Prospective evaluation of faecal neutrophil-derived proteins in identifying intestinal inflammation: combination of parameters does not improve diagnostic accuracy of calprotectin

Home-based fecal calprotectin utilization in a general pediatric gastroenterology clinic

OBJECTIVE

Remote investigation and monitoring have gained importance in ambulatory practice. A home-based fecal calprotectin (FC) test has been developed where the sample is processed and analyzed at home through a smartphone application. We aimed to assess the use of standard ELISA (sFC) versus home-based (hFC) FC testing in a general pediatric gastroenterology clinic.

METHODS

Ambulatory pediatric patients with hFC or sFC performed between August 2019 and November 2020 were included. Data regarding demographics, clinical characteristics, medication use, investigations, and final diagnosis, categorized as inflammatory bowel disease (IBD), functional gastrointestinal (GI) disorders, organic non-IBD (ONI) GI disorders, non-GI disorders, and undetermined after 6 months of investigation, were recorded.

RESULTS

A total of 453 FC tests from 453 unique patients were included. Of those, 249 (55%) were hFC. FC levels (median) were higher in children with IBD compared to non-IBD diagnosis (sFC 795 vs. 57 μg/g, hFC 595 vs. 47 μg/g, p < 0.001), and in ONI compared to functional GI disorders (sFC 85 vs. 54 μg/g, p = 0.003, hFC 57 vs. 40 μg/g, p < 0.001). No significant difference was observed between different ONI GI disorders or subtypes of functional disorders. Age did not significantly influence levels.

CONCLUSIONS

Overall, hFC and sFC provide similar results in the general pediatric GI ambulatory setting. FC is a sensitive but not disease-specific marker to identify patients with IBD. Values appear to be higher in ONI GI disorders over functional disorders, although cut-off values have yet to be determined.

Application of SWATH Mass Spectrometry and Machine Learning in the Diagnosis of Inflammatory Bowel Disease Based on the Stool Proteome

Inflammatory bowel disease (IBD) flare-ups exhibit symptoms that are similar to other diseases and conditions, making diagnosis and treatment complicated. Currently, the gold standard for diagnosing and monitoring IBD is colonoscopy and biopsy, which are invasive and uncomfortable procedures, and the fecal calprotectin test, which is not sufficiently accurate. Therefore, it is necessary to develop an alternative method. In this study, our aim was to provide proof of concept for the application of Sequential Window Acquisition of All Theoretical Mass Spectra-Mass spectrometry (SWATH-MS) and machine learning to develop a non-invasive and accurate predictive model using the stool proteome to distinguish between active IBD patients and symptomatic non-IBD patients. Proteome profiles of 123 samples were obtained and data processing procedures were optimized to select an appropriate pipeline. The differentially abundant analysis identified 48 proteins. Utilizing correlation-based feature selection (Cfs), 7 proteins were selected for proceeding steps. To identify the most appropriate predictive machine learning model, five of the most popular methods, including support vector machines (SVMs), random forests, logistic regression, naive Bayes, and k-nearest neighbors (KNN), were assessed. The generated model was validated by implementing the algorithm on 45 prospective unseen datasets; the results showed a sensitivity of 96% and a specificity of 76%, indicating its performance. In conclusion, this study illustrates the effectiveness of utilizing the stool proteome obtained through SWATH-MS in accurately diagnosing active IBD via a machine learning model.

Systematic review with meta-analysis: Diagnostic performance of faecal calprotectin in distinguishing inflammatory bowel disease from irritable bowel syndrome in adults

BACKGROUND

Symptoms of inflammatory bowel disease (IBD) often overlap with those of irritable bowel syndrome (IBS).

AIM

To evaluate the diagnostic performance of faecal calprotectin in distinguishing patients with IBD from those with IBS METHODS: We searched MEDLINE, Embase, Scopus, and Cochrane Library databases up to 1 January 2023. Studies were included if they assessed the diagnostic performance of faecal calprotectin in distinguishing IBD from IBS (defined according to the Rome criteria) using colonoscopy with histology or radiology as reference standard in adults. We calculated summary sensitivity and specificity and their 95% confidence intervals (CI) using a random-effect bivariate model. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies II.

RESULTS

We included 17 studies with a total of 1956 patients. The summary sensitivity was 85.8% (95% CI: 78.3-91), and the specificity was 91.7% (95% CI: 84.5-95.7). At a prevalence of IBD of 1%, the negative predictive value was 99.8%, while the positive predictive value was only 9%. Subgroup analyses showed a higher sensitivity in Western than in Eastern countries (88% vs 73%) and at a cut-off of ≤50 μg/g than at >50 μg/g (87% vs. 79%), with similar estimates of specificity. All studies were at "high" or "unclear" risk of bias.

CONCLUSIONS

Faecal calprotectin is a reliable test in distinguishing patients with IBD from those with IBS. Faecal calprotectin seems to have a better sensitivity in Western countries and at a cut-off of ≤50 μg/g.

Association of fecal calprotectin level with eosinophilic gastrointestinal disease in Iranian pediatrics

Introduction

Fecal calprotectin (FC) is a noninvasive biomarker for assessing the inflammatory status of the gastrointestinal tract. The aim of this study was to determine the association between FC levels and Eosinophilic colitis (EC) before and after treatment in pediatrics.

Method

In this cross-sectional study, 330 patients with rectorrhagia and FC levels > 200 μg/g were included in the study. Patients were then subjected to colonoscopy, and if 30 or more eosinophils were observed in the pathology of at least two parts of the colon, EC was diagnosed. Of the 330 patients included in the study, 14 patients were diagnosed as EC. Treatment included seven food elimination diet (food allergens) for 3 months. After 3 months, FC levels were repeated and colonoscopy was performed.

Results

The mean age of the children was 5.9 years. After the elimination diet, the number of eosinophils in all segments of colon significantly decreased (P < 0.001) and according to the pathology report, the number of eosinophils improved in 42.9% of patients. Also, the mean number of segments involved in the colon of patients was significantly decreased (P < 0.001). Mean FC levels were significantly decreased after 3 months (P < 0.001). The cut-off point of 114 μg/g of FC had sensitivity (75%), specificity (67%), positive predictive value (75%), negative predictive value (67%), accuracy (71.4%), and area under the ROC curve (0.708) acceptable in predicting EC.

Conclusion

This study showed that FC levels can be elevated in patients with EC, which is easily corrected with a targeted elimination of food allergens.

Local Colonic Administration of a Serine Protease Inhibitor Improves Post-Inflammatory Visceral Hypersensitivity in Rats

Dysregulation of the protease-antiprotease balance in the gastrointestinal tract has been suggested as a mechanism underlying visceral hypersensitivity in conditions such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). We aimed to study the potential therapeutic role of an intracolonically administered serine protease inhibitor for the treatment of abdominal pain in a post-inflammatory rat model for IBS. An enema containing 2,4,6-trinitrobenzene sulfonic acid (TNBS) was used to induce colitis in male Sprague-Dawley rats, whereas controls received a saline solution. Colonoscopies were performed to confirm colitis and follow-up mucosal healing. In the post-inflammatory phase, the serine protease inhibitor UAMC-00050 (0.1-5 mg/kg) or its vehicle alone (5% DMSO in H2O) was administered in the colon. Thirty minutes later, visceral mechanosensitivity to colorectal distensions was quantified by visceromotor responses (VMRs) and local effects on colonic compliance and inflammatory parameters were assessed. Specific proteolytic activities in fecal and colonic samples were measured using fluorogenic substrates. Pharmacokinetic parameters were evaluated using bioanalytical measurements with liquid chromatography-tandem mass spectrometry. Post-inflammatory rats had increased trypsin-like activity in colonic tissue and elevated elastase-like activity in fecal samples compared to controls. Treatment with UAMC-00050 decreased trypsin-like activity in colonic tissue of post-colitis animals. Pharmacokinetic experiments revealed that UAMC-00050 acted locally, being taken up in the bloodstream only minimally after administration. Local administration of UAMC-00050 normalized visceral hypersensitivity. These results support the role of serine proteases in the pathophysiology of visceral pain and the potential of locally administered serine protease inhibitors as clinically relevant therapeutics for the treatment of IBS patients with abdominal pain.

