In this case series, we report six patients with severe, treatment-refractory Darier disease, or dyskeratosis follicularis, also known as ATP2A2-nEDD (nonsyndromic epidermal differentiation disorder), treated with off-label biologic therapy, including dupilumab (n = 3), secukinumab followed by guselkumab (n = 1), and ustekinumab (n = 2). All patients had longstanding disease with recurrent flares, frequent infections and substantial impairment of quality of life, despite multiple conventional treatments. All biologic treatments were well tolerated, with no serious adverse events. Dupilumab consistently improved pruritus but had limited effects on skin lesions. Secukinumab and guselkumab provided only transient or partial disease control. In contrast, both patients treated with ustekinumab achieved pronounced and sustained clinical improvement, with markedly reduced disease severity and pruritus, and considerable improved quality of life. The pronounced and sustained responses observed with ustekinumab support its prioritization for future studies in Darier disease.

IκBζ (NFKBIZ) has been implicated as a key co-transcription factor in psoriasis pathogenesis. While its role in keratinocytes is well established, the involvement in dermal fibroblasts, another critical skin cell type, remains underexplored. This study characterizes cytokine-induced NFKBIZ regulation in human dermal fibroblasts in vitro and integrates spatial transcriptomics to determine NFKBIZ expression patterns in psoriatic skin biopsies. Primary dermal fibroblasts were stimulated with IL-17A, IL-17F, and TNF. Signaling pathways and gene regulation were examined using chemical inhibitors, siRNA knockdown, qPCR, and Western blotting. Additionally, spatial transcriptomics (CosMx™) assessed NFKBIZ expression in paired lesional and non-lesional psoriatic skin biopsies. Results showed significant upregulation of IκBζ expression in dermal fibroblasts following stimulation with both IL-17A and IL-17F. The NF-κB signaling pathway was identified as the primary regulator of NFKBIZ induction. NFKBIZ knockdown significantly reduced cytokine-induced expression of inflammatory mediators (CXCL8, CCL20, CCL2), confirming its regulatory role. Spatial transcriptomics further confirmed NFKBIZ expression in dermal fibroblasts in vivo, particularly in lesional psoriatic skin. This study establishes IκBζ as a critical modulator of inflammatory responses in dermal fibroblasts, expanding its recognized role beyond keratinocytes and immune cells, and highlights IκBζ inhibition as a potential therapeutic strategy.

Chronic inflammatory skin diseases such as psoriasis and hidradenitis suppurativa are driven by cytokines, including IL-17A and TNF. Although biologics targeting these cytokines have transformed therapy, the transcriptional contributions of individual skin-resident cell types remain unclear, and dermal fibroblasts have been largely overlooked compared with keratinocytes. To address this, we compared the transcriptional responses of primary human dermal fibroblasts and keratinocytes following in vitro stimulation with IL-17A, TNF, or both, using bulk RNA sequencing and Western blotting. Dermal fibroblasts mounted a stronger and broader proinflammatory response than keratinocytes. This was particularly evident in response to TNF and combined TNF/IL-17A stimulation, with enrichment for immune signalling and chemotaxis pathways and robust induction of chemokine genes, including CCL20, CXCL8, and IL6. Keratinocytes primarily upregulated genes associated with epithelial differentiation, barrier function, and protein regulation, including IL36G, S100A7A, and DEFB4A. The heightened fibroblast responsiveness correlated with increased TNF sensitivity and substantially higher TNFR2 (TNFRSF1B) expression and signalling compared with keratinocytes, suggesting a fibroblast-specific mechanism amplifying inflammatory responses. These findings challenge the keratinocyte-centric view of skin inflammation and identify dermal fibroblasts as active contributors and potential therapeutic targets in TNF- and Th17-driven skin diseases.

