Microscopic colitis found together with celiac disease in a female population is associated with one episode of lymphocytic colitis.

BACKGROUND: Microscopic colitis (MC) is considered a chronic disease associated with autoimmune disease, smoking, and drugs. The aim was to examine the association between MC and celiac disease, adjusted for smoking, considering subtypes and clinical course of the disease in a retrospectively collected female cohort. METHODS: Women (n = 240), ≤ 73 years, diagnosed as MC in medical records or pathological registers were invited. One hundred and fifty-eight women accepted to be included. Participants completed a study questionnaire about sociodemographic factors, lifestyle habits, and medical history; the Rome III questionnaire; and the visual analog scale for irritable bowel syndrome (VAS-IBS). Participants were categorized into collagenous colitis (CC) (n = 92) and lymphocytic colitis (LC) (n = 66) or MC with one episode of the disease (n = 70) and refractory MC (n = 88). Presence of IBS-like symptoms were noted. Blood samples were collected and analyzed for anti-transglutaminase antibodies. Differences between groups were calculated and logistic regression was adjusted for smoking habits. RESULTS: MC and celiac disease debuted simultaneously in half of the cases. Celiac disease was most prevalent in LC (12.1% vs. 3.3%; p = 0.05) and MC with one episode (12.9% vs. 2.3%; p = 0.01). Anti-transglutaminase antibodies were found in one patient with one episode of MC. Corticosteroid use was most often found in CC (37.0% vs. 21.2%; p = 0.037) and refractory MC (38.6% vs. 20.0%; p = 0.015). Past smokers were most prevalent in patients with one episode of MC (54.3 vs. 29.5%; p = 0.007). Current smoking was the smoking habit with highest prevalence of IBS-like symptoms. When adjusted for smoking habits, celiac disease was associated with LC (OR: 4.222; 95% CI: 1.020-17.469; p = 0.047) and tended to be inversely associated with refractory MC (OR: 0.210; 95% CI: 0.042-1.506; p = 0.058). CONCLUSION: Celiac disease is most common in patients with one episode of LC. The question remains whether LC in combination with celiac disease should be classified as celiac disease or two different entities.

Clinicopathologic Characterization of Lymphocytic Colitis in the Pediatric Population.

BACKGROUND: Lymphocytic colitis (LC) in the pediatric population has been associated with immune dysregulation. METHODS: Single-center retrospective study of pediatric LC. RESULTS: 50 patients (35 female, 70%) with a median age of 12 years at diagnosis (interquartile range: 5.7-15.8) of LC were identified. At presentation, 11 patients (22%) had malnutrition, 16 (32%) had a known underlying immune dysregulation, 4 (8%) had celiac disease (CD), and none had a diagnosis of inflammatory bowel disease. The most common medications prior to diagnosis were non-steroidal anti-inflammatory drugs, proton pump inhibitor, and selective serotonin reuptake inhibitors (10% each). Colonic biopsies showed a median number of intraepithelial lymphocytes (IELs)/100 epithelial cells of 48 (range: 25-85), and only 10% of cases had neutrophilic cryptitis. Upper gastrointestinal tract findings included lymphocytic esophagitis (4%), and duodenal IELs without and with villous blunting (9% each) (n: 47). Ten patients (23%) had increased IELs in the terminal ileum (n: 43). Treatments including 5-ASA, budesonide, prednisone, and gluten-free diet improved symptoms in <50% of patients (n: 42), and all follow-up colonoscopies showed persistent LC (n: 13). CONCLUSION: Our study supports the association of LC with immune-mediated conditions, most commonly celiac disease. Symptomatic improvement was seen in <50% of patients with none of the patients with repeat colonoscopy showing histologic improvement.

Appendectomy and Future Risk of Microscopic Colitis: A Population-Based Case-Control Study in Sweden.

