocultures with osteoclast precursors.

RESULTS

In mice, we identified bone marrow (BM) CD4(+) T cells producing interleukin (IL)-17 and tumour necrosis factor (TNF)-α as an osteoclastogenic T cell subset referred to as Th17 TNF-α(+) cells. During chronic inflammation, these cells migrate to the BM where they survive in an IL-7-dependent manner and where they promote the recruitment of inflammatory monocytes, the main osteoclast progenitors. A population equivalent to the Th17 TNF-α(+) cells was also detected in patients with Crohn's disease.

CONCLUSIONS

Our results highlight the osteoclastogenic function of the Th17 TNF-α(+) cells that contribute to bone loss in vivo in IBD.

Targeting tumour necrosis factor receptor 1 assembly reverses Th17-mediated colitis through boosting a Th2 response

OBJECTIVE

The soluble preligand assembly domain (PLAD) of tumour necrosis factor receptor 1 (TNFR1) interferes with receptor trimerisation to block downstream signalling, and mediates Th17 suppression. We explored the therapeutic potential of recombinant PLAD.Fc protein on a spontaneous experimental colitis.

DESIGN

A T-cell-specific BLIMP-1 knockout mouse model with mixed Th1/Th17 responses, resembling human Crohn's disease (CD) was established, and its colitogenic phenotype was characterised. Mice, 9 weeks old, were treated with PLAD.Fc protein at 5 mg/kg of body weight twice per week for 16 weeks, and presence of colitis was monitored by the appearance of diarrhoea, weight loss, and by histological colonic scoring. Activation status, cytokine profiles, and transcription factors in T cells were further analysed.

RESULTS

The colitogenic phenotype in BLIMP-1 knockout mice was alleviated when an interleukin (IL)-23 knockdown transgene was introduced, indicating a therapeutic potential by downregulating IL-23-Th17 axis in these knockout mice. In PLAD.Fc-treated group, the mouse body weight remained stable and only mild disease scores were revealed. The percentage of naive CD4 T cells was increased and that of effector/memory CD4 T cells was decreased after PLAD.Fc-treatment. Moreover, the levels of IFN-γ, IL-17, IL-21, IL-22, IL-23R, granulocyte-macrophage colony-stimulating factor (GM-CSF) and TNF-α were diminished. Strikingly, Th2-associated cytokines (IL-4, IL-13 and IL-10) in sera, as well as percentages of Th2 cells, were increased in PLAD.Fc-treated mice. However, PLAD.Fc-mediated suppression of effector phenotypes in Th1/Th17 was abrogated after neutralising IL-10.

CONCLUSIONS

The Th2 cytokine milieu induced by PLAD.Fc rebalanced T-helper cell subsets and conferred a protection against colitis in BLIMP-1 knockout mice.

MicroRNAs: new players in IBD

MicroRNAs (miRNAs) are small non-coding RNAs, 18-23 nucleotides long, which act as post-transcriptional regulators of gene expression. miRNAs are strongly implicated in the pathogenesis of many common diseases, including IBDs. This review aims to outline the history, biogenesis and regulation of miRNAs. The role of miRNAs in the development and regulation of the innate and adaptive immune system is discussed, with a particular focus on mechanisms pertinent to IBD and the potential translational applications.

CCL20/CCR6-mediated migration of regulatory T cells to the Helicobacter pylori-infected human gastric mucosa

BACKGROUND

Helicobacter pylori-induced peptic ulceration is less likely to occur in patients with a strong gastric anti-inflammatory regulatory T cell (Treg) response. Migration of Tregs into the gastric mucosa is therefore important.

OBJECTIVE

To identify the homing receptors involved in directing Tregs to the gastric mucosa, and investigate how H pylori stimulates the relevant chemokine responses.

DESIGN

Gastric biopsy samples and peripheral blood were donated by 84 H pylori-infected and 46 uninfected patients. Luminex assays quantified gastric biopsy chemokine concentrations. Flow cytometry was used to characterise homing receptors on CD4(+)CD25(hi) Tregs. H pylori wild-type and isogenic mutants were used to investigate the signalling mechanisms behind CCL20 and IL-8 induction in gastric epithelial cell lines. Transwell assays were used to quantify Treg migration towards chemokines in vitro.

RESULTS

CCL20, CXCL1-3 and IL-8 concentrations were significantly increased in gastric biopsy samples from H pylori-infected patients. CCR6 (CCL20 receptor), CXCR1 and CXCR2 (IL-8 and CXCL1-3 receptors) were expressed by a higher proportion of peripheral blood Tregs in infected patients. Most gastric Tregs expressed these receptors. H pylori induced CCL20 production by gastric epithelial cells via cag pathogenicity island (cagPAI)-dependent NF-κB signalling. Foxp3(+), but not Foxp3(-), CD4 cells from infected mice migrated towards recombinant CCL20 in vitro.

