Elevated NLRP1 and IL ‐1β Expression Supports Inflammasome Activation in SJS / TEN

BACKGROUND: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare, life-threatening mucocutaneous reactions most commonly triggered by medications. While cytotoxic T-cell-mediated keratinocyte death is considered central to disease pathogenesis, the contribution of innate immune pathways, particularly NLRP1-mediated inflammasome activation, remains insufficiently characterized. METHODS: In this retrospective study, we analyzed skin biopsy specimens from 22 patients with histopathologically confirmed SJS/TEN and 18 controls with normal skin. Immunohistochemical staining for NLRP1 and IL-1β was semiquantitatively assessed using H-scores, and clinical features including suspected triggers, SCORTEN, and outcomes were recorded. RESULTS: NLRP1 and IL-1β expression in both epidermal keratinocytes and dermal lymphocytes was significantly elevated in SJS/TEN compared with controls (all p < 0.05), and NLRP1 levels demonstrated a strong positive correlation with SCORTEN (p < 0.001). No significant differences in expression were observed between survivors and non-survivors. CONCLUSION: These findings support a role for inflammasome activation in SJS/TEN pathogenesis and suggest that NLRP1 may serve as a potential biomarker of disease severity. Larger, prospective studies are warranted to confirm these observations.