Human type 1 innate lymphoid cells accumulate in inflamed mucosal tissues.

Innate lymphoid cells (ILCs) are effectors of innate immunity and regulators of tissue modeling. Recently identified ILC populations have a cytokine expression pattern that resembles that of the helper T cell subsets T(H)2, T(H)17 and T(H)22. Here we describe a distinct ILC subset similar to T(H)1 cells, which we call 'ILC1'. ILC1 cells expressed the transcription factor T-bet and responded to interleukin 12 (IL-12) by producing interferon-γ (IFN-γ). ILC1 cells were distinct from natural killer (NK) cells as they lacked perforin, granzyme B and the NK cell markers CD56, CD16 and CD94, and could develop from RORγt(+) ILC3 under the influence of IL-12. The frequency of the ILC1 subset was much higher in inflamed intestine of people with Crohn's disease, which indicated a role for these IFN-γ-producing ILC1 cells in the pathogenesis of gut mucosal inflammation.

Human IL-25- and IL-33-responsive type 2 innate lymphoid cells are defined by expression of CRTH2 and CD161.

Innate lymphoid cells (ILCs) are emerging as a family of effectors and regulators of innate immunity and tissue remodeling. Interleukin 22 (IL-22)- and IL-17-producing ILCs, which depend on the transcription factor RORγt, express CD127 (IL-7 receptor α-chain) and the natural killer cell marker CD161. Here we describe another lineage-negative CD127(+)CD161(+) ILC population found in humans that expressed the chemoattractant receptor CRTH2. These cells responded in vitro to IL-2 plus IL-25 and IL-33 by producing IL-13. CRTH2(+) ILCs were present in fetal and adult lung and gut. In fetal gut, these cells expressed IL-13 but not IL-17 or IL-22. There was enrichment for CRTH2(+) ILCs in nasal polyps of chronic rhinosinusitis, a typical type 2 inflammatory disease. Our data identify a unique type of human ILC that provides an innate source of T helper type 2 (T(H)2) cytokines.

The transcription factor GATA3 is essential for the function of human type 2 innate lymphoid cells.

Type 2 innate lymphoid cells (ILC2s) are part of a large family of ILCs that are important effectors in innate immunity, lymphoid organogenesis, and tissue remodeling. ILC2s mediate parasite expulsion but also contribute to airway inflammation, emphasizing the functional similarity between these cells and Th2 cells. Consistent with this, we report that the transcription factor GATA3 was highly expressed by human ILC2s. CRTH2(+) ILC2s were enriched in nasal polyps of patients with chronic rhinosinusitis, a typical type 2-mediated disease. Nasal polyp epithelial cells expressed TSLP, which enhanced STAT5 activation, GATA3 expression, and type 2 cytokine production in ILC2s. Ectopic expression of GATA3 in Lin(-)CD127(+)CRTH2(-) cells resulted in induction of CRTH2 and the capacity to produce high amounts of type 2 cytokines in response to TSLP plus IL-33. Hence, we identify GATA3, potently regulated by TSLP, as an essential transcription factor for the function of human ILC2s.

Endoscopic and surgical treatment outcomes of colitis-associated advanced colorectal neoplasia: a multicenter cohort study.

BACKGROUND: Inflammatory bowel disease (IBD) patients are at increased risk of advanced neoplasia (high-grade dysplasia or colorectal cancer). The authors aimed to (1) assess synchronous and metachronous neoplasia following (sub)total or proctocolectomy, partial colectomy or endoscopic resection for advanced neoplasia in IBD, and (2) identify factors associated with treatment choice. MATERIAL AND METHODS: In this retrospective multicenter cohort study, the authors used the Dutch nationwide pathology databank (PALGA) to identify patients diagnosed with IBD and colonic advanced neoplasia (AN) between 1991 and 2020 in seven hospitals in the Netherlands. Logistic and Fine & Gray's subdistribution hazard models were used to assess adjusted subdistribution hazard ratios for metachronous neoplasia and associations with treatment choice. RESULTS: The authors included 189 patients (high-grade dysplasia n =81; colorectal cancer n =108). Patients were treated with proctocolectomy ( n =33), (sub)total colectomy ( n =45), partial colectomy ( n =56) and endoscopic resection ( n =38). Partial colectomy was more frequently performed in patients with limited disease and older age, with similar patient characteristics between Crohn's disease and ulcerative colitis. Synchronous neoplasia was found in 43 patients (25.0%; (sub)total or proctocolectomy n =22, partial colectomy n =8, endoscopic resection n =13). The authors found a metachronous neoplasia rate of 6.1, 11.5 and 13.7 per 100 patient-years after (sub)total colectomy, partial colectomy and endoscopic resection, respectively. Endoscopic resection, but not partial colectomy, was associated with an increased metachronous neoplasia risk (adjusted subdistribution hazard ratios 4.16, 95% CI 1.64-10.54, P <0.01) compared with (sub)total colectomy. CONCLUSION: After confounder adjustment, partial colectomy yielded a similar metachronous neoplasia risk compared to (sub)total colectomy. High metachronous neoplasia rates after endoscopic resection underline the importance of strict subsequent endoscopic surveillance.

