[Chimerism: origin and medical implications]

The organism whose cells come from different individuals is called chimera. It is frequently observed in nature: pregnancy, organ transplantation or transfusion are considered chimeric cell sources. It has been involved in autoimmune diseases development such as scleroderma, because of similarities between it and graft versus host disease, long term persistence of fetal cells in women and the finding of greater number of chimeric cells in affected women than healthy ones. It is not strictly a disease but might be considered helpful in non-invasive prenatal diagnosis and damaged organs regeneration.