Acute dehydrating disease caused by Vibrio cholerae serogroups O1 and O139 induce increases in innate cells and inflammatory mediators at the mucosal surface of the gut

BACKGROUND AND AIMS: The general concept is that as Vibrio cholerae is not invasive, it mediates a non-inflammatory type of infection. This is being re-evaluated based on available data that natural cholera infection or cholera toxin induces a Th2-type of immune profile and stimulates the humoral immune response, innate cells, and mediators in the host. METHODS: To perform a comprehensive analyses of the inflammatory components, we studied mucosal biopsies from patients, both adults and children with acute watery diarrhoea caused by V cholerae O1 and O139. Patients with cholera, adults (n = 30) and children (n = 18), as well as healthy controls (n = 24) were studied. Histochemical, immunohistochemical, and ultrastructural studies were carried out to elucidate the contribution of the different factors using paraffin and frozen duodenal and/or rectal sections as appropriate. Samples were collected during the acute stage and during early and/or late convalescence. RESULTS: Following natural cholera infection, patients responded with increases in neutrophil polymorphs during the acute stage (p<0.001) compared with healthy controls whereas mucosal mast cells (MMC) (p = 0.008) and eosinophils (p = 0.034) increased in the gut during convalescence. Electron microscopic analyses of duodenal biopsies from adult patients showed increased piecemeal degranulation in both MMC and eosinophils and accumulation of lipid bodies in MMC. Duodenal biopsies from V cholerae O1 infected patients showed upregulation of myeloperoxidase, lactoferrin, PGHS-1, SCF, tryptase, tumour necrosis factor alpha, alpha-defensin, and eotaxin during the acute stage and chymase, interleukin 3 and major basic protein during convalescence. CONCLUSION: We have shown that innate cells and their mediators are upregulated in acute watery diarrhoea. These cells and factors of the innate arm may be important in the host's defence against cholera. Such effects may need to be simulated in a vaccine to achieve long lasting protection from cholera.     

Increased nitrite and nitrate concentrations in sera and urine of patients with cholera or shigellosis

OBJECTIVES: Nitric oxide (NO) is an important regulator of cell function. In the intestine, NO regulates blood flow, peristalsis, secretion, and is associated with inflammation and tissue injury. The objectives of this study were to assess and compare the role of NO in cholera, a noninflammatory enteric infection, and in shigellosis, a bacterial inflammation of the colon. METHODS: We determined serum and urinary concentrations of nitrite and nitrate during acute illness and early convalescence in 45 hospitalized children: 24 with cholera and 21 with shigellosis; 18 healthy children served as controls. Nitrite and nitrate concentrations were determined spectrophotometrically using Greiss reaction-dependent enzyme assay. RESULTS: Serum nitrite and nitrate concentrations were significantly (p < 0.05) increased during acute illness compared to the early convalescence in both cholera and shigellosis. Urinary nitrite and nitrate excretions were significantly (p < 0.01) increased during acute disease in shigellosis, but not in cholera. Nitrite concentrations correlated with stool volume (r2 = 0.851) in cholera and with leukocytosis (r2 = 0.923) in shigellosis. CONCLUSIONS: Both cholera and shigellosis are associated with increased production of NO, suggesting its pathophysiologic roles in these diseases.     

Enteric viral infections as a cause of diarrhoea in the acquired immunodeficiency syndrome

