Autologous Bone Marrow Transplantation - Blog Science Connections

CALLA-Negative Clonogenic Cultures in
CALLA-Positive B-Cell Precursor Acute
Lymphoblastic Leukemia
Fatih M. CJckun, John H. Kersey, Daniel A Vallera,
Norma K C. Ramsay, Kevin G. Waddick, and
Kazimiera J. Gajl-Peczalska
A variety of immunologic strategies is being evaluated for effective ex vivo
purging of residual leukemic cells from autografts. The alternatives include
treatment of marrow with monoclonal antibodies (MAbs) plus complement,
with immunotoxins, and with MAbs linked to magnetic beads (1). For a MAb to
be of therapeutic value in autologous bone marrow transplantation (ABMT) for
acute lymphoblastic leukemia (ALL), it must be reactive with the majority of
clonogenic ALL blasts in autografts. Choosing a MAb for ex vivo marrow
purging has been exclusively based on the immunologic surface marker
profiles of the bulk of marrow blasts at diagnosis or relapse. Given the high
degree of heterogeneity in ALL, the immunophenotype of marrow blasts may
not reliably predict the immunophenotype of clonogenic ALL cells. Currently,
very little is known about the immunologic surface marker profiles of
clonogenic blasts in ALL. The paucity of knowledge largely reflects the historic
difficulties in cloning ALL blasts.
To learn more about these cells, we have developed colony assays that
enable us to culture leukemic cells of B lineage (2,3) and T lineage from freshly
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