BACKGROUND AND AIMS: Microscopic colitis (MC) is an inflammatory bowel disease and a common cause of chronic diarrhea. Appendectomy has been suggested to have immunomodulating effects in the colon, influencing the risk of gastrointestinal disease. The relationship between appendectomy and MC has only been sparsely studied. METHODS: This was a case-control study based on the nationwide ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) cohort, consisting of histopathological examinations in Sweden, linked to national registers. Patients with MC were matched to population controls by age, sex, calendar year of biopsy, and county of residence. Data on antecedent appendectomy and comorbidities were retrieved from the Patient Register. Unconditional logistic regression models were conducted presenting odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for country of birth and matching factors. Further subanalyses were made based on MC subtypes (lymphocytic colitis and collagenous colitis), follow-up time postappendectomy and severity of appendicitis. RESULTS: The study included 14,520 cases of MC and 69,491 controls, among these 7.6% (n = 1103) and 5.1% (n = 3510), respectively, had a previous appendectomy ≥1 year prior to MC or matching date. Patients with a previous appendectomy had an increased risk of MC in total (OR, 1.50; 95% CI, 1.40-1.61) and per the collagenous colitis subtype (OR, 1.67; 95% CI, 1.48-1.88) or lymphocytic colitis subtype (OR, 1.42; 95% CI, 1.30-1.55). The risk remained elevated throughout follow-up, and the highest risk was observed in noncomplicated appendicitis. CONCLUSIONS: This nationwide case-control study found a modestly increased risk of developing MC following appendectomy.

Regional differences in the incidence of lymphocytic and collagenous colitis over time.

BACKGROUND: In microscopic colitis (MC), the incidence has increased over the last decades. The aim of the present study was to determine the incidence of lymphocytic (LC) and collagenous colitis (CC) in the county Skåne (Scania), southern Sweden, during the period 2010-20 with focus both on the temporal and spatial variations. METHODS: The MC diagnosis was retrieved from the biopsy registries at the Departments of Pathology. Established diagnostic criteria (increased lymphocyte count, inflammation in lamina propria and in CC a collagen band) were used for diagnosis. Age, gender, date for diagnosis and municipality of residence were retrieved for all patients. RESULTS: In total 1985 patients could be identified with a mean age of 62.9 years (SD 15.7) whereof 1415 were women. The incidence for CC was stable with a total age-standardized rate (ASR) per 100 000 person-years of 6.34, (range 4.6-8.1). In LC the ASR was 7.90 (range 1.7-15.2) but increased markedly 2015-20 reaching 15.2 in 2019. Also, the northwest part of the region showed significantly higher ASR:s of LC during the last part of the decade in comparation to the whole region. CONCLUSIONS: The incidence of CC was stable during the period while LC differed substantially in a way that indicates that it most probably must be two different disease entities. In LC, in view of the marked and rapid increase, although no definitive explanation could be found, causative environmental factors could be contemplated, why further studies are indicated.

Lymphocytic colitis with macroscopic findings.

The clinical case of a patient in the fifth decade of life with a diagnosis of lymphocytic colitis is presented, who comes for chronic diarrhea, which receives treatment with Budesonide with partial response.

The Epidemiology of Microscopic Colitis in Olmsted County, Minnesota: Population-Based Study From 2011 to 2019.

BACKGROUND & AIMS: Epidemiologic studies from Europe and North America have reported an increasing incidence of microscopic colitis (MC) in the late 20th century, followed by a plateau. This population-based study assessed recent incidence trends and the overall prevalence of MC over the past decade. METHODS: Residents of Olmsted County, MN, diagnosed with collagenous colitis (CC) or lymphocytic colitis (LC) between January 1, 2011, and December 31, 2019 were identified using the Rochester Epidemiology Project. Clinical variables were abstracted by chart review. Incidence rates were age- and sex-adjusted to the 2010 US population. Associations between incidence and age, sex, and calendar periods were evaluated using Poisson regression analyses. RESULTS: A total of 268 incident cases of MC were identified with a median age at diagnosis of 64 years (range, 19-90 y); 207 (77%) were women. The age- and sex-adjusted incidence of MC was 25.8 (95% CI, 22.7-28.9) cases per 100,000 person-years. The incidence of LC was 15.8 (95% CI, 13.4-18.2) and CC was 9.9 (95% CI, 8.1-11.9) per 100,000 person-years. A higher MC incidence was associated with increasing age and female sex (P < .01). There was no significant trend in age- and sex-adjusted incidence rate over the study period (P = .92). On December 31, 2019, the prevalence of MC, LC, and CC (including cases diagnosed before 2011) was 246.2, 146.1, and 100.1 per 100,000 persons, respectively. CONCLUSIONS: The incidence of MC and its subtypes was stable between 2011 and 2019, but its prevalence was higher than in previous periods. The incidence of MC continues to be associated with increasing age and female sex.

