Defining T-cell Interactions and Targets in Drug Reaction with Eosinophilia and Systemic Symptoms Using Single-Cell and Spatial Profiling

About This Grant

Project Summary Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) is a rare but severe treatment-limiting hypersensitivity reaction with delayed onset, multiorgan involvement, and significant mortality and long-term morbidity. Cases typically arising in the post-marketing phase of drug development complicate drug safety monitoring and mandate long-term avoidance of multiple medications when DRESS occurs with multiple drugs administered concurrently. HLA class I associations have enabled genetic screening for select drugs, but their limited predictive value, lack of known or well-studied associations for many agents generalizable across populations highlight the need for deeper mechanistic understanding. DRESS is classified as a type IVb hypersensitivity reaction involving CD4⁺ T cell subsets, including Th2 cells that recruit eosinophils, Th1 cells that drive cytotoxic inflammation through IFN-γ and TNF signaling, and regulatory T cells that modulate immune activity, alongside cytotoxic CD8⁺ Tc2 cells that mediate keratinocyte damage. Recent single-cell analyses in refractory DRESS has shown activation of JAK-STAT signaling in both CD4⁺ and CD8⁺ T cells, with clinical improvement following JAK inhibition. Currently corticosteroids and drug withdrawal are standard, but relapse and chronic immune activation remain major challenges. Our testable hypothesis is that CD4⁺ subsets— including Th1, Th2, and Tregs—influence CD8⁺ T cell cytotoxicity, spatial organization, and clonal expansion in DRESS-affected skin. We further posit that the balance and spatial arrangement of these CD4⁺ subsets shape the severity and tissue distribution of CD8⁺-mediated injury through coordinated cytokine signaling and cell–cell interactions. We will apply innovative and distinct single-cell studies to different sample sets in two parallel non- interdependent aims. In Aim 1 we will use 10X-HT-5’-scTCR-RNA-Cite-seq to profile immune subsets from cryopreserved DRESS-affected, unaffected, and HLA-sex matched cryopreserved control skin using to identify clonal TCR expansion, effector signatures, and CD4+–CD8+ T-cell signaling pathways. We will compare this to our existing single-cell atlas of >150,000 cells from skin and blister fluid from patients with acute Stevens- Johnson syndrome and toxic epidermal necrolysis (SJS/TEN). In Aim 2 we will use 10X-Visium-HD which the specific goal to map the localization of CD4⁺ and CD8⁺ T cell subsets using an independently collected bank of FFPE tissue from the same patients in Aim 1 and spatial transcriptomics, comparing this to existing spatial data from SJS/TEN skin and new data generated from healthy FFPE biopsies from HLA-sex matched controls. Using the same controls we will also differentially profile transcriptional states of keratinocytes and other cells to define the spatial geography of DRESS-specific immune signatures. This work will generate foundational insight into DRESS immunopathogenesis and enable future studies to define HLA-restricted, drug-modified peptide antigens and develop targeted diagnostic and therapeutic strategies. Our research aligns with the NIAID charter to conduct and support research to understand, treat, and prevent infectious, immunologic, and allergic diseases.