Circulating Conventional and Plasmacytoid Dendritic Cell Subsets Display Distinct Kinetics during In Vivo Repeated Allergen Skin Challenges in Atopic Subjects

Figure 3

DC subsets exhibit different kinetic patterns in the peripheral blood following repeated allergen skin challenges in vivo. Gating strategies utilized to identify cDC and pDC subsets in the peripheral blood by flow cytometry. (a) For cDC identification, a 3-step analysis was performed. Initially, CD33^pos cells were selected (Gate 1) to differentiate between mature lymphoid cells or lymphoid precursors (CD33^neg) from other cells of myeloid origin that include cDCs. Next, all CD(14+16)^dimtoneg/ILT3^pos cells are selected in Gate 2 to exclude monocytes, macrophages, NK cells, and neutrophils. Gate 3 is drawn around CD33^bright/ILT3^pos cells, so cDCs are characterized as CD33^bright/ILT3^pos/CD(14+16)^dimtoneg. (b) Regarding pDCs, initially all CD123^pos cells are selected (Gate 1) and then gated on the basis of CD(14+16)^neg expression (Gate 2) to exclude monocytes, lymphocytes, and most granulocytes. Gate 3 is drawn around CD123^bright/ILT3^bright cells, strictly selecting pDCs and excluding basophils, so pDCs are characterized as CD123^bright/ILT3^bright/CD(14+16)^neg. Representative FACS plots are shown. The percentages of pDCs (c) and cDCs (d) in the peripheral blood at baseline and following in vivo allergen challenges are shown. Data are expressed as median with interquartile range (first and third quartiles).

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