Histologic mucosal healing (HMH) has emerged as a crucial target in managing inflammatory bowel disease, complementing the established goal of endoscopic mucosal healing. This review evaluates the significance of HMH in both Crohn's disease (CD) and ulcerative colitis (UC). In UC, strong evidence shows that HMH correlates with improved long-term outcomes, including reduced hospitalization rates, and decreased need for corticosteroids and colectomy. Histologic healing is increasingly being incorporated as an endpoint in RCTs. Small-molecule therapies, such as S1P modulators and Jak inhibitors, have demonstrated particular efficacy in achieving HMH in UC. Real-world evidence (RWE) further supports HMH's utility as a predictive marker for favorable clinical outcomes in UC. In CD, however, HMH's role is less clear, given challenges in assessing and standardizing histologic healing. RCTs, such as SERENITY and VIVID, show that advanced therapies can achieve HMH in CD, though inconsistent histologic scoring and remission criteria complicate conclusions. Some studies suggest that histologic remission at induction may predict sustained remission, but real-world data offer mixed results regarding its prognostic value. This review provides an overview of current literature, emphasizing the need for standardized histologic assessment and extended studies, particularly for CD, while affirming HMH's growing importance in achieving deeper remission in UC.

Identifying reliable prognostic factors for pediatric-onset Crohn's disease (CD) is important for guiding early treatment. This study aimed to evaluate the validity of various clinical parameters for predicting long-term intestinal complications in pediatric-onset CD patients with CD in Taiwan.

This was a single-center, retrospective study. Patients diagnosed with CD under 18 years of age at our hospital between January 1999 and December 2021 were enrolled. The baseline clinical variables and the Pediatric Crohn's Disease Activity Index (PCDAI) were obtained. Patients were categorized into low-, medium-, or high-risk groups based on the 2020 European Crohn's and Colitis Organization and European Society for Pediatric Gastroenterology Hepatology and Nutrition (ECCO-ESPGHAN) guidelines. The primary endpoint was the occurrence of new intestinal complications.

Among 53 enrolled patients (33 males and 20 females), 8 patients (33.96%) developed intestinal complications during the follow-up period (median 6.42 years, 3.17-9.75 years). Patients in the initial ECCO-ESPGHAN medium- or high-risk group had a 4.71-fold higher risk of intestinal complications than those in the low-risk group [hazard ratio = 4.71, p = 0.023] after adjusting for PCDAI in the multivariate Cox proportional hazard analysis. The other clinical variables did not reach statistical significance in predicting intestinal complications. The positive and negative predictive values of the ECCO-ESPGHAN stratification method for intestinal complications were 48.15% and 80.77%, respectively.

ECCO-ESPGHAN risk stratification is an effective early predictor of long-term intestinal complications in the Taiwanese population and may be used in clinical practice to guide early advanced therapy.

Crohn's disease is a chronic inflammatory bowel disease that affects the ileum and/or large intestine. At the same time, it can also affect any other part of the human body, i.e., from the mouth to the anus. In Crohn's disease, the physiology and functioning of the epithelial barrier are inhibited due to the correlation of various factors, such as the environment, genetic susceptibility or intestinal microbiota. The symptoms are very troublesome and cause a significant reduction in quality of life, sometimes occurring with paralyzing permanent damage to the digestive tract, requiring enteral or parenteral nutrition throughout life. In order to make a proper and accurate diagnosis, an appropriately selected diagnostic path in a given clinical entity is necessary. Standard diagnostic methods are: laboratory examination, histopathological examination, endoscopic examination, X-ray, computed tomography, ultrasound examination and magnetic resonance imaging. Medical biology and the analysis of metalloproteinases have also proved helpful in diagnosing changes occurring as a result of Crohn's disease. Here we provide a thorough review of the latest reports on Crohn's disease and its genetic conditions, symptoms, morphology, diagnosis (including the analysis of Crohn's disease biomarkers, i.e., metalloproteinases) and treatment.

Inflammatory bowel diseases (IBD) are systemic immune-mediated conditions with predilection for the gastrointestinal tract and include Crohn's disease and ulcerative colitis. Despite the advances in the fields of basic and applied research, the etiopathogenesis remains largely unknown. As a result, only one third of the patients achieve endoscopic remission. A substantial portion of the patients also develop severe clinical complications or neoplasia. The need for novel biomarkers that can enhance diagnostic accuracy, more precisely reflect disease activity, and predict a complicated disease course, thus, remains high. Genomic and transcriptomic studies contributed substantially to our understanding of the immunopathological pathways involved in disease initiation and progression. However, eventual genomic alterations do not necessarily translate into the final clinical picture. Proteomics may represent a missing link between the genome, transcriptome, and phenotypical presentation of the disease. Based on the analysis of a large spectrum of proteins in tissues, it seems to be a promising method for the identification of new biomarkers. This systematic search and review summarize the current state of proteomics in human IBD. It comments on the utility of proteomics in research, describes the basic proteomic techniques, and provides an up-to-date overview of available studies in both adult and pediatric IBD.

Detection of possible predictive factors of endoscopic recurrence after ileocecal resection in Crohn's disease could be very beneficial for the individual adjustment of postoperative therapy. The aim of this study was to verify, whether immunohistochemical detection of calprotectin in resection margins is useful in diagnostics of endoscopic recurrence.

