Chromosome studies in patients with Philadelphia chromosome-positive chronic myeloid leukemia submitted to bone marrow transplantation--results of a European Cooperative Study.

The karyotypes of 74 patients with Ph-positive chronic myeloid leukemia submitted to bone marrow transplantation collected from nine institutions were studied serially before and after transplantation. In 13 cases sporadic Ph-positive metaphases were detected without signs of relapsing disease at various intervals after transplantation. These data indicate that the leukemic clone may not be completely suppressed by the conditioning treatment and that other biological mechanisms may be involved in destroying this clone or controlling its expansion.