Thiopurine has been used to maintain remission and to reduce antidrug antibody formation in monoclonal antibody therapy in patients with inflammatory bowel disease (IBD). The use of thiopurine is limited by side effects such as leukopenia. Thiopurine S-methyltransferase (TPMT) variants are associated with thiopurine-induced leukopenia in Westerners, but the frequency of the risk alleles is low in Asians. Recently, a variant in the nudix hydrolase 15 (NUDT15) gene (R139C, c.415C > T) was reported to be associated with early severe leukopenia in Asians. NUDT15 is an enzyme that converts 6-thio-(deoxy)guanosine triphosphate (6-T(d)GTP) to 6-thio-(deoxy)guanosine monophosphate (6-T(d)GMTP). The R139C variant impairs the stability of the protein and increases incorporation of 6-TGTP and 6-TdGTP into RNA and DNA, respectively, resulting in leukopenia. The frequency of C/C, C/T, and T/T are approximately 80%, 20%, and 1%, respectively in East Asians. Early leukopenia occurred in less than 3% of patients with C/C and in around 20% of those with C/T, whereas it occurred in almost all patients with T/T. Patients homozygous for this variant also develop severe hair loss. The measurement of NUDT15 R139C can increase the safety of thiopurine dramatically and is a successful example of personalized medicine in the field of IBD.

BACKGROUND/AIMS: Recent research has highlighted the importance of interactions between commensal fungi and intestinal inflammation. However, there are few studies investigating whether commensal fungi contribute to inflammation in patients with Crohn's disease (CD). The aim of this study is to investigate reveal interactions between commensal fungi and host immune cells in CD. METHODS: CD14-positive monocytes were isolated from peripheral blood mononuclear cells from healthy human volunteers and then differentiated in the presence of macrophage colony-stimulating factor (M-CSF) (referred to as M-macrophages, M-Mϕs) or M-CSF and interferon-γ (IFN-γ) (referred to as M-gamma macrophages, Mγ-Mϕs). Cytokine production by these in vitro differentiated macrophages in response to β-(1,3)-glucan was analyzed by flow cytometry. Expression of Dectin-1 was examined using flow cytometry, western blotting, and quantitative reverse transcription-polymerase chain reaction. Cytokine production by in vitro differentiated macrophages in response to β-(1,3)-glucan was measured in the presence of an anti-Dectin-1 receptor antagonist, anti-Syr, or an anti-Fas-1 antibody. Cytokine production by lamina propria mononuclear cells (LPMCs) derived from CD patients in response to β-(1,3)-glucan was also analyzed. RESULTS: Mγ-Mϕs produced a large amount of tumor necrosis factor-α (TNF-α) and interleukin-6 in response to β-(1,3)-glucan. Dectin-1 expression was significantly higher in Mγ-Mϕs than in M-Mϕs. The increase in TNF-α production by Mγ-Mϕs stimulated with glucan was reversed by blocking Dectin-1, Syr or Fas-1. LPMCs derived from CD patients stimulated with β-(1,3)-glucan produced significantly higher amount of TNF-α than LPMCs derived from UC patients. CONCLUSIONS: These results suggest that commensal fungal microbiota may contribute to the pathogenesis of CD by inducing macrophages-derived pro-inflammatory cytokines.
Blotting, Western ; Candida albicans* ; Candida* ; Crohn Disease* ; Cytokines* ; Flow Cytometry ; Fungi ; Healthy Volunteers ; Humans ; In Vitro Techniques ; Inflammation ; Interleukin-6 ; Macrophage Colony-Stimulating Factor ; Macrophages* ; Microbiota ; Monocytes ; Mucous Membrane* ; Necrosis ; Tumor Necrosis Factor-alpha