Accumulation of bioactive lipids during storage of blood products is not cell but plasma derived and temperature dependent.

BACKGROUND: Bioactive lipids (lysophosphatidylcholines [lysoPCs]) accumulating during storage of cell-containing blood products are thought to be causative in onset of transfusion-related acute lung injury through activation of neutrophils. LysoPCs are thought to be derived from cell membrane degradation products such as phosphatidylcholines (PC) by partial hydrolysis of PC, a process that is catalyzed by phospholipase A(2) (PLA(2) ). STUDY DESIGN AND METHODS: We investigated the underlying mechanisms of lysoPC generation and its contribution to in vitro neutrophil-priming capacity during storage of red blood cells (RBCs), platelet (PLTs) concentrates, and cell-free plasma. Blood from healthy volunteers was drawn, processed, and stored according to Sanquin Blood Bank protocols. RESULTS: Storage of RBCs in saline-adenine-glucose-mannitol (SAGM) did not result in accumulation of lysoPCs or neutrophil-priming capacity. Replacement of SAGM by plasma as RBC storage medium caused elevated lysoPC levels on Day 0, which did not further increase during storage. Cell-free plasma stored at 22°C showed accumulation of lysoPCs during storage, which was not present at 4°C. Addition of a soluble PLA(2) or cytosolic PLA(2) inhibitor did not prevent accumulation of lysoPCs in plasma. In PLTs, lysoPC accumulation during storage was plasma dependent, but lysoPCs did not explain the observed neutrophil-priming effect as preventing accumulation of lysoPCs by removing the plasma fraction did not prevent the neutrophil-priming capacity. CONCLUSION: Accumulation of lysoPCs during storage is not cell but plasma derived and storage temperature dependent and does not explain the neutrophil-priming effect of aged products.

[Acute liver failure due to food supplements]. / Acuut leverfalen na gebruik van voedingssupplementen.

BACKGROUND: Acute liver failure resulting from the use of food supplements is rare. However, due to the rapid rise in the use of food supplements, the incidence of liver damage is increasing. CASE DESCRIPTION: We describe the cases of two women with menopausal symptoms who developed liver failure shortly after starting to take food supplements containing plant extracts. Both women consequently underwent a liver transplant. CONCLUSION: Food supplements are not regarded as medicines, but fall under regulations pertaining to foodstuffs. This means they can be put on the market without their safety having first been checked. The old Dutch saying 'if it doesn't do any good, it won't do any harm' is certainly not applicable here. Is it time for a new law?

TNF-anti-TNF Immune Complexes Inhibit IL-12/IL-23 Secretion by Inflammatory Macrophages via an Fc-dependent Mechanism.