Background and aims The role of non-cytomegalovirus (CMV) enteric viral infection in causing diarrhoea in patients with human immunodeficiency virus (HIV) is poorly understood. We aimed to investigate the prevalence of these infections in acute and chronic diarrhoea. Methods Stool specimens from 377 HIV-infected patients presenting with diarrhoea were studied prospectively for evidence of non-CMV enteric viral infection. Patients with diarrhoea underwent investigation for gastrointestinal pathogens, including electron microscopic examination of stool for enteric viruses. We collected data on patients in whom enteric virus was identified and examined the association of enteric virus infection with diarrhoeal symptomatology. Results Eighty-nine (10.3%) stool specimens from 60 (15.9%) HIV⁺ individuals were positive for coronavirus (n = 13, 22%), rotavirus (n = 11, 18%), adenovirus (n = 30, 50%) and small round structured viruses (n = 5, 8%) or dual infection (n = 2, 3%). Thirty-four of 52 (65%) patients available for analysis had acute diarrhoea, and 18/52 (35%) had chronic diarrhoea. Twenty-three of 52 (44%) patients had a concurrent gut pathogen. After exclusion of concurrent pathogens enteric viral infections were found to be significantly associated with acute as opposed to chronic diarrhoea (P = 0.004). The presence of adenovirus colitis was significantly more likely to be associated with chronic diarrhoea (15/21 cases) than adenovirus isolated from stool alone (9/23 cases) (P = 0.03). There was a trend towards an association between adenovirus colitis and colonic cytomegalovirus infection (P = 0.06). Conclusion Enteric viral infection is strongly associated with acute diarrhoea in patients with HIV. Light microscopic examination of large bowel biopsies can identify adenovirus colitis which is significantly associated with chronic diarrhoea, and in addition may facilitate gastrointestinal co-infection with CMV.     

Quantitative and Ultrastructural Analysis of Rectal Mucosal Mast Cells in Acute Infectious Diarrhea

The role of mast cells, potential mediators ofmucosal immunity and inflammation, was studiedmorphologically in the rectal mucosa in two acutediarrheal diseases, cholera and shigellosis.Quantitation of mucosal mast cells showed that they weresignificantly higher in the deeper lamina propria whereblood vessels and nerves were more abundant. There wasno difference in mast cell counts or degranulation in the mucosa in both groups of patients andcontrols. Intraepithelial mast cells were decreased inthe patients. The prevalence of lipid bodies wassignificantly higher in mast cells from patients with cholera and shigellosis (P < 0.01). Thesefindings suggest that mast cell populations are moredense around blood vessels and nerves and thatinflammatory mediators derived from arachidonic acidmetabolites, as indicated by the lipid bodies, are theresponse of mast cells to the alterations in diarrhea,despite differences in the etiology ofdiarrhea.     

An unusual endoscopic diagnosis for acute epigastric pain

Chemotactic, phagocytic, and oxidative metabolic activity of exudative leukocytes was measured in patients with Crohn's disease (n = 20) and with ulcerative colitis (n = 20). Unstimulated and casein-stimulated migration in Boyden chambers did not differ from that of healthy controls (n = 21). Patients with Crohn's disease had reduced serum-independent phagocytosis compared with healthy controls (p < 0.01) and patients with ulcerative colitis (p < 0.01). Serum-dependent phagocytosis by leukocytes from patients with Crohn's disease did not differ from that in controls but was slightly increased in patients with ulcerative colitis (p < 0.02). Unstimulated leukocytes showed increased oxidative metabolic activity in both patient groups compared with controls (p < 0.01), which was negatively correlated with the disease activity in Crohn's disease (p < 0.02). The study shows that mobilized leukocytes from patients with Crohn's disease differ from those mobilized in ulcerative colitis and supports the concept of an abnormal inflammatory reaction in Crohn's disease.     

Rectal Substance P Concentrations Are Increased in Ulcerative Colitis But Not in Crohn's Disease

Substance P, a neurotransmitter found in colonic mucosa, can alter gut immunologic, vascular, and motor phenomena. Thus, it may have an important role in the pathogenesis of ulcerative colitis (UC) and Crohn's disease (CD). By radioimmunoassay of the extracts of endoscopically obtained rectal mucosal biopsies in affected patients, we evaluated mucosal substance P levels. Non-inflammatory bowel disease patients undergoing lower endoscopies and biopsies served as controls. There were significantly increased concentrations of substance P in patients with UC, compared with controls ( p < 0.05) and compared with patients with CD ( p < 0.005). The mucosal levels in CD patients were significantly lower than in controls ( p < 0.05). Patients with active rectal CD had lower levels than patients with no evidence of active rectal disease. For the CD and UC patients, there was a strongly positive correlation between rectal mucosal substance P concentrations and total histologic inflammation scores ( r = 0.7, p = 0.001). A strong correlation existed for rectal mucosal substance P concentrations and mucosal mononuclear cell scores ( r = 0.7, p = 0.001) and for rectal mucosal substance P concentrations and the combined scores of mucosal neutrophils and eosinophils ( r = 0.7, p = 0.002).
In conclusion, the rectal mucosal substance P concentrations in patients with UC and CD are significantly different. Thus, substance P may have a different role in the pathogenesis of each of these entities. It is possible that the elevated concentrations in patients with UC are contributing to the increased inflammation seen in these patients. Alternatively, measured mucosal substance P levels may simply reflect the end result of the different inflammatory processes in UC and CD, rather than the cause. It is possible that the inflammatory cells are contributing to the measured concentrations.     

