Bilateral diffuse pulmonary ectopic ossification after marrow allograft in a dog. Evidence for allotransplantation of hemopoietic and mesenchymal stem cells.

In light of recent studies showing successful transplantation of both bony and stromal elements by marrow transplantation, we report an unexpected phenomenon occurring in a canine radiation chimera. Nine hundred fifty-six days after a successful and uneventful DLA-matched marrow allograft, a dog suddenly died of respiratory failure. Autopsy revealed extensive ossification of the lungs with multiple sites of trilineage marrow engraftment. The entire complement of bony elements can apparently be allografted using marrow grafting techniques.