BACKGROUND AND AIMS: We have recently shown that the mode of action of IgG1 anti-tumour necrosis factor [TNF] antibodies in inflammatory bowel disease [IBD] requires Fcγ-receptor [FcγR] engagement on macrophages. Here we examine the effect of Fcγ-receptor signalling by anti-TNF on macrophage IL-12/IL-23 secretion. METHODS: Cytokine production by human inflammatory macrophages was assessed at the level of RNA and protein. TNF-anti-TNF immune complex formation was determined by size-exclusion chromatography and signalling visualized by immunofluorescence. IL-12/IL-23p40 was measured in CD14+ lamina propria cells from IBD patients. RESULTS: Infliximab and adalimumab potently suppressed IL-12/IL-23 production by inflammatory macrophages, but Fab' fragment certolizumab did not. IL-12/IL-23 suppression depended on Syk activity and was mediated at the level of IL-12/IL-23p40 mRNA. Etanercept, a soluble TNF receptor fused to an Fc-region, did not inhibit IL-12/L-23 secretion, suggesting that the presence of an Fc-region was not sufficient. Infliximab and adalimumab formed immune complexes with soluble TNF whereas etanercept did not, suggesting that FcγR-mediated suppression of IL-12/IL-23 required the formation of immune complexes. Indeed, non-specific IgG1 immune complexes, but not uncomplexed IgG1, similarly suppressed IL-12/IL-23 secretion. Finally, infliximab significantly decreased IL-12/IL-23p40 production in myeloid cells isolated from the lamina propria of IBD patients. CONCLUSIONS: TNF-anti-TNF antibody immune complexes potently inhibit IL-12/IL-23 expression by inflammatory macrophages. Our data suggest that anti-TNFs and antibodies against IL-12/IL-23 may therefore have partially overlapping modes of action in patients with IBD.

ATG16L1 and NOD2 polymorphisms enhance phagocytosis in monocytes of Crohn's disease patients.

AIM: To investigate if the presence of relevant genetic polymorphisms has effect on the effectual clearance of bacteria by monocytes and granulocytes in patients with Crohn's disease (CD). METHODS: In this study, we assessed the differential responses in phagocytosis by measuring the phagocytic activity and the percentage of active phagocytic monocytes and granulocytes in inflammatory bowel disease patients as well as healthy controls. As both autophagy related like 1 (ATG16L1) and immunity-related guanosine triphosphatase gene are autophagy genes associated with CD and more recently nucleotide-binding ligomerization domain-containing protein 2 (NOD2) has been identified as a potent inducer of autophagy we genotyped the patients for these variants and correlated this to the phagocytic reaction. The genotyping was done with restriction fragment length polymorphisms analysis and the phagocytosis was determined with the pHrodo™ Escherichia coli Bioparticles Phagocytosis kit for flowcytometry. RESULTS: In this study, we demonstrate that analysis of the monocyte and granulocyte populations of patients with CD and ulcerative colitis showed a comparable phagocytic activity (ratio of mean fluorescence intensity) between the patient groups and the healthy controls. CD patients show a significantly higher phagocytic capacity (ratio mean percentage of phagocytic cells) compared to healthy controls (51.91% ± 2.85% vs 37.67% ± 7.06%, P = 0.05). The extend of disease was not of influence. However, variants of ATG16L1 (WT: 2.03 ± 0.19 vs homozygoot variant: 4.38 ± 0.37, P < 0.009) as well as NOD2 (C-ins) (heterozygous variant: 42.08 ± 2.94 vs homozygous variant: 75.58 ± 4.34 (P = 0.05) are associated with the phagocytic activity in patients with CD. CONCLUSION: Monocytes of CD patients show enhanced phagocytosis associated with the presence of ATG16L1 and NOD2 variants. This could be part of the pathophysiological mechanism resulting in the disease.

Effects of infliximab retreatment after consecutive discontinuation of infliximab and adalimumab in refractory Crohn's disease.

BACKGROUND: Switches between anti-tumor necrosis factor agents in the treatment of Crohn's disease (CD) occur in case of treatment failure, intolerance, or patient preference. No data are currently available on the usefulness of a second infliximab treatment after earlier discontinuation and previous switch to an alternative anti-tumor necrosis factor agent. In this study, we evaluated the clinical benefit of infliximab retreatment in patients with CD after sequential use of both infliximab and adalimumab. METHODS: Twenty-nine patients with CD who had received earlier treatments with sequential infliximab and adalimumab and were then restarted on infliximab were retrieved from a multicenter registry designed for the follow-up of adalimumab treatment for CD. Short-term and sustained effects of infliximab retreatment were evaluated retrospectively by reviewing clinical records. Follow-up was 18 months for all patients. RESULTS: In 13/29 (45%) patients, infliximab was reintroduced at intensified dosing schedule (>5 mg/kg or <8 wk) for 23/29 (79%) of patients similar to the schedule who were on at time of previous discontinuation. During the second infliximab treatment course, dosing was further intensified in 11 out of 29 (38%) patients. After 18 months 18/29 (62%), patients were still on continued therapy of their second infliximab treatment. Infliximab was discontinued (after a median of 7 mo) in 11 out of 29 patients for loss of response (n = 7 [24%]), intolerance (n = 3 [10%]), or non-compliance (n = 1 [3%]). Use of induction schedule or concomitant immunomodulators were not significantly associated with treatment benefit. CONCLUSIONS: The majority of patients with CD benefit from a second treatment with infliximab after previous treatment with infliximab and adalimumab, which offer a meaningful therapeutic option in often highly refractory patients.

