Fibrosis-related transcriptome unveils a distinctive remodeling matrix pattern in penetrating ileal Crohn's disease.

BACKGROUND AND AIMS: Stricturing (B2) and penetrating (B3) ileal Crohn's disease have been reported to present similar levels of histopathological transmural fibrosis. This study aimed to compare the fibrosis-related transcriptomic profiles of penetrating and stricturing ileal Crohn's disease. METHODS: Using Nanostring technology and comparative bioinformatics, we analyzed the expression of 787 fibrosis-related genes in 36 ileal surgical specimens, 12 B2 and 24 B3, the latter including 12 cases with associated stricture(s) (B3s) and 12 without (B3o). Quality control of extracted RNA was performed according to Nanostring parameters and principal component analysis for the distribution analysis. For the selection of the differentially expressed genes a p-adjusted <0.05 and Fold Change ≤-1.5 or ≥ 1.5 was adopted. qPCR and immunohistochemistry analyses were used to validate selected differentially expressed genes. RESULTS: We included 34 patients with B2 and B3 phenotypes, balanced for age at diagnosis, age at surgery, gender, Crohn's disease localization, perianal disease and therapy. Inflammation and fibrosis histopathological scoring were similar in all cases. B2 and B3 groups showed a very good clustering regarding 30 significantly differentially expressed genes, all being remarkably upregulated in B3. More than half of these genes were involved in Crohn's disease fibrogenesis, while eight differentially expressed genes were so in other organs. The most significantly active biologic processes and pathways in penetrating disease were response to TGFßand matrix organization and degradation, as validated by immunohistochemistry. CONCLUSIONS: Despite the histopathological similarities in fibrosis between stricturing and penetrating ileal Crohn's disease, their fibrosis-related transcriptomic profiles are distinct. Penetrating disease exhibits a distinctive transcriptomic landscape related to enhanced matrix remodeling.

How to Evaluate Fibrosis in IBD?

In this review, we will describe the importance of fibrosis in inflammatory bowel disease (IBD) by discussing its distinct impact on Crohn's disease (CD) and ulcerative colitis (UC) through their translation to histopathology. We will address the existing knowledge on the correlation between inflammation and fibrosis and the still not fully explained inflammation-independent fibrogenesis. Finally, we will compile and discuss the recent advances in the noninvasive assessment of intestinal fibrosis, including imaging and biomarkers. Based on the available data, none of the available cross-sectional imaging (CSI) techniques has proved to be capable of measuring CD fibrosis accurately, with MRE showing the most promising performance along with elastography. Very recent research with radiomics showed encouraging results, but further validation with reliable radiomic biomarkers is warranted. Despite the interesting results with micro-RNAs, further advances on the topic of fibrosis biomarkers depend on the development of robust clinical trials based on solid and validated endpoints. We conclude that it seems very likely that radiomics and AI will participate in the future non-invasive fibrosis assessment by CSI techniques in IBD. However, as of today, surgical pathology remains the gold standard for the diagnosis and quantification of intestinal fibrosis in IBD.

How many biomarker measurements are needed to predict prognosis in Crohn's disease patients under infliximab?-A prospective study.

BACKGROUND: Timely stratification of Crohn's disease (CD) is essential for patients' management. The use of noninvasive accurate biomarkers is key to monitor treatment and to pursue mucosal healing, the ultimate treatment endpoint in CD. OBJECTIVE: We aimed to evaluate the performance of readily available biomarkers and develop risk matrices to predict CD progression. METHODS: Data from 289 CD patients receiving infliximab (IFX) maintenance therapy for 2 years was collected; those patients were included in DIRECT, a prospective multicenter observational study. Disease progression was evaluated using two composite outcomes incorporating clinical and drug-related factors, the first including IFX dose and/or frequency adjustments. Univariate and multivariable logistic regressions were used to calculate the odds ratios (OR) and to develop risk matrices. RESULTS: The isolated presence of anemia at least once during follow-up was a significant predictor of disease progression (OR 2.436 and 3.396 [p ≤ 0.001] for composite outcomes 1 and 2, respectively) regardless of confounding factors. Isolated highly elevated C-reactive protein (CRP; >10.0 mg/L) and fecal calprotectin (FC; >500.0 µg/g) in at least one visit were also significant predictors, while milder elevations (3.1-10.0 mg/L and 250.1-500.0 µg/g) were only relevant when detected in at least two visits (consecutive or not). The combination of biomarkers in risk matrices had good ability to predict progression; patients simultaneously presenting anemia, highly elevated CRP and FC at least once had 42%-63% probability of achieving the composite outcomes. CONCLUSION: The combined evaluation of hemoglobin, CRP, and FC in at least one time point and their incorporation into risk matrices seems to be the optimal strategy for CD management, as data from additional visits did not meaningfully influence the predictions and may delay decision-making.

