Colonic mucosal interleukin-6 in inflammatory bowel disease.

Interleukin-6, a cytokine produced by various cell types, has a major role in inflammatory and immunological reactions. To define its potential role in inflammatory bowel disease, its concentrations in endoscopic biopsy samples from patients with ulcerative colitis and Crohn's disease were measured. The involved colonic mucosa from active disease was found to contain significantly larger amounts of interleukin-6 than that from inactive disease or normal controls. Colonic mucosal interleukin-6 levels correlated well with the grade of macroscopic inflammation, especially in patients with ulcerative colitis. The levels of interleukin-6 decreased in parallel with clinical improvement following the start of therapy in patients with both forms of inflammatory bowel disease. Mucosal interleukin-6 is thus concluded to accurately reflect the degree of colonic inflammation and may be importantly associated with inflammatory and immunological phenomena seen in inflammatory bowel disease.     

Lamina propria and circulating interleukin-6 in newly diagnosed pediatric inflammatory bowel disease patients

OBJECTIVES: Understanding cytokine production patterns in early mucosal lesions of pediatric patients newly diagnosed with inflammatory bowel disease (IBD) may be critical to understanding IBD pathogenesis. Interleukin-6 (IL-6) has a central role in a multitude of immune system reactions; however, inconsistent lamina propria and serum IL-6 has been reported in IBD patients. Newly diagnosed pediatric IBD patients have not previously been evaluated for lamina propria or serum IL-6. METHODS: Serum and intestinal lamina propria biopsy whole organ culture supernatants were evaluated by ELISA for IL-6 obtained from newly diagnosed IBD patients, before initiation of immunomodulatory therapies. RESULTS: Levels of lamina propria IL-6 demonstrated significant correlation with graded severity of histological inflammation (p < 0.001). Log-transformed serum and organ culture IL-6 levels demonstrated significant correlation (p < 0.0001, R2 = 0.6226). Assigning a demarcation level of >400 pg/ml, serum IL-6 concentrations were a superior marker for the presence of microscopic intestinal inflammation than erythrocyte sedimentation rate (ESR), with a sensitivity of 82%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 82%. When evaluating subtypes of IBD, serum IL-6 levels were correlated more significantly with active disease in ulcerative colitis patients (p = 0.01, R2 = 0.74) than in Crohn's disease patients (p = 0.21, R2 = 0.33). CONCLUSIONS: This study outlines graded production of IL-6 in intestinal lamina propria and serum of newly diagnosed pediatric IBD patients, confirming the presence of IL-6 in early IBD patients. In addition, serum IL-6 may be a good predictor of IBD in pediatric patients with suspected or newly diagnosed IBD.     

Significance of interleukin-6 in patients with inflammatory bowel disease

The significance of interleukin-6 (IL-6) in patients with inflammatory bowel disease (IBD) was studied by measuring the IL-6 level in serum and colonic tissue by means of an enzyme-linked immunosorbent assay (ELISA), and by examining its localization using an immunohistochemical method. The serum IL-6 level reflected the degree of disease activity, and the extent of affected area, and was also correlated with the serum C-reactive protein (CRP) level. In the colonic mucosa of active IBD, the tissue IL-6 level was markedly elevated, and immunoreactive products of anti-IL-6 antibody were present in infiltrative mononuclear cells in the lamina propria. This indicates that IL-6 production in these cells is enhanced at the site of affected intestine. These results, together with its biological activity and the type of cell producing it, suggest that IL-6 is an available marker to assess disease conditions of IBD and that it might be also involved in the pathophysiology of IBD.     

Soluble interleukin 2 and CD8 and CD4 receptors in inflammatory bowel disease.

