In GVHD, immune cells called T -cells from the donor bone marrow attack the tissues of the recipient, causing some of the same symptoms as those seen in systemic sclerosis. Not everyone accepts that idea. Y chromosome DNA sequences in the blood of 32 of 69 women with systemic sclerosis and in only 1 of 25 healthy women. Jimenez and his colleagues also found Y chromosome sequences in the skin lesions of 11 of 19 affected women. Jimenez says that he and his colleagues have early indications that the fetal cells containing the Y chromosome sequences are T -helper cells, which secrete substances called cytokines.
Cytokines are chemical messengers that activate the immune system.
He speculates that these cells arise from immature fetal stem cells, which cross over into the mother's circulation and then mature. We need to see how mature the cells we've found are. If Jimenez and his coworkers are right, it could revolutionize therapy for systemic sclerosis and scleroderma, which now consists of nothing more than blood pressure-lowering drugs to slow kidney damage. And if they can identify distinguishing molecules on the surfaces of the fetal cells, those molecules could serve as the basis for vaccines that would wake up the mother's immune system and sic it on the foreign cells. Jimenez acknowledges that environmental factors, such as exposure to toxins, must also play a role.