Extended diagnostic criteria for plasmacytoid dendritic cell leukaemia

Abstract

SummaryThe diagnosis of plasmacytoid dendritic cell leukaemia (pDCL) CD123 was expressed at significantly higher levels in pDCL and apDCL. BDCA-2 was expressed on 12/16 pDCL and on 2/4 apDCL, but was never detected in the 113 non-pDC acute leukaemia cases. BDCA-4 expression was found on 13/16 pDCL, but also in 12% of non-pDC acute leukaemia. High levels of LILRA4 and TCL1A transcripts distinguished pDCL and apDCL from all other acute leukaemia (except B-cell acute lymphoblastic leukaemia for TCL1A). We thus propose a diagnosis strategy, scoring first the CD4 + CD56 +/) MPO neg cCD3 neg cCD79a neg CD11c neg profile and then the CD123 high , BDCA-2 and BDCA-4 expression. Atypical pDCL can be also identified this way and non-pDC acute leukaemia excluded: this scoring strategy is useful for diagnosing pDCL and apDCL.

Blastic plasmacytoid dendritic cell neoplasm with leukemic presentation: an Italian multicenter study

“…TCL1 and CD2AP), might be of great support for definitely establishing the diagnosis and for excluding potential mimickers of BPDCN (acute myeloid and monocytic leukemias, precursor lymphoblastic T-cell leukemia/lymphomas and T-and NK/T cell lymphomas). 8,[17][18][19] In our experience 37% of cases were not confirmed after review, so we underline that cases should be discussed in a multidisciplinary meeting including at least a hematologist and a pathologist, and we emphasize the importance of accurate immunohistochemical and cytofluorimetric analyses, with extended panels also including antibodies for dendritic cell lineage in cases of unclassifiable acute leukemia, monoblastic forms and doubtful cases.…”

Immunophenotyping of acute leukemia and lymphoproliferative disorders: a consensus proposal of the European LeukemiaNet Work Package 10

“…16 Dendritic cell (DC) precursors. [17][18][19] Basophils and mast cell precursors. 20,21 Rare acute undifferentiated leukemias express no markers considered specific for myeloid or lymphoid lineage, 7 and usually display the immature immunophenotype CD34 þ / CD45 dim .…”

“…51,52 Bright cytoplasmic expression of the mucosialin CD68 is characteristic of most AML blast cells, but a weak staining can be seen in a subset of B-ALL. 53 CD68 also belongs to the complementary panel useful for the characterization of plasmacytoid DCs, 19,45 which also includes the interleukin-3 receptor CD123 and DC differentiation antigens of the BDCA family. 19 CD123 is also expressed on a subset of B-ALL, where it can be used for the detection of MRD.…”

“…53 CD68 also belongs to the complementary panel useful for the characterization of plasmacytoid DCs, 19,45 which also includes the interleukin-3 receptor CD123 and DC differentiation antigens of the BDCA family. 19 CD123 is also expressed on a subset of B-ALL, where it can be used for the detection of MRD. 54 A subset of AML also expresses CD123, which makes this marker a possible hallmark of leukemia stem cells, and therefore a potential therapeutic target in CD123 þ cases.…”

Plasmacytoid Dendritic Cell Leukemia: A Rapidly Evolving Disease Presenting with Skin Lesions Sensitive to Radiotherapy plus Hyperthermia

“…pDCL is a recently described entity characterized by the abnormal expansion of CD4 ϩ CD56 ϩ cells expressing CD123, TL1-A, and HLA-DR and lacking conventional myeloid and lymphoid T-and B-cell antigens [1]. These elements, which also identify CD4 ϩ CD56 ϩ hematodermic neoplasm (HDN) [2], have been indicated as the malignant counterpart of plasmacytoid dendritic cells [3].…”