Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 14, 2021; 27(30): 5047-5059
Published online Aug 14, 2021. doi: 10.3748/wjg.v27.i30.5047
Gastrointestinal mucosal immunity and COVID-19
Tsvetelina Velikova, Violeta Snegarova, Alexander Kukov, Hristiana Batselova, Antoaneta Mihova, Radislav Nakov
Tsvetelina Velikova, Alexander Kukov, Antoaneta Mihova, Department of Clinical Immunology, University Hospital Lozenetz, Medical Faculty, Sofia University, St. Kliment Ohridski, Sofia 1407, Bulgaria
Violeta Snegarova, Clinic of Internal Diseases, Naval Hospital – Varna, Military Medical Academy, Medical Faculty, Medical University, Varna 9000, Bulgaria
Hristiana Batselova, Department of Epidemiology and Disaster Medicine, Medical University, Plovdiv, University Hospital "St George", Plovdiv 6000, Bulgaria
Radislav Nakov, Clinic of Gastroenterology, Tsaritsa Joanna University Hospital, Medical University of Sofia, Sofia 1527, Bulgaria
Author contributions: All the authors wrote sections in the paper; All authors revised and approved the final version of the manuscript.
Conflict-of-interest statement: The authors declare that they have no competing interests.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Tsvetelina Velikova, MD, PhD, Assistant Professor, Department of Clinical Immunology, University Hospital Lozenetz, Medical Faculty, Sofia University, St. Kliment Ohridski, Kozyak 1 str, Sofia 1407, Bulgaria.
Received: March 3, 2021
Peer-review started: March 3, 2021
First decision: April 17, 2021
Revised: May 1, 2021
Accepted: July 12, 2021
Article in press: July 12, 2021
Published online: August 14, 2021
Core Tip

Core Tip: The gastrointestinal tract is a frequent route of infection with severe acute respiratory syndrome coronavirus 2. Given the complex interactions between the virus and the mucosal immune system after exposure, additional research is needed to elucidate the immune mechanisms and processes in the gut mucosa. The hallmark of all immune responses is the recruitment of various immune cells, such as neutrophils, dendritic cells, macrophages, and T cells in the gut mucosa. However, the mucosal inflammatory response could change intercellular space between enterocytes, leading to an increase in intestinal permeability that allows various bacterial antigens and toxins to enter the bloodstream, further complicating the disease state of coronavirus disease 2019 patients.