Serum levels of soluble interleukin 2 receptor (sIL-2R) have been proposed as a clinical marker of inflammatory bowel disease. The source of sIL-2R in patients with Crohn's disease and ulcerative colitis is unknown, and other soluble receptors have not been investigated. In the present study, sIL-2R and soluble CD8 and CD4 levels were measured in plasma and culture supernatants of peripheral blood and intestinal mucosal mononuclear cells from patients with inflammatory bowel disease, surgical controls, and healthy subjects. Level of plasma sIL-2R was significantly higher in patients with Crohn's disease and ulcerative colitis than in healthy volunteers. Intestinal cells always produced more sIL-2R than peripheral cells. Spontaneous sIL-2R production by mucosal cells was significantly elevated in Crohn's disease but not in ulcerative colitis supernatants compared with levels of surgical controls. Soluble CD8 and CD4 were poor indicators of systemic or mucosal immunity. A positive correlation was found between plasma sIL-2R and spontaneous production by intestinal cells of patients with Crohn's disease and surgical control patients, whereas ulcerative colitis plasma sIL-2R correlated with spontaneous production by peripheral cells. The association of plasma or spontaneous sIL-2R levels with the degree of intestinal inflammation was weak, and there was a wide overlap with control values. Therefore, caution should be used before considering sIL-2R an accurate marker of inflammatory bowel disease activity.     

Characterization of circulating interleukin-1 receptor antagonist expression in children with inflammatory bowel disease

The cytokines IL-1 and IL-6 appear to be important in the pathogenesis of inflammatory bowel disease (IBD). Recently, a naturally occurring interleukin-1 receptor antagonist, designated IL-1ra, which inhibits IL-1 activityin vitro andin vivo has been described. The purpose of the present study was to assess the circulating levels and relative relationships of IL-1ra, IL-1, and IL-6 in children with IBD of varying severity. Serum/plasma samples were obtained from 32 children with ulcerative colitis, 45 with Crohn's disease, and 24 control patients. Cytokine assays were performed by enzymelinked immunoassay. IL-1ra levels were significantly elevated in children with ulcerative colitis or Crohn's disease of moderate/severe activity compared to patients with inactive/mild IBD or control subjects (P<0.001). IL-1 was only detectable in the circulation of two subjects with severe colitis (one ulcerative colitis, one Crohn's disease), and both had extremely elevated IL-1ra levels. IL-1ra levels were significantly related to IL-6 levels for patients with IBD (P<0.00001). Our results suggest that circulating IL-1ra appears in increasing concentrations in children with mounting degrees of disease severity as determined by clinical scoring methods as well as by the level of IL-6. Future work will need to address the clinical and prognostic value of measuring circulating IL-1ra in individuals with inflammatory bowel disease.     

Soluble interleukin-2 receptor in Crohn's disease: relation of serum concentrations to disease activity.

Serum concentrations of soluble interleukin-2 receptor (sIL-2R) were measured as a marker of immune activation in a group of 30 patients with Crohn's disease. sIL-2R concentrations were determined by enzyme linked immunosorbent assay during periods of active and inactive disease and correlated with standard parameters of disease activity. Serum concentrations of sIL-2R were significantly raised in patients with active Crohn's disease compared with patients with inactive disease (p less than 0.001) and control subjects. There was a significant correlation between serum sIL-2R concentrations and disease activity as assessed by the Harvey-Bradshaw index (r = 0.42, p less than 0.01), platelet numbers (r = 0.49, p less than 0.01), and orosomucoid (r = 0.47, p less than 0.01), alpha 1 antitrypsin (r = 0.44, p less than 0.01), and C reactive protein concentrations (r = 0.48, p less than 0.001) but not with the erythrocyte sedimentation rate. Measurement of serum sIL-2R concentration is a simple and useful laboratory means of assessing disease activity. Raised concentrations in patients with active Crohn's disease is further evidence for in vivo immune activation occurring in this disease.     

