Figure 1: Flow cytometric analysis of pDCs, mDCs, basophils and the relationship of decreased pDCs with elevated HHV-6 IgG levels. (a) Demonstration of gating strategy for calculating the frequencies of pDCs (green rectangle), mDCs (brown rectangle) and basophil (blue rectangle). (b) The alterations of pDC ratio in different disease groups. Significant decreasing trend of pDC is shown in DRESS versus ODE or MPE [Table 1 and Supplementary Table 3]. (c) The pDC frequency (closed items) and HHV-6 IgG ELISA (open items) or DNA positivity (labeled as asterisks) against disease course in cases 13, 15, and 20. A decrease in pDC frequencies and correlated escalation of HHV-6 IgG level are shown. APC: Labeling CD11c, FITC: Labeling T- and B-cell linages (Linage Cocktail-1 including CD3, CD14, CD16, CD19, CD20, and CD56), FSC: Forward scatter, lin 1 dim, Lineage Cocktail 1 diminished, PE: Labeling CD123, PED: Prednisolone-equivalent dose; PerCP: Labeling HLA-DR, SSC: Side scatter, pDCs: Plasmacytoid dendritic cells, mDCs: myeloid dendritic cells, HHV-6: Human herpesvirus 6, IgG: Immunoglobulin G, DRESS: Drug reaction with eosinophilia and systemic symptoms, ODE: Other drug eruptions, MPEs: Maculopapular eruptions.