Faecal Inflammatory Biomarkers and Gastrointestinal Symptoms after Bariatric Surgery: A Longitudinal Study

Background

Bariatric surgery induces various gastrointestinal (GI) modifications. We performed the first study longitudinally assessing the effect of bariatric surgery on faecal inflammatory biomarker levels and its relation with GI complaints.

Method

Faecal calprotectin, lactoferrin, and calgranulin-C levels were determined in 41 patients (34 Roux-en-Y [RYGB], 7 sleeves) before and at 6-16 weeks, 6 months, and 1 year after surgery. Changes in biomarker levels and percentage of patients above reference value were determined. Gastrointestinal symptom rating scale (GSRS) was used to assess GI complaints at corresponding time points. The postoperative relation between GSRS score and biomarker levels above reference value was investigated.

Results

After RYGB, median calprotectin levels are significantly higher (>188, 104-415 μg/g) than before surgery (40, 19-78 μg/g; p < 0.001), and over 90% of patients have levels above reference value 1 year after surgery. Median lactoferrin was 0.4 (0.2-1.6) μg/g before, and >5.9 (1.8-13.6) μg/g after surgery (p < 0.001). Median calgranulin-C levels remained far below the reference value and were 0.13 (0.05-0.24) μg/g before and <0.23 (0.06-0.33) μg/g after surgery. Similar results were found after sleeve gastrectomy. No difference was seen in GSRS score for patients with calprotectin and lactoferrin levels above reference values.

Conclusion

Faecal inflammatory biomarkers calprotectin and lactoferrin, but not calgranulin-C, rise above reference values shortly after bariatric surgery and remain elevated in the majority of patients. The discrepancy between calprotectin and calgranulin-C levels suggests no GI inflammation. Furthermore, patients after RYGB with biomarkers above the population reference value do not seem to have more GI complaints.

Test accuracy of faecal calprotectin for inflammatory bowel disease in UK primary care: a retrospective cohort study of the IMRD-UK data

OBJECTIVE

To estimate the test accuracy of faecal calprotectin (FC) for inflammatory bowel disease (IBD) in the primary care setting using routine electronic health records.

DESIGN

Retrospective cohort test accuracy study.

SETTING

UK primary care.

PARTICIPANTS

5970 patients (≥18 years) without a previous IBD diagnosis and with a first FC test between 1 January 2006 and 31 December 2016. We excluded multiple tests and tests without numeric results in units of µg/g.

INTERVENTION

FC testing for the diagnosis of IBD. Disease status was confirmed by a recorded diagnostic code and/or a drug code of an IBD-specific medication at three time points after the FC test date.

MAIN OUTCOME MEASURES

Sensitivity, specificity, and positive and negative predictive values for the differential of IBD versus non-IBD and IBD versus irritable bowel syndrome (IBS) at the 50 and 100 µg/g thresholds.

RESULTS

5970 patients met the inclusion criteria and had at least 6 months of follow-up data after FC testing. 1897 had an IBS diagnosis, 208 had an IBD diagnosis, 31 had a colorectal cancer diagnosis, 80 had more than one diagnosis and 3754 had no subsequent diagnosis. Sensitivity, specificity, and positive and negative predictive values were 92.9% (88.6% to 95.6%), 61.5% (60.2% to 62.7%), 8.1% (7.1% to 9.2%) and 99.6% (99.3% to 99.7%), respectively, at the threshold of 50 µg/g. Raising the threshold to 100 µg/g missed less than 7% additional IBD cases. Longer follow-up had no effect on test accuracy. Overall, uncertainty was greater for specificity than sensitivity. General practitioners' (GPs') referral decisions did not follow the anticipated clinical pathways in national guidance.

CONCLUSIONS

GPs can be confident in excluding IBD on the basis of a negative FC test in a population with low pretest risk but should interpret a positive test with caution. The applicability of national guidance to general practice needs to be improved.

Laboratory Assessment of Disease Activity in Pediatric Patients with Inflammatory Bowel Disease: What’s New?

Laboratory tests are an integral part of both the diagnostic and follow-up algorithm of patients with inflammatory bowel disease (IBD). Their advantages over other non-invasive methods for assessing disease activity are greater objectivity than clinical activity indices and imaging studies. This review aims to analyze shortly the most common laboratory tests used to assess disease activity in pediatric patients with IBD. In addition to the conventional blood and serum markers that are not specific for gut inflammation, although routinely used, we also reviewed the established fecal markers such as calprotectin, lactoferrin, M2-pyruvate kinase, osteoprotegerin, HMGB1, chitinase 3-like 1, and the promising non-coding microRNA. In conclusion, neither marker is unique to the pediatric IBD. More clinical data are required to assess biomarkers’ full potential for diagnosis, management, and follow-up of pediatric IBD patients.

Efficacy of stool multiplex polymerase chain reaction assay in adult patients with acute infectious diarrhea

BACKGROUND

Recently, stool multiplex polymerase chain reaction (PCR) tests have been developed for identifying diarrhea-causing bacterial pathogens. Furthermore, fecal calprotectin is a well-known effective marker for intestinal mucosal inflammation.

AIM

To evaluate the efficacy of stool multiplex PCR and fecal calprotectin in acute infectious diarrhea.

METHODS

Overall, 400 patients with acute infectious diarrhea were enrolled from Kangdong Sacred Heart Hospital (January 2016 to December 2018). Multiplex PCR detected 7 enteropathogenic bacteria including Salmonella, Campylobacter, Shigella, Escherichia coli O157:H7, Aeromonas, Vibrio, and Clostridium difficile. We reviewed clinical and laboratory findings using stool multiplex PCR.

RESULTS

Stool multiplex PCR test detected considerably more bacterial pathogens than stool culture (49.2% vs 5.2%), with Campylobacter as the most common pathogen (54%). Patients with positive stool PCR showed elevated fecal calprotectin expression compared to patients with negative stool PCR (1124.5 ± 816.9 mg/kg vs 609 ± 713.2 mg/kg, P = 0.001). C-reactive protein (OR = 1.01, 95%CI: 1.001-1.027, P = 0.034) and sigmoidoscopy-detected colitis (OR = 4.76, 95%CI: 1.101-20.551, P = 0.037) were independent factors in stool PCR-based detection of bacterial pathogens. Sensitivity and specificity of calprotectin were evaluated to be 70.5% and 60.9%, respectively (adjusted cut-off value = 388 mg/kg).

CONCLUSION

Stool multiplex PCR test has increased sensitivity in detecting pathogens than conventional culture, and it is correlated with calprotectin expression. Stool multiplex PCR and calprotectin may be effective in predicting clinical severity of infectious diarrhea.

The Role of Fecal Calprotectin in Patients with Systemic Sclerosis and Small Intestinal Bacterial Overgrowth (SIBO)

Fecal calprotectin (FC) is a quick, cost-effective, and noninvasive test, which is used to diagnose patients with active inflammatory bowel diseases (IBD). Recent studies suggest the possible predictive role of FC in the diagnosis of small intestinal bacterial overgrowth (SIBO) in patients with systemic sclerosis (SSc). This study aimed to assess the predictive value of FC in SSc patients and its’ possible use as a SIBO marker. A total of 40 SSc patients and 39 healthy volunteers were enrolled in the study. All subjects completed questionnaires evaluating gastrointestinal symptoms, FC measurements, and lactulose hydrogen breath test (LHBT) assessing SIBO presence. After rifaximin treatment, patients with SIBO underwent the same diagnostic procedures. Significantly higher FC values were observed in the study group compared to controls (97 vs. 20 μg/g; p < 0.0001) and in SSc patients diagnosed with SIBO compared to SSc patients without SIBO (206 vs. 24 μg/g; p = 0.0010). FC turned out to be a sensitive (94.12%) and specific (73.68%) marker in the detection of SIBO in patients with SSc (AUC = 0.82, 95% CI = 0.66–0.93; p < 0.0001). Our study suggests the potential value of FC in SSc in detecting gastrointestinal impairment and its promising role as an additional diagnostic tool for SIBO.