Characterization of antigen-presenting dendritic cells in the peripheral blood and colonic mucosa of patients with ulcerative colitis

OBJECTIVE: Increased lymphocyte activation and production of inflammatory cytokines are implicated in the pathogenesis of ulcerative colitis. Because antigen-presenting dendritic cells play a cardinal role in the activation and survival of activated lymphocytes, the aim of the present study was to characterize dendritic cells in ulcerative colitis. DESIGN: This study was designed to compare the phenotypes and functions of peripheral blood dendritic cells among healthy normal volunteers and patients with ulcerative colitis or Crohn's disease. Activated dendritic cells were also localized at the colonic mucosa. METHODS: Peripheral blood dendritic cells were generated from 15 patients with ulcerative colitis, 10 patients with Crohn's disease and 15 healthy control volunteers. The stimulatory capacities of dendritic cells were analysed in an allogenic mixed lymphocyte reaction. Nitric oxide was detected by the Griess method. Single- and dual-colour flow cytometry was employed to study the levels of maturation of dendritic cells. Activated dendritic cells were localized immunohistochemically in the colonic mucosa. RESULTS: In comparison to normal controls, peripheral blood dendritic cells from patients with ulcerative colitis showed significantly increased stimulatory capacities (P < 0.05) and produced significantly higher levels of nitric oxide (P < 0.05). The numbers of activated dendritic cells were also significantly higher in ulcerative colitis (P < 0.05). Mature and activated dendritic cells expressing the CD83 antigen were detected at the inflamed colonic mucosa in patients with ulcerative colitis and Crohn's disease. CONCLUSIONS: Activated and mature dendritic cells may have a role in the induction of an exacerbated immune response in ulcerative colitis. This study provides the scientific and logical basis for blocking the maturation and activation of dendritic cells in ulcerative colitis as a new therapeutic intervention.     

Lymphoblastic response to autologous colon epithelial cells in ulcerative colitis in vitro

The blastic transformation in vitro of peripheral blood lymphocytes was measured by the 72-hour uptake of tritiated thymidine (³H-6-thymidine) in 23 patients with mucosal ulcerative colitis, three patients with acute Crohn's colitis with rectal involvement, and seven normal subjects. The 23 patients with ulcerative colitis were subdivided into three groups, graded according to severity into seven with acute, severe, nine with active, chronic, and seven with quiescent disease.

In the control cultures of lymphocytes without any added potential stimulant the uptake of ³H-6-thymidine in the clinical subgroup of seven patients with acute, severe ulcerative colitis was significantly greater than in seven normal subjects (p<0·01). This contrasted with a reduced uptake of ³H-6-thymidine by lymphocytes from seven patients with acute severe colitis when compared with seven normal subjects after stimulation with phytohaemagglutinin-P (PHA-P) (p<0·01).

In further duplicate cultures of lymphocytes specifically stimulated by an equal number of viable autologous rectal epithelial cells, the uptake of ³H-6-thymidine was significantly greater in seven patients with acute severe colitis when compared with seven normal subjects (p<0·01). The results in three patients with acute Crohn's colitis with rectal involvement showed no such evidence of lymphocyte sensitivity to autologous rectal epithelial cells and their uptake of ³H-6-thymidine lay within the normal range.

Evidence that the degree of lymphoblastic transformation was related to the clinical severity of ulcerative colitis was provided by the results obtained in the unstimulated and epithelial cell stimulant cultures. The uptake of ³H-6-thymidine was directly related to the clinical severity of ulcerative colitis in the three subgroups studied.

In addition, four of the seven patients with acute severe colitis were studied later in clinical remission. They were then found to have a significantly reduced uptake of ³H-6-thymidine in response to autologous rectal epithelial cells (p < 0·01).

