Recent studies indicate that there is bi-directional traffic of cells during normal human pregnancy. Fetal cells have been found to persist in the maternal peripheral blood for many years after pregnancy. Many autoimmune diseases are more prevalent in women, and some of them have peak incidence at late stages of childbearing years. Chronic graft versus host disease (cGVHD) is a known condition of chimerism and has clinical similarities to some rheumatic autoimmune diseases, notably systemic sclerosis, Sjögren's syndrome and systemic lupus erythematosus. This article explores the hypothesis that fetal microchimerism contributes to the pathogenesis of some autoimmune diseases, based on reviews of previous studies that have worked with this hypothesis. Technical and conceptual considerations are presented for a critical appraisal of the available literature.
microchimerism; rheumatic autoimmune disease; autoimmunity; systemic sclerosis; systemic lupus erythematosus