Transcriptome analysis of primary Sézary cells. (A) Volcano plot of the 153 differentially expressed genes identified from RNA prepared from CD4⁺CD7⁺ Sézary cell from 6 SS patients compared with similarly purified cells from 9 normal volunteers that were used to perform transcriptome analysis on 41 059 gene transcripts. Red dots represent differently expressed genes with fold changes more than 4. P < .01. Genes on the right arm are overexpressed in Sézary cells, whereas those on the left arm are underexpressed in Sézary cells. (B) Hierarchical unsupervised clustering of the 153 genes, which clearly demonstrates a separation between Sézary cells and the normal T lymphocyte controls.