Casteele, Niels Vande

Aims Accurate determination of histological activity in ulcerative colitis (UC) is essential given its diagnostic and prognostic importance. Data on the relationship between histology and immune cell markers are limited. We aimed to evaluate the association between histological disease activity and immune cell marker concentration in colonic biopsies from patients with UC. Methods Sigmoid colon biopsies from 20 patients with UC were retrospectively assessed using the Robarts Histopathology Index (RHI). Targeted mass spectrometry determined the concentration of 18 immune cell markers (cluster of differentiation (CD) 4, CD8, CD19, CD20, CD40, CD56, CD68, CD103, forkhead box p3 (FOXP3), human leucocyte antigen, DR alpha chain (HLA-DRA), interleukin 10 (IL-10), IL-23 subunit alpha (IL-23A), IL-23 receptor (IL-23R), IL-2 receptor alpha chain (IL-2RA), Ki67, lymphocyte-activation gene 3 (LAG-3), programmed cell death protein 1 (PD-1) and PD ligand 1 (PD-L1)). The association between RHI score and immune cell marker concentration was quantified using Spearman’s rank correlation coefficient (ρ) and related 95% CIs. Results Fourteen of the 18 immune cell marker proteins were detected, with tissue concentration ranging from 0.003 to 11.53 fmol/µg. The overall RHI score was positively correlated with CD19, CD20, CD40, FOXP3, LAG-3, PD-1 and PD-L1 concentration (ρ=0.596–0.799) and negatively correlated with CD56 concentration (ρ=−0.460). There was no significant association between RHI score and CD4, CD8, CD68, CD103, HLA-DRA or Ki67 concentration. Conclusions This study provides insight into the correlation between immune cell marker expression and histological disease activity and the possible molecular and immunological determinants underlying microscopic disease activity in UC.

SummaryBackgroundThe optimal ulcerative colitis biopsy protocol is unclear.AimTo evaluate the number of biopsies required to accurately assess microscopic disease activity in ulcerative colitisMethodsBiopsies from patients with ≥4 rectosigmoid samples, and clinical and endoscopic data, were retrospectively obtained from a prospective biobank. Histology and endoscopic videos were read blindly. A 4‐biopsy Robarts Histopathology Index (RHI) reference score, consisting of the worst item‐level ratings from four biopsies, was compared to 1‐, 2‐ and 3‐biopsy estimates. Agreement was determined using bivariate errors‐in‐variable regression analysis (acceptance interval: ±8.25). Endoscopic activity and disease location subgroup analyses were also performed.ResultsForty‐six patients had ≥4 rectosigmoid biopsies available (N = 287). The 2‐biopsy (tolerance interval: −7.66, 4.79) and 3‐biopsy (tolerance interval: −4.86, 3.46) RHI scores demonstrated acceptable agreement with 4‐biopsy scores. One‐biopsy scores demonstrated unacceptable agreement (tolerance interval: −13.99, 7.78). Mean RHI scores using the 2‐, 3‐ and 4‐biopsy approaches were similar (6.1 ± 9.6 P = 0.36; 6.8 ± 10.5, P = 0.7; 7.5 ± 11.2), whereas the 1‐biopsy estimate was lower (4.4 ± 8.1, P = 0.06). Histological remission rates were identical for the 2‐, 3‐ and 4‐biopsy methods (65.2%, P = 1.0). Subgroup analysis demonstrated that three biopsies were required in patients with endoscopically active disease. Sampling additional colonic locations yielded lower histological remission rates compared to rectosigmoid sampling alone (33.3% vs 61.9%, P = 0.1).ConclusionsA minimum of two — conservatively, three — biopsies are required to reliably assess disease activity in a single colonic segment using the RHI. Further studies are needed of endoscopically active patients and sampling locations. These results have implications for biopsy strategies in clinical trials and practice.

