Abstract

The fetal microchimerism theory for the pathogenesis of systemic sclerosis (SSc) has compelling biologic support, including the female predominance of the disease, the mean age of onset after childbearing years, similarities between diffuse cutaneous SSc and graft-versus-host disease, as well as the detection of microchimeric cells in peripheral blood and skin of SSc patients. The previous issue of Arthritis Research and Therapy presents findings of a positive association between pregnancy complications and future diagnosis of SSc in parous women. Before interpreting the results of this epidemiologic study as support for fetal microchimerism, however, other theories for the observed associations must be considered.