Tacrolimus is a calcineurin inhibitor used for the treatment of corticosteroid-refractory ulcerative colitis (UC). Two randomized controlled trials and a number of retrospective studies have assessed the therapeutic effect of tacrolimus in UC patients. These studies showed that tacrolimus has excellent short-term efficacy in corticosteroid-refractory patients, with the rates of clinical response ranging from 61% to 96%. However, the long-term prognosis of patients treated with tacrolimus is disappointing, and almost 50% of patients eventually underwent colectomy in long-term follow-up. Tacrolimus can achieve mucosal healing in 40-50% of patients, and this is associated with a favorable long-term prognosis. Anti-tumor necrosis factor (TNF)-alpha antibodies are another therapeutic option in corticosteroid-refractory patients. A prospective head-to-head comparative study of tacrolimus and infliximab is currently being performed to determine which treatment is more effective in corticosteroid-refractory patients. Several retrospective studies have demonstrated that switching between tacrolimus and anti-TNF-alpha antibody therapy was effective in patients who were refractory to one of the treatments. Most adverse events of tacrolimus are mild; however, opportunistic infections, especially pneumocystis pneumonia, are the most important adverse events, and these should be carefully considered during treatment. Several issues on tacrolimus treatment in UC patients remain unsolved (e.g., use of tacrolimus as remission maintenance therapy). Further controlled studies are needed to optimize the use of tacrolimus for the treatment of UC.
Antibodies ; Calcineurin ; Colectomy ; Colitis, Ulcerative* ; Cyclosporine ; Follow-Up Studies ; Humans ; Infliximab ; Necrosis ; Opportunistic Infections ; Pneumonia, Pneumocystis ; Prognosis ; Tacrolimus*

Crohn's disease and ulcerative colitis represent two distinct forms of inflammatory bowel diseases (IBD). In this paper, we discuss how immunological mechanisms contribute to the pathogenesis of IBD. Intestinal homeostasis is sustained by various kinds of cells, such as epithelial cells, lymphocytes, antigen presenting cells, and other innate immune cells. We pay special attention to intestinal CD14+ macrophages. Intestinal macrophages play a central role in the regulation of immune responses against commensal bacteria. In the physiological condition, intestinal macrophages lack the expression of innate-immune receptor CD14 and do not produce proinflammatory cytokines. We identified a unique macrophage subset of IBD in the human intestine, which expressed both macrophage (CD14, CD33, CD68) and dendritic cell (DC) markers (CD205, CD209) and produced larger amounts of proinflammatory cytokines, such as interleukin (IL)-23 and tumor necrosis factor (TNF)-alpha. In addition, the CD14+ macrophages contributed to interferon (IFN)-gamma production rather than IL-17 production by lamina propria mononuclear cells dependent on IL-23. We discuss herein this IL-23/IFN-gamma-positive feedback loop in IBD patients. We also discuss IFN-gamma and IL-17 production from mucosal T cells and natural killer (NK) cells. Here, we show our recent findings about the plasticity of T helper cells in colitis. Th 17 cells express T-bet, and finally lose the expression of retinoic acid-related orphan receptor (ROR)gammat, the master regulator of Th 17 cells, and are differentiated 'alternative Th 1 cells.' In addition to Th 1 cells, mucosal NK cells are also important sources of IFN-gamma. Some of our ideas may be provocative, but we hope this review paper will provide new and firm understanding of the pathogenesis of IBD.
Antigen-Presenting Cells ; Bacteria ; Child ; Child, Orphaned ; Colitis ; Colitis, Ulcerative ; Crohn Disease ; Cytokines ; Dendritic Cells ; Epithelial Cells ; Homeostasis ; Humans ; Inflammatory Bowel Diseases ; Interferons ; Interleukin-17 ; Interleukin-23 ; Interleukins ; Intestines ; Killer Cells, Natural ; Lymphocytes ; Macrophages ; Mucous Membrane ; Plastics ; T-Lymphocytes ; T-Lymphocytes, Helper-Inducer ; Tumor Necrosis Factor-alpha

The incidence and prevalence of inflammatory bowel diseases (IBDs) including ulcerative colitis and Crohn disease are rapidly increasing in Western countries and in developed Asian countries. Although biologic agents targeting the immune system have been effective in patients with IBD, cessation of treatment leads to relapse in the majority of patients, suggesting that intrinsic immune dysregulation is an effect, not a cause, of IBD. Dramatic changes in the environment, resulting in the dysregulated composition of intestinal microbiota or dysbiosis, may be associated with the fundamental causes of IBD. Japan now has upgraded water supply and sewerage systems, as well as dietary habits and antibiotic overuse that are similar to such features found in developed Western countries. The purpose of this review article was to describe the association of diet, particularly Japanese food and microbiota, with IBD.
Animals ; *Asian Continental Ancestry Group ; Diet/*ethnology ; Evidence-Based Medicine ; Food Habits/ethnology ; Humans ; Incidence ; Inflammatory Bowel Diseases/diagnosis/diet therapy/*ethnology/immunology/*microbiology ; Intestines/immunology/*microbiology ; Japan/epidemiology ; *Microbiota ; Prevalence ; Probiotics/therapeutic use ; Prognosis ; Risk Factors