Screening prior to biological therapy in Crohn's disease: adherence to guidelines and prevalence of infections. Results from a multicentre retrospective study.

BACKGROUND: Screening for opportunistic infections prior to starting biological therapy in patients with inflammatory bowel disease is recommended. AIMS: To assess adherence to screening for opportunistic infections prior to starting biological therapy in Crohn's disease patients and its yield. METHODS: A multicentre retrospective study was conducted in Crohn's disease patients in whom infliximab or adalimumab was started between 2000 and 2010. Screening included tuberculin skin test, interferon-gamma release assay or chest X-ray for tuberculosis. Extended screening included screening for tuberculosis and viral infections. Patients were followed until three months after ending treatment. Primary endpoints were opportunistic and serious infections. RESULTS: 611 patients were included, 91% on infliximab. 463 (76%) patients were screened for tuberculosis, of whom 113 (24%) underwent extended screening. Screening for tuberculosis and hepatitis B increased to, respectively, 90-97% and 36-49% in the last two years. During a median follow-up of two years, 64/611 (9%, 3.4/100 patient-years) opportunistic infections and 26/611 (4%, 1.6/100 patient-years) serious infections were detected. Comorbidity was significantly associated with serious infections (hazard ratio 3.94). CONCLUSIONS: Although screening rates for tuberculosis and hepatitis B increased, screening for hepatitis B was still suboptimal. More caution is required when prescribing biologicals in patients with comorbid conditions.

Adalimumab for Crohn's disease: long-term sustained benefit in a population-based cohort of 438 patients.

BACKGROUND AND AIMS: Adalimumab is an effective therapy for induction and maintenance of Crohn's disease. However, results in clinical trials don't necessarily reflect daily clinical practice. Therefore, we assessed real-life long-term clinical response to adalimumab in a large population-based cohort and identified clinical parameters affecting response METHODS: All consecutive patients in North-Holland that started adalimumab between 2003 and 2011 were included, of which medical charts were reviewed. Response to induction therapy was assessed after 3months. Sustained benefit of maintenance therapy was calculated from Kaplan-Meier survival tables depicting ongoing adalimumab treatment. Regression analyses were performed to identify factors predicting response to adalimumab therapy. RESULTS: In total 438 Crohn's patients started adalimumab with 92.5% response to the induction phase. After 1year 83.3% showed sustained benefit of maintenance treatment, followed by 74.0% after 2years. Nevertheless, one third of patients were in steroid-free remission at the end of their follow-up. Response to induction was negatively affected by longer disease duration (OR 1.05; p<0.01) and strictures (OR 3.73; p=0.04). Increased CRP levels predicted higher rates of initial response (OR 0.31; p<0.01). Concomitant thiopurines in the first 6months of adalimumab treatment decreased the risk to fail maintenance therapy (HR 0.69, p=0.05). Previous infliximab therapy did not affect response to adalimumab, however dose escalation was more often deemed necessary (p<0.01). CONCLUSION: Adalimumab was successful in the majority of patients, with 10% loss of response per subsequent year. Concomitant thiopurines might improve adalimumab maintenance treatment.

Ten years of infliximab for Crohn's disease: outcome in 469 patients from 2 tertiary referral centers.

