A simplified flow cytometric assay was developed that could identify a high proportion of children with acute lymphoblastic leukemia (ALL) who would have an excellent early treatment response and a high likelihood of cure

10-02-2006

According to recent research published in the journal Blood, "Bone marrow normal lymphoid progenitors (CD19+, CD10+, and/or CD34+) are exquisitely sensitive to corticosteroids and other antileukemic drugs. We hypothesized that, in patients with B-lineage ALL, cells with this phenotype detected early in treatment should be leukemic rather than normal."

"We therefore developed a simple and inexpensive flow cytometric assay for such cells and prospectively applied it to bone marrow samples collected on day 19 from 380 children with B-lineage ALL," explained E. Coustansmith and colleagues, St. Jude Children's Hospital & Research Center. "In 211 patients (55.5%), these cells represented 0.01% or more of the mononuclear cells; results correlated remarkably well with those of more complex flow cytometric and molecular minimal residual disease (MRD) evaluations.

"Among 84 uniformly treated children, the 10-year incidence of relapse or remission failure was 28.8%+/-7.1% (SE) for the 42 patients with 0.01% or more leukemic cells on day 19 detected by the simplified assay versus 4.8%+/-3.3% for the 42 patients with lower levels (p=.003). These assay results were the strongest predictor of outcome, even after adjustment for competing clinicobiologic variables."

The researchers concluded, "Thus, this new assay would enable most treatment centers to identify a high proportion of children with ALL who have an excellent early treatment response and a high likelihood of cure."

Coustansmith and colleagues published their study in Blood (A simplified flow cytometric assay identifies children with acute lymphoblastic leukemia who have a superior clinical outcome. Blood, 2006;108(1):97-102).

For additional information, contact D. Campana, St. Jude Children's Hospital & Research Center, Dept. of Hematology Oncology, 332 N Lauderdale St., Memphis, TN 38105, USA.