     

A New Rat Model Links Two Contemporary Theories in Irritable Bowel Syndrome

Rationale Two proposed hypotheses for irritable bowel syndrome (IBS) are acute gastroenteritis and bacterial overgrowth. We studied whether acute infection with Campylobacter could precipitate bacterial overgrowth in a rat model in order to link the two hypotheses. Methods Sprague-Dawley outbred rats were randomly administered a vehicle or Campylobacter jejuni strain 81-176 by oral gavage. Three months after clearance of the infectious agent, rats had a stool consistency evaluation. After euthanasia, lumenal bacteria counts were measured via quantitative real-time PCR from self-contained segments of the duodenum, jejunum, ileum, cecum and left colon. Adjacent sections of bowel were fixed in formalin for evaluation of intraepithelial lymphocyte counts. Results Three months after clearance of Campylobacter infection, 57% of Campylobacter infected rats had some alteration in stool consistency compared to 7.4% in mock-infected controls (P < 0.001). Among the rats that received Campylobacter, 27% had evidence of bacterial overgrowth by PCR. These rats also had the highest prevalence of altered stool form and had lower body weight. Consistent with post-infectious IBS in humans, bacterial overgrowth rats demonstrated a significant increase in rectal and left colon intraepithelial lymphocytes. Conclusions Acute infection with C. jejuni 81-176 precipitates alterations in stool consistency, bacterial overgrowth and rectal lymphocytosis consistent with findings in IBS patients.     

Preoperative radiotherapy downregulates the nuclear expression of hypoxia-inducible factor-1α in rectal cancer

Abstract

Objective. To assess the value of hypoxia-inducible factor-1α (HIF-1α) expression as a predictor of disease outcome in rectal cancer treated by preoperative radio- or chemoradiotherapy. Material and methods. Operative samples from 168 rectal cancer patients and 79 respective preoperative biopsies were analyzed for nuclear HIF-1α protein expression using immunohistochemistry by three approaches: (a) positive/negative, (b) the percentage of HIF-positive cancer cells and (c) staining intensity. The patients had received either short- (n = 75) or long-course radiotherapy with or without chemotherapy (n = 39) or no treatment preoperatively (n = 54). Results. HIF-1α staining was positive in 70% of the diagnostic biopsies but negative in most of the post-radiotherapy specimens (60%). HIF-1α expression in the biopsies was downregulated in 56% of samples taken after preoperative treatment, while negative HIF-1α expression was upregulated in 25% of samples. Patients who had HIF-negative tumours after long-course radiotherapy had significantly (P = 0.001) better disease-specific survival (DSS) in univariate analysis. In the multivariate (Cox) regression model, HIF-1α lost its significance and only being in the preoperative treatment group was an independent predictor of disease-free survival. In a similar Cox model, disease recurrence and the number of metastatic lymph nodes were independent predictors of DSS. Conclusions. HIF-1α expression was positive in most of the preoperative biopsies but downregulated in most of the operative samples, implicating that preoperative radiotherapy downregulates HIF-1α expression in rectal cancer. Negative HIF expression after preoperative long-course radiotherapy was associated with significantly better DSS.     

Double-Blind Pilot Study of Mesalamine vs. Placebo for Treatment of Chronic Diarrhea and Nonspecific Colitis in Immunocompetent HIV Patients

Chronic diarrhea and colitis are common in patients positive for human immunodeficiency virus (HIV) under highly active antiretroviral treatment (HAART). This prospective double-blind study explores the effect of mesalamine vs. placebo in HIV-positive patients. Thirteen HIV-infected patients with noninfectious chronic diarrhea and > 250 CD4+ cells/mm³ were randomized to mesalamine (2.4 g/day; n = 9) or placebo (n = 4) for 6 weeks. Colonoscopy was performed at baseline and week 6, and biopsies were obtained to calculate the Biopsy Activity Index (BAI). Diarrhea was assessed at baseline and end of treatment using the Disease Activity Index (DAI). Patients and clinicians completed Patient Global Improvement index (PGI) and Clinical Global Improvement index (CGI) at weeks 2 and 6. Comparisons at week 6 were statistically significant between mesalamine and placebo groups for BAI (P = 0.03), DAI (P = 0.007), PGI (P = 0.008), and CGI (P = 0.008). Furthermore, major improvements were documented in the mesalamine group at week 6 compared to baseline for all variables, whereas the placebo group did not have any. Mesalamine was effective for treatment of chronic diarrhea and moderate nonspecific colitis in HIV patients.     

