Detection of cellular microchimerism of male or female origin in systemic sclerosis patients by polymerase chain reaction analysis of HLA-Cw antigens

Objective. Systemic sclerosis (SSc; scleroderma), a disease of unknown orig in, displays many similarities to chronic graft-versus-host disease. It occ urs most frequently in women after the childbearing years. In recent studie s, the presence of Y-chromosome DNA derived from male fetuses was detected, but DNA from female fetuses could not be investigated in those studies. Th e present study was undertaken to investigate cellular microchimerism of ei ther male or female origin in DNA from patients with SSc. Methods. DNA from peripheral blood cells of 63 patients with SSc, 64 health y individuals, and 24 non-SSc disease controls was examined by polymerase c hain reaction analysis of HLA-Cw antigens. Results. Cellular microchimerism of either male or female origin was detect ed in 41 of 63 SSe patients (65%), in contrast to 18 of 64 normal controls (28%) (chi(2) = 15.98, P-corr = 0.00006) and 8 of 24 disease controls (33%) (chi(2) = 5.89, P-corr = 0.015). Conclusion. 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.