It has been reported that more male
DNA of presumed fetal origin is present in the blood and skin of women with
systemic sclerosis (SSc) as compared with healthy controls after delivery, but these findings are controversial. We sought to determine whether male cell
DNA is present in SSc using a quantitative polymerase chain reaction for Y chromosome
DNA. The study groups comprised 57 healthy women, 49 patients with SSc and 30 patients with
connective tissue diseases other than SSc who had given birth to at least one son and/or had experienced fetal loss. The intensity of the PCR bands on negatives of gel photographs was quantified with a video densitometer linked to a computer analysis system. Positive Y chromosome
DNA was found in 20 healthy women, 14 SSc patients and 6 patients with
connective tissue diseases other than SSc. The occurrence rate of
DNA equivalents of male cells among the three groups showed no significant differences. The number of male cell
DNA equivalents per 80 ng tissue
DNA in SSc patients (4.59+/-9.63), however, was significantly higher than in healthy women (1.83+/-4.96; P < 0.05) and in patients with
connective tissue diseases other than SSc (0.27+/-0.64; P < 0.01). The occurrence rate of fetal loss in male cell
DNA-positive SSc (eight) was significantly higher than in male cell
DNA-negative SSc patients (four; P < 0.01). No correlation was found between the number of male cell
DNA equivalents and birth of sons or clinicolaboratory findings. These results indicate that the elevated amount of male cell
DNA in SSc skin tissue may contribute to the pathogenesis of SSc.