When people receive a bone marrow transplant after high-dose chemotherapy, some of the transplanted cells regenerate the blood-making cells that were destroyed. In past experiments in mice, Helen Blau, PhD, the Donald E. and Delia B. Baxter Professor of Pharmacology at the School of Medicine, found that cells from the transplant could also relocate to tissues throughout the body rather than being restricted to the bone marrow and blood.
"Now we know that it can also happen in humans," said James Weimann, PhD, first author on the paper and a senior research scientist in Blau's lab.
Blau and Weimann looked at brain samples taken from women who underwent chemotherapy to treat their leukemia and then later received bone marrow transplants from male donors. These samples were ideal for this experiment because the donor cells contained a Y sex chromosome whereas cells in the women contained only X chromosomes. Any Y chromosome that Blau and Weimann identified must have come from the transplant donor.
To look for the telltale Y chromosome, the researchers used molecules with a double identity. One part of the molecule could bind to either the X or Y chromosome, while the other part acted as a fluorescent molecular beacon. The molecule that bound the X chromosome had a red beacon whereas the Y-recognizing molecule had a green beacon. When they put these stains on the preserved samples, the X chromosomes glowed red and any Y chromosomes glowed green. Weimann then searched the samples under a microscope for green chromo
Contact: Amy Adams
Stanford University Medical Center