In this study we included pediatric patients with Crohn's disease who underwent ileocecal resection, regardless of pre-operative or post-operative therapy (n=48). We collected laboratory, clinical, surgical, endoscopic and histopathological data at the time of surgery and at 6 months after surgery. The immunohistochemical staining of calprotectin antigen was performed on all paraffin blocks from the resection margins.

Out of 48 patients 52% had endoscopic recurrence in the anastomosis (defined by Rutgeerts score) within 6 months after surgery. The number of cells positive for calprotectin in the proximal resection margin was negatively associated with recurrence (P=0.008), as was the elevated level of total calprotectin (from both resection margins). There was no correlation of calprotectin in distal resection margin and endoscopic recurrence. Fecal calprotectin over 100 ug/g (P=0.0005) and high CRP (P<0.001) at 6 months after ileocecal resection and peritonitis (P=0.048) were associated with endoscopic recurrence.

Approximately half of the patients developed endoscopic recurrence within 6 months after ileocecal resection. The predictive value of tissue calprotectin is questionable, as it is negatively associated with endoscopic recurrence. There are other potentially useful predictors, such as CRP and fecal calprotectin at 6 months after resection and the presence of peritonitis.

A better understanding of prognostic factors within the heterogeneous spectrum of pediatric Crohn's disease (CD) should improve patient management and reduce complications. We aimed to identify evidence-based predictors of outcomes with the goal of optimizing individual patient management.

A survey of 202 experts in pediatric CD identified and prioritized adverse outcomes to be avoided. A systematic review of the literature with meta-analysis, when possible, was performed to identify clinical studies that investigated predictors of these outcomes. Multiple national and international face-to-face meetings were held to draft consensus statements based on the published evidence.

Consensus was reached on 27 statements regarding prognostic factors for surgery, complications, chronically active pediatric CD, and hospitalization. Prognostic factors for surgery included CD diagnosis during adolescence, growth impairment, NOD2/CARD15 polymorphisms, disease behavior, and positive anti-Saccharomyces cerevisiae antibody status. Isolated colonic disease was associated with fewer surgeries. Older age at presentation, small bowel disease, serology (anti-Saccharomyces cerevisiae antibody, antiflagellin, and OmpC), NOD2/CARD15 polymorphisms, perianal disease, and ethnicity were risk factors for penetrating (B3) and/or stenotic disease (B2). Male sex, young age at onset, small bowel disease, more active disease, and diagnostic delay may be associated with growth impairment. Malnutrition and higher disease activity were associated with reduced bone density.

These evidence-based consensus statements offer insight into predictors of poor outcomes in pediatric CD and are valuable when developing treatment algorithms and planning future studies. Targeted longitudinal studies are needed to further characterize prognostic factors in pediatric CD and to evaluate the impact of treatment algorithms tailored to individual patient risk.

Diagnosis of pediatric inflammatory bowel diseases (IBD) remains challenging. We aimed at the value of immunohistochemical assessment of CD30+ lymphocytes in the intestinal mucosa in differential diagnosis between pediatric Crohn's disease (CD) and ulcerative colitis (UC) and its utility as a predictor of future differentiation in patients with IBD unclassified (IBDU).

Seventy-four treatment naive pediatric patients with IBD (33 CD, 30 UC and 11 IBDU) were enrolled into the study. Biopsy samples from six different regions (terminal ileum, cecum, ascending colon, transverse colon, descending colon and rectum) were immunohistochemically stained with anti-CD30 antibody, and the number of positive cells per one high power field was quantified.

Significant differences between CD and UC were found when compared total counts of CD30+ cells in median numbers, mean values and maximal numbers and also for separate counts in terminal ileum, transverse colon, descending colon and rectum. The most profound difference between CD and UC was shown for total median values of CD30+ cells and for the values in rectal localization. The difference was independent on the intensity of inflammation. A cutoff value of 2.5 CD30+ cells with sensitivity 83% and specificity 90% was found for the rectum. There was no difference between patients with CD and IBDU, but a marked difference between UC and IBDU patients was revealed.

Histopathological assessment of biopsy with rectal CD30+ count is reliable and simple method that could help in differential diagnosis among IBD subtypes in children with IBD.

In adults, infliximab (IFX) levels correlate with disease activity, and antibodies to IFX (ATIs) predict treatment failure. We aimed to determine the association of IFX levels and ATIs with disease activity in a paediatric population. We prospectively collected blood, stool, and clinical data from 65 patients (age 10.5-15.1 years) with Crohn's disease (CD) before IFX administration, and measured IFX trough levels, ATIs, and faecal calprotectin levels (CPT). Samples were collected during maintenance therapy. We used multivariate analysis to identify the predictors of IFX levels.

Lower levels of IFX were associated with ATIs positivity (OR 0.027, 95% CI 0.009-0.077). Higher C-reactive protein (CRP) level, erythrocyte sedimentation rate, and CPT levels were found in patients with lower IFX levels. The optimal combination of sensitivity (0.5) and specificity (0.74) for disease activity was calculated for IFX levels ≥1.1 µg/mL using CRP level <5 mg/L as a marker of laboratory remission. In a model that used CPT ≤100 µg/g as the definition of remission, the optimal IFX trough level was 3.5 µg/mL. No independent association between remission and ATIs was found in our study population. However, we found an independentz association between IFX levels and serum albumin levels (OR 1.364, 95% CI 1.169-1.593), p < 0.001. Key Messages: The paediatric population was similar to adult populations in terms of the association between IFX and ATIs as well as between IFX and disease activity.