Transmural remission improves clinical outcomes up to 5 years in Crohn's disease.

INTRODUCTION: Evidence supporting transmural remission (TR) as a long-term treatment target in Crohn's disease (CD) is still unavailable. Less stringent but more reachable targets such as isolated endoscopic (IER) or radiologic remission (IRR) may also be acceptable options in the long-term. METHODS: Multicenter retrospective study including 404 CD patients evaluated by magnetic resonance enterography and colonoscopy. Five-year rates of hospitalization, surgery, use of steroids, and treatment escalation were compared between patients with TR, IER, IRR, and no remission (NR). RESULTS: 20.8% of CD patients presented TR, 23.3% IER, 13.6% IRR and 42.3% NR. TR was associated with lower risk of hospitalization (odds-ratio [OR] 0.244 [0.111-0.538], p < 0.001), surgery (OR 0.132 [0.030-0.585], p = 0.008), steroid use (OR 0.283 [0.159-0.505], p < 0.001), and treatment escalation (OR 0.088 [0.044-0.176], p < 0.001) compared to no NR. IRR resulted in lower risk of hospitalization (OR 0.333 [0.143-0.777], p = 0.011) and treatment escalation (OR 0.260 [0.125-0.540], p < 0.001), while IER reduced the risk of steroid use (OR 0.442 [0.262-0.745], p = 0.002) and treatment escalation (OR 0.490 [0.259-0.925], p = 0.028) compared to NR. CONCLUSIONS: TR improved clinical outcomes over 5 years of follow-up in CD patients. Distinct but significant benefits were seen with IER and IRR. This suggests that both endoscopic and radiologic remission should be part of the treatment targets of CD.

Exploring the Ways of "The Great Imitator": A Case Report of Syphilitic Hepatitis.

Introduction: Syphilis is a chronic infection caused by Treponema pallidum. Manifestations of this disease are vast, and syphilitic hepatitis is a rarely depicted form of secondary syphilis. Case Presentation: We report the case of a 63-year-old man with worsening jaundice, maculopapular rash and perianal discomfort. Proctological examination with anoscopy revealed a perianal gray/white area with millimetric pale granules along the anal canal. Liver function tests showed a mixed pattern. Venereal Disease Research Laboratory, T. pallidum hemagglutination assay and IgM fluorescent treponemal antibody absorbance were positive. The patient was successfully treated with a single dose of penicillin G. Discussion/Conclusion: Syphilitic hepatitis is scarcely reported in the literature. Secondary syphilis with mild hepatitis rarely leads to hepatic cytolysis and jaundice. Many signs of secondary syphilis including syphilitic hepatitis may be linked to immune responses initiated during early infection. Over the past decades, evidence has emerged on the importance of innate and adaptive cellular immune responses in the immunopathogenesis of syphilis. This report raises awareness to a clinical entity that should be considered in patients at risk for sexually transmitted diseases, who present with intestinal discomfort or liver dysfunction, as it is a treatable and fully reversible condition.