Serum interleukin-8 in inflammatory bowel disease

To investigate the relationship between serum concentrations of interleukin-8 (IL-8) and disease activity in inflammatory bowel disease, serum IL-8 concentrations were measured by enzyme-linked immunosorbent assay (ELISA) in 93 patients. Interleukin-8 levels were compared with plasma interleukin-6 (IL-6) levels in 80 of these patients. Interleukin-8 levels were also measured in ten patients with active Crohn's disease, before and after treatment with a defined formula polymeric diet. Of these patients, 70 out of 93 IL-8 concentrations were below the detection limit of the assay. Levels were higher in patients with active ulcerative colitis (median < 20 pg/mL, 75th centile value = 190) compared with inactive disease (median and 75th centile value < 20; P 0.05). Interleukin-8 concentrations correlated with a combined score for disease severity and extent (P= 0.01). Thirty-eight per cent (8/20) of patients with active Crohn's disease also had high levels of IL-8 but there was no significant difference between active and inactive disease. There was no correlation between serum IL-8 and plasma IL-6; on the contrary, very few patients had raised blood levels of both cytokines. In the diet treated group, serum IL-8 fell significantly after treatment (median = 37 pg/mL, range < 20–4615 before treatment, median < 20, range < 20–104 after treatment; P= 0.03). The results suggest that although IL-8 may be involved in the inflammatory process in inflammatory bowel disease, it is a poor marker of disease activity.     

Elevation of interleukin-6 in inflammatory bowel disease is macrophage- and epithelial cell-dependent

Local interleukin-6 (IL-6) activity was studied using colonic mucosal tissues in inflammatory bowel disease (IBD) and inflammatory control patients. Active IBD specimens exhibited significantly higher IL-6 activity than control specimens in both cultures of isolated lamina propria mononuclear cells (LPMC) and mucosal tissues with an increased number of IL-6-producing cells. However, the activity in inactive IBD or inflammatory controls did not differ from controls. Northern blot analysis demonstrated IL-6 messenger RNA in LPMC and colonic epithelial cells isolated from active IBD specimens but not in control cells. Furthermore, immunofluorescent microscopic study of active IBD specimens showed more conspicuous staining of IL-6 in infiltrating LPMC (mostly CD68⁺ cells) and colonic epithelial cells. These results suggest that elevation of local IL-6 activity may be a characteristic feature of active IBD and both macrophages and colonic epithelial cells are the major cell types responsible for this phenomenon.     

The subpopulations of circulating white blood cells in inflammatory bowel disease.

A detailed analysis of the species of lymphocytes was carried out in 58 patients with inflammatory bowel disease (IBD). These individuals were further divided into 31 with Crohn's disease (CD) and 27 with ulcerative colitis (UC). There were 13 CD patients with only small bowel involvement called "regional enteritis" and 18 who had some degree of colonic involvement called "ileocolitis". Similarly, the UC group was subdivided into 9 patients with disease confined to the rectosigmoid area called "proctosigmoiditis" and 18 with more extensive involvement called "universal colitis". We also studied 13 patients who had undergone previous colectomy and ileostomy and 78 healthy age- and sex-matched controls. Although there was no increase in the absolute number of lymphocytes in patients with ileocolitis and universal colitis, the percentage of these cells was decreased because of an increase in both polymorphonuclear leukocytes and monocytes. In IBD and its subgroups, mean T lymphocytes, determined by the sheep red blood cell rosette technique, were not significantly different from the controls either in percentage or absolute number. Furthermore, no difference was noted between UC and CD. However, there seems to be a subpopulation of patients with UC or CD whose T cells are reduced below 1 SD of the mean. There was also no difference in the number of immunoglobulin-bearing B cells in both diseases; however, when the B cells were enumerated by their ability to rosette with antibody-complement-coated sheep cells (EAC), we found a marked decrease in percentage (P less than 0.001) and absolute number (P less than 0.0005) relative to the control population. The decrease bore a direct relation to the severity of the disease process and, although more marked in patients with UC, was present in CD also.     

白细胞介素23与炎症性肠病

炎症性肠病(IBD)是一类病因不明的胃肠道慢性非特异性炎症,包括克罗恩病(CD)和溃疡性结肠炎(UC).促炎因子和抗炎因子的失衡被视为一个重要的病因[1].白细胞介素23(IL-23)属于前炎性因子,在IBD的发生、发展中起重要作用.此文就近年来IL-23在IBD发生、发展和治疗中的作用作一综述.     

