We herein describe an unusual case of acute myeloid leukaemia (AML) showing strong cytochemical reactivity for myeloperoxidase (MPO) but surprisingly no reactivity using flow cytometry for any of the lineage-specific cell surface markers, i.e. myelomonocytic antigens CD13, CD14 and CD33; or B-lymphoid antigens CD19, CD20 and immunoglobulins; or T-lymphoid antigens CD2, CD3 and CD5.
Following evaluation by the Mann-Whitney test, we found that t(8;21) AMLs showed a significantly higher expression of CD19, CD34, CD56, CD45RA and CD54.
Lymphoid marker expression in 59 cases of de novo childhood acute myeloid leukemia (AML) was as follows: CD2 (15.5%), CD4 (73.8%), CD7 (25.8%), CD19 (22%) and CD56 (28.9%).
The activation of B-cell-specific genes, such as CD19 and PAX5, is a hallmark of t(8;21) acute myeloid leukemia (AML) which expresses the translocation product RUNX1/ETO.
With the clinical success of anti-CD19 chimeric antigen receptor (CAR) T cell therapies against B-lineage malignancies, many studies have attempted to translate the success of CAR T cell therapy to other malignancies, including AML.
Leukemic cells from an 8-year-old girl with ANLL-M2 expressed precursor B-cell antigen CD19, but none of the myeloid antigens CD11b, CD13, CD14 and CD33.
The acute biphenotypic leukaemia cases consisted of four major immunophenotypic subgroups: CD2+ AML (11), CD19+ AML (8), CD13 and/or CD33+ ALL (24), CD11b+ ALL (5) and others (4).
We studied the S-phase DNA content of immunophenotypically defined BM subpopulations (CD2+; CD19+; CD2/CD19+; glycophorin-A+; CD14+; CD13+; CD33+ and CD13/CD33+) in 18 patients with acute myeloid leukemia (AML), including three patients with M6 AML.
Frequent expression of CD19 was found in the blastic population of t(8;21) AML (18 of 23 cases) without other B-cell antigens and Ig gene rearrangements.
The relative frequency of CD19 and CD56 expression in AML with t(8;21) was higher than those with other chromosomal abnormalities or normal karyotype (P = 0.011 and 0.005, respectively).
We compared, by fluorescence in situ hybridization, CD19-positive and CD19-negative cells from nine patients with acute leukemia: three non-t(8;21) AML, three t(8;21) AML and three cases of acute lymphoblastic leukemia.
Clinical trials are underway investigating non-HLA matched T cells expressing anti-CD19 CARs for the treatment of B cell acute lymphoblastic leukemia (B-ALL) and anti-CD123 CAR for acute myeloid leukemia (AML).