Gastrointestinal Infection and Risk of Microscopic Colitis: A Nationwide Case-Control Study in Sweden.

BACKGROUND AND AIMS: Gastrointestinal infections have been linked to changes in the composition and function of gut microbiome and development of inflammatory bowel diseases. We therefore sought to examine the relationship between gastroenteritis and risk of microscopic colitis (MC). METHODS: We conducted a case-control study of all adult patients with MC diagnosed between 1990 and 2016 in Sweden matched to up to 5 general population controls according to age, sex, calendar year, and county. Cases of MC were identified using Systematized Nomenclature of Medicine codes from the ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) study, a cohort of gastrointestinal pathology reports from all 28 pathology centers in Sweden. We used logistic regression modeling to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). RESULTS: Through December of 2016, we matched 13,468 MC cases to 64,479 controls. The prevalence of previous diagnosed gastrointestinal infection was 7.5% among patients with MC, which was significantly higher than in controls (3.0%, Pcomparison < .001). After adjustment, gastroenteritis was associated with an increased risk of MC (aOR 2.63; 95% CI 2.42-2.85). Among specific pathogens, Clostridioides difficile (aOR 4.39; 95% CI 3.42-5.63), Norovirus (aOR 2.87; 95% CI 1.66-4.87), and Escherichia species (aOR 3.82; 95% CI 1.22-11.58), but not Salmonella species, were associated with an increased risk of MC. The association between gastrointestinal infections and risk of MC was stronger for collagenous subtype (aOR 3.23; 95% CI 2.81-3.70) as compared with lymphocytic colitis (aOR 2.51; 95% CI 2.28-2.76; Pheterogeneity = .005). The associations remained significant after adjustment for immune-mediated conditions and polypharmacy and when compared with unaffected siblings. CONCLUSION: In a nationwide study, we found that gastrointestinal infection, particularly Clostridioides difficile, is associated with an increased risk of subsequent MC. This study was approved by the Regional Ethics Committee, Stockholm, Sweden (Protocol no. 2014/1287-31/4).

Transient Lymphocytic Colitis After SARS-CoV2 mRNA Vaccine.

This is the first scientific report describing lymphocytic colitis after administration of the Pfizer severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) messenger RNA (mRNA) vaccine. The patient developed liquid stools, abdominal pain, and nausea within 24 hours of receiving the second dose. Symptoms were persistent for 3 months but improved 113 days after onset. Laboratory profiles and gastrointestinal polymerase chain reaction were normal. Esophagogastroduodenoscopy and colonoscopy performed 98 days after onset revealed patchy erythema in the descending colon and rectosigmoid. Mucosal evaluation revealed lymphocytic colitis. Review of the Vaccine Adverse Event Reporting System revealed 5 cases of microscopic colitis after the second mRNA dose. This report and Vaccine Adverse Event Reporting System cases suggest providers should consider microscopic colitis in the differential diagnosis of patients with severe, persistent diarrhea after the SARS-CoV2 mRNA vaccine.

Bile Acid Sequestrant Therapy in Microscopic Colitis.

