Engraftment of leukocyte subsets following autologous bone marrow transplantation in acute myeloid leukemia using anti-myeloid (CD14 and CD15) monoclonal antibody-purged bone marrow.

The cell surface phenotype of leukocyte subsets during reconstitution following autologous bone marrow transplantation (ABMT) using bone marrow purged with anti-myeloid monoclonal antibodies (MoAbs) and complement (C') was evaluated in 20 patients with acute myeloid leukemia (AML). Repopulation of B and T lymphocytes, natural killer (NK) cells, and myeloid cells was assessed by phenotypic analysis using two-color cytofluorography of peripheral blood mononuclear cells (PBMNC) at several time points up to 2 years post-transplantation. In spite of removal of the majority of monomyeloid cells of the autograft by purging with anti-CD14 and anti-CD 15, engraftment occurred rapidly. The myeloid cells appeared normal by surface phenotype. An early rise in NK cells, characterized by expression of CD57 and CD 16, was seen. The CD4:CD8 ratio remained low throughout the study period, primarily due to a persistently low CD4 level. ABMT using bone marrow purged with the anti-myeloid MoAbs PM-81 and AML-2-23 and C' resulted in prompt engraftment of neutrophils. Although there was a prolonged time for recovery of lymphocyte subsets, this did not result in an increased risk of early infectious complications. Late infectious complications post-transplantation were limited to herpes zoster infection in one patient 18 months post-transplantation, and bacterial meningitis in that same patient 2 months later. This study demonstrates that ABMT in patients with AML using bone marrow purged with the anti-myeloid MoAbs PM81 (anti-CD15) and AML-2-23 (anti-CD14) and C' results in rapid hematologic engraftment and delayed phenotypic immunologic reconstitution without significant acute or chronic clinical toxicities.