Faecal calprotectin as a diagnostic marker of inflammatory bowel disease in patients with gastrointestinal symptoms: meta-analysis

Colonoscopy is the standard medical procedure to identify inflammatory bowel disease (IBD) in patients with gastrointestinal symptoms. Noninvasive measurement of faecal calprotectin concentration may replace colonoscopy in this indication. The study aimed to assess efficacy of faecal calprotectin as a diagnostic marker of IBD in patients with symptoms suggestive of such diagnosis. Meta-analysis of diagnostic accuracy studies was performed. Cochrane, EMBASE and MEDLINE databases were searched until December 2018. Inclusion criteria comprised experimental and observational studies, adults with gastrointestinal symptoms, calprotectin as index and colonoscopy as reference test, presence of data on/enabling the calculation of diagnostic accuracy parameters. For each study, sensitivity and specificity of faecal calprotectin were analysed as bivariate data. Nineteen studies were identified. The total number of patients was 5032. Calculated pooled sensitivity and specificity were 0.882 [95% confidence interval (CI), 0.827-0.921] and 0.799 (95% CI, 0.693-0.875), respectively. Following faecal calprotectin incorporation in the diagnostic work-up of 100 people with suspected IBD, 18 non-IBD patients will have a colonoscopy performed and one patient with the disease will not be referred for this examination. Faecal calprotectin concentration measurement is a useful screening test to rule out IBD, at the same time reducing the need for colonoscopy by 66.7%.

AGA Technical Review on the Evaluation of Functional Diarrhea and Diarrhea-Predominant Irritable Bowel Syndrome in Adults (IBS-D)

BACKGROUND & AIMS

The evaluation of patients with chronic watery diarrhea represents a diagnostic challenge for clinicians because organic causes, including inflammatory bowel disease, microscopic colitis, and chronic infection, must be differentiated from functional diarrhea and diarrhea-predominant irritable bowel syndrome. The purpose of this review is to summarize the available evidence on the usefulness of diagnostic tests in such patients.

METHODS

We searched MEDLINE and EMBASE via OVID, from 1978 until April 2017. We included diagnostic test accuracy studies reporting on the use of fecal and blood tests for the evaluation of adult patients with functional diarrhea, including irritable bowel syndrome. We assessed the risk of bias of included studies using a modified version of the Quality Assessment of Diagnostic Accuracy Studies II, and the certainty in the evidence using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. We calculated pooled sensitivity and specificity, and the proportion of patients with true and false positive and negative results. We evaluated the following tests: erythrocyte sedimentation rate, C-reactive protein, fecal lactoferrin, fecal calprotectin, serologic tests for celiac disease, tests for bile acid diarrhea, the commercially available version of anti-cytolethal distending toxin B and anti-vinculin antibodies, and tests for Giardia infection. We did not evaluate breath tests for small intestinal bacterial overgrowth, as they are not part of a standard diarrhea workup.

RESULTS

Thirty-eight studies proved eligible to evaluate 1 or more of these tests. Erythrocyte sedimentation rate and C-reactive protein were similar at discriminating organic from functional disease, with sensitivity and specificity, respectively, of 0.54-0.78 and 0.46-0.95 for erythrocyte sedimentation rate and 0.73 and 0.78 for C-reactive protein. Among fecal tests, fecal calprotectin in a range of 50-60 μg/g (pooled sensitivity 0.81; 95% confidence interval [CI], 0.75-0.86; pooled specificity 0.87; 95% CI, 0.78-0.92) and fecal lactoferrin in a range of 4.0-7.25 μg/g (pooled sensitivity 0.79; 95% CI, 0.73-0.84; pooled specificity 0.93; 95%CI 0.63-0.99) presented the lowest proportion of false-negative results (low certainty in the evidence). Among tests for celiac disease, IgA tissue transglutaminase presented the best diagnostic test accuracy (sensitivity range, 0.79-0.99; specificity range, 0.90-0.99) with moderate certainty in the evidence. Among tests for bile acid diarrhea, the ⁷⁵selenium homotaurocholic acid test performed better than serum fibroblast growth factor 19 and 7α-hydroxy-4-cholesten-3-one, but is not available in the United States. There was insufficient evidence to recommend serologic tests for irritable bowel syndrome at this time. There are several good diagnostic tests for Giardia infection.

CONCLUSIONS

Moderate to low certainty in the evidence indicates that available fecal and blood tests may play a role in the diagnostic workup of adult patients with functional diarrhea. At the moment, no tests are available to reliably rule in irritable bowel syndrome.

Does fecal calprotectin equally and accurately measure disease activity in small bowel and large bowel Crohn's disease?: a systematic review

Fecal calprotectin (FC) is a highly sensitive disease activity biomarker in inflammatory bowel disease. However, there are conflicting reports on whether the diagnostic accuracy in Crohn's disease is influenced by disease location. The aim of this study was to undertake a systematic review of the published literature. Relevant databases were searched from inception to November 8, 2016 for cohort and case control studies which had data on FC in patients with isolated small bowel (SB) and large bowel (LB) Crohn's disease. Reference standards for disease activity were endoscopy, magnetic resonance imaging, computed tomography or a combination of these. The QUADAS-2 research tool was used to assess the risk of bias. There were 5,619 records identified at initial search. The 2,098 duplicates were removed and 3,521 records screened. Sixty-one full text articles were assessed for eligibility and 16 studies were included in the final review with sensitivities and specificities per disease location available from 8 studies. Sensitivities of FC at SB and LB locations ranged from 42.9% to 100% and 66.7% to 100% respectively while corresponding specificities were 50% to 100% and 28.6% to 100% respectively. The sensitivities and specificities of FC to accurately measure disease activity in Crohn's disease at different disease locations are diverse and no firm conclusion can be made. Better studies need to be undertaken to categorically answer the effect of disease location on the diagnostic accuracy of FC.

Accuracy of fecal calprotectin for the prediction of endoscopic activity in patients with inflammatory bowel disease

BACKGROUND

Fecal calprotectin is a noninvasive marker of inflammatory bowel disease.

AIM

To evaluate the accuracy of calprotectin for prediction of endoscopic activity in inflammatory bowel disease.

METHODS

One-hundred patients were prospectively included. Quantum Blue^® (Bühlmann) kits were used to determine calprotectin. Endoscopic activity was calculated. Various serum markers (platelets, leukocytes, C-reactive protein, and albumin) were recorded.

RESULTS

Calprotectin was higher in patients with endoscopic activity than in those without activity: in ulcerative colitis, with the low- (29 ± 14 vs. 301 ± 174, p < 0.001) and high- (99 ± 727 vs. 617 ± 801, p < 0.001); and in Crohn's disease, with the low- (29 ± 59 vs. 124 ± 268, p < 0.01) and high-range kit (99 ± 37 vs. 287 ± 607, p < 0.01). Serological marker concentrations did not vary with endoscopic activity. The area under the ROC curve of calprotectin for the prediction of endoscopic activity was 0.9 in ulcerative colitis and 0.8 in Crohn's disease. The best cut-off points for the detection of activity in ulcerative colitis were 50 for the low- (sensitivity 85%, specificity 79%) and 102 for the high- (sensitivity 85%, specificity 79%); in Crohn's disease, 54 for the low- (sensitivity 71%, specificity 75%) and 122 for the high-range kit (sensitivity 71%, specificity 75%).

CONCLUSIONS

Fecal calprotectin concentration has good diagnostic accuracy for the detection of endoscopic activity in inflammatory bowel disease and performs better in ulcerative colitis than in Crohn's disease.

Surrogate Fecal Biomarkers in Inflammatory Bowel Disease: Rivals or Complementary Tools of Fecal Calprotectin?