GOALS: There is an unmet need in investigating corticosteroid-sparing treatments for induction and maintenance of remission in microscopic colitis (MC). The authors' aim was to evaluate the outcomes of patients with MC treated with bile acid sequestrants (BAS). BACKGROUND: MC is a common chronic diarrheal illness. Budesonide is effective induction therapy, but relapses are high after cessation of treatment. STUDY: Our cohort consisted of patients enrolled in our institutional MC registry, a biorepository of histology-confirmed diagnoses of MC. Patients receiving BAS for the treatment of MC were reviewed at each clinical visit for efficacy or ability to decrease budesonide maintenance dosing. RESULTS: The authors included 79 patients (29 collagenous colitis and 50 lymphocytic colitis) with a median follow-up period of 35 months (range, 1 to 120). Most patients were female individuals (78%) and the median age was 69 years (range, 29 to 87). BAS therapy was used in 21 patients who were budesonide-naive, with a response rate of 76% (16/21). In patients treated previously with budesonide, 46 patients were budesonide-dependent and given BAS as maintenance therapy. Of these patients, 23 (50%) were able to decrease their budesonide dosing and 9 (20%) were able to stop budesonide completely. Seven of 46 patients (15%) stopped BAS because of intolerance, perceived lack of benefit, or treatment of concomitant diarrhea illness. CONCLUSIONS: BAS may be an effective corticosteroid-sparing option in the treatment of MC and should be considered after budesonide induction. Larger controlled studies are needed to confirm the efficacy for long-term maintenance and tolerability of BAS in patients with MC.

Abnormal findings on abdominopelvic cross-sectional imaging in patients with microscopic colitis: a retrospective, multicenter study.

OBJECTIVES: Patients with microscopic colitis may have subtle macroscopic findings on colonoscopy such as erythema, edema, or altered vascular pattern; however, radiographic abnormalities on cross-sectional imaging have not been investigated. We aimed at identifying the abdominopelvic radiographic abnormalities in patients with microscopic colitis, as well as possible correlation with endoscopic findings and the need for extended duration of treatment. MATERIALS AND METHODS: This was a retrospective study of patients with biopsy-proven microscopic colitis at two tertiary centers between 1 January 2010 and 30 April 2020. Patients underwent computed tomography scan or magnetic resonance imaging within 30 days of a diagnostic flexible sigmoidoscopy or colonoscopy. Patients with colon ischemia and other causes of colitis were excluded. Radiographic abnormalities from imaging reports included bowel wall thickening, mucosal hyperenhancement and mesenteric fat stranding. Univariate and multivariable logistic regression models were used to identify predictors of radiographic abnormalities. RESULTS: 498 patients with microscopic colitis underwent abdominopelvic cross-sectional imaging within 30 days of flexible sigmoidoscopy/colonoscopy. Lymphocytic colitis was diagnosed in 54.6% of patients, and collagenous colitis in 45.4%. Endoscopic and radiographic abnormalities were identified in 16.1% and 12.4% of patients, respectively. Radiographic abnormalities were associated with the need for budesonide therapy (p = .029) and budesonide therapy long-term (p = .0028). Budesonide therapy long-term (p = .047) was associated with radiographic abnormalities in multivariate analysis. CONCLUSIONS: Radiographic abnormalities may be present on abdominopelvic cross-sectional imaging in a minority of patients with biopsy-proven microscopic colitis, suggesting cross-sectional imaging has low clinical value in the evaluation and treatment of this disease.

Microscopic colitis in Northern Ireland: an updated clinicopathological audit and assessment of compliance with European guidelines.

AIM: We previously reported the first population-based study of the epidemiology of microscopic colitis in Northern Ireland. The aim of the current study is to provide updated data on incidence, diagnostic methods and clinicopathological associations, following dissemination of the previous report. A further aim was to compare the findings against relevant recommendations from the 2020 European guidelines. METHOD: Study cases were identified via the Belfast Health and Social Care Trust pathology laboratory system for new cases of collagenous colitis or lymphocytic colitis diagnosed from 2017 to 2020 inclusive. Demographic and clinical information was collated from electronic healthcare records. RESULTS: Two hundred and seventeen new diagnoses of microscopic colitis were made between 2017 and 2020, comprising 89 (41%) collagenous colitis and 128 (59%) lymphocytic colitis. The overall incidence of microscopic colitis, expressed per 100,000 adult population, ranged from 7.6 to 11.5 (5.9 to 9.0 per 100,000 total population). The 2019 peak of 11.5 cases per 100,000 adult population represents a 71.6% increase in incidence compared with the mean incidence of 6.7 per 100,000 adult population from previous data for 2008-2016. There has also been a significant increase in number of cases diagnosed on separate sampling from the right and left colon (85% in 2019-2020 compared with 30% in 2008-2016; p < 0.001). Overall compliance with coeliac serology testing has improved, with 89% tested in 2017-2018 compared with 75% in 2008-2016. CONCLUSION: Clinicopathological communication has contributed to an increased incidence of microscopic colitis in Northern Ireland through better endoscopic diagnostic sampling and pathology coding practices. Coeliac serology testing has also improved, although continued clinical awareness is required of the need for coeliac serology testing in all patients diagnosed with microscopic colitis.