Intestinal interleukin-13 in pediatric inflammatory bowel disease patients

BACKGROUND: Interleukin-13 (IL-13) is a multifunctional cytokine whose net principle action is to diminish inflammatory responses. Dysregulation of IL-13 production has been proposed to contribute to intestinal inflammation in inflammatory bowel disease (IBD) patients. Previous studies implicate IL-13 in IBD pathogenesis; however, they fail to accurately reflect in vivo intestinal IL-13 production. We evaluate IL-13, IL-6, and IL-1beta elaborations from colonic organ cultures of pediatric IBD patients METHODS: Endoscopic lamina propria biopsies or surgical specimens from pediatric patients with IBD were organ cultured and supernatants evaluated by enzyme-linked immunosorbent assay for IL-1beta, IL-6, and IL-13. RESULTS: IL-13 concentrations were significantly reduced in ulcerative colitis (UC) patients when compared with normal controls (P = 0.002) and Crohn disease (CD) patients (P = 0.001). End-stage UC patients at colectomy had lower intestinal IL-13 production than all other UC patients (P = 0.002). No significant correlation was found between IL-13 concentration and histologic disease severity (P = 0.134). CONCLUSIONS: Diminished intestinal IL-13 production is present in UC patients and wanes further with clinical disease progression. These findings suggest that UC patients may be differentiated from CD patients by intestinal IL-13 quantitation, and UC patients may benefit from IL-13 enhancing therapies.     

趋化因子及其受体与炎症性肠病

炎症性肠病(IBD)包括溃疡性结肠炎(UC)和克罗恩病(CD),是一类慢性反复发作的肠道非特异性炎症性疾病,其病因和发病机制尚未完全阐明,免疫反应异常是其重要特点.趋化因子是炎症反应中白细胞募集的最重要的调节因子,很多趋化因子参与IBD的发病.此文就近年来趋化因子及其受体与炎症性肠病的研究进展作一综述.     

Toll样受体与炎症性肠病

Toll样受体(TLRs)是天然免疫系统中的细胞跨膜受体,可识别病原相关分子模式(PAMP).不同的PAMP激活不同的TLR,TLR在髓样分化蛋白(MD2)、CD14辅助下,通过MyD88依赖型信号通路或非MyD88依赖型信号通路激活核因子-κB(NF-κB)、干扰素调节因子3/7(IRF3/7)及活化蛋白-1(AP-1),最终诱导下游目的基因表达.TLR对肠黏膜天然免疫反应调节发挥关键作用;而病原微生物在IBD的发生中起重要作用.生理情况下,肠上皮细胞持续表达TLR3和TLR5,而TLR2和TLR4几乎无法检测到;但在IBD患者的肠上皮细胞表面,却可检测到TLR2和TLR4的表达.随着对TLR信号通路研究和认识的不断深入,以TLR为靶点的药物研究也正成为一个热点.     

Toxic oxygen metabolite production by circulating phagocytic cells in inflammatory bowel disease.

To investigate the possibility that the oxidative capacity of phagocytic cells may be defective in inflammatory bowel disease, toxic oxygen metabolite production by circulating neutrophils and monocytes has been measured by luminol dependent chemiluminescence. Neutrophils from patients with Crohn's disease and ulcerative colitis produced significantly lower chemiluminescent responses after chemotactic stimulation with formylmethionylleucylphenylalanine (fMLP) than neutrophils from control patients, p = 0.018 and 0.043 respectively. Chemiluminescent responses of neutrophils from patients with inflammatory bowel disease, however, were similar to control responses when cells were stimulated with latex beads or phorbol myristate acetate. Monocytes from patients with Crohn's disease produced significantly greater levels of chemiluminescence than control monocytes when stimulated with either fMLP (p less than 0.002), phorbol myristate acetate (p less than 0.0005) or latex beads (p less than 0.002). Monocytes from patients with ulcerative colitis also produced significantly greater levels of chemiluminescence than controls when stimulated with latex beads (p less than 0.5) or phorbol myristate acetate (p less than 0.0005), although there was no difference in the level of chemiluminescence in response to fMLP. These results exclude a generalised defect in phagocytic cell oxidase activity in inflammatory bowel disease and suggest that circulating monocytes are 'activated'.     

