Blood fetal microchimerism in primary biliary cirrhosis

The autoimmune nature of primary biliary cirrhosis (PBC) is well establishe d. We tested the hypothesis that fetal microchimerism indicated by the pers istence of circulating fetal cells in women years after pregnancy might con tribute to the aetiopathogenesis of PBC through a graft-versus-host-like re sponse. We extracted DNA from the peripheral blood cells of 36 women carefu lly selected from 173 consecutive PBC patients, who were matched with 36 he althy women by age, age of last son, and number of children. Both patients and controls had to have male offspring, and no history of miscarriages or blood transfusions; they could not be twins. We tested all of the samples f or the presence of two specific Y-chromosome sequences (SY154 and SRY) by a mplifying DNA in a nested polymerase chain reaction. Y-chromosome-specific DNA was detected in the peripheral blood cell DNA of 13 (36%) of the 36 wom en with PBC and in 11 (31%) of the 36 healthy controls. The two groups of P BC patients with and without male DNA sequences were similar in terms of th eir clinical, biochemical, and serological features. Y-chromosome sequences were found in three of the four PBC women with associated systemic scleros is. All of the 24 Y-positive samples contained SY154 sequences, but only th ree PBC patients and six controls showed the presence of both SY154 and SRY sequences. This discrepancy may suggest that not only fetal cells but also fragments of fetal DNA are present in maternal circulation. Overall, our d ata do not support the hypothesis that fetal microchimerism plays a signifi cant role in the onset or progression of PBC.