Clinical Characteristics and Treatment Response in Microscopic Colitis Based on Age at Diagnosis: A Multicenter Retrospective Study.

BACKGROUND: Microscopic colitis (MC) primarily affects older adults; thus, data in younger patients are scarce. AIMS: To compare clinical characteristics and treatment response by age at diagnosis. METHODS: This retrospective cohort study was performed at Mayo Clinic and Massachusetts General Hospital. Patients were chosen consecutively using established databases. Patients were 'younger' if age at diagnosis was ≤ 50 years and 'older' if age > 50 years. Treatment outcomes were captured for induction (12 ± 4 weeks), based on the total number of daily stools, and defined as remission (complete resolution), response (≥ 50% improvement), non-response (< 50% improvement), and intolerance. Patients were considered 'responders' if they had remission or response and 'non-responders' if they had non-response or intolerance. RESULTS: We included 295 patients (52 younger, 243 older). There were no differences in sex, race, MC subtype, and diarrhea severity between groups (all P > 0.05). Younger patients were more likely to have celiac disease (17.3% vs. 5.8%, P = 0.01), while older patients had higher BMI (mean 25.0 vs. 23.8 kg/m2, P = 0.04) were more likely smokers (53.9% vs. 34.6%, P = 0.01) and use NSAIDs (48.6% vs. 15.4%, P < 0.01) and statins (22.6% vs. 3.8%, P < 0.01). Overall treatment response was highest for budesonide (88.3%) and did not differ when comparing older to younger patients (90.6% vs. 77.8%, P = 0.12) or by MC subtype (LC, 81.5% vs. CC, 92.9%, P = 0.07). CONCLUSIONS: There are no significant differences in MC treatment response based on age or disease subtype. These findings support treating patients with MC based on symptom severity rather than age.

[Lymphocytic colitis caused by medicine ingredient modification].

A 49-year-old woman was referred to our hospital for further evaluation and treatment of diarrhea. Colonoscopic findings revealed indistinct vascular patterns and extensive edema in a colon segment, and white granular mucosa and crack-like appearance in the sigmoid colon and rectum. She was diagnosed with lymphocytic colitis (LC) based on lymphocytic infiltration into the epithelium on histopathological examination. Diarrhea symptoms resolved after long-term medication withdrawal. This medicine's composition was changed 4 years ago and this modification possibly triggered LC.

Increasing Incidence of Microscopic Colitis in a Population-Based Cohort Study in Switzerland.

Microscopic colitis (MC) is a chronic inflammatory disease of the colon that presents with chronic, nonbloody watery diarrhea and only few or no endoscopic abnormalities. Histologic examination discriminates lymphocytic colitis (LyC; presence of ≥20 intraepithelial lymphocytes per 100 surface epithelial cells) and collagenous colitis (CC; colonic subepithelial collagen band >10 µm in diameter).1,2 MC not otherwise specified describes a subgroup of patients who do not fulfill the diagnostic criteria for either CC or LyC.1,2 Population-based epidemiologic data regarding MC are scarce. We aimed to evaluate the clinical presentation at diagnosis, incidence, and prevalence of MC in Cantons of Vaud and Fribourg, Switzerland.

Quantifying intraepithelial lymphocytes and subepithelial collagen band in microscopic colitis, extracting insights into the interrelationship of lymphocytic and collagenous colitis.