BACKGROUND

Current noninvasive methods for assessing intestinal inflammation in inflammatory bowel disease (IBD) remain unsatisfactory. Along with C-reactive protein and erythrocyte sedimentation rate, fecal calprotectin (FC) is the standard test for assessing IBD activity, even though its specificity and accuracy are not optimal and it lacks a validated cutoff. Over the past few decades, several fecal markers released from intestinal inflammatory cells have been investigated in IBD; they are the subject of this systematic review.

METHODS

A systematic electronic search of the English literature up to April 2017 was performed using Medline and the Cochrane Library. Only papers written in English that analyzed fecal biomarkers in IBD were included. In vitro studies, animal studies, studies on blood/serum samples, and studies analyzing FC or fecal lactoferrin alone were excluded.

RESULTS

Out of 1023 citations, 125 eligible studies were identified. Data were grouped according to each fecal marker including S100A12, high-mobility group box 1, neopterin, polymorphonuclear neutrophil elastase, fecal hemoglobin, alpha1-antitrypsin, human neutrophil peptides, neutrophil gelatinase-associated lipocalin, chitinase 3-like-1, matrix metalloproteinase 9, lysozyme, M2-pyruvate kinase, myeloperoxidase, fecal eosinophil proteins, human beta-defensin-2, and beta-glucuronidase. Some of these markers showed a high sensitivity and specificity and correlated with disease activity, response to therapy, and mucosal healing. Furthermore, they showed a potential utility in the prediction of clinical relapse.

CONCLUSIONS

Several fecal biomarkers have the potential to become useful tools complementing FC in IBD diagnosis and monitoring. However, wide variability in their accuracy in assessment of intestinal inflammation suggests the need for further studies.

Fecal calprotectin in inflammatory bowel diseases: update and perspectives

Inflammatory bowel diseases (IBDs) are chronic diseases that result from the inflammation of the intestinal wall, suspected in any patient presenting with intestinal symptoms. Until recently, the diagnosis was mainly based on both clinical and endoscopic arguments. The use of an easy, fast, reliable, non-invasive, and inexpensive biological assay is mandatory not only in diagnosis but also in evolutionary and therapeutic monitoring. To date, the fecal calprotectin is the most documented in this perspective. This marker allows the discrimination between functional and organic bowel processes with good performance. The determination of the fecal calprotectin level contributes to the evaluation of the degree of disease activity and to monitoring of therapeutic response.

A prospective study of fecal calprotectin and lactoferrin as predictors of small bowel Crohn's disease in patients undergoing capsule endoscopy

BACKGROUND

Capsule endoscopy (CE) is often used to investigate small bowel Crohn's disease (CD).

AIM

The aim of this study is to prospectively assess the value of fecal calprotectin and lactoferrin to predict CE findings.

PATIENTS AND METHODS

Sixty-eight consecutive patients that were referred for CE were included. Stool samples for calprotectin and lactoferrin and blood samples were collected for relevant parameters. Correlation between fecal markers and CE findings was assessed and receiver operating characteristic (ROC) curves were built to determine the predictive values of fecal markers for the diagnosis of CD.

RESULTS

Fecal calprotectin data was available for all the patients and lactoferrin data for 38. CE findings compatible with CD were found in 23 (33%) patients and 45 (67%) were negative for CD. The average age of the CD group was 34 compared to 46 in the non-CD group (p = .048). Median calprotectin and lactoferrin in the CD group and in the control group were 169 mg/kg vs. 40 (p = .004) and 6.6 mg/kg vs. 1 (p = .051), respectively. The area under the ROC curve was 0.767 for calprotectin and 0.70 for lactoferrin. A fecal calprotectin concentration of 95 mg/kg and fecal lactoferrin of 1.05 mg/kg had a sensitivity, specificity, positive predictive value and negative predictive value of 77 and 73%, 60 and 65%, 50 and 50%, and 84 and 84% in predicting CE findings compatible with CD.

CONCLUSIONS

Fecal markers are simple and noninvasive surrogates for predicting CE findings compatible with CD. Fecal markers can help determine which patients should be referred for CE. ClinicalTrials.gov Identifier: NCT01266629.

Fecal calprotectin for diagnosis of inflammatory bowel disease: A meta-analysis

AIM

To evaluate the value of the fecal calprotectin in the diagnosis of inflammatory bowel disease (IBD) patients systematically.

METHODS

PubMed, EMBASE, CNKI, and Wanfang digital journals database were searched for the studies which evaluated the value of the fecal calprotectin in the diagnosis of IBD patients. Meta-Disc 1.40 was used to calculate the pooled sensitivity, specificity and 95% confidence intervals (95%CI). The summary receiver operating characteristic curve (SROC), the area under the curve (AUC), and Q* were also calculated.

RESULTS

A total of 13 studies involving 721 IBD patients and 664 controls were finally included in this meta-analysis. The pooled sensitivity and specificity were 0.86 (95%CI: 0.84-0.88) and 0.76 (95%CI: 0.74-0.79), respectively. The AUC was 0.9169, and the Q* was 0.8498.

CONCLUSION

Fecal calprotectin is a good noninvasive marker with high sensitivity and specificity in the diagnosis of IBD patients.

Correlation Between Calprotectin and Modified Rutgeerts Score

BACKGROUND

Endoscopic recurrence after surgery for Crohn's disease (CD) is high, and it has important prognostic value. Crohn's disease will recur in the majority of patients after surgery. Fecal calprotectin (FC) and lactoferrin (FL) have attracted interest in the postoperative setting for predicting relapse. We have evaluated the accuracy of FC and FL in diagnosing endoscopic recurrence (ER) using the modified Rutgeerts score (MRS) compared with the Rutgeerts score (RS).

METHODS

A series of consecutive patients who underwent ileocolonic resection for Crohn's disease were evaluated. Biomarkers, clinical indexes, and fecal markers were recorded on the day of ileocolonoscopy. ER was defined as a MRS ≥ i2b or a RS ≥ i2.

RESULTS

Ninety-nine patients were included in this prospective cohort. The median time between surgery and colonoscopy was 87.5 months (IQR, 31-137). FC and FL levels were higher in patients with ER than in those in remission (Median FC, 196.5 μg/g [IQR, 96-634 μg/g] versus 42.1 μg/g [IQR 19-91.60 μg/g; P < 0.001]; Median FL, 23.27 μg/g [IQR 8.9-47.8 μg/g] versus 2 μg/g [IQR 0.9-7.26 μg/g; P < 0.001]). Using the MRS, 34% of patients presented with ER compared with 76% if the RS was used. The RS performed worse than the MRS with a decrease in sensitivity (74% versus 48% for FC and 85% versus 55% for FL) and in NPV (91% versus 33% for FC, and 90% versus 37% for FL). Furthermore, the accuracy of the MRS was higher than that of the RS (75% versus 55%).

CONCLUSIONS

Both FC and FL proved to correlate well with endoscopic findings in the evaluation of Crohn's disease after surgery. Both markers predicted recurrence with greater accuracy when the MRS was used. Fecal markers can be used to monitor disease recurrence after intestinal resection, with patients being selected to undergo further endoscopic evaluation.

The Role of Laboratory Tests in Crohn's Disease

In the past, laboratory tests were considered of limited value in Crohn's disease (CD). In the era of biologics, laboratory tests have become essential to evaluate the inflammatory burden of the disease (C-reactive protein, fecal calprotectin) since symptoms-based scores are subjective, to predict the response to pharmacological options and the risk of relapse, to discriminate CD from ulcerative colitis, to select candidates to anti-tumor necrosis factors [screening tests looking for hepatitis B virus and hepatitis C virus status and latent tuberculosis], to assess the risk of adverse events (testing for thiopurine metabolites and thiopurine-methyltransferase activity), and to personalize and optimize therapy (therapeutic drug monitoring). Pharmacogenetics, though presently confined to the assessment of thiopurineme methyltransferase polymorphisms and hematological toxicity associated with thiopurine treatment, is a promising field that will contribute to a better understanding of the molecular mechanisms of the variability in response to the drugs used in CD with the attempt to expand personalized care and precision medicine strategies.