BACKGROUND: Aim was to assess the long-term clinical efficacy of infliximab therapy in patients with Crohn's disease treated in a cohort of 2 tertiary referral centers in the Netherlands. METHODS: All consecutive patients with Crohn's disease treated with infliximab were assessed. Endpoints were primary clinical efficacy, sustained benefit, efficacy of retreatment, surgical intervention rates, and safety. Sustained benefit was determined by Kaplan-Meier analysis. The estimated 5-year benefit was calculated. RESULTS: A total of 469 patients were included. Median follow-up length was 4.5 years (interquartile range, 2.7-6.8). Seventy patients (15%) had unsuccessful remission induction, and 316 patients received maintenance therapy. Scheduled maintenance regimen was successful in 169 of 276 (61%). Episodic maintenance therapy was successful in 19 of 40 patients (48%). Estimated 5-year sustained benefit was 55.7% (95% confidence interval, 48.8-62.6). Concomitant thiopurines were associated with improved sustained benefit. A second course of infliximab after previous discontinuation was prescribed in 131 patients with similar efficacy rates. Abdominal surgical intervention rate per 100 patient-years was significantly reduced after infliximab initiation in patients with a scheduled maintenance regime (reduction, 2.70; 95% confidence interval, -4.82 to -0.35; P = 0.018). Mortality and malignancy rates were 1.9% (0.39/100 patient-years) and 3.4% (0.70/100 patient-years), respectively. CONCLUSIONS: The present study shows an estimated 5-year sustained benefit of 55.7% in patients with Crohn's disease treated with infliximab maintenance therapy. Remission induction and maintenance were equally successful in patients starting infliximab and patients who temporarily stopped and were retreated. Long-term use of infliximab was safe and reduced the need for surgery in patients on scheduled maintenance therapy.

Anti-inflammatory effects of urocanic Acid derivatives in models ex vivo and in vivo of inflammatory bowel disease.

Urocanic acid (UCA) derivatives were tested for their anti-inflammatory activity in inflammatory bowel disease (IBD) in two models: ex vivo and an experimental mouse model. Ex vivo: inflamed colonic tissue was incubated in culture medium with or without the UCA derivatives. Biopsies, incubated with UCA derivatives, produced lower levels of proinflammatory cytokines IL-6 and IL-8 as compared to control biopsies. The same compounds also showed increased levels of IL-10, providing an additional indication for anti-inflammatory properties. In vivo: a combination of two imidazoles and a combination of two of their ethyl esters were administered to mice while colitis was induced by oral administration of dextran sodium sulfate (DSS). Some parameters did not show conclusive effects, but the imidazoles and their ethyl esters reduced the area of inflammation and the number of infiltrating neutrophils. Fibrosis and the sum of all histological aspects were reduced by the imidazoles, whereas the ethyl esters reduced the colon weight to length ratio. These results suggest that the UCA derivatives have anti-inflammatory effect on IBD. In addition, fine tuning of the ex vivo model may provide an elegant way to predict anti-inflammatory effects of potential drugs in humans, which may decrease the need for animal experiments.

Functional Differences between Human NKp44(-) and NKp44(+) RORC(+) Innate Lymphoid Cells.

Human RORC(+) lymphoid tissue inducer cells are part of a rapidly expanding family of innate lymphoid cells (ILC) that participate in innate and adaptive immune responses as well as in lymphoid tissue (re) modeling. The assessment of a potential role for innate lymphocyte-derived cytokines in human homeostasis and disease is hampered by a poor characterization of RORC(+) innate cell subsets and a lack of knowledge on the distribution of these cells in adults. Here we show that functionally distinct subsets of human RORC(+) innate lymphoid cells are enriched for secretion of IL-17a or IL-22. Both subsets have an activated phenotype and can be distinguished based on the presence or absence of the natural cytotoxicity receptor NKp44. NKp44(+) IL-22 producing cells are present in tonsils while NKp44(-) IL-17a producing cells are present in fetal developing lymph nodes. Development of human intestinal NKp44(+) ILC is a programmed event that is independent of bacterial colonization and these cells colonize the fetal intestine during the first trimester. In the adult intestine, NKp44(+) ILC are the main ILC subset producing IL-22. NKp44(-) ILC remain present throughout adulthood in peripheral non-inflamed lymph nodes as resting, non-cytokine producing cells. However, upon stimulation lymph node ILC can swiftly initiate cytokine transcription suggesting that secondary human lymphoid organs may function as a reservoir for innate lymphoid cells capable of participating in inflammatory responses.