CD13 was the commonest cross lineage antigen, expressed in B-ALL (25.6%, n=70/273), followed by CD33 (17.9%, n=49) and combined CD13/CD33 (11.3%, n=31/273) expression.
The aim of our study was to evaluate in a large series of cases of acute lymphoblastic leukemia (ALL) the expression of specific antigens, CD19, CD20, CD22, and CD33, for which MoAbs are available for clinical use.
A 35-year-old man was diagnosed as ALL because of the infiltration of CD10(+)CD19(+)CD33(+)CD34(+) lymphoblasts in the bone marrow and the expression of p190-type BCR/ABL fusion transcript.
Comparison of these and previously published cases demonstrates that the translocation predominately occurs in children and young adults with precursor B-ALL and is typically characterized by low CD10 expression and high CD33 expression.
In whole ALL, CD13/CD33 was associated closely with the presence of stem-cell antigen CD34, and in T-lineage ALL, CD13/CD33 had a significant correlation with additional stem-cell features, such as HLA-DR, multidrug resistance 1 (MDR1) and c-kit gene expression.
Coexpression of myeloid antigens (CD13 and/or CD33) was observed in six of 16 common ALL patients as well as in the one child with early T-lineage ALL phenotype.
As concerns immunophenotypic findings, blast cells from two of three AML patients expressed CD7 and CD34, while those from the T-ALL case displayed CD33 and CD34 along with CD7.
Stimulation of nonleukemic cell population seen in two other cases of cALL was associated with residual erythroid and granulocyte-macrophage colony forming cells after liquid culture as defined in parallel clonogenic assays in one and detection of CD 33+ and CD 13+ cells after culture in the other cALL sample.