Concentrations of neutrophil-derived proteins in meconium and their correlations

AIM

The aim was to measure concentrations of four neutrophil-derived proteins in meconium as biomarkers describing prenatal environment.

METHODS

Calprotectin, lactoferrin, myeloperoxidase and PMN-elastase concentrations were measured using ELISA kits in serial meconium portions (n = 81) from 20 healthy neonates.

RESULTS

The highest concentration was for calprotectin (286.5 ± 214.6 µg/g) with a positive correlation (r = 0.75, p < 0.0001) with myeloperoxidase (1.81 ± 1.72 µg/g). For PMN-elastase (1.70 ± 2.69 µg/g) a negative correlation was observed with calprotectin and myeloperoxidase (r = -0.51, p < 0.0001; r = -0.60, p < 0.0001, respectively). Concentration of lactoferrin (45.07 ± 78.53 µg/g) correlated only with that of myeloperoxidese (r = 0.36, p = 0.0009).

CONCLUSION

Calprotectin, lactoferrin, myeloperoxidase and PMN-elastase concentrations in meconium are interrelated. These proteins may serve as objective biomarkers describing and/or assessing the intrauterine environment.

Comparison of Fecal Inflammatory Markers in Crohn's Disease

BACKGROUND

Fecal biomarkers are used increasingly to monitor Crohn's disease (CD). However, the relative accuracy of different markers in identifying inflammation has been poorly evaluated. We evaluated fecal calprotectin (FC), lactoferrin (FL), and S100A12 (FS) using endoscopic validation in a prospective study of the progression of CD after intestinal resection.

METHODS

Data were collected from 135 participants in a prospective, randomized, controlled trial aimed at preventing postoperative CD recurrence. Three hundred nineteen stool samples were tested for FC, FL, and FS preoperatively and 6, 12, and 18 months after resection. Colonoscopy was performed at 6 and/or 18 months. Endoscopic recurrence was assessed blindly using the Rutgeerts score. C-reactive protein (CRP) and Crohn's Disease Activity Index (CDAI) were assessed.

RESULTS

FC, FL, and FS concentrations were elevated preoperatively (median: 1347, 40.9, and 8.4 μg/g, respectively). At 6 months postoperatively, marker concentrations decreased (166, 3.0, 0.9 μg/g) and were higher in recurrent disease than remission (275 versus 72 μg/g, P < 0.001; 5.7 versus 1.6 μg/g, P = 0.007; 2.0 versus 0.8 μg/g, P = 0.188). FC > 135 μg/g, FL > 3.4 μg/g, and FS > 10.5 μg/g indicated endoscopic recurrence (score ≥ i2) with a sensitivity, specificity, and negative predictive value (NPV) of 0.87, 0.66, and 91%; 0.70, 0.68, and 81%; 0.91, 0.12, and 71%, respectively. FC and FL correlated significantly with the presence and severity of endoscopic recurrence, whereas FS, CRP and CDAI did not.

CONCLUSIONS

FC was the optimal fecal marker for monitoring disease activity in postoperative CD and was superior to CRP and CDAI. FL offered modest sensitivity for detecting recurrent disease, whereas S100A12 was sensitive but had low specificity and NPV.

Determination of faecal inflammatory marker concentration as a noninvasive method of evaluation of pathological activity in children with inflammatory bowel diseases

PURPOSE

The optimization of procedure evaluating the severity of inflammatory bowel diseases (IBD) using non-invasive methods.

PATIENTS/METHODS

One hundred and nine children with IBD hospitalized in gastroenterology ward between 2009 and 2011 participated in the study. Activity of the disease was evaluated in each patient. Concentration of three inflammatory markers: dimeric form of tumor pyruvate kinase (M2-PK), calprotectin and lactoferrin was evaluated using immunoenzymatic tests.

RESULTS

Existence of a significant correlation between the faecal level of all tested markers and the stage of clinical activity of the disease was demonstrated in children with IBD, both in Crohn's disease (M2-PK p<0.01; calprotectin p=0.005; lactoferrin p<0.01) and in ulcerative colitis group (M2-PK p<0.01; calprotectin p=0.004; lactoferrin p<0.01). A significant difference in the level of markers was found between children with unclassified colitis and the group of patients with ulcerative colitis and Crohn's disease, but there was no difference between Crohn's disease and ulcerative colitis. The increase in the level of one marker correlated with increasing level of other markers (p<0.01). Faecal markers seem to correlate well with majority of indicators of inflammatory condition in blood.

CONCLUSIONS

Measuring M2-PK, lactoferrin and calprotectin levels in faeces seem to be a useful indicator of the level of disease activity in children with IBD.

Semiquantitative fecal calprotectin test in postinfectious and non-postinfectious irritable bowel syndrome: cross-sectional study

CONTEXT AND OBJECTIVE

The presence of a certain degree of inflammation in the gut wall is now accepted in irritable bowel syndrome (IBS). Fecal calprotectin is considered to be a reliable test for detecting intestinal inflammation. Our aim was to assess the presence of inflammation in postinfectious IBS (PI-IBS), compared with non-postinfectious IBS (NPI-IBS). A secondary objective was to determine the usefulness of a rapid fecal calprotectin test in inflammatory bowel diseases (IBD).

DESIGN AND SETTING

This was a cross-sectional study. Patients with IBS and IBD at a single tertiary gastroenterology center were prospectively included in this study.

METHODS

116 patients with Rome III IBS score (76 females; 48 ± 12 years) were investigated; 24 patients (15 females) had PI-IBS. Intestinal inflammation was assessed using the semiquantitative fecal calprotectin test. The results were expressed as T1, T2 or T3 according to the severity of inflammation (< 15 μg/g; 15-60 μg/g; > 60 μg/g). Using the same test, we evaluated 20 patients with IBD (12 males; 47 ± 13 years).

RESULTS

None of the patients with IBS had a T2 or T3 positive test. Among PI-IBS patients, 33% had a T1 positive test. Among NPI-IBS patients, 9.8% had a T1 positive test, which was significantly different to PI-IBS. The calprotectin test was positive in all IBD patients: 80% with T3, 10% with T2 and 10% with T1.

CONCLUSIONS

Using a semiquantitative test for fecal calprotectin, positive tests were more frequent in PI-IBS patients than in NPI-IBS patients.

Fecal calprotectin is a useful marker to diagnose ulcerative colitis from irritable bowel syndrome

Background:

This study was aimed to evaluate the predictive value of fecal calprotectin in patients with ulcerative colitis from patients with irritable bowel syndrome (IBS).

Materials and Methods:

Between May and October 2013, 88 adult patients, between the age 18 and 65 years with a history of chronic diarrhea of unknown origin were assessed. Standard colonoscopies were performed in all patients to assess ulcerative colitis. Before colonoscopies, they were asked to supply a stool specimen. Fecal calprotectin value was measured using a commercial enzyme-linked immunosorbent assay kit.

Results:

The mean of age, gender combination, and body mass index were not significantly different between patients with ulcerative colitis or IBS. The duration of disease in ulcerative colitis patients was significantly higher than IBS patients (P < 0.0001). The level of calprotectin in ulcerative colitis patients was significantly higher than IBS patients (265.9 vs 115.8, respectively, P = 0.001). Also, cutoff value >164 μg/g with sensitivity and specify of 57 (CI: 41%–71.6%), and 75 (CI: 59.7%–56.8%), respectively, was the best for discrimination between patients with ulcerative colitis and those with IBS.

Conclusion:

Our results show that fecal calprotectin as a noninvasive method, which can be used to identify patients with ulcerative colitis from IBS patients has low sensitivity and specificity.