A Prospective Randomized Controlled Trial of Intravenous Ciprofloxacin as an Adjunct to Corticosteroids in Acute,Severe Ulcerative Colitis

Background: The role of antibiotics in the treatment of ulcerative colitis is controversial. This study aims at assessing the therapeutic role of ciprofloxacin as an adjunct to corticosteroids in acute severe ulcerative colitis. Methods: In this prospective, randomized, double-blind, placebo-controlled trial, 55 consecutive patients fulfilling the criteria of Truelove and Witts for severe ulcerative colitis were randomized on admission to the hospital to receive intravenously ciprofloxacin (400 mg b.i.d.) (n = 29) or placebo (n = 27). All patients received parenteral nutrition, intravenous hydrocortisone (100 mg q.i.d.) and hydrocortisone enemas (100 mg b.i.d.). Patients were assessed after 10 days of continuous treatment, or at any time a severe complication occurred. Results: At study entry, there were no significant differences between treatment groups in any patient or disease-related parameter. Twenty-three of 29 patients (79.3%) treated with ciprofloxacin and 20 of 26 patients (77%) treated with placebo showed substantial improvement and were given oral steroids (P &gt; 0.1). Six patients in each group did not improve (n = 10) or developed complications (n = 2). Nine of these 12 patients underwent emergency colectomy; three patients consented to receive intravenous cyclosporin but did not achieve remission of colitis and they underwent elective colectomy. There were no perioperative or late deaths. Conclusions: A short course of intravenous ciprofloxacin does not seem to augment the effect of corticosteroids for patients with acute, severe ulcerative colitis.     

Altered Expression of the Lymphocyte Activation Markers CD30 and CD27 in Patients with Pouchitis

Background: The mechanism underlying the development of ileal pouch inflammation in ulcerative colitis patients (pouchitis) after restorative proctocolectomy is unclear. Persistent systemic T cell activation or expansion of specific memory cell populations could predispose certain patients to develop local inflammation within the neo-rectum. Therefore, the aim was to study the expression of the lymphocyte activation markers CD27, CD30, CD25 and CD69 on the CD45RO+ memory cell subset of isolated peripheral blood mononuclear cells (PBMC), soluble CD30 levels and mucosal CD30 expression in patients with pouchitis and in controls. Methods: Flow cytometry was performed on PBMC isolated from patients with pouchitis (n = 9), without pouchitis (n = 10) and normal controls (n = 9). Serum CD30 was measured in patients with pouchitis (n = 25), without pouchitis (n = 26) and normal controls (n = 20) by ELISA. CD30 expression was quantified in pouchitis (n = 15) and normal pouch (n = 15) mucosa using a three-stage immunoperoxidase method. Results: Naïve CD45RO-CD27+ PBMC were significantly decreased in pouchitis (25.6%) compared to normal controls (34.4%), (P = 0.03). CD30, CD25 and CD69 subsets did not differ between the groups. Serum CD30 was increased in pouchitis patients 58 (1-380) U/ml compared to non-pouchitis 16.5 (1-290) U/ml, P = 0.007, and normal controls 11 (2-80) U/ml, P = 0.0005. In the mucosa, the numbers of CD30+ cells were increased in pouchitis compared to noninflamed pouches (P = 0.02). Conclusions: Increased sCD30 in pouchitis is associated with elevated mucosal expression. Of the activation markers studied, only the circulating naïve CD27+ population differed in pouchitis patients compared with controls. The observed decrease in this cell type may reflect antigen priming and subsequent loss of CD27 implying that antigen driven activation of specific T cell subsets may occur in pouchitis.     

Ulcerative colitis: one disease or two? (Quantitative histological differences between distal and extensive disease).

Cell counts and measurements of mucosal architecture were made on rectal biopsies from nine patients with total colitis, eight with left sided colitis, 15 with distal colitis, and 11 with proctitis. The mean total lamina propria cell count in proctitis and distal colitis approached twice that of extensive left sided and total colitis (p less than 0.001) and in distal proctocolitis the cell numbers are further increased in the chronic over the acute phase. This difference was not explained by age, duration, activity, or treatment. The predominantly increased lymphoid and mononuclear cell infiltrate in distal proctocolitis indicates a different pattern of immune response, suggesting a separate process from extensive colitis or a more intense reaction resulting in localisation of disease.     

