Comparison of peripheral blood versus bone marrow blasts immunophenotype in pediatric acute leukemias

Due to continued improvement in molecular and immunodiagnostic methods, more leukemia subtypes are being defined and diagnosed by their genetic and immunophenotypic profiles rather than by morphologic features alone. These advances, while relegating morphologic review and bone marrow (BM) blast counts to a lesser relevance, have elevated expectations of a full diagnostic work up using any specimen containing blasts, regardless of BM blast status. In some clinical situations, the pathologist is often asked to render a complete diagnostic and prognostic work up of leukemia on a peripheral blood (PB) sample, due to poor specimen quality or blast yield in a BM sample, with the intuitive assumption that PB and BM blasts, in the same patient and at a given point of time, are identical.

In an attempt to evaluate the immunophenotypic aspects of this assumption, we searched our records for cases of acute leukemia that had immunophenotyping of both PB and BM at the time of diagnosis, and found five cases: two acute myeloid leukemia (AML) and three acute lymphoblastic leukemia (ALL) cases. Utilizing similar pre-analytical conditions and similar FC gating strategy, positivity of the blasts in PB vs BM for some commonly used markers was compared. Significant differences were seen in several myeloid, lymphoid, and platelet markers in all patients. This discordance may carry significant clinical implications.

Key-words:

Pediatric leukemia - Immunophenotype - Flow cytometry

Publication History

Received: 13 May 2011

Accepted: 12 August 2011

Article published online:
23 May 2022