Inflammatory bowel disease (IBD) is one of the most currently investigated human disorders. IBD is a prototypical complex disease, characterized by heterogeneous and chronic manifestations, induced by interacting genomic, environmental, microbial, and immunological factors. Expansion of IBD knowledge has helped in developing new therapies to counteract intestinal inflammation with a significant success degree. Despite this progress, much more remains to be done regarding gaining a complete interpretation of IBD pathogenesis, identifying inflammation before its clinical manifestation, implementing lifestyle modifications, and developing agents that can modify the disease course. One of the limitations to achieve these goals is the lack of an integrated vision of the mentioned major constituents of IBD pathogenesis, more appropriately defined by the terms ‘genome’, ‘exposome’, ‘microbiome’, and ‘immunome’.

Regarding inflammation, the investigation of IBD pathogenesis had almost exclusively centred on the study of pro-inflammatory immune-mediated events. To understand the mechanisms of tissue damage, the investigation of immune responses to IBD has to be evaluated in the context of exposome- and microbiome-derived effects. To date, indeed, none of these ‘omes’ are apparently capable of causing IBD in isolation, but it is hypothesized that a “network effect”, in which dysregulation of individual –omes causes gut inflammation mediated by dysfunctional molecular modules, could be implicated in the disease development. The outcome of this effect is the ‘IBD interactome’ or more appropriately the ‘IBD integrome’. To define the IBD interactome, new concepts and tools are needed to implement a systematic approach; an unbiased data-driven integration strategy that reveals key players in the system, pinpoints the central drivers of inflammation and enables the development of targeted therapies.

Powerful bioinformatics tools are available to explore and take advantage of the massive amount of information that can be generated by the analysis of the various “omes” and their intricate interactions, aiming to identify the molecular interactome and contribute to build a comprehensive molecular IBD map. This novel approach could enable the identification of IBD molecular subtypes, correlations with clinical phenotypes, and elucidation of the central hubs of the IBD interactome, allowing the development of personalized medicine with effective therapies to individual patients.

This Special Issue therefore aims to collect original research and review articles concerning new insights into the immunome in IBD.

Potential topics include but are not limited to the following:

• Investigation of immunome in IBD in the context of exposome- and microbiome-derived effects
• Breakthroughs in the current understanding of the role of ‘omics’ in IBD pathogenesis and prognosis
• The prospect of 'IBD interactome' in personalized medicine