Methodological approach to minimal residual disease detection by flow cytometry in adult B-lineage acute lymphoblastic leukemia.

A flow cytometric approach to minimal residual disease (MRD) monitoring useful in childhood B-lineage acute lymphoblastic leukemia (ALL) is discussed here in the context of ALL in adults. Of 64 leukemia samples analyzed, 95.3% had at least one abnormal phenotype (57.3% had two or more) as compared to physiologic B-cell precursors in adult bone marrow. The method was sensitive enough to detect one leukemic cell among 10,000 normal cells in 16/19 experiments (84.2%). Blast phenotypes were stable in culture and at relapse, and were useful for MRD monitoring in patients. Marker combinations for childhood ALL are also applicable to adult cases.