FIGURE LEGENDS
Figure 1 . IFN-γ release enzyme-linked immunospot (ELISpot) assay release for peripheral blood mononuclear cells (PBMC) and blister fluid cells (BFC). Data is for cryogenically stored PBMC and BFC samples from Cases 1-4 (Supplementary Table 1). A positive result is defined by greater than or equal to 50 spot forming units (SFU) per million cells (green dotted line). The maximum doses for each drug were shown to not elicit responses and cell death on a healthy control sample, using flow cytometry  (7-AAD staining) or Lactate Dehydrogenase (LDH) viability assay ([19] and Supplementary Figure 4). SMX, Sulfamethoxazole; TMP, Trimethoprim.
Figure 2. Lymphocyte composition of blood and blister samples.Donor-matched BFC and PBMC were analysed by flow cytometry. A.Graphs show percentages of total IFN-γ+ and CD3+ lymphocytes (left of red line) among total live lymphocytes (gated as per Supplementary Figure 1i). T cells (CD3+) (gated after exclusion of CD14 (monocytes) and CD19 (B cells) as per Supplementary Figure 1ii) were subsequently analysed for: CD4 and CD8 co-receptors (CD4/CD8 double-negative cells are indicated as DN), CD45RO (memory), CD69 (activation), CD69 and CD103 co-expression (egress/tissue residency/memory), γδ T cell receptor (TCR), binding to MR1 5-OP-RU tetramers[20, 21] (MAIT cells), or expression of the NK receptor CD56 (NK-like T cells) (right of red line). B. Graphs show proportions of CD4, CD8 and CD4/CD8 DN T cells, γδ T cells, MAIT cells and CD56+ T cells amongst IFN-γ-secreting cells, gated as per Supplementary Figure 2.