Introdução: A sífilis é uma infeção crónica provocada pelo Treponema pallidum. As manifestações desta doença são vastas e a hepatite sifilítica é uma forma de sífilis secundária raramente descrita. Caso Clínico: Apresentamos o caso de um doente de 63 anos com icterícia de agravamento progressivo, rash maculopapular e desconforto perianal. O exame proctológico complementado por anuscopia revelou uma região perianal cinzenta-esbranquiçada com grânulos pálidos milimétricos ao longo do canal anal. Testes de função hepática revelaram um padrão misto e o Venereal Disease Research Laboratory, T. pallidum hemagglutination assay e IgM fluorescent treponemal antibody absorbance foram positivos. O doente foi tratado com sucesso com uma dose única de penicilina G. Discussão/Conclusão: São raros os casos de hepatite sifilítica descritos na literatura. Sífilis secundária com hepatite ligeira raramente conduz a citólise hepática e icterícia. Muitos dos sinais de sífilis secundária, incluindo a hepatite sifilítica, parecem estar associados a respostas imunitárias iniciadas durante o período de infeção precoce. Ao longo das últimas décadas, têm surgido evidências crescentes sobre a importância das respostas imunes inata e adaptativa na patogénese da sífilis. Este caso clínico descreve uma entidade nosológica que deve ser considerada em doentes em risco de contraírem doenças sexualmente transmissíveis, que se apresentem com desconforto intestinal ou disfunção hepática, visto tratar-se de uma condição tratável e totalmente reversível.

Subclinical Persistent Inflammation as Risk Factor for Crohn's Disease Progression: Findings From a Prospective Real-World Study of 2 Years.

BACKGROUND AND AIMS: Subclinical intestinal inflammation is common in Crohn's disease (CD). We aimed to explore its impact in the disease progression of infliximab-treated patients and the usefulness of fecal calprotectin (FC) and C-reactive protein (CRP) as surrogate minimally invasive biomarkers. METHODS: The registry-based, prospective, observational, multicenter DIRECT (study to investigate the correlation of fecal calprotectin with serum Drug levels and development of an antI-dRug antibodiEs among adult patients with inflammatory bowel disease reCeiving anti-TNF-alfa treatment or vedoluzimab treatment) study followed infliximab-treated CD patients for 2 years in a tertiary care setting. Persistent inflammation definition was based on FC (>150 µg/g, >250 µg/g, or >350 µg/g) or serum CRP (>3 µg/mL) concentrations over 2 consecutive or at least 3 visits. Patients were categorized according to a composite outcome reflecting disease progression that incorporated surgery; hospitalizations; new fistulae, abscess, or stricture; and treatment escalation. RESULTS: Of 322 DIRECT study patients, 180 asymptomatic, infliximab treated on maintenance regimen were included in the analysis. Patients developing the composite endpoint (n = 96) presented higher median levels of FC (205 [interquartile range, 98-515] µg/g; P = .045) but not of CRP (2.50 [interquartile range, 0.80-6.00] µg/mL; P = .895). Biomarker-defined persistent subclinical inflammation prevalence ranged from 24% to 81%. Considering FC >250 µg/g in 2 consecutive visits, prevalence was 50%, odds of achieving the endpoint were increased 3-fold (odds ratio, 2.996 [95% confidence interval, 1.557-5.776]), and time-to-outcome occurrence was significantly lower among subjects with persistent inflammation (median time: 11 months). Both clinical-related and treatment-related components were significantly associated with persistent inflammation. Definitions based on CRP >3 µg/mL, FC >150 µg/g, FC >350 µg/g, double biomarkers (FC >250 µg/g and/or CRP >3 µg/mL), or more visits did not improve predictive ability. CONCLUSIONS: Persistent inflammation, defined simply and readily by FC >250 µg/g over 2 consecutive visits, was associated with a significantly higher risk and shorter time to occurrence of a composite outcome reflecting disease progression in asymptomatic infliximab-treated CD patients.

Ileal Crohn's Disease Exhibits Similar Transmural Fibrosis Irrespective of Phenotype.

