What is "microchimerism"

n. (context biology English) The presence of a small number of cells in an organism that are genetically different from those of the organism itself; typically transmitted between a mother and fetus

Microchimerism (abbreviated Mc) is the presence of a small number of cells that originate from another individual and are therefore genetically distinct from the cells of the host individual. This phenomenon may be related to certain types of autoimmune diseases; however, the mechanisms responsible for this relationship are unclear.