For the control of Crohn's disease (CD) a thorough assessment of the small intestine is essential; several modalities may be utilized, with cross-sectional imaging being important. Magnetic resonance (MR) enterography, i.e., MRE is recommended as a modality with the highest accuracy for CD lesions. MRE and MR enteroclysis are the two methods performed following distension of the small intestine. MRE has sensitivity and specificity comparable to computed tomography enterography (CTE); although images obtained using MRE are less clear compared with CTE, MRE does not expose the patient to radiation and is superior for soft-tissue contrast. Furthermore, it can assess not only static but also dynamic and functional imaging and reveals signs of CD, such as abscess, comb sign, fat edema, fistula, lymph node enhancement, less motility, mucosal lesions, stricture, and wall enhancement. Several indices of inflammatory changes and intestinal damage have been proposed for objective evaluation. Recently, diffusion-weighted imaging has been proposed, which does not need bowel preparation and contrast enhancement. Comprehension of the characteristics of MRE and other modalities is important for better management of CD.
Abscess ; Animals ; Capsule Endoscopy ; Comb and Wattles ; Comprehension ; Constriction, Pathologic ; Crohn Disease* ; Diffusion Magnetic Resonance Imaging ; Edema ; Fistula ; Humans ; Intestine, Small* ; Lymph Nodes ; Sensitivity and Specificity

Background/Aims: Patients with ulcerative colitis (UC) are at an increased risk of certain infections and malignancies compared with the general population. Incidence rates (IRs) of hospitalized infections, herpes zoster (HZ), and malignancies in patients with UC, stratified by treatment, in Japan were estimated. Methods: This retrospective study identified patients with UC treated with corticosteroids, immunosuppressants, or tumor necrosis factor inhibitors (TNFi) from 2 administrative databases (Japan Medical Data Center [JMDC] and Medical Data Vision [MDV]). IRs (unique patients with events per 100 patient‐years) were estimated for hospitalized infections, HZ, and malignancies, between June 2010 and May 2018. Results: Among 6,033 MDV patients with UC receiving corticosteroids, immunosuppressants, or TNFi, IRs (95% confidence intervals) were: hospitalized infections, 1.73 (1.52–1.93); HZ, 1.00 (0.85–1.16), and malignancies, 1.48 (1.29–1.66). Among 958 JMDC patients with UC receiving corticosteroids, immunosuppressants, or TNFi, IRs (95% confidence intervals) were: HZ, 1.82 (1.27–2.37) and malignancies, 1.35 (0.87–1.82). In both cohorts, IRs of malignancies were generally similar among patients receiving immunosuppressants, TNFi, or combination therapy (immunosuppressants and TNFi); this was also true for IRs of hospitalized infections and HZ in the MDV cohort. IRs of hospitalized infections, HZ, and malignancies were higher in patients receiving calcineurin inhibitors compared with immunosuppressants or TNFi, in both cohorts. Conclusions IRs of hospitalized infections, HZ, and malignancies among patients with UC were generally similar regardless of UC treatment, except for calcineurin inhibitors.

Background/Aims: A previous study demonstrated that half of patients started oral corticosteroids (OCS) for ulcerative colitis (UC) exacerbations at lower doses than recommended by Japanese treatment guidelines (initial OCS prednisolone equivalent dose, 30–40 mg). This may relate to physician’s concern about infection, especially pneumonia including Pneumocystis jirovecii pneumonia (PJP), from high OCS doses. We assessed whether pneumonia incidence is increased with guideline-recommended OCS initial doses. Methods: This retrospective cohort study used the Japan Medical Data Center claims database (2012–2021). The whole cohort consisted of all UC patients who started OCS during the study period meeting the inclusion and exclusion criteria. The matched cohort was created by propensity score matching; the lower (initial OCS dose < 30 mg), guideline-recommended (30–40 mg), and higher groups ( > 40 mg) in a 2:2:1 ratio. Pneumonia incidence in the primary analysis was evaluated in the matched cohort. A Poisson regression model determined pneumonia-related risk factors in the whole cohort. Results: After screening, 3,349 patients comprised the whole cohort; 1,775 patients comprised the matched cohort (lower dose, n = 710; guideline-recommended dose, n = 710; higher dose, n = 355). The incidence of any pneumonia was low; no differences were observed in incidence rates across these dose subgroups. In total, 3 PJP cases were found in the whole cohort, but not detected in the matched cohort. Several risk factors for any pneumonia were identified, including age, higher comorbidities index, treatment in large facility and hospitalization. Conclusions The incidence of pneumonia, including PJP, in UC patients was low across initial OCS dose treatment subgroups.

