These mature pDCs show largely the same immunoprofile as their reactive counterparts, CD123, BDCA2
, and TCL1 positive, but occasionally aberrantly express CD2, CD5, CD7, CD10, CD13, CD14, CD15, and CD33.
is a specific marker for pDC in immunostaining, it was reported that BDCA2
was an inhibiting signal for TLR9-mediated IFN-[alpha] synthesis in pDCs  and BDCA2+ pDC produced a very low amount of IFN-[alpha] in lymph node .
The diagnosis is mainly provided by detection of [CD4.sup.+] [CD56.sup.+], [CD123.sup.high], [TCL-1.sup.+], and blood dendritic cell antigen-2 (BDCA2
)/[CD303.sup.+] Lin- blasts .
They also express CD303 (blood dendritic cell antigen 2, BDCA2
), cutaneous lymphocyte-associated antigen (CLA), granzyme B, and TCL1.
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.
Within the fraction [CD.sup.3-] [CD19.sup.-] [CD56.sup.-], cells expressing CD11c were considered conventional dendritic cells, whereas the BDCA2
expressing cells were classified as plasmacytoid dendritic cells.