Abstract Background The operating properties of histologic indices are poorly characterized in Crohn’s disease (CD) and no validated index exists. We assessed the reliability and responsiveness of histologic indices/items, developed an exploratory index, and compared different methods of scoring. Methods Using baseline and week 12 histologic image sets from the EXTEND placebo-controlled trial, blinded central readers scored 4 histologic indices (the Global Histologic Activity Score [GHAS], Geboes Score [GS], Robarts Histopathology Index [RHI], and Nancy Index [NHI]) and 3 additional novel items identified by an expert panel (mucin depletion, basal plasmacytosis, and pyloric gland metaplasia in the ileum). Reliability and responsiveness were evaluated for a global score (4 colonic segments + ileum), colonic score (4 colonic segments) and ileal score (ileum only) using the intraclass correlation coefficient (ICC) and area under the receiver operating curve (AUC), respectively. Change was defined using treatment assignment and improvement in histologic disease activity as measured on a 100-mm visual analogue scale (VAS) in responsiveness testing. Exploratory indices were developed using backward stepwise linear regression analysis. Candidate independent variables were items with an ICC ≥0.4 and AUC ≥0.56. The VAS served as the dependent variable. Results Paired histologic images were analysed from 55 subjects. Inter-rater reliability was substantial to almost perfect (ICC=0.73-0.85) and responsiveness was small to large (treatment assignment AUC=0.50-0.65; VAS AUC=0.71-0.94). The GHAS, GS, RHI, and NHI reached the minimum threshold for reliability (ICC ≥0.4) and responsiveness (AUC ≥0.56) regardless of whether the global and colonic scores were calculated using the worst affected segment, average of the included segments, or sum of the included segments (Table 1-3). Five items were tested as candidate predictors. Three exploratory indices were developed, each consisting of 3 items: a global index (neutrophils in the lamina propria, neutrophils in the epithelium, and erosion/ulceration), colonic index (chronic inflammatory infiltrate, neutrophils in the lamina propria, and erosion/ulceration) and ileal index (chronic inflammatory infiltrate, neutrophils in the epithelium, and erosion/ulceration). The novel indices highly correlated with the GHAS, GS, RHI, and NHI, with correlation coefficients ≥0.80 (Table 4). Conclusion The 4 existing indices were similarly reliable and responsive in measuring CD histologic activity, regardless of the method for calculating global and colonic scores and could be used in clinical trials. Attempts at novel index development did not offer benefit over current histologic indices.

The T-lymphocyte–mediated inflammation in Crohn's disease can be assessed by quantifying CD3-positive T-lymphocyte counts in colonic sections. We developed and validated a process to reliably quantify immunohistochemical marker-positive cells in a high-throughput setting using whole slide images (WSIs) of CD3-immunostained colonic and ileal tissue sections. In regions of interest (ROIs) and/or whole tissue sections of 40 WSIs from 36 patients with Crohn's disease, CD3-positive cells were quantified by an expert gastrointestinal pathologist (gold standard) and by image analysis algorithms developed with software from 3 independent vendors. Semiautomated quantification of CD3-positive cell counts estimated in 1 ROI per section were accurate when compared with manual analysis (Pearson correlation coefficient, 0.877 to 0.925). Biological variability was acceptable in digitally determined CD3-positive cell measures between 2 to 5 ROIs annotated on the same tissue section (coefficient of variation <25%). Results from computer-aided analysis of CD3-positive T lymphocytes in a whole tissue section and the average of results from 2 to 5 ROIs per tissue section lacked reliability (overestimation or underestimation and systematic bias), suggesting that absolute quantification of CD3-positive T lymphocytes in a whole tissue section may be more accurate. Semiautomated image analysis in WSIs demonstrated reproducible CD3-positive cell measures across 3 independent algorithms. A computer-aided digital image analysis method was developed and validated to quantify CD3-positive T lymphocytes in colonic and ileal biopsy sections from patients with Crohn's disease. Results support consideration of this digital analysis method for use in future Crohn's disease clinical studies.

Abstract Background Eosinophils have been implicated in the pathogenesis of ulcerative colitis and have been associated with disease course and therapeutic response. However, associations between eosinophil density, histologic activity, and clinical features have not been rigorously studied. Methods A deep learning algorithm was trained to identify eosinophils in colonic biopsies and validated against pathologists’ interpretations. The algorithm was applied to sigmoid colon biopsies from a cross-sectional cohort of 88 ulcerative colitis patients with histologically active disease as measured by the Geboes score and Robarts histopathology index (RHI). Associations between eosinophil density, histologic activity, and clinical features were determined. Results The eosinophil deep learning algorithm demonstrated almost perfect agreement with manual eosinophil counts determined by 4 pathologists (interclass correlation coefficients: 0.805–0.917). Eosinophil density varied widely across patients (median 113.5 cells per mm2, interquartile range 108.9). There was no association between eosinophil density and RHI (P = 0.5). Significant differences in eosinophil density were seen between patients with Montreal E3 vs E2 disease (146.2 cells per mm2 vs 88.2 cells per mm2, P = 0.005). Patients on corticosteroids had significantly lower eosinophil density (62.9 cells per mm2 vs 124.1 cells per mm2, P = 0.006). No association between eosinophil density and biologic use was observed (P = 0.5). Conclusions We developed a deep learning algorithm to quantify eosinophils in colonic biopsies. Eosinophil density did not correlate with histologic activity but did correlate with disease extent and corticosteroid use. Future studies applying this algorithm in larger cohorts with longitudinal follow-up are needed to further elucidate the role of eosinophils in ulcerative colitis.