Allergic reactions to 6-mercaptopurine during treatment of inflammatory bowel disease.

Hypersensitivity reactions to 6-mercaptopurine (6-MP) or azathioprine occur during the treatment of inflammatory bowel disease (IBD), raising significant diagnostic and therapeutic challenges. Charts of 591 patient with IBD treated with 6-MP in a single center were retrospectively reviewed. All allergic reactions were recorded along with results of rechallenge, desensitization, and subsequent course of IBD. Sixteen (2.7%) allergic reactions to 6-MP were noted, with fever being the most common (14 cases). Nine of these were rechallenged with 6-MP with recurrence of the same symptoms. Azathioprine was tried in six patients and in five the same symptoms recurred. Four patients underwent successful desensitization to either 6-MP or azathioprine; all four plus another patient who tolerated direct switch to azathioprine entered long-term remission. Among the remaining 11, 5 required surgery, 2 are well on methotrexate, and 4 have chronic symptoms while being treated with other medications. If an allergic reaction to 6-MP occurs during the treatment of IBD, direct switching to azathioprine is probably not justified. Instead, desensitization to either 6-MP or azathioprine should be attempted. Patients who can tolerate these medications after previous allergic reactions have improved outcomes compared with patients who resort to other forms of treatment.     

Roles of G protein-coupled receptors in inflammatory bowel disease

Inflammatory bowel disease(IBD) is a complex disease with multiple pathogenic factors. Although the pathogenesis of IBD is still unclear, a current hypothesis suggests that genetic susceptibility, environmental factors, a dysfunctional immune system, the microbiome, and the interactions of these factors substantially contribute to the occurrence and development of IBD. Although existing and emerging drugs have been proven to be effective in treating IBD,none can cure IBD permanently. G protein-coupled receptors(GPCRs) are critical signaling molecules implicated in the immune response, cell proliferation,inflammation regulation and intestinal barrier maintenance. Breakthroughs in the understanding of the structures and functions of GPCRs have provided a driving force for exploring the roles of GPCRs in the pathogenesis of diseases, thereby leading to the development of GPCR-targeted medication. To date, a number of GPCRs have been shown to be associated with IBD, significantly advancing the drug discovery process for IBD. The associations between GPCRs and disease activity, disease severity, and disease phenotypes have also paved new avenues for the precise management of patients with IBD. In this review, we mainly focus on the roles of the most studied proton-sensing GPCRs, cannabinoid receptors,and estrogen-related GPCRs in the pathogenesis of IBD and their potential clinical values in IBD and some other diseases.     

Adherence to treatment in inflammatory bowel disease.

AIM: Adherence to therapy is important to ensure success. We wanted to explore this feature in patients with inflammatory bowel disease. PATIENTS AND METHODS: We explored adherence to treatment and its modifiers in 40 patients with inflammatory bowel disease using a battery of tests. RESULTS: A 67% of patients (95% CI: 51-81%) acknowledged a certain degree of involuntary nonadherence, and 35% (95% CI: 20-51%) of voluntary nonadherence. Overall, 72% (95% CI: 56-85%) of patients had some form of nonadherence. An objective correlation of these self-reported data was assessed by the determination of urine salicylate levels in the subset of patients treated with mesalazine or its derivatives (15 cases). Two of them (13%) had no detectable urinary drug levels, indicating complete nonadherence. Voluntary nonadherence was higher in patients with lower scores in the intestinal (p = 0.02) and social areas (p = 0.015) of IBDQ-32, as well as in those with less active Crohn s disease (p < 0.005), patients with high depression scores and high patient-physician discordance (p = 0.01), patients with long-standing disease (p = 0.057), patients who considered themselves not to be well informed about the treatment they were getting (p = 0.04) or who trusted their attending physicians less (p = 0.03). CONCLUSIONS: Intentional nonadherence to therapy is prevalent among patients with inflammatory bowel disease. A correction of factors associated to poor adherence could lead to higher therapeutic success.