IntroductionPsoriasis is a common chronic inflammatory skin disease. Treatments lead to Q6 substantial improvement of most psoriasis plaques. However, it can be challenging to reach disease resolution in certain hard to treat areas such as scalp, and lower extremity. Here we map histologic and spatial transcriptomic differences between psoriasis lesions across different anatomical locations, to understand if differences can be linked to plaque-site specific treatment resistance.MethodsQuantitative immunohistochemical analysis and transcriptomic digital spatial profiling were performed on skin punch biopsies obtained from unaffected areas on the trunk, lesional (LS) areas of the scalp, upper extremity and lower extremity of 12 patients with psoriasis. Histological analysis showed no significant differences in epidermal thickness among LS skin from different body locations.ResultsImmunohistochemical markers (CD3, CD4, CD8, CD103, CD207, IL-12RB1, IL-17A, IL-23R, RORγt, FOXP3, and MPO) did not differ significantly between LS sites. Whole transcriptome spatial RNA profiling identified several differentially expressed genes that revealed site-specific transcriptomic differences. Notably, IL-23 signaling was significantly enriched in the lower extremity epidermis, and IL-17 signaling was more pronounced in the epidermis of LS samples.DiscussionThese findings highlight minimal histological and immunohistochemical variation, yet significant transcriptomic and pathway differences between psoriasis body locations, suggesting potential targets for site-specific therapeutic strategies.

IntroductionHidradenitis suppurativa is a painful inflammatory disease characterised by diverse cutaneous lesions that exhibit distinct clinical morphologies. The study aimed to examine the transcriptome of the various hidradenitis suppurativa lesion types.MethodsTranscriptomic analyses were performed using bulk RNA sequencing to examine the various lesion types, including draining tunnels, inflammatory nodules, non-draining tunnels, non-lesional skin from patients with hidradenitis suppurativa and normal skin from healthy individuals.Results/discussionPrincipal component and differential expression analyses revealed that these different lesion types exhibit distinct expression profiles while sharing common transcriptional features. Enrichment analysis of exclusively differentially expressed genes for each lesion type showed increased antigen presentation and cytotoxic T cell response in inflammatory nodules, including genes such as CD8B, HLA-C, and HLA-F. In accordance, cell-type enrichment analysis showed an elevated CD8+ T cell signature in inflammatory nodules. Gene set variation analysis demonstrated distinct inflammatory pathway signatures in hidradenitis suppurativa lesions, including heightened IL-1 signalling in draining tunnels with significant upregulation of IL1B and its receptor IL1R, but not IL1A. Furthermore, IL17A and IL17F were significantly increased in draining tunnels, inflammatory nodules, and non-draining tunnels, with IL17F showing the highest expression in draining tunnels. MMP3, MMP8, and MMP10 were preferentially upregulated in draining tunnels, indicating a role in tunnel activity. Moreover, AQP4 and AQP5 were significantly downregulated in both lesional and non-lesional hidradenitis suppurativa skin, suggesting a possible involvement in preclinical pathogenic events.ConclusionDistinct molecular signatures specific for each lesion type were identified, which may reflect differences in molecular mechanisms. These findings underscore the importance of distinguishing between lesion types in translational and clinical studies.

T helper 17 (Th17)-mediated skin diseases, such as psoriasis and hidradenitis suppurativa, are driven by a dysregulated cytokine network where the specific contribution of Interleukin (IL)-17F has historically been underestimated due to its lower intrinsic potency compared to IL-17 A. To elucidate the role of IL-17F in the dermal compartment, we performed bulk RNA sequencing on primary human dermal fibroblasts stimulated with recombinant IL-17 A or IL-17F, either alone or in combination with Tumor Necrosis Factor (TNF). While single stimulation confirmed the superior potency of IL-17 A, the addition of TNF completely abolished this hierarchy. Transcriptional profiling demonstrated that TNF synergizes potently with IL-17F, amplifying its inflammatory output to levels almost indistinguishable from the IL-17 A and TNF combination. This synergistic interplay drove a robust upregulation of pathogenic mediators, including neutrophil-attracting chemokines (CXCL1, CXCL8) and tissue-destructive enzymes (MMP1). These findings challenge the paradigm of IL-17F as a redundant homolog, demonstrating that within a TNF-rich pro-inflammatory environment, IL-17F overcomes its limited basal potency to mirror the inflammatory drive of IL-17 A functionally. This mechanism provides a biological rationale for the superior clinical efficacy observed with dual IL-17 A/F inhibition in chronic inflammatory skin diseases.

