Intestinal Neuroimmunology and Its Implications in Food Allergy

Decades of research have elucidated diverse aspects of neuroimmunology. This interdisciplinary field originates from the observation almost one century ago that local sensory signals in the skin regulate mast cell degranulation, a key event in allergic reactions. With this historical perspective, the current research has expanded in different dimensions, including hormonal mechanisms, direct immunomodulation by neural signals, and immune barriers in the central nervous system. Notably, neural innervations in the gastrointestinal tract can establish complex crosstalk with various immune cells through the release of specific neurotransmitters (e.g., norepinephrine or acetylcholine) or neuropeptides (e.g., calcitonin gene-related peptide), which engage the corresponding receptors expressed on immune cells (e.g., mast cells or innate lymphoid cells). Such neuroimmune interactions have become a frontier topic in biomedical science over the past years. In this review, we aim to summarize the current knowledge of neuroimmunology, with a focus on the gastrointestinal tract. We then highlight the implications of such neuroimmune interactions in the disease context of food allergy.