Decreased mucosal IgA levels in ileum of patients with chronic ulcerative colitis

Patients with chronic ulcerative colitis (CUC) are known to have decreased spontaneous IgA secretion by colonic mononuclear cells. The aim of this study was to determine whether a similar alteration exists in the apparently healthy ileum of patients with CUC. The concentration of IgA was measured in the supernatant from homogenized mucosal ileal biopsies using a sandwich-type ELISA. The concentration of IgA was significantly (P=0.025) decreased in the ileum of patients with CUC (N=24) in comparison to normal ileum (N=10). The number of mucosal IgA-containing mononuclear cells (MNC) was also determined using an avidin-biotin-immunoperoxidase technique on paraffin-embedded ileal sections. Although reduced, the number of positive cells and their distribution was not significantly different in the ileum of patients with CUC (N=20) when compared to normal ileum (N=10). We suggest that decreased mucosal IgA levels are a panintestinal condition in CUC and that this is a primary alteration rather than a secondary response to the inflammatory process. Considering the role of IgA, we propose that decreased mucosal IgA levels in CUC may predispose to the disease by a reduction of the immune-mediated exclusion mechanism and/or by an impairment of the down-regulation of the inflammatory response.     

The pseudomembranous colitis associated with clindamycin therapy--a viral colitis.

Four patients are described who developed pseudomembranous colitis in association with clindamycin therapy. Rectal biopsies from two patients were studied with the electron microscope and compared with the ultrastructural appearance of the rectal mucosa from seven normal people. Ultrastructural evidence for a viral colitis was obtained. The significance of the clindamycin therapy to the viral colitis and the contribution of the viral colitis to the clinical state are discussed.     

Cytomegalovirus colitis in patients without inflammatory bowel disease: A single center study

Abstract

Objective. Cytomegalovirus (CMV) aggravates preexisting inflammatory bowel disease (IBD), and there are numerous reports of CMV colitis in IBD patients. However, little attention has been paid to CMV colitis in non-IBD patients. The aim was to determine the clinical manifestations, endoscopic appearance, and clinical course of CMV colitis in non-IBD patients. Material and methods. We reviewed medical records of patients diagnosed with CMV colitis based on immunohistochemical studies of biopsy specimens or surgical specimens between 1998 and 2009. Results. The medical records of 43 patients were reviewed. Subjects included individuals with AIDS, and those undergoing chemotherapy, steroid therapy, or transplantation, as well as individuals with other co-morbidities and individuals with no previous illnesses. Frequent symptoms were non-bloody diarrhea, abdominal pain, fever, and hematochezia. Macroscopically normal rectosigmoid mucosa was observed in eight of 21 patients who underwent full-length colonoscopy. Endoscopic findings were varied, and included macroscopically normal (n = 2), colitis alone (n = 12), ulcer alone (n = 5), and ulcer with colitis (n = 22). The ulcer margin was well-circumscribed in 12 of 21 patients. Thirty-six patients were administered antiviral agents and two patients died. All patients who were not treated with an antiviral agent recovered spontaneously while waiting for their biopsy results. Conclusions. Colonoscopy is preferred to sigmoidoscopy for diagnosis of CMV colitis. Antiviral therapy should not be mandatory for a subset of patients with CMV colitis.     

Histochemical demonstration of desialation and desulphation of normal and inflammatory bowel disease rectal mucus by faecal extracts.

