ABSTRACT
BACKGROUND: Mesenchymal stem cells are a kind of adult stem cells with self-renewal and multi-directional differentiation potential. These cells have the functions of immunoregulation, regulation of cell growth and repair of injury. In recent years, it has been found that when inflammatory injury occurs, mesenchymal stem cells can regulate the secretion of inflammatory factors, and function on the damaged region, thereby repairing and improving tissue damage caused by inflammation. OBJECTIVE: To review the immunoregulatory effects of mesenchymal stem cells on T lymphocytes, B lymphocytes, dendritic cells and natural killer cells when the body is in an inflammatory state. METHODS: A computer-based search of PubMed and CNKI was performed for articles published from 2000 to 2018 using the keywords of"inflammatory microenvironment, mesenchymal stem cell, immune response, T cell, B cell, DC, NK cell" in English and Chinese, respectively. Seventy-six articles related to the topic and with reliable arguments were finally included in result analysis. RESULTS AND CONCLUSION: The interaction between mesenchymal stem cells and inflammatory cells determines the result of tissue damage repair. In an inflammatory state, the biological characteristics of mesenchymal stem cells will undergo certain changes, but mesenchymal stem cells can still exert immunomodulatory effects by secretion of various soluble cytokines or via cell contact. There are still many problems to be further explored to facilitate better clinical application of mesenchymal stem cells.