a scRNA-defined uniform manifold approximation and projection (UMAP) of 109,888 live cells from normal skin, burn blister fluid, unaffected skin, affected skin, and/or blister fluid from 15 patients with acute SJS/TEN. b Expression distribution for key cell types, including immune and stromal populations. The majority UMAP location of each subset is labeled with the percentage of each subset within that location indicated. c Integrated scCITE-seq expression of subset-defining cell surface proteins for T cells (CD3, CD4, CD8), NK cells (CD56), DC (CD1c), monocytes and macrophages (CD14, CD11c), and B cells (CD19) on a representative UMAP of 17,404 cells obtained within a single 10x run (SJS/TEN blister fluid from n = 4 patients). Heatmap expression (high to low, red to blue) for each surface protein and average box plot expression is shown between scRNA-defined subsets (n = 11,261 CD8 + T cells, 593 CD4 + T cells, 727 NK cells, 536 DC, 3177 monocytes, 1034 macrophages, 45 B cells). The bounds of the box represent the interquartile range from the 25th to 75th percentile, the center line shows the median expression, and the whiskers identify maximum and minimum values to the 10th and 90th percentile, respectively. Outliers are shown. d Individual scRNA-defined UMAPs for tissue-relevant controls from unrelated donors (burn blister fluid, normal skin) and skin and blister fluid from patients with SJS/TEN. e, f scRNA-defined cell representation. Proportional representation of (e) all subsets in individual samples (culprit drug listed for each patient) and (f) rare, unconventional, and innate-like lymphoid cell (ILC) populations as a proportion of total CD8+ T cells, CD4+ T cells, or NK cells in each sample. The average expression is shown for patients with multiple samples from the same time point, indicated by an asterisk. Figure created using Visual Genomics Analysis Studio (VGAS)89. Source data are provided as a Source Data file. MSC, Mesenchymal stromal cell; HSC, Hematopoietic stem cell; NK, Natural killer; DC, Dendritic cell; Tconv, T conventional cell; ILC, innate-like lymphoid cell; Unaff, Unaffected; Aff, Affected; SJS/TEN, Stevens-Johnson syndrome and toxic epidermal necrolysis.