Experiments were carried out to assess the susceptibility of normal and inflammatory bowel disease rectal mucus to desulphation and desialation by faecal extracts and by bacterial sialidase. The effects were assessed histochemically using a combined high iron diamine (HID) and alcian blue (AB) stain for sulphomucins and sialomucins. Rectal mucus in biopsies from controls (irritable bowel syndrome) and patients with ulcerative colitis or Crohn's disease was resistant to desialation by Clostridium perfringens sialidase, but susceptible to desialation and desulphation by bacteria-free extracts of normal faeces. Periodic acid-Schiff (PAS) staining of adjacent sections similarly treated showed retention of neutral mucus. One faecal extract selectively desulphated all 42 biopsies, causing the goblet cells to change from HID positive to AB positive, suggesting that most, or all HID positive cells also contain sialomucins. This alters the interpretation of previous histochemical studies. Faecal extracts from patients with active ulcerative colitis (n = 6) had desialating and desulphating effects similar to faecal extracts from normal subjects (n = 6). Ulcerative colitis (n = 21), Crohn's disease (n = 18), and control (irritable bowel syndrome) (n = 17) rectal biopsies all showed similar susceptibility to desulphation by a pooled normal faecal extract, but rectal biopsies from patients with Crohn's disease proved more resistant to desialation than control or ulcerative colitis biopsies (p less than 0.02). These studies imply that colonic mucus undergoes continual desulphation and desialation in vivo as a result of faecal enzyme activity that is probably mainly of bacterial origin. Altered susceptibility of colonic mucus to this may be important in the pathogenesis of colonic disease.     

Increased frequency of intestinal CD4+ T cells reactive with mycobacteria in patients with Crohn's disease

Abstract

Objective. The aim of this study was to assess the frequency of mycobacteria and Escherichia coli reactive T cells in intestinal biopsies from patients with Crohn's disease (CD) and ulcerative colitis (UC). Materials and methods. The biopsies were obtained by colonoscopy from adult patients with active CD (n = 5) and active UC (n = 4). The number of CD4+ T cell clones expanded and screened from each patient varied from 383 to 3972 giving a total of 16639 individual clones. The T cell clones were tested for responses to Mycobacterium avium subspecies paratuberculosis (MAP) and E. coli. The cytokine profile of 42 individual T cell clones from four CD patients was assessed. Results. The frequency of mycobacteria reactive T cell clones in CD patients ranged from 0.17 to 1.63% and was higher (p = 0.038) than the frequency of E. coli reactive T cells ranging from 0 to 0.18%. No or very low numbers of mycobacteria reactive clones were detected in three UC patients while the fourth UC patient had a frequency similar to what was observed in CD patients. The frequencies of E. coli reactive T cell clones in UC patients ranged from 0 to 0.52%. T cell clones (n = 42) from CD patients all produced IL-17 and/or IFN-γ. Several clones were also able to produce IL-10. Conclusions. The high frequency of intestinal tissue resident T cells reactive to mycobacteria suggests that an adaptive immune response have taken place and argues that these bacteria may contribute to the chronic inflammation in CD.     

Macroscopic findings,incidence and characteristics of microscopic colitis in a large cohort of patients from the United Kingdom

Objective: Microscopic colitis (MC) is classically associated with normal or near-normal endoscopic appearances. However, non-specific macroscopic findings have been described, the importance of biopsy location for confirming a diagnosis of MC is unclear, and reported incidence data from the United Kingdom are limited. This study was designed to assess macroscopic features, incidence, demographics, and location and positivity of biopsy samples in MC.

Materials and methods: Retrospective, cross-sectional study of individuals with newly diagnosed MC.

Results: From 2010 to 2015, 540 cases of MC were reported. Macroscopic findings occurred in 16.5% (n?=?89) cases, with trends towards increased frequency of ulceration or linear scarring in collagenous colitis (CC). The mean incidence of MC was 11.3 per 100,000 population/year, including 291 (53.9%) with CC (incidence 6.1 per 100,000/year), 203 (37.6%) with lymphocytic colitis (incidence 4.2 per 100,000/year) and 46 (8.5%) with MC, not otherwise specified. Most individuals were female (70.2%). Common features in patients with MC included symptom duration?<6 months, weight loss, abdominal pain and use of proton pump inhibitors, statins, or non-steroidal anti-inflammatory drugs. In individuals with right- and left-sided biopsies taken, 98.2% had diagnostic features in both. However, rectal biopsies were only positive in 88.7%.

Conclusions: One in six patients with MC demonstrated distinct macroscopic findings at colonoscopy. Our data confirm a female preponderance in MC, a relatively short symptom duration and use of certain drugs as common features. Both right- and left-sided biopsies were frequently positive, suggesting flexible sigmoidoscopy and biopsy could confirm a diagnosis in certain individuals.