INTRODUCTION: In Crohn's disease (CD), the assessment of transmural inflammation and fibrosis is of utmost importance. This study aimed to quantify these parameters in CD ileal specimens and correlate them with disease progression. METHODS: This is a retrospective unicentric study based on the analysis of archived specimens (n = 103) of primary ileal resection. Data were retrieved from a prospective national inflammatory bowel disease registry. Two pathologists, blinded for CD phenotype and clinical indications for surgery, examined 3 sections per patient and graded inflammation and fibrosis, based on a histopathological score. RESULTS: Penetrating (B3, n = 74) CD exhibited significantly higher inflammation in diseased areas, compared with stricturing (B2, n = 29) disease (score 3: 96% vs 76%, P = 0.005 in inflamed areas; 78% vs 55%, P = 0.019 in most affected areas). This was also observed for the comparison of B2 CD with B3 CD with (B3s, n = 54) and without associated stricture (B3o, n = 20): B3s vs B2: 81% vs 55%, P = 0.033 in most affected areas; B3o vs B2: 100% vs 76%, P = 0.006 in inflamed areas; 70% vs 55%, P = 0.039 in most affected areas. We could not show differences in fibrosis scores between the subphenotypes. Postoperative new penetrating events occurred only in B3s (n = 6, 11%, P = 0.043) patients. The changing of biologic therapy after surgery correlated with severe inflammation at the proximal ileal margin (55% changed vs 25% not changed, P = 0.035). DISCUSSION: In our cohort, fibrosis scores and fibromuscular changes were comparable, irrespective of CD phenotype. Inflammation severity was the major differentiator between penetrating and stricturing disease.JOURNAL/cltg/04.03/01720094-202104000-00012/inline-graphic1/v/2021-04-13T161901Z/r/image-tiff.

Histologic Features of Colon Biopsies (Geboes Score) Associated With Progression of Ulcerative Colitis for the First 36 Months After Biopsy.

BACKGROUND & AIMS: In addition to findings from endoscopy, histologic features of colon biopsies have been associated with outcomes of patients with ulcerative colitis (UC). We investigated associations between Geboes scores (a system to quantify structural changes and inflammatory activity in colon biopsies) and UC progression, and the time period over which this association is valid. METHODS: We analyzed data from 399 asymptomatic patients with UC enrolled in the ACERTIVE study, followed at 13 inflammatory bowel disease (IBD) centers in Portugal through 31 December 2019. Blood and stool samples were collected and analyzed, and all patients underwent sigmoidoscopy within 24 h of sample collection. We assessed baseline endoscopic status (Mayo endoscopic subscore), histologic features of 2 sigmoid and 2 rectal biopsies (Geboes score), and concentration of fecal calprotectin (FC). The primary outcome was UC progression (surgical, pharmacologic, and clinical events). We generated survival curves for 36 months or less and more than 36 months after biopsy according to Geboes score using the Kaplan-Meier method and compared findings with those from a log rank test. Cox regression was adjusted for Mayo endoscopic subscore, Geboes score, and level of FC; results were expressed as adjusted hazard ratios (HR) with 95% CIs. RESULTS: Patients with Geboes scores >2B.0, Geboes scores >3.0, or Geboes scores >4.0 had a higher frequency of, and a shorter time to UC progression, than patients with Geboes scores ≤2B.0, Geboes scores ≤3.0, or Geboes score ≤4.0 (P < .001). Disease progression occurred earlier in patients with Geboes scores >2B.0, Geboes scores >3.0, or Geboes scores >4.0 compared with patients with Geboes scores ≤2B.0 (HR, 2.021; 95% CI, 1.158-3.526), Geboes scores ≤3.0 (HR, 2.007; 95% CI, 1.139-3.534), or Geboes scores ≤4.0 (HR, 2.349; 95% CI, 1.269-4.349), respectively, in the first 36 months after biopsy. Similar results were found for patients with concentrations of FC below 150 µg/g. CONCLUSIONS: We found histologic features of colon biopsies (Geboes score) to be an independent risk factor for progression of UC in the first 36 months after biopsy.

Transmural Histological Scoring Systems in Crohn's Disease: A Systematic Review With Assessment of Methodological Quality and Operating Properties.

