Chisato Tawada ¹, Yoko Ueda ², Yoko Mizutani ¹, Xiaoyu Zang ¹, Kayoko Tanaka ¹, Hiroaki Iwata ¹

Exp Dermatol. 2025 Mar;34(3):e70076. doi: 10.1111/exd.70076.

Reactive oxygen species (ROS) are involved in the pathogenesis of generalised pustular psoriasis (GPP), but this involvement has not been fully elucidated. We performed the diacron-reactive oxygen metabolite (d-ROM) test and the biological antioxidant potential (BAP) test on sera from nine patients with active GPP who were hospitalised and treated at our hospital, (6/9 with GMA) including three patients with pustular psoriasis of pregnancy (PPP). The serum d-ROM and BAP levels were evaluated before treatment and at 1 month of treatment. We also performed immunostaining of 4-hydroxy-2-nonenal (4-HNE) in skin tissues. In the GPP patients, the average d-ROM levels were significantly reduced at 1 month of treatment (reduced to 343.0 ± 82.1 U.Carr from 423.2 ± 95.0 U.Carr, p = 0.005). The Generalised Pustular Psoriasis Area and Severity Index (GPPASI) score correlated with d-ROM levels (r = 0.57, p = 0.10), suggesting that those levels reflect the disease severity. In normal pregnancy, d-ROM values are known to increase from mid-term to late-term. The d-ROM values increased when GPP worsened in the case of PPP. Immunohistochemical staining of 4-HNE was positive for subcorneal pustules, neutrophils, and for the cytoplasm of epidermal keratinocytes, especially in upper epidermal layers. Our findings indicate that 4-HNE may play an important role in GPP and PPP.