Microscopic colitis (MC) is the umbrella term for the conditions termed lymphocytic colitis (LC) and collagenous colitis (CC). LC with thickening of the subepithelial collagen band or CC with increased number of intraepithelial T- lymphocytes (IELs) is often seen in MC and may lead to difficulties in correct histological classification. We investigated the extent of overlapping features of CC and LC in 60 cases of MC by measuring the exact thickness of the subepithelial collagen band in Van Gieson stained slides and quantifying number of IELs in CD3 stained slides by digital image analysis. A thickened collagen band was observed in nine out of 29 cases with LC (31%) and an increased number of IELs in all 23 cases of CC (100%). There was no correlation between the thickness of the collagen band and number of IELs. Due to the increased number of IELs in all cases of CC we consider the lymphocytic inflammatory infiltration of the mucosa to be the essential histopathological feature of MC. However, although LC and CC are related due to the lymphocytic inflammation, the non-linear correlation of number of IELs and thickness of the collagenous band indicate differences in their pathogenesis.

Epidemiological and clinical characteristics, and response to treatment in 113 patients with microscopic colitis. / Características epidemiológicas, clínicas y respuesta al tratamiento en 113 pacientes con colitis microscópica.

OBJECTIVE: To study the epidemiological and clinical characteristics, and response to treatment in patients with microscopic colitis. PATIENTS AND METHOD: Epidemiological, clinical, blood test and endoscopic data were retrospectively collected from 113 patients with microscopic colitis. Response to treatment was analyzed in 104 of them. Efficacy and relapse after treatment with budesonide were assessed using survival curves (Kaplan-Meier). RESULTS: 78% of the patients were women, with a mean age of 65 ± 16 years. In smokers, the mean age was 10 years younger. 48% of them had some concomitant autoimmune disease; 60% suffered a single outbreak of the disease. The clinical presentation was similar in both subtypes, although patients with collagenous colitis had a chronic course more frequently (48% vs. 29%, p = 0.047). The remission rate with budesonide was 93% (95% CI 82-98). The cumulative incidence of relapse, after a median follow-up of 21 months, was 39% (95% CI 26-54%): 19% at one year, 32% at two years, and 46% at three years of follow-up. There were no differences in clinical response to budesonide based on smoking habit or microscopic colitis subtype. CONCLUSIONS: Microscopic colitis is more frequent in elderly women. Smoking was associated with earlier onset of the disease, although it did not influence the clinical course or response to treatment. The majority (> 90%) of patients treated with budesonide achieved remission, although nearly half subsequently relapsed.

A 5-year clinicopathological study on microscopic colitis at a Malaysian tertiary hospital.

INTRODUCTION: Microscopic colitis (MC) is a well-recognised cause of chronic diarrhoea in Western countries. It is classically associated with normal endoscopic findings and a higher prevalence among patients with autoimmune disease. Local information regarding this disease remains scarce. We identified patients diagnosed with MC over a five-year period, and then proceeded to analyse the clinical characteristics of these cases. MATERIALS AND METHODS: A retrospective study was conducted by identifying all histologically confirmed colitis cases diagnosed at Hospital Universiti Sains Malaysia from January 2015 until December 2019. Clinicodemographic data was retrieved from case notes of patients. RESULTS: Of the 299 cases with histological colitis, 23 (7.7%) were initially identified as MC. Two cases had incomplete data, while two others were excluded as the diagnoses were revised to inflammatory bowel disease. An incidence of 14 MC cases/1000 case-year was obtained using the 21 MC cases seen within the five-year period. MC subtypes for the 19 analysed cases i.e., lymphocytic colitis and collagenous colitis accounted for 13 (68.4%) and 6 (31.6%) cases, respectively. Eleven patients (57.9%) were females (M:F ratio 1:1.5) with a median age of 51 years. Only nine (47.3%) presented with diarrhoea; one subject (5.4%) had an autoimmune condition (Hashimoto thyroiditis). Normal endoscopic findings were found in 89.5% of patients. CONCLUSION: Approximately half of the subjects in our study who had histologically confirmed MC did not present with diarrhoea. Adequate biopsy samples despite normal colonoscopy findings are important in order to not miss the diagnosis of MC.