BACKGROUND: The relative proportion of inflammation and fibrosis in a stricture is highly relevant in defining the clinical approach for Crohn's disease [CD] patients. Whereas transmural inflammation in CD can be accurately estimated by cross-sectional imaging, evaluating the extent and severity of fibrosis still requires surgical pathology of intestinal resection specimens. This study systematically reviewed all existing transmural histopathological scoring systems developed for the assessment of inflammation and/or fibrosis in CD. METHODS: A systematic review of histopathological scoring systems for the assessment of transmural inflammation and/or fibrosis in CD, focusing on originally developed scoring systems. Risk of bias, methodological quality, and operating or psychometric properties [validity, reliability, responsiveness, and feasibility] of each histological scoring system were analysed. RESULTS: A total of 29 original scoring systems were included in this review. Three scoring systems were highlighted as the most widely reproduced, one aimed at assessing inflammation only and two aimed at assessing inflammation and fibrosis. These scores were more widely reproduced probably due to their ease of application in clinical studies. Two highly comprehensive scores were identified, showing good operating properties and high methodological quality, as well as the lowest risk of bias; these should, therefore, be further validated in clinical research studies. CONCLUSIONS: This study reviewed all existing transmural histopathological scoring systems for the assessment of inflammation and/or fibrosis in CD and identified the most reliable and accurate scores for clinical research and clinical practice settings.

Serum Dipeptidyl Peptidase 4: A Predictor of Disease Activity and Prognosis in Inflammatory Bowel Disease.

BACKGROUND: Serum dipeptidyl peptidase 4 (DPP-4) has drawn particular interest as a biomarker in inflammatory bowel disease (IBD), as this protease inactivates several peptides that participate in the inflammatory cascade. METHODS: Two prospectively recruited cohorts consisting of 195 patients (101 had Crohn's disease [CD] and 94 had ulcerative colitis [UC]) were evaluated using clinical indexes and followed up to assess for treatment escalation. Sixty-eight patients underwent endoscopic evaluation at baseline. In the second cohort of 46 biologically treated patients, treatment response was assessed. Serum DPP-4, C-reactive protein (CRP), and fecal calprotectin levels were quantified at baseline and during follow-up. RESULTS: Median DPP-4 levels were significantly lower in active IBD patients when compared with remitters (CD: 1043 [831-1412] vs 1589 [1255-1956] ng/mL; P < 0.001; UC: 1317 [1058-1718] vs 1798 [1329-2305] ng/mL; P = 0.001) and healthy controls (2175 [1875-3371] ng/mL). In fact, DPP-4 was able to distinguish clinical and endoscopic activity from remission, with areas under the curve (AUC) of 0.81/0.93 (CD) and 0.71/0.79 (UC), along with the need for treatment escalation, with comparable AUCs of 0.79 (CD) and 0.77 (UC). Furthermore, DPP-4 levels were higher in responders to treatment and more pronounced among UC (1467 [1301-1641] vs 1211 [1011-1448] ng/mL; P < 0.001) than CD patients (1385 [1185-1592] vs 1134 [975-1469] ng/mL; P = 0.015). CONCLUSIONS: Our results suggest that serum DPP-4 can be used as a noninvasive biomarker of IBD activity and biological treatment response and a predictor of treatment escalation, particularly when combined with other biomarkers.

Comparing the Continuous Geboes Score With the Robarts Histopathology Index: Definitions of Histological Remission and Response and their Relation to Faecal Calprotectin Levels.

BACKGROUND AND AIMS: The histological status of ulcerative colitis [UC] patients in clinical and endoscopic remission has gained space as an important prognostic marker and a key component of disease monitoring. Our main aims were to compare two histological indexes-the continuous Geboes score [GS] and the Robarts Histopathology index [RHI]-regarding their definitions of histological remission and response, and the ability of faecal calprotectin [FC] levels to discriminate between these statuses. METHODS: This was an analysis of three prospective cohorts including 422 patients previously enrolled in other studies. RESULTS: The two continuous scores [GS and RHI] were shown to be significantly correlated [correlation coefficient of 0.806, p < 0.001] and particularly close regarding their definition of histological response: 95% and 88% of all patients classified as having/not having [respectively] histological response according to RHI also did so according to GS. Moreover, median FC levels in patients with histological response were lower than those in patients without histological response [GS: 73.00 vs 525.00, p < 0.001; RHI: 73.50 vs 510.00, p < 0.001]; a similar trend was observed when FC levels of patients in histological remission were compared to those of patients with histological activity [GS: 76.00 vs 228.00, p < 0.001; RHI: 73.50 vs 467.00, p < 0.001]. FC levels allowed us to exclude the absence of histological remission [according to RHI] and absence of histological response [according to RHI and GS], with negative predictive values varying from 82% to 96%. However, optimization of the FC cut-off to exclude the absence of histological remission, as for the continuous GS, falls within values that resemble those of the healthy population. CONCLUSION: The continuous GS and RHI histological scores are strongly correlated in their definitions of histological response. An absence of histological remission could only be excluded at physiological levels of FC.

