However, it is now known to be derived from the recently recognized subtype of dendritic cells named plasmacytoid dendritic cells (PDC) which are characterized by expression of CD4, CD56, and more PDC-specific markers such as CD123 and CD303. (1-4)
At the point, more specific markers for blastic plasmacytoid dendritic cells, such as CD123, TCL1, CD303, CD2AP, BCL11a, and SPIB, are helpful in this differentiation.
A highly suspected diagnosis of BPDCN can be made when skin lesions exist, four antigens among CD4, CD56, CD123, TCL1, and CD303
are expressed by neoplastic cells and myeloid/lymphoid system specific markers such as CD117, MPO, CD20, and CD3 are negative. This patient did not have skin lesions and the immunophenotypic characteristic of BPDCN.
However, Syk may also negatively regulate the TLR7 pathway upon the stimulation ofthe regulatory immunoreceptors CD303
and CD85g in pDC, which suggests the presence of a dual role for Syk in the regulation of the TLR7 pathway .
BPDCN characteristically expresses CD4, CD56, CD43, CD45, and PDC-associated antigens such as CD123, TCL-1, BDCA2 (CD303) without expression of T-cell, B-cell, and NK-cell or myelomonocytic lineage specific markers, although expression of CD2 and CD7 is not an uncommon finding.
showed that CD123 and CD303 (BDCA2) were expressed in 11 out of 123 (9%) and 4 out of 124 (3%) myeloid leukemia cutis (LC) cases, respectively.
Abbreviations, CD numeration, and alternate names: DEC-205 (CD205), B220 (CD45R), PDCA-1 (plasmacytoid DC Ag-1; CD317; Bst2), Siglec H (Sialic acid-binding immunoglobulin-like lectin H), Langerin (CD207), CD141 (BDCA-3), CD1c (BDCA-1), and CD303
They also express CD303
(blood dendritic cell antigen 2, BDCA2), cutaneous lymphocyte-associated antigen (CLA), granzyme B, and TCL1.
Human plasmacytoid DCs lack myeloid antigens and express CD123, CD303
, and CD304 .