INTRODUCTION: We applied the Grading of Recommendations, Assessment, Development, and Evaluation framework to evaluate the performance of fecal calprotectin (FC) as an alternative to endoscopy in patients with moderate-to-severe ulcerative colitis (UC) treated with a biologic agent or tofacitinib. METHODS: Individual participant data from the trials of infliximab, golimumab, vedolizumab, and tofacitinib for UC were pooled to generate prevalence of endoscopic activity (Mayo endoscopy score) across different combinations of the rectal bleeding score (RBS) and stool frequency score (SFS). These estimates were then combined with the data from an updated systematic review of the operating properties of FC to generate clinical scenario–specific assessments of the performance of FC as a predictor of endoscopic disease activity. A prespecified threshold of acceptability for false-negative (FN) and false-positive (FP) test results was set at 5%. RESULTS: For patients with UC achieving RBS 0 + SFS 0/1, FC ≤ 50 μg/g may avoid endoscopy in 50% patients with a FN rate <5%. Similarly, for patients with RBS 2/3 + SFS 2/3, FC ≥ 250 μg/g potentially avoids endoscopy in approximately 50% patients with an FP rate <5%. The greatest uncertainty in the diagnostic performance for FC was observed in patients with UC achieving RBS 0 but having SFS 2/3, where FN and FP rates were consistently >10%, and endoscopic evaluation may be warranted. DISCUSSION: Two clinical scenarios were identified where FC can be used with confidence for monitoring treatment response to biologics or tofacitinib in patients with UC without the requirement for endoscopy.

SummaryBackgroundThe appropriate location for biopsy procurement relative to an ulcer in active Crohn's disease is unknown.AimTo explore the relationship between biopsy location, histological disease activity, proinflammatory gene expression and the presence of inflammatory cells.MethodsFifty‐one patients with Crohn's disease and ulcers >0.5 cm diameter in the colon and/or ileum were prospectively enrolled at three centres. Biopsies were obtained from 0 mm, 7 to 8 mm and 21 to 24 mm from the edge of the largest ulcer. Histological activity was blindly assessed with the Global Histological Disease Activity Score, the Robarts Histopathology and Nancy Histological indices. Messenger ribonucleic acid (mRNA) levels for interleukins‐6, ‐8 and ‐23 (p19 and p40 subunits), CD31 and S100A9 were measured using quantitative polymerase chain reaction. The number of CD3+, CD68+ and myeloperoxidase‐positive cells was quantified by immunohistochemistry. Data were analysed using mixed models with location and segment as fixed effects and patients as random effect to account for correlation among segments within a patient.ResultsHistological disease activity scores (P < 0.0001), proinflammatory gene expression levels (P < 0.005) and numbers of myeloperoxidase‐positive cells (P < 0.0001) were highest in biopsies from the ulcer edge in the colon and ileum, with decreasing gradients observed with distance from the edge (P < 0.05). No differences between colonic and ileal samples were detected for the parameters measured at any location.ConclusionsBiopsies from the ulcer edge in patients with Crohn's disease yielded the greatest histological disease activity and mRNA levels and had similar readouts in the colon and ileum. Research is needed to confirm this conclusion for other measures.

OBJECTIVES: Histologic remission is a potentially valuable means of assessing disease activity and treatment response in ulcerative colitis (UC). However, the efficacy of existing therapies to achieve this outcome is unclear. We performed a systematic review and meta-analysis of histologic outcomes in UC randomized controlled trials and examined the relationship between histologic and endoscopic outcomes. METHODS: MEDLINE, EMBASE, CENTRAL, and the Cochrane IBD Register were searched for randomized controlled trials of aminosalicylates, corticosteroids, immunosuppressives, biologics, and small molecules. Histologic and endoscopic remission and response data were independently extracted and pooled using binomial–normal random-effect or fixed-effect models. Pooled efficacy estimates were calculated as risk ratios (RRs) using the Mantel–Haenszel method. Univariable and multivariable random-effect meta-regression models examined factors associated with histologic remission. RESULTS: Seventy-four studies (68 induction and 7 maintenance) were identified. Topical aminosalicylate enemas [37.2%, 95% confidence interval (CI), 29.0–46.3] and suppositories (44.9%, 95% CI, 28.9–62.3) had the highest induction of histologic remission rates. Aminosalicylate enemas (RR = 4.14, 95% CI, 2.35–7.31), aminosalicylate suppositories (RR = 3.94, 95% CI, 1.26–12.32), and budesonide multimatrix (RR = 1.47, 95% CI 1.08–1.99) had higher histologic remission rates than placebo. Data were lacking for biologics and immunosuppressives. The pooled histologic remission rate for placebo in induction studies was 10.4% (95% CI, 7.1–15.2). Histologic and endoscopic remission correlated strongly ( r = 0.66; 95% CI, 0.50–0.78). In multivariate analysis of placebo-arm data, less severe clinical disease activity and corticosteroid use were associated with higher histologic remission rates. Similarly, mild clinical disease activity was associated with higher histologic remission rates when active-arm data were analyzed. CONCLUSIONS: Histologic remission rates for current UC treatments ranged from 15.0% to 44.9% according to drug class and patient population with the highest rates observed for topical aminosalicylates. Placebo remission rates were low with relatively narrow CIs. These data provide benchmarks to inform future trial design. Histologic remission is a potential treatment target in clinical practice.