Systemic sclerosis (SSc; scleroderma), a disease of unknown origin, displays many similarities to chronic graft-versus-host disease. It occurs most frequently in women after the childbearing years. In recent studies, the presence of Y-chromosome DNA derived from male fetuses was detected, but DNA from female fetuses could not be investigated in those studies. The present study was undertaken to investigate cellular microchimerism of either male or female origin in DNA from patients with SSc.
DNA from peripheral blood cells of 63 patients with SSc, 64 healthy individuals, and 24 non-SSc disease controls was examined by polymerase chain reaction analysis of HLA-Cw antigens.
Cellular microchimerism of either male or female origin was detected in 41 of 63 SSc patients (65%), in contrast to 18 of 64 normal controls (28%) (chi2 = 15.98, Pcorr = 0.00006) and 8 of 24 disease controls (33%)(chi2= 5.89, Pcorr, = 0.015).
These findings support the hypothesis that microchimeric cells persisting in the circulation or tissues of SSc patients could be involved in disease pathogenesis by initiating a graft-versus-host-like reaction.