Simultaneous or sequential expression of lymphoid and myeloid phenotypes in acute leukemia

Abstract

Acute mixed myeloid-lymphoid leukemia is uncommon. We report four cases in which myeloid and lymphoid cell markers were observed simultaneously or sequentially when 94 patients with acute leukemia were phenotyped according to the French-American-British (FAB) classification system, with cytochemical stains, and with immunologically defined differentiation markers (identified by monoclonal antibodies and antiterminal deoxynucleotidyl transferase [TdT]). In one case, conversion from acute lymphoblastic leukemia to acute myeloid leukemia was noted (FAB L1, TdT+ to FAB M4, Auer rods, TdT-). In another patient, two distinct populations of myeloid and lymphoid blast cells were observed simultaneously (TdT-, LeuM1+/TdT+, LeuM1-). In two additional patients, acute leukemia was characterized by the expression of both lymphoid and myeloid markers on the same cell (TdT+/Leu M1+, B4+/Leu M1+ and greater than or equal to 70% TdT+, T11+, My9+). The Philadelphia (Ph1) chromosome was negative in all cases, though other chromosomal abnormalities were noted in three out of four cases. Malignant transformation of a pluripotential stem cell for both lymphoid and myeloid lineages, with or without the Ph1 chromosome marker, could explain the coexistence of distinct populations of lymphoblasts and myeloblasts in acute leukemia. Acute leukemia with a biphenotypic profile may reflect genome depression accompanying neoplasia.

Immunodiagnosis of acute leukemia displaying ectopic antigens: Proposal for a classification of promiscuous phenotypes

“…About 20% of Samples showed a slight, limited deviation from the expected antigen constellation (pattern B). These cases are to be operationally considered unambiguous and diagnosable, although, according to a biological point of view, previous studies termed similar phenotypes as "lineage infidelities" or "acute mixed lineage leukemias" [ 13,15,. We believe that our classification may provide a positivity; white areas indicate ectopic antigen expression.…”

“…It is now accepted that immunophenotypic analysis of leukemic cells have an impact on routine diagnostic screening in hematology laboratories, making a critical contribution to the final diagnosis in about 20% of cases and playing an useful confirmatory role in all the remaining cases [4-51. However, although immunological typing is now reaching a stage of general acceptance of its 0 1989 Alan R. Liss, Inc. ability to diagnose accurately acute leukemia [6-111, several difficulties still prevent the successful application of such a new tool in a number of hematology laboratories. Major complications are related to the progressive identification of complex or unexpected leukemic surface membrane mosaics [12][13][14][15].…”

Solid‐Phase enzyme immunoassay for terminal deoxynucleotidyl transferase (abbott tdt‐eia) in extracts of whole blood and mononuclear cells isolated from bone marrow and blood

“…It was of particular interest that 6 of 9 MNC cxtracts from bone marrow and 2 of 3 MNC extracts from blood obtained lrom patients with undifferentiated leukemia (AUL) or acute leukemia (AL) were TdT-positive. Others have reported TdT-positive AUL/AL patients using the polymerase and immunofluorescence assays (14,20,23,28,38). These patients may be classified as myeloid or lymphoid (23) or express both cell types (38).…”

“…Others have reported TdT-positive AUL/AL patients using the polymerase and immunofluorescence assays (14,20,23,28,38). These patients may be classified as myeloid or lymphoid (23) or express both cell types (38). Some TdT-positive AUL/AL patients have been successfully treated with lymphoid drug regimens (35) while others have not (33).…”

Phenotypic characterization of ‘non‐T, non‐B’ acute lymphoblastic leukemia by a new panel (BL) of monoclonal antibodies

“…1977). In human, the existence of such common stem cells was suggested from the occurrence of simultaneous or sequential expression of lymphoid and myeloid phonotypes in acute leukemia (Neame et al, 1985). Recently, sIg + B1 + (B-cells) have been identified in human pluripotent hematopoietic colonies (Fauser et af., 1985).…”