Inflammatory Bowel Disease (IBD) is characterised by chronic intestinal inflammation developing in genetically susceptible subjects in association with a dysregulated immune response, intestinal dysbiosis and environmental triggers. IBD is most often polygenic, involving more than 200 risk loci that include over 300 genes identified through genome-wide association studies. Approximately 25% of incident cases of IBD occur during childhood. Among these cases, diagnosis is most commonly made during adolescence, while in about 15% the diagnosis is established prior to six years of age, with up to 6% diagnosed before three years of age. IBD in this subgroup of patients is referred to as “very early onset IBD” (VEO-IBD) and shows significant differences from IBD in older children and in adults. VEO-IBD cases usually present with more severe clinical disease unresponsive to conventional IBD therapy and a greater proportion of cases feature underlying monogenic defects, often involving genes associated with primary immunodeficiencies (PID).

Histological scoring systems have been developed to standardise the assessment of microscopic inflammation, offering insights into disease severity, activity, prognosis and response to therapy. There is growing interest in the assessment of histological disease activity based on the concept that histological healing is associated with better clinical outcomes and may be the ultimate therapeutic goal, particularly in Ulcerative Colitis (UC) [1].

The last decade has seen a dramatic increase in drugs available for the treatment of IBD. However, each of these novel biologics or small molecules achieves disease remission in only a relatively small proportion of patients [1].To date, implementation in clinical practice of evidence that assists in better evaluating the chance of therapy success in a particular patient for a particular drug is limited. Therefore, when choosing a drug for a patient with IBD who is starting therapy or needs to switch drugs, a trial-and-error approach may be unavoidable.

To address this unmet clinical need, several research groups have now turned their attention to biomarker discovery to allow development of an evidence-based personalised treatment strategy [2]. At this year’s Congress of ECCO in Stockholm, I had the opportunity to provide an update on the field of biomarker discovery from the perspective of a pathologist. In this issue of ECCO News, I want  to share with you the most important points from that H-ECCO Masterclass talk.

The theme of the 19^th ECCO Congress in Stockholm, “Crossing borders in IBD”, was reflected in the aim of our educational meeting, which extended beyond the histopathological aspects of IBD. The objective was to highlight the collaboration between different specialisations, mirroring the multidisciplinary nature of our daily practice.  This was clearly evident in the various topics covered during our initial session. Additionally, the Congress theme resonated in the diverse composition of our audience. Feedback revealed an equal division between pathologists and specialists from other fields. 

Fibrosis and other connective tissue abnormalities are common in IBD, especially in Crohn’s Disease. The main clinical consequence is strictures, occurring most often in the small bowel or at the ileocaecal/ileocolic junction. Surgery may be necessary for stricture management.

Very Early Onset Inflammatory Bowel Disease (VEO-IBD) is a complex subset of IBD that uniquely affects children under six years of age [1]. This category includes neonatal onset (within the first month of life), infantile onset (before two years) and early childhood onset (between two and six years) [2]. In comparison with patients with older onset IBD, those with VEO-IBD demonstrate a more heterogeneous phenotype and the aetiology is more closely related (in approximately 25%–30% of cases) to monogenic or digenic defects involving genes associated with primary immunodeficiency [3]. Moreover, VEO-IBD patients show higher rates of positive family history, a more aggressive clinical trajectory and increased resistance to conventional therapies effective in managing IBD among older patients [4].

At the 18^th Congress of ECCO in Copenhagen in 2023, many exciting projects on artificial intelligence (AI) were presented. Most of these projects focused on the role of AI in endoscopy. As a pathologist, I asked myself the following question: What about the role of AI in the histological evaluation of IBD?

The pathologist plays an important role in establishing the diagnosis and in assessing therapy response. Given that in many parts of the world IBD prevalence is still rising and histological remission may soon become a treatment target, the workload for pathologists is expected to increase. Therefore, as it promises to guide and thereby reduce time spent on biopsy assessment, AI is an interesting tool for pathologists. Moreover, it may aid the mission of H-ECCO to “raise standards of IBD pathology reporting” by mitigating problems associated with inter-observer variability.

After two years of virtual meetings, the main goal of the 18^th ECCO Congress, held in Copenhagen (March 1–4, 2023), was “Let’s get physical”. During this conference we enjoyed the face-to-face interaction, which provided a positive boost to the 8^th H-ECCO Masterclass. The aim of our meeting was not only to discuss the histopathological aspects of Inflammatory Bowel Disease but also to demonstrate the interaction between the different specialisms, which reflects the multidisciplinary collaboration in our daily practice.

Gert de Hertogh © ECCO

The 15^th Congress of ECCO was held in Vienna, Austria between February 12 and 15, 2020. During this meeting, it was decided that I would take over from Roger Feakins as second Chair of the H(istology)-ECCO Committee. The committee was at that time one of the most recently established. Its primary aim is to expand the knowledge of IBD histopathology by organising a yearly masterclass. However, the framework of ECCO also offers many other opportunities to support clinical decision-making, by linking with the other committees and by participation in the composition of ECCO Practice Guidelines, Position Statements and Topical Reviews.

Gert de Hertogh © ECCO

The past 6 months of 2022 have seen the publication of two important papers, one by F. Magro et al. (“The ECCO position on harmonisation of Crohn’s disease mucosal histopathology” [1]) and the other by I.O. Gordon et al. (“International consensus to standardise histopathological scoring for small bowel strictures in Crohn’s disease” [2]).