Background/Aims: Mirikizumab is a p19-directed anti-interleukin-23 antibody with potential efficacy against ulcerative colitis (UC). We evaluated the efficacy and safety of mirikizumab in a Japanese subpopulation with moderately to severely active UC from the LUCENT-1 and LUCENT-2 studies. Methods: LUCENT-1 and LUCENT-2 were phase 3, randomized, double-blind, placebo-controlled trials of mirikizumab therapy in adults with moderately to severely active UC. LUCENT-1 was a 12-week induction trial where patients were randomized 3:1 to receive intravenous mirikizumab 300 mg or placebo every 4 weeks (Q4W). Patients achieving a clinical response with mirikizumab following the induction study were re-randomized 2:1 to double-blind treatment with either mirikizumab 200 mg or placebo subcutaneously Q4W during the 40-week maintenance study. The primary outcomes were clinical remission at week 12 of LUCENT-1 and week 40 of LUCENT-2. Results: A total of 137 patients enrolled in Japan were randomized to mirikizumab (n = 102) or placebo (n = 35). Compared with placebo, patients who received mirikizumab showed numerically higher clinical remission at week 12 of induction (32.4% [n = 33] vs. 2.9% [n = 1]) and at week 40 of maintenance (48.9% [n = 23] vs. 28.0% [n = 7]). A greater number of patients achieved key secondary endpoints in the mirikizumab group compared with placebo. The frequency of treatment-emergent adverse events was similar across mirikizumab and placebo groups. Efficacy and safety results observed in the Japanese subpopulation were generally consistent with those in the overall population. Conclusions Mirikizumab induction and maintenance treatments were effective in Japanese patients with moderately to severely active UC. No new safety concerns were identified.

BACKGROUND/AIMS: Recent developments in analytical techniques including next-generation sequencing have clarified the correlation between intestinal microbiota and inflammatory bowel disease. Fecal microbiota transplantation (FMT) for patients with ulcerative colitis (UC) is proposed as a potential approach to resolving their dysbiosis; however, its safety and efficacy have not been confirmed. This single-arm, open-label, non-randomized study aimed to evaluate the safety and efficacy of FMT for Japanese patients with UC as the first registered clinical trial in Japan. METHODS: We enrolled 10 patients with active UC despite medical therapy. The donors were the patients' relatives and were carefully screened for infectious diseases. Fecal material was administered via colonoscopy, and the primary endpoint was the presence or absence of serious adverse events related to FMT. The secondary endpoint was a change in partial Mayo score at 12 weeks post-FMT. Scores ≤2 were considered a clinical response. Fecal samples were collected to follow changes in gut microbiota, while extracted complementary DNA were analyzed by a next-generation sequencer. We obtained written informed consent from all patients and donors. This study was approved by our Institutional Review Board and is registered in the University hospital Medical Information Network (UMIN) Clinical Trials Registry (UMIN 000012814). RESULTS: Five patients with moderate disease and five with severe disease were enrolled. No severe adverse effects were observed. One patient achieved clinical response; however, none of the patients' microbiota diversity recovered to the donor levels. CONCLUSIONS: The use of single FMT for UC was safe; however, we failed to show its clinical efficacy and potential to change the intestinal microbiota.
Asian Continental Ancestry Group* ; Colitis, Ulcerative* ; Colonoscopy ; Communicable Diseases ; DNA, Complementary ; Dysbiosis ; Ethics Committees, Research ; Fecal Microbiota Transplantation* ; Gastrointestinal Microbiome* ; Humans ; Inflammatory Bowel Diseases ; Information Services ; Informed Consent ; Japan ; Microbiota ; Tissue Donors ; Treatment Outcome ; Ulcer*