Biomarkers as potential treatment targets in inflammatory bowel disease: A systematic review

There is increasing interest in the concept of 'treat-to-target' in inflammatory bowel disease as a mechanism to standardize management and prevent complications. While clinical, radiographic and endoscopic treatment end points will figure prominently in this promising management paradigm, the role that noninvasive biomarkers will play is currently undefined. The goal of the present systematic review was to investigate the potential value of biomarkers as treatment targets in inflammatory bowel disease, with particular focus on those best studied: serum C-reactive protein (CRP) and fecal calprotectin. In Crohn disease, elevated CRP levels at baseline predict response to anti-tumour necrosis factor agents, and normalization is usually associated with clinical and endoscopic remission. CRP and hemoglobin levels can be used to help predict clinical relapse in the context of withdrawal of therapy. Ultimately, the authors conclude that currently available biomarkers should not be used as treatment targets in inflammatory bowel disease because they have inadequate operational characteristics to make them safe surrogates for clinical, endoscopic and radiographic evaluation. However, CRP and fecal calprotectin are important adjunctive measures that help alert the clinician to pursue further investigation.

A meta-analysis of the utility of C-reactive protein, erythrocyte sedimentation rate, fecal calprotectin, and fecal lactoferrin to exclude inflammatory bowel disease in adults with IBS

OBJECTIVES

Irritable bowel syndrome (IBS) is viewed as a diagnosis of exclusion by most providers. The aim of our study was to perform a systematic review and meta-analysis to evaluate the utility of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), fecal calprotectin, and fecal lactoferrin to distinguish between patients with IBS and inflammatory bowel disease (IBD) and healthy controls (HCs).

METHODS

A systematic online database search was performed. Included studies were prospective, adult, diagnostic cohort studies with any of the four tests. The means and s.d. values of biomarker logarithms were estimated based on studies that gave medians and either confidence intervals for the median, interquartile ranges, or ranges. We used a Naive Bayes approach to estimate the probability of being a HC, having IBS, or having IBD based on the biomarker values.

RESULTS

Systematic review identified 1,252 citations. After cross-referencing medical subject headings, detailed evaluation identified 140 potentially relevant journal articles/abstracts for CRP, ESR, calprotectin, and lactoferrin of which 4, 4, 8, and 2 fulfilled our inclusion criteria, respectively. None of the biomarkers reliably distinguished between IBS and healthy controls. At a CRP level of ≤0.5 or calprotectin level of ≤40 μg/g, there was a ≤1% probability of having IBD. Individual analysis of ESR and lactoferrin had little clinical utility.

CONCLUSION

CRP and calprotectin of ≤0.5 or 40, respectively, essentially excludes IBD in patients with IBS symptoms. The addition of CRP and calprotectin to symptom-based criteria may improve the confident diagnosis of IBS.

Selected biologic markers of inflammation and activity of Crohn's disease

The study aimed to compare the accuracy of selected biologic markers in assessing the disease activity in patients with Crohn's disease (CD). The analysis included serum IL-2, IL-6, IL-17, TNF-α, IFN-γ, hsCRP, peripheral CD4 + CD25 + FOXP3 + regulatory T cells, as well as fecal calprotectin and lactoferrin. A group of 55 adults with CD was enrolled to the study. Disease activity was assessed using Crohn's Disease Endoscopic Index of Severity (CDEIS), which currently represents the gold standard for the evaluation of endoscopic activity. For clinical activity scoring, the Crohn's Disease Activity Index (CDAI) was used. Concentrations of investigated markers were estimated by means of flow cytometry and enzyme-linked immunosorbent assays, and the results were correlated with both indices. The study demonstrated that both fecal markers, i.e. calprotectin (r = 0.827, p < 0.001) and lactoferrin (r = 0.704, p < 0.001), correlate closely with CDEIS score, and might be used to evaluate the severity of CD in clinical setting. The correlation of those markers with CDAI was also significant, with r = 0.742 for calprotectin (p < 0.001) and r = 0.675 for lactoferrin (p < 0.05). As for the other investigated markers, only hsCRP (r = 0.672, p < 0.001) and IL-17 (r = 0.296, p < 0.005) correlated closely with CDEIS. The correlation of the markers with CDAI was also significant, though weaker, with r = 0.518 for hsCRP (p < 0.001) and r = 0.296 for IL-17 (p < 0.05). The study showed that IL-17, despite its vague role in the pathogenesis of CD, might be a useful marker, comparable with hsCRP, in assessing the activity of the disease.

Fecal Calprotectin is an Accurate Tool and Correlated to Seo Index in Prediction of Relapse in Iranian Patients With Ulcerative Colitis

Background:

The natural clinical course of Ulcerative Colitis (UC) is characterized by episodes of relapse and remission. Fecal Calprotectin (FC) is a relatively new marker of intestinal inflammation and is an available, non-expensive tool for predicting relapse of quiescent UC. The Seo colitis activity index is a clinical index for assessment of the severity of UC.

Objectives:

The present study aimed to evaluate the accuracy of FC and the Seo colitis activity index and their correlation in prediction of UC exacerbation.

Patients and Methods:

In this prospective cohort study, 157 patients with clinical and endoscopic diagnosis of UC selected randomly from 1273 registered patients in Fars province’s IBD registry center in Shiraz, Iran, were followed from October 2012 to October 2013 for 12 months or shorter, if they had a relapse. Two patients left the study before completion and one patient had relapse because of discontinuation of drugs. The participants' clinical and serum factors were evaluated every three months. Furthermore, stool samples were collected at the beginning of study and every three months and FC concentration (commercially available enzyme linked immunoassay) and the Seo Index were assessed. Then univariate analysis, multiple variable logistic regression, Receiver Operating Characteristics (ROC) curve analysis, and Pearson’s correlation test (r) were used for statistical analysis of data.

Results:

According to the results, 74 patients (48.1%) relapsed during the follow-up (33 men and 41 women). Mean ± SD of FC was 862.82 ± 655.97 μg/g and 163.19 ± 215.85 μg/g in relapsing and non-relapsing patients, respectively (P < 0.001). Multiple logistic regression analysis revealed that age, number of previous relapses, FC and the Seo index were significant predictors of relapse. ROC curve analysis of FC level and Seo activity index for prediction of relapse demonstrated area under the curve of 0.882 (P < 0.001) and 0.92 1(P < 0.001), respectively. Besides, FC level of 341 μg/g was identified as the cut-off point with 11.2% and 79.7% relapse rate below and above this point, respectively. Additionally, Pearson correlation coefficient (r) between FC and the Seo index was significant in prediction of relapse (r = 0.63, P < 0.001).

Conclusions:

As a simple and noninvasive marker, FC is highly accurate and significantly correlated to the Seo activity index in prediction of relapse in the course of quiescent UC in Iranian patients.

Fecal calprotectin in diagnosis and clinical assessment of inflammatory bowel disease

The fecal neutrophil-derived biomarker calprotectin has several features of an ideal noninvasive test for detecting intestinal inflammation: it is simple, reliable, and low in cost. Its utility in differentiating inflammatory bowel diseases (IBDs) from functional conditions such as irritable bowel syndrome is well documented. Fecal calprotectin (FC) correlates closely with endoscopic activity of IBD. Emerging evidence suggest its usefulness in serial monitoring of disease activity and of therapy success in IBD. A low FC concentration predicts persistence of clinical remission especially in non-symptomatic ulcerative colitis and Crohn's colitis. Here, an overview is given to the current role of FC in diagnosis and clinical assessment of IBD.

The role and utility of faecal markers in inflammatory bowel disease

Crohn's disease and ulcerative colitis are characterized by periods of symptomatic relapse and remission. Diagnosis and assessment of inflammatory bowel disease has so far been based on clinical evaluation, serum parameters, radiology and endoscopy. Faecal markers such as calprotectin or lactoferrin have emerged as new diagnostic tools to detect and monitor intestinal inflammation. This review focuses on their potential clinical applications and limitations in the management of inflammatory bowel disease.

