Use of granulocyte-macrophage colony-stimulating factor in two children treated with cord blood transplantation

Cord blood contains stem cells in amounts similar to or slightly less than those present in a bone marrow collection to be used for bone marrow transplantation (BMT). Too few cord blood transplants (CBT) have yet been performed to define the ability to achieve engraftment and the rate of engraftment. Two cord blood transplants have been performed using granulocyte-macrophage colony stimulating factor (GM-CSF) to hasten engraftment. Two children, aged 5 and 6 years received a CBT using HLA-identical stem cells collected at the birth of a sibling. One child had X-linked lymphoproliferative disease (XLP), and the other, acute lymphoblastic leukemia in second complete remission. One had an ABO and one an Rh blood group mismatch. Conditioning therapy consisted of cyclophosphamide, melphalan, and antithymocyte globulin or busulphan and cyclophosphamide. Graft-versus-host disease prophylaxis was methotrexate and cyclosporine or cyclosporine. Both children were given GM-CSF at 5 micrograms/kg/day from day 1 until the absolute neutrophil count (ANC) reached 1.0 x 10(9)/L for 3 consecutive days. If this level was not reached by day 14, the dose of GM-CSF was doubled. Both children engrafted rapidly, with ANCs reaching 0.5 x 10(9)/L in 12 and 16 days. Engraftment was confirmed by blood group in both and sex chromosome typing in one. Both children developed mild GVHD localized to skin, which resolved with steroid therapy. The child with XLP was cured and has survived for 34 months; the second child has survived 27 months with normal marrow function but has had a relapse of leukemia.(ABSTRACT TRUNCATED AT 250 WORDS)