Mast cells, food allergies and inflammatory bowel disease: a possible link to neoplasia

Abstract

Relationships between food allergy and IBD are still to be discussed, persistent or repetitive exposure to allergens may result in chronic inflammatory status. In return, IgE-mediated food allergy is more frequent in patients having IBD, especially in children with ulcerative colitis. Concurrently, rats previously sensitised to precise antigen and exposed to audio-visual stress had excessive mast cell concentration and activity in small and large intestines. Besides, permanent stimulation of immune system through altered intestinal permeability to antigen passage would then result in larger formation and release of immunoglobulins and inflammatory mediators, enhancing the risks of developing hypersensitivity responses. Furthermore, mast cells are recruited and activated in both food allergic response and IBD. Aside from inducing tissue injury, chronic inflammation like seen in the case of food allergy and IBD, would favour mast cell mobilization as well as carcinogenesis. Here, mast cells and certain of their inflammatory mediators such as vascular endothelial growth factors and interleukins act on both angiogenesis and mast cell attraction necessary for tumour expansion and propagation. For instance dogs suffering from IBD may be predisposed to lymphosarcoma similarly to human Crohn’s disease and/or ulcerative colitis. On the other hand, allergooncology focused on reduced risks of skin cancer of atopic patients. As for colorectal cancer of dogs, patients with allergic conditions were found to be at lower risks for neoplasia. In fact, mast cells would participate in the immune defence against cancer formation through protective IgE pathways observed during allergic reactions and thrombosis formation in tumours due to heparin release. In parallel, significance of food allergies and inflammatory bowel disease (IBD) is growing in both human and veterinary medicines as their incidence increases in industrialised and developing countries. It appears to be linked to better health conditions and changes in consumption habit as seen in expanding pet food industry. However, despite animal comparative model research, investigations in food allergies in human are still confronting isotype specific response challenges specific to each species. Regarding IBD, its clear aetiology in small animal practice remains unknown but seems to share common features with human Crohn’s disease and ulcerative colitis. Better understanding of food allergies, IBD and their possible link to neoplastic transformation in dogs could throw the door wide open to future applications in human oncology.