Evolution and outgrowth of drug-resistant cancer cells are common causes of treatment failure. Patients with leukemic cutaneous T-cell lymphoma have a poor prognosis because of the development of drug resistance and severe bacterial infections. In this study, we show that most patients with leukemic cutaneous T-cell lymphoma harbor multiple genetically distinct subclones that express an identical clonal antigen receptor but display distinct phenotypes and functional properties. These coexisting malignant subclones exhibit differences in tissue homing, metabolism, and cytokine expression and respond differently to extrinsic factors like Staphylococcus aureus and cancer drugs. Indeed, although S. aureus toxins selectively enhance activation and proliferation of certain subclones, these responsive subclones are also the most intrinsically sensitive to cancer drugs when the stimuli are removed. Consequently, although the divergent evolution of malignant subclones drives aggressiveness, adaptability, and drug resistance by removing extrinsic stimuli and mapping malignant subclones, we can expose inherent vulnerabilities that can be exploited in the treatment of these cancers. SIGNIFICANCE:Cancer cells have inherent disparity in hallmark traits, such as aggressiveness and intrinsic drug resistance. We show that segregation of hallmark traits on different coexisting subclones is common and augments adaptability, aggressiveness, and drug resistance of the overall cancer population. Importantly, this segregation exposes vulnerabilities that can be exploited in individualized therapies.

S1 shows sample and analysis pipeline overview. S2 shows malignant-associated gene and surface marker expression in PT17. S3 shows single-cell subclone identification by scTCR-seq, transcriptome and copy-number aberration inference. S4 shows subclonal copy-number aberration co-occurence. S5 shows subclone expression profile stability over time. S6 shows subclonal evolution by matching CITE-seq to flow cytometry. S7 shows validation of inferred CNAs by whole-exome and whole-genome sequencing. S8 shows tissue-associated subclone marker expression in PT09. S9 shows subclonal skin homing/retention markers. S10 shows additional subclonally activated pathways. S11 shows subclonal activation by S. aureus enterotoxins. S12 shows additional S. aureus enterotoxin response signature pathways. S13 shows flow validation of S. aureus enterotoxin response group differences. S14 shows subclonal Romidepsin resistance replicates from same patient at two blood draws. S15 shows subclonal response to inflammatory cytokines and Streptococcal SpeC. S16 shows paired TCR V-gene usage of malignant cells. S17 shows validation of flow cytometry gating and malignant purity estimation.

Background:Microvascular changes and angiogenesis play a key role in psoriasis and atopic dermatitis (AD), affecting lesional and, in AD, also nonlesional skin. Studies on nonlesional psoriatic skin show conflicting results. Both diseases involve inflammation-driven vascular changes. Optical coherence tomography angiography (OCTA) is a noninvasive tool for assessing capillary morphology and disease progression. Objectives:To examine microvascular alterations in psoriasis and AD using OCTA, assessing differences in lesional and nonlesional skin compared with healthy control skin; and to examine the potential of laser speckle contrast imaging (LSCI)-guided OCTA in monitoring skin in the same populations. Methods:Ten patients with psoriasis, 10 patients with AD and 5 healthy control participants were recruited. OCTA was used to measure microvascular parameters, including capillary loop depth, superficial plexus depth, vessel diameter, vessel density, vessel length and fractal dimension. LSCI-guided OCTA identified areas with the highest degree of inflammation within lesional skin. Comparisons were made between lesional and nonlesional skin in patients with psoriasis and AD. Results:Significant differences in microvascularity were found between lesional and nonlesional skin in patients with psoriasis and AD, as well as in comparison with healthy control participants. Differences in microvascular morphology were also identified in nonlesional skin of patients with psoriasis and healthy control participants, indicating systemic capillary changes. LSCI-guided OCTA did not enhance capillary detection. Conclusions:Our results suggest that psoriasis may involve systemic microvascular changes beyond local inflammation. While OCTA is a promising noninvasive tool, further research is needed to elucidate its clinical value.