Sexual Quality of Life in Inflammatory Bowel Disease: A Multicenter, National-Level Study.

BACKGROUND: The impact of inflammatory bowel disease (IBD) on sexual health is a leading concern among patients. Most studies focus on sexual dysfunction rather than patient-perceived sexual quality of life (SQoL). We aimed to assess SQoL in IBD patients compared with healthy controls. METHODS: This is a multicenter, cross-sectional study of IBD patients (n = 575 with Crohn's disease and n = 294 with ulcerative colitis), compared with healthy controls (n = 398), that used an anonymous self-administered questionnaire. This multimodal questionnaire included sociodemographic data and 4 validated instruments: Short IBD Questionnaire, Social Desirability Scale, Sexual QoL Questionnaire-Male/Female, Nine-item Patient Health Questionnaire. RESULTS: Inflammatory bowel disease patients reported lower SQoL (men: 77.29 vs 83.83; P < 0.001; women: 70.40 vs 81.63; P < 0.001) compared with controls. Among IBD patients, SQoL was positively correlated with health-related quality of life (HRQoL) and negatively correlated with depression symptoms. Perianal disease was associated with lower HRQoL and higher incidence of depression, but only impacted SQoL in men. In linear regression analysis for men, SQoL was associated with age, marital status, and depression (ß, -2.101; 95% confidence interval [CI], -2.505 to -1.696; P < 0.001). In women, SQoL was associated with depression (ß, -1.973; 95% CI, -2.313 to -1.632; P < 0.001) only. CONCLUSIONS: Patients with IBD had impaired SQoL compared with healthy controls. Age, widow status, and depression were independent predictors of SQoL in men with IBD, whereas in women depression was the only independent predictor. Emotional and self-esteem issues were the main concerns reported by IBD patients regarding sexual health.

Soluble human Suppression of Tumorigenicity 2 is associated with endoscopic activity in patients with moderate-to-severe ulcerative colitis treated with golimumab.

BACKGROUND: Suppressor of Tumorigenicity 2 (ST2) is an IL33 receptor detected in the mucosa and serum of ulcerative colitis (UC) patients. We evaluated soluble ST2 (sST2) as a surrogate biomarker of disease outcome and therapeutic response, in moderate-to-severe UC patients treated with golimumab. METHODS: We conducted an open-label single-arm multicentre prospective study. At screening/baseline, week 6 (W6) and week 16 (W16), clinical and endoscopic activity (total Mayo score), histologic activity (Geboes index) and biomarkers were evaluated. RESULTS: From 38 patients, 34 (89.5%) completed W6 and 29 (76.3%) completed W16. Mean age (±SD) was 34.6 ± 12.6 years; 55.9% were female. At W16, 62.1% achieved clinical response. Patients with endoscopic activity at W6 (n = 20) had higher baseline sST2 (median, 24.5 versus 18.7 ng/ml, p = 0.026) and no decrease from baseline (median change, 0.8 versus -2.7, p = 0.029). At W6, sST2 levels correlated with endoscopic activity (rs = 0.45, p = 0.007) but not with histological activity (rs = 0.25, p = 0.151). The best cut-offs for endoscopic activity were sST2 = 16.9 ng/ml (sensitivity = 85%; specificity = 71%) and faecal calprotectin (FC) = 353 µg/g (sensitivity = 90%, specificity = 67%). Patients with histological activity at W6 (n = 27) had higher baseline ST2 levels (median, 23.0 versus 13.7 ng/ml, p = 0.035). sST2 did not correlate with FC or serum C-reactive protein. FC levels correlated with histological activity and baseline FC were higher when Geboes ⩾3.1 at W6. CONCLUSIONS: sST2 may be a surrogate biomarker of UC activity and therapeutic response as it correlates with endoscopic and clinical activity at W6 of golimumab treatment, and subjects with endoscopic and histological activity at W6 had higher baseline ST2 levels.

