REGIONAL SPECIALIZATION OF THEADAPTIVE IMMUNE SYSTEM WITHIN THEHUMAN GUT

Abstract: Background The human intestine is the largest immune organ in the human body and is constantly exposedto a great number of antigens and bacteria. This requires a balance between tolerogenic andimmunogenic responses to avoid inflammation. The small and large intestine have differentanatomy, physiological functions and are affected differently by diseases. Many studies onintestinal immunity do not distinguish between the small and large intestine, and most studiesare performed on mice. To fully understand human intestinal immunity, there is a need for morestudies on humans that also treat the different intestinal regions as separate compartments. Aim To summarize possible differences in the adaptive immune system in the human intestine, withspecial focus on antigen presenting dendritic cells and T lymphocytes. Methods A systematic review was performed on previously published articles that examined humanintestinal immunity with focus on adaptive immunity. The articles were obtained from thedatabase PubMed using MeSH terms. The articles were selected based on certain inclusion andexclusion criteria and their quality was evaluated. Results The collected data from included articles clearly show a difference in small and large intestinaladaptive immunity regarding distribution and functions of dendritic cells and T lymphocytes. Conclusion More knowledge about the differences in the properties of the immune system in differentregions of the intestine would probably contribute to a greater understanding of theimmunological basis of diseases affecting the intestines and might be valuable for developingnew treatment possibilities.