Chris Long (who was the main case study) had a bone marrow transplant. Although the transplant had done its job, it went further. The DNA from the donor was no longer only affecting Long's blood. Traces of DNA not originally belonging to Long was found in mouth swabs as well as semen samples. It was found that both DNA were in his body. Other cases of this have been noted, and it has played a role in a few criminal instances, as the DNA found at a crime scene showed that there were more than one person who committed the crime, or that it was a completely different person. However, many of these cases all involved a bone marrow transplant, which showed more than one DNA profile.
I think that this is pretty odd as the donors DNA literally spread, and in more than one case so this isn't just a random, once in a lifetime situation. I figured the bone marrow transplant would most definitely effect a patients blood, but not spread throughout his body so that he would have more than one strand of DNA. I'm curious to see how this pans out in the future, and if they will run tests on whether this effects the children's DNA and if it would match the original patients DNA.