Accuracy of Faecal Calprotectin and Neutrophil Gelatinase B-associated Lipocalin in Evaluating Subclinical Inflammation in UlceRaTIVE Colitis-the ACERTIVE study.

BACKGROUND AND AIMS: Mucosal healing and histological remission are different targets for patients with ulcerative colitis, but both rely on an invasive endoscopic procedure. This study aimed to assess faecal calprotectin and neutrophil gelatinase B-associated lipocalin as biomarkers for disease activity in asymptomatic ulcerative colitis patients. METHODS: This was a multicentric cross-sectional study including 371 patients, who were classified according to their endoscopic and histological scores. These results were evaluated alongside the faecal levels of both biomarkers. RESULTS: Macroscopic lesions [i.e. endoscopic Mayo score ≥1] were present in 28% of the patients, and 9% had active disease according to fht Ulcerative Colitis Endoscopic Index of Severity. Moreover, 21% presented with histological inflammation according to the Geboes index, whereas 15% and 5% presented with focal and diffuse basal plasmacytosis, respectively. The faecal levels of calprotectin and neutrophil gelatinase B-associated lipocalin were statistically higher for patients with endoscopic lesions and histological activity. A receiver operating characteristic-based analysis revealed that both biomarkers were able to indicate mucosal healing and histological remission with an acceptable probability, and cut-off levels of 150-250 µg/g for faecal calprotectin and 12 µg/g for neutrophil gelatinase B-associated lipocalin were proposed. CONCLUSIONS: Faecal calprotectin and neutrophil gelatinase B-associated lipocalin levels are a valuable addition for assessment of disease activity in asymptomatic ulcerative colitis patients. Biological levels of the analysed biomarkers below the proposed thresholds can rule out the presence of macroscopic and microscopic lesions with a probability of 75-93%. However, caution should be applied whenever interpreting positive results, as these biomarkers present consistently low positive predictive values.

Detection of anti-infliximab antibodies is impacted by antibody titer, infliximab level and IgG4 antibodies: a systematic comparison of three different assays.

BACKGROUND: There is scant information on the accuracy of different assays used to measure anti-infliximab antibodies (ADAs), especially in the presence of detectable infliximab (IFX). We thus aimed to evaluate and compare three different assays for the detection of IFX and ADAs and to clarify the impact of the presence of circulating IFX on the accuracy of the ADA assays. METHODS: Blood samples from 79 ulcerative colitis (UC) patients treated with infliximab were assessed for IFX levels and ADAs using three different assays: an in-house assay and two commercial kits, Immundiagnostik and Theradiag. Sera samples with ADAs and undetectable levels of IFX were spiked with exogenous IFX and analyzed for ADAs. RESULTS: The three assays showed 81-96% agreement for the measured IFX level. However, the in-house assay and Immundiagnostik assays detected ADAs in 34 out of 79 samples, whereas Theradiag only detected ADAs in 24 samples. Samples negative for ADAs with Theradiag, but ADA-positive in both the in-house and Immundiagnostik assays, were positive for IFX or IgG4 ADAs. In spiking experiments, a low concentration of exogenous IFX (5 µg/ml) hampered ADA detection with Theradiag in sera samples with ADA levels of between 3 and 10 µg/ml. In the Immundiagnostik assay detection interference was only observed at concentrations of exogenous IFX higher than 30 µg/ml. However, in samples with high levels of ADAs (>25 µg/ml) interference was only observed at IFX concentrations higher than 100 µg/ml in all three assays. Binary (IFX/ADA) stratification of the results showed that IFX+/ADA- and IFX-/ADAs+ were less influenced by the assay results than the double-positive (IFX+/ADAs+) and double-negative (IFX-/ADAs-) combination. CONCLUSIONS: All three methodologies are equally suitable for measuring IFX levels. However, erroneous therapeutic decisions may occur when patients show double-negative (IFX-/ADAs-) or double-positive (IFX+/ADAs+) status, since agreement between assays is significantly lower in these circumstances.