A predictive model combining fecal calgranulin B and fecal occult blood tests can improve the diagnosis of colorectal cancer

AIM

Current fecal screening tools for colorectal cancer (CRC), such as fecal occult blood tests (FOBT), are limited by their low sensitivity. Calgranulin B (CALB) was previously reported as a candidate fecal marker for CRC. This study investigated whether a combination of the FOBT and fecal CALB has increased sensitivity and specificity for a diagnosis of CRC.

MATERIALS AND METHODS

Patients with CRC (n = 175), and healthy individuals (controls; n = 151) were enrolled into the development (81 cases and 51 controls) and validation (94 cases and 100 controls) sets. Stool samples were collected before bowel preparation. CALB levels were determined by western blotting. FOBT and fecal CALB results were used to develop a predictive model based on logistic regression analysis. The benefit of adding CALB to a model with only FOBT was evaluated as an increased area under the receiver operating curve (AUC), partial AUC, and reclassification improvement (RI) in cases and controls, and net reclassification improvement (NRI).

RESULTS

Mean CALB level was significantly higher in CRC patients than in controls (P<0.001). CALB was not associated with tumor stage or cancer site, but positivity on the FOBT was significantly higher in advanced than in earlier tumor stages. At a specificity of 90%, the cross-validated AUC and sensitivity were 89.81% and 82.72%, respectively, in the development set, and 92.74% and 79.79%, respectively, in the validation set. The incremental benefit of adding CALB to the model, as shown by the increase in AUC, had a p-value of 0.0499. RI in cases and controls and NRI all revealed that adding CALB significantly improved the prediction model.

CONCLUSION

A predictive model using a combination of FOBT and CALB may have greater sensitivity and specificity and AUC for predicting CRC than models using a single marker.

Fecal biomarkers in the diagnosis and monitoring of Crohn's disease

The diagnosis and monitoring of Crohn's disease has traditionally relied on clinical assessment, serum markers of inflammation, and endoscopic examination. Fecal biomarkers such as calprotectin, lactoferrin, and S100A12 are predominantly derived from neutrophils, are easily detectable in the feces, and are emerging as valuable markers of intestinal inflammation. This review focuses on the role of fecal biomarkers in the diagnosis and monitoring of Crohn's disease, in particular how these biomarkers change with disease activity and remission, how they can be used to monitor the response to medical therapy, their value in predicting clinical relapse, and their role in monitoring the postoperative state.

Fecal lactoferrin in discriminating inflammatory bowel disease from irritable bowel syndrome: a diagnostic meta-analysis

Background

To perform a meta-analysis evaluating the diagnostic ability of fecal lactoferrin (FL) to distinguish inflammatory bowel disease (IBD) from irritable bowel syndrome (IBS).

Methods

The Medline, EMBASE, Web of Science, Cochrane library and CNKI databases were systematically searched for studies that used FL concentrations to distinguish between IBD and IBS. The sensitivity, specificity, and other diagnostic indexes of FL were pooled using a random-effects model.

Results

Seven studies, involving 1012 patients, were eligible for inclusion. In distinguishing IBD from IBS, FL had a pooled sensitivity of 0.78 (95% confidence interval [CI]: 0.75, 0.82), a specificity of 0.94 (95% CI: 0.91, 0.96), a positive likelihood ratio of 12.31 (95% CI: 5.93, 29.15), and a negative likelihood ratio of 0.23 (95% CI: 0.18, 0.29). The area under the summary receiver-operating characteristic curve was 0.94 (95% CI: 0.90, 0.98) and the diagnostic odds ratio was 52.65 (95% CI: 25.69, 107.91).

Conclusions

FL, as a noninvasive and simple marker, is useful in differentiating between IBD and IBS.

Clinical utility of fecal biomarkers for the diagnosis and management of inflammatory bowel disease

Diagnosis and monitoring of inflammatory bowel diseases rely on clinical, endoscopic, and radiologic parameters. Inflammatory biomarkers have been investigated as a surrogate marker for endoscopic diagnosis of inflammatory activity. Fecal inflammatory biomarkers such as calprotectin and lactoferrin are direct products of bowel inflammation and provide an accurate and noninvasive diagnostic and monitoring modality for Crohn's disease and ulcerative colitis. This report contains an overview of the currently existing literature pertaining to clinical implications of fecal biomarkers for diagnosis, monitoring, and prediction of outcomes of inflammatory bowel disease.

Colonic immunopathogenesis of Clostridium difficile infections

There are major gaps in our understanding of the immunopathogenesis of Clostridium difficile infections (CDIs). In this study, 36 different biomarkers were examined in the stools of CDI and non-CDI patients using the Proteome Profiler human cytokine array assay and quantitative enzyme-linked immunosorbent assay. Diarrheal stools from patients with CDI (CDI-positive diarrheal stools) showed higher relative amounts of the following inflammatory markers than the diarrheal stools from CDI-negative patients (CDI-negative diarrheal stools): C5a, CD40L, granulocyte colony-stimulating factor, I-309, interleukin-13 (IL-13), IL-16, IL-27, monocyte chemoattractant protein 1, tumor necrosis factor alpha, and IL-8. IL-8 and IL-23 were present in a larger number of CDI-positive diarrheal stools than CDI-negative diarrheal stools. Th1 and Th2 cytokines were not significantly different between the CDI-positive and CDI-negative diarrheal stools. Lactoferrin and calprotectin concentrations were also higher in the CDI-positive diarrheal stools. Our results demonstrate that CDI elicits a proinflammatory host response, and we report for the first time that IL-23 is a major marker in CDI-positive diarrheal stools. IL-23 may explain the lack of a robust immunological response exhibited by a proportion of CDI patients and may relate to recurrence; the IL-23 levels induced during CDI in these patients may be inadequate to sustain the cellular immunity conferred by this cytokine in promoting the induction and proliferation of effector memory T cells.

Diagnostic utility of faecal biomarkers in patients with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common functional gastrointestinal (GI) disorder characterized by unspecific symptoms. In clinical practice it is crucial to distinguish between non-inflammatory functional problems and inflammatory, malignant or infectious diseases of the GI tract. Differentiation between these involves the use of clinical, radiological, endoscopic, histological and serological techniques, which are invasive, expensive, time-consuming and/or hindered by inaccuracies arising from subjective components. A range of faecal markers now appears to have the potential to greatly assist in the differentiation of inflammatory bowel disease (IBD) and IBS. Faecal markers of neutrophil influx into the mucosa are reliable indicators of intestinal inflammation and their role has been mainly studied in discriminating IBD from non-IBD conditions (including IBS) rather than organic from non-organic diseases. Phagocyte-specific proteins of the S100 family (S100A12, calprotectin) are amongst the most promising faecal biomarkers of inflammation. Faecal leukocyte degranulation markers (lactoferrin, polymorphonuclear elastase and myeloperoxidase) have also been suggested as diagnostic tools for the differentiation of IBD and IBS. More recently, additional proteins, including granins, defensins and matrix-metalloproteases, have been discussed as differential diagnostic markers in IBD and IBS. In this review, some of the most promising faecal markers, which have the potential to differentiate IBD and IBS and to advance diagnostic practices, will be discussed.

Diagnostics and prognostics of inflammatory bowel disease with fecal neutrophil-derived biomarkers calprotectin and lactoferrin

Crohn's disease (CD), ulcerative colitis (UC), and colitis unclassified, collectively defined as inflammatory bowel disease (IBD), are the consequence of chronic inflammatory reactions in the gastrointestinal tissue. Endoscopy with biopsies is the mainstay in the diagnosis of this inflammation and is also important in the assessment of disease activity and monitoring of treatment. Furthermore, mucosal healing is increasingly becoming a therapeutic target for treatment of IBD and the golden standard of assessing it is endoscopy. However, due to the costs, invasiveness, and to limited endoscopic capacity, the need is strong for reliable surrogate markers of intestinal inflammation. Bowel contents, being in close contact with intestinal mucosa, can take up molecules that are measurable from stool samples and thus can serve as markers of inflammation. The fecal neutrophil-derived biomarkers, especially calprotectin and lactoferrin, have several features of an ideal test for detecting intestinal inflammation: they are noninvasive, simple, and low in cost. The utility of these biomarkers in distinguishing IBD from noninflammatory conditions such as irritable bowel syndrome is well documented. They correlate closely with endoscopic activity both in CD and UC. They allow serial monitoring of disease activity and of treatment success, and can even serve in predicting clinical relapse in unsymptomatic patients or sustained remission after induction with TNF-α-blocking agents. In this review an overview will be given to the role of fecal neutrophil-derived biomarkers calprotectin and lactoferrin in diagnostics and prognostics of IBD.

