Immune privileges as a result of mutual regulation of the immune and stem systems

Abstract

The immune privileges of cancer stem cells are a well-known and widely studied problem, as the presence of such cells in tumors is associated with refractoriness, recurrence, and metastasis. Accumulating evidence also suggests the presence of immune privileges for non-pathologic stem cells in addition to their other defense mechanisms against damaging factors. This similarity between pathologic and normal stem cells raises the question of why stem cells have such a potentially damaging property. The regulation of vital processes of autoimmunity control and regeneration by interactions between immune cells, stem cells and their microenvironment are reviewed as determinants of stem cell immune privilege formation. A deep mutual integration in the regulation of stem and immune cells is noted. Based on the diversity and complexity of the mutual regulation of stem cells, their microenvironment and the immune system, I propose to use the term “stem system”.