Ph1 negative haematological chimaerism after marrow transplantation in Ph1 positive chronic granulocytic leukaemia.

A 17-year-old girl with Philadelphia chromosome (Ph1) positive chronic granulocytic leukaemia (CGL) who has undergone two bone marrow transplants from her HLA identical brother is described. Following the second transplant, cytogenetic analysis of her bone marrow cells showed haematological chimaerism with equal numbers of normal male cells and Ph1 negative female cells indicating the probable eradication of the Ph1 positive clones with the retention of normal host stem cells.