Age, leukocyte count, sex, immunophenotype (expression of cytoplasmic immunoglobulin [Ig] and of surface antigens CD10 and CD34), and DNA index (ratio of the flow cytometry-determined DNA content of leukemia cells to that of normal diploid cells) were the variables used in the evaluation of four antimetabolite-based chemotherapy regimens in 1,535 children with the newly diagnosed B-progenitor cell ALL between February 1986 and May 1990.
In three other patients the translocation was detected either at lineage conversion from ALL to M5 AML (n = 2) or from AML to CD10- B-precursor ALL (n = 1).
In My-B-lineage ALL, rearrangements of TCR beta chain gene were restricted to certain subgroups (Groups III & IV) of patients who expressed CD10 surface antigens but lacked cytoplasmic Ig.
Thirty-seven of them were common-ALL positive for CD10 "common-ALL antigen (CALLA)" (NL-1), CD19(B4) and HLA-DR. One was pre-B ALL negative for CALLA and another null-ALL which expressed HLA-DR alone.
The CALLA- or pre-B phenotype and the presence of chromosomal translocations in most infants with ALL provide a biological explanation for their poor prognosis.
Lymphoblast immunophenotypes were those of HLA-DR+, CALLA+ ALL (six patients); HLA-DR+, CALLA- ALL (four patients); pre-B cell ALL (two patients); T cell ALL (four patients); and undefined ALL (three patients).