CONCLUSIONS

As well as increasing Treg numbers, H pylori infection induces a change in their characteristics. Expression of CCR6, CXCR1 and CXCR2 probably enables their migration towards CCL20 and IL-8 in the infected gastric mucosa. Such qualitative changes may also explain how H pylori protects against some extragastric inflammatory disorders.

Altered intestinal microbiota and blood T cell phenotype are shared by patients with Crohn's disease and their unaffected siblings

OBJECTIVE

Crohn's disease (CD) is associated with intestinal dysbiosis, altered blood T cell populations, elevated faecal calprotectin (FC) and increased intestinal permeability (IP). CD-associated features present in siblings (increased risk of CD) but not in healthy controls, provide insight into early CD pathogenesis. We aimed to (1) Delineate the genetic, immune and microbiological profile of patients with CD, their siblings and controls and (2) Determine which factors discriminate between groups.

DESIGN

Faecal microbiology was analysed by quantitative PCR targeting 16S ribosomal RNA, FC by ELISA, blood T cell phenotype by flow cytometry and IP by differential lactulose-rhamnose absorption in 22 patients with inactive CD, 21 of their healthy siblings and 25 controls. Subject's genotype relative risk was determined by Illumina Immuno BeadChip.

RESULTS

Strikingly, siblings shared aspects of intestinal dysbiosis with patients with CD (lower concentrations of Faecalibacterium prausnitzii (p=0.048), Clostridia cluster IV (p=0.003) and Roseburia spp. (p=0.09) compared with controls). As in CD, siblings demonstrated a predominance of memory T cells (p=0.002) and elevated naïve CD4 T cell β7 integrin expression (p=0.01) compared with controls. FC was elevated (>50 μg/g) in 8/21 (38%) siblings compared with 2/25 (8%) controls (p=0.028); whereas IP did not differ between siblings and controls. Discriminant function analysis determined that combinations of these factors significantly discriminated between groups (χ(2)=80.4, df=20, p<0.001). Siblings were separated from controls by immunological and microbiological variables.

CONCLUSIONS

Healthy siblings of patients with CD manifest immune and microbiological abnormalities associated with CD distinct from their genotype-related risk and provide an excellent model in which to investigate early CD pathogenesis.

Anti-TNF antibody-induced psoriasiform skin lesions in patients with inflammatory bowel disease are characterised by interferon-γ-expressing Th1 cells and IL-17A/IL-22-expressing Th17 cells and respond to anti-IL-12/IL-23 antibody treatment

BACKGROUND

We analysed incidence, predictors, histological features and specific treatment options of anti-tumour necrosis factor α (TNF-α) antibody-induced psoriasiform skin lesions in patients with inflammatory bowel diseases (IBD).

DESIGN

Patients with IBD were prospectively screened for anti-TNF-induced psoriasiform skin lesions. Patients were genotyped for IL23R and IL12B variants. Skin lesions were examined for infiltrating Th1 and Th17 cells. Patients with severe lesions were treated with the anti-interleukin (IL)-12/IL-23 p40 antibody ustekinumab.

RESULTS

Among 434 anti-TNF-treated patients with IBD, 21 (4.8%) developed psoriasiform skin lesions. Multiple logistic regression revealed smoking (p=0.007; OR 4.24, 95% CI 1.55 to 13.60) and an increased body mass index (p=0.029; OR 1.12, 95% CI 1.01 to 1.24) as main predictors for these lesions. Nine patients with Crohn's disease and with severe psoriasiform lesions and/or anti-TNF antibody-induced alopecia were successfully treated with the anti-p40-IL-12/IL-23 antibody ustekinumab (response rate 100%). Skin lesions were histologically characterised by infiltrates of IL-17A/IL-22-secreting T helper 17 (Th17) cells and interferon (IFN)-γ-secreting Th1 cells and IFN-α-expressing cells. IL-17A expression was significantly stronger in patients requiring ustekinumab than in patients responding to topical therapy (p=0.001). IL23R genotyping suggests disease-modifying effects of rs11209026 (p.Arg381Gln) and rs7530511 (p.Leu310Pro) in patients requiring ustekinumab.

CONCLUSIONS

New onset psoriasiform skin lesions develop in nearly 5% of anti-TNF-treated patients with IBD. We identified smoking as a main risk factor for developing these lesions. Anti-TNF-induced psoriasiform skin lesions are characterised by Th17 and Th1 cell infiltrates. The number of IL-17A-expressing T cells correlates with the severity of skin lesions. Anti-IL-12/IL-23 antibody therapy is a highly effective therapy for these lesions.