Lymphocytic colitis in the setting of teriflunomide use for relapsing multiple sclerosis.

Teriflunomide is an oral monotherapy used to treat relapsing multiple sclerosis. Although teriflunomide may be associated with gastrointestinal symptoms, these events are mild and self-limiting. We present a 39-year-old female who developed severe diarrhea and lost 20 pounds within 3 weeks of starting teriflunomide. Despite discontinuing teriflunomide and undergoing cholestyramine washout, her symptoms persisted. Celiac disease on genetic testing was positive, but no anti-transglutaminase and anti-endomysial antibodies were detected. She underwent colonoscopy and biopsy was consistent with lymphocytic colitis. Remission was achieved within days of starting budenoside. Our case describes a rare, but serious, gastrointestinal adverse event of teriflunomide.

Campylobacter concisus is prevalent in the gastrointestinal tract of patients with microscopic colitis.

OBJECTIVES: Microscopic colitis (MC) is potentially induced by an inflammatory reaction to a luminal gut factor. The emerging pathogen Campylobacter concisus is associated with prolonged diarrhoea and subsequently increased risk of MC. We aimed to examine the prevalence of C. concisus in clinical samples from MC patients, analyse the subtypes collagenous colitis (CC) and lymphocytic colitis (LC), and characterise C. concisus isolates from MC patients by genomic sequencing. METHODS: Mucosal biopsies were collected by sigmoidoscopy in 55 MC patients (CC n = 34, LC n = 21). Saliva and faecal samples were also collected. A two-step cultivation method and PCR established C. concisus prevalence. Biopsy and faecal isolates were sequenced for genomic analysis. RESULTS: Cultivation revealed C. concisus in saliva 55/55, faeces 14/55 and biopsies 69/436, which was confirmed by PCR in faeces 28/55 and biopsies 215/430. Interestingly, biopsy prevalence was higher in CC patients than in LC patients both by cultivation (50/270 vs.19/166, p = .058) and by PCR (175/270 vs. 40/160, p < .0001). Long disease duration also affected biopsy prevalence both by cultivation 30/244 (<2 years) vs. 39/192 (>2 years) (p = .025) and by PCR 103/239 (<2 years) vs. 112/191 (>2 years) (p = .002). Genomic analysis on sixty biopsy and twenty faecal isolates revealed division into two clusters/genomospecies and a high presence of various, putative virulence genes (zot, exotoxin 9 and hcp). CONCLUSIONS: Campylobacter concisus was prevalent in MC patients. Interestingly, the biopsy prevalence differed in biopsies from CC and LC patients and with regard to disease duration. Further studies are needed to elucidate this possible association.

Microscopic colitis and its associations with complications observed in classic inflammatory bowel disease: a systematic review.

Objectives: Crohn's disease and ulcerative colitis are associated with an increased risk to develop anemia, cutaneous diseases, liver diseases, malignancy, osteoporosis, rheumatic diseases, thromboembolism and uveitis. The association between these diseases and microscopic colitis (MC) is not known. The aim of the present systematic review was to examine associations between MC and diseases observed in association with Crohn's disease and ulcerative colitis.Material and methods: According to the review protocol, original articles which described the prevalence of abovementioned diseases in relation to MC, were searched for in PubMed, Embase and Web of Science.Results: After exclusion of duplicates, 928 articles remained. Based on relevancy of their title, abstract or type of article, 16 articles were ordered in full text and after assessment, nine articles could be included in the review. A second research strategy with individual diseases rendered further two articles. Seven articles covered malignancy/neoplasia, where four showed no association with malignancy and three a reduced association compared with controls. Four articles covering rheumatic diseases showed an association between these diseases and MC. One study showed an association between MC and osteoporosis, whereas one did not. One study showed an association between MC and cutaneous diseases, whereas anemia, eye diseases and thromboembolism showed no associations.Conclusions: Due to short follow-up time in small studies, with selection bias due to exclusion of former or prevalent malignancy in an older population, no conclusions can be drawn concerning the true association between MC and malignancy. Rheumatic diseases seem to be associated with MC.