S100A12 and hBD2 correlate with the composition of the fecal microflora in ELBW infants and expansion of E. coli is associated with NEC

Objective. To describe the development of the gut microbiota in extremely low birth weight (ELBW) infants with and without necrotizing enterocolitis (NEC) between April 2008 and December 2009, fecal microflora was prospectively analyzed in fecal samples of all ELBW infants using real-time PCR assays. In addition, fecal inflammatory were measured. Results. Fecal microflora established early in ELBW infants and microbiota composition remained stable over the first 28 days of life except for the prevalence of C. difficile which decreased with decreasing antibiotic use. Infants who subsequently developed NEC had an increase of total bacterial count (9.8-fold) 24 h prior to clinical symptoms mainly due to the expansion of E. coli species (21.6-fold), whereas microbiota composition did not differ from healthy ELBW infants five days before onset of NEC. Importantly, S100A12 and hBD2 positively correlated with the total and E. coli bacterial CFU/g feces (r² 0.4 and 0.64, resp.). Conclusions. In summary, we found evidence for a disturbed homeostasis between the intestinal microbiome and host immunity in ELBW infants with NEC. Moreover, S100A12 and hBD2 correlate with the fecal microbiota thus linking the intestinal innate immune response to the bacterial colonization thus possibly providing a diagnostic tool in the future.

Review article: Associations between immune activation, intestinal permeability and the irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS), one of the most common gastrointestinal disorders, markedly impairing patients' quality of life. Drug development for IBS treatment has been hampered by the lack of understanding of IBS aetiology. In recent years, numerous data have emerged that suggest the involvement of immune activation in IBS, at least in a subset of patients.

AIM

To determine whether immune activation and intestinal permeabilisation are more frequently observed in IBS patients compared with healthy controls.

METHODS

The scientific bibliography was searched using the following keywords: irritable bowel syndrome, inflammation, immune activation, permeabilisation, intestine, assay, histology and human. The retrieved studies, including blood, faecal and histological studies, were analysed to provide a comprehensive and structured overview of the available data including the type of assay, type of inflammatory marker investigated or intestinal segment studied.

RESULTS

Immune activation was more frequently observed in IBS patients than in healthy controls. An increase in the number of mast cells and lymphocytes, an alteration in cytokine levels and intestinal permeabilisation were reported in IBS patients. No consistent changes in the numbers of B cells or enterochromaffin cells or in mucosal serotonin production were demonstrated.

CONCLUSIONS

The changes observed were modest and often heterogeneous among the studied population. Only appropriate interventions improving irritable bowel syndrome symptoms could highlight and confirm the role of immune activation in this pathophysiology.

Monoclonal antibody testing for fecal calprotectin is superior to polyclonal testing of fecal calprotectin and lactoferrin to identify organic intestinal disease in patients with abdominal discomfort

BACKGROUND AND AIMS

Fecal calprotectin and lactoferrin are sensitive markers of mucosal inflammation. We compared three different assays in their ability to identify patients with organic intestinal disease.

METHODS

In a post-hoc analysis of a prospective study, we examined 405 unselected patients with abdominal complaints referred for endoscopy to the University Hospital Basel, Switzerland. Calprotectin (EK-CAL, Bühlmann Laboratories, Switzerland; PhiCal, Calpro AS, Norway) and lactoferrin (IBD-Scan, Techlab, USA) were measured using enzyme-linked immunosorbent assays. The presence of a clinically significant endoscopic finding was the primary endpoint of the study. Final diagnoses were adjudicated blinded to calprotectin values.

RESULTS

The prevalence of organic intestinal disease was 35.3%. Receiver operating characteristics analysis calculated an area under the curve (AUC) for EK-CAL of 0.918, which was significantly better than for PhiCal (AUC 0.842, P<0.001) and IBD-Scan (AUC 0.830, P=0.003) to identify patients with organic intestinal disease. Overall test accuracy was 88.1% for EK-CAL, 83.7% for PhiCal, and 81.3% for IBD-Scan. Optimal cut-off value calculated for PhiCal and IBD-Scan were lower than recommended by the manufacturer.

CONCLUSIONS

Monoclonal testing of calprotectin is superior to both polyclonal calprotectin testing and fecal lactoferrin in identifying symptomatic patients with organic intestinal disease.

Human β-defensin 2 expression in ELBW infants with severe necrotizing enterocolitis

BACKGROUND

The aim of this study was to analyze whether the mucosal innate immune response of extremely-low-birth-weight (ELBW) infants might play a role in the development of necrotizing enterocolitis (NEC).

METHODS

Between April 2008 and December 2009 antimicrobial peptides were prospectively measured in fecal samples of ELBW infants. In cases requiring abdominal surgery, full-thickness gut biopsies were analyzed for expression of human β-defensin 2 (hBD2), interleukin-8 (IL-8), villin, MD2, and Toll-like receptor 4 (TLR4).

RESULTS

Fecal hBD1 concentrations were consistently low in all patients, whereas hBD2 concentrations were high in meconium, particularly in clinical chorioamnionitis, and then dropped, followed by a steady increase after day 14. Infants with moderate NEC showed significantly increased fecal hBD2 concentrations before clinical symptoms, in contrast to infants developing severe NEC. Analysis of intestinal resection material obtained from patients with severe NEC revealed low hBD2 mRNA and protein levels, and increased expression of the inflammatory cytokine IL-8.

CONCLUSION

High hBD2 concentrations, reflecting strong intestinal immune responses, were associated with moderate courses of the disease. In severe NEC, low hBD2 expression was accompanied by low TLR4/MD2 expression, suggesting an inadequate response to luminal bacteria, possibly predisposing those infants to the development of NEC.

Fecal calprotectin as a correlative marker in clinical severity of infectious diarrhea and usefulness in evaluating bacterial or viral pathogens in children

BACKGROUND

Calprotectin is a marker associated with intestinal inflammation. The aim of this study is to explore the diagnostic value of fecal calprotectin in predicting bacterial/viral diarrhea and the application of fecal calprotectin in the clinical course of infectious diarrhea.

METHODS

Patients ages from 3 months to 10 years with infectious diarrhea were enrolled, and from each patient, 2 to 3 stool samples were collected. Fecal calprotectin levels were determined by enzyme-linked immunosorbent assay and compared by pathogen and disease activity. A univariate linear regression was used to determine the correlation between fecal calprotectin and the clinical parameters, and generalized estimating equations (GEEs) were used for the time course analyses.

RESULTS

The data include 451 evaluations for 153 individuals across 3 different time points. The fecal calprotectin level was higher in patients with Salmonella infection (median with range 765 [252-1246] μg/g) or Campylobacter infection (689 [307-1046] μg/g) compared with patients with rotavirus infection (89 [11-426] μg/g), norovirus infection (93 [25-405] μg/g), or adenovirus infection (95 [65-224] μg/g). Fecal calprotectin concentrations were elevated in patients with severe (843 [284-1246] μg/g) or moderate (402 [71-995] μg/g) disease activity compared with those with mild (87 [11-438] μg/g) disease activity (P < 0.05). GEE analysis suggests that fecal calprotectin is correlated with clinical severity (e.g., Vesikari score) and may provide information for disease management.

CONCLUSIONS

Fecal calprotectin levels increased during bacterial infection and as disease severity increased, and its levels on the initial evaluation and follow-up visit are correlated with clinical severity. Fecal calprotectin may be a useful marker for application in children during infectious diarrhea.