Single nucleotide polymorphisms (SNPs) in the endoplasmic reticulum aminopeptidase 1 (ERAP1) and ERAP2 genes have been associated with susceptibility to various immune-mediated inflammatory diseases (IMIDs). We utilized a unique cohort from the National Centre for Autoimmune Diseases (NCAS) to investigate whether specific SNPs in ERAP1 and ERAP2 act as a shared genetic susceptibility factor across various IMIDs. The study population comprised 171 patients from the NCAS cohort with two or more IMIDs and 57 healthy controls. Using real-time PCR allelic discrimination methods, we genotyped specific SNPs in ERAP1 (rs30187, rs27524), ERAP2 (rs2248374) and HLA-C (rs4406273). The distribution of ERAP1 and ERAP2 risk/minor alleles, genotypes and haplotypes was similar in the NCAS cohort and in healthy controls. When stratifying for HLA-C*06:02 positive psoriasis patients, a disease-associated haplotype A-A-T (rs2248374, rs27524, rs30187) was identified, significantly increasing the odds for having psoriasis and one or more IMIDs (OR = 3.41, 95 % CI: 1.32 - 8.78, p = 0.008). While SNPs in ERAP1 and ERAP2 may not constitute a shared susceptibility factor across all IMIDs, this study suggests a complex interaction between HLA types, ERAP1, and ERAP2, potentially influencing the development of certain MHC-I-associated disorders.

Psoriasis, a chronic inflammatory skin disorder characterised by erythematous and scaly plaques, can be both physically and emotionally distressing for patients. Dead Sea climatotherapy (DSC), a treatment modality combining sun exposure, mineral-rich water and mud therapy during 4 weeks at Ein Gedi, Israel, is used for a small group of patients with psoriasis. This study aimed to investigate the cellular composition of psoriatic skin lesions at relapse after complete clearance from DSC. Skin biopsies from baseline, end of treatment and relapse were collected from eight patients with plaque psoriasis who achieved complete clearance from Dead Sea climatotherapy treatment. These biopsies were subjected to immunohistochemistry, RNA sequencing and quantitative polymerase chain reaction analysis (qPCR). Our findings demonstrate that DSC effectively reduces inflammatory markers to levels comparable to baseline non-lesional skin in the short term. The differential expression analysis identified several upregulated differentially expressed genes, including OSM, CXCL8, TREM1, CXCL1, CSF3R, BCL2A1 and CXCL2, in relapsed psoriasis skin compared with baseline lesional skin. These findings were confirmed by qPCR analysis. Pathway enrichment analysis indicated a marked upregulation of neutrophil-associated pathways in relapse skin compared with baseline lesional skin. Immunohistochemical staining for neutrophil markers, such as CD11b, CD15, CD66b, CD207, MPO and NE, showed a non-significant trend towards enhanced neutrophil infiltration and activation at relapse. In conclusion, while DSC provides short-term effectiveness in managing psoriasis, the initial relapse phase is associated with neutrophil activation and migration. Thus, targeting neutrophils early in the psoriasis disease course may disturb the evolution of psoriasis, potentially preventing disease chronicity.

Antibodies used (with vendor, catalogue number and RRID)

Cutaneous T-cell lymphomas are a heterogeneous group of non-Hodgkin lymphomas. Early stages are often controlled with skin-directed therapy, such as topical corticosteroids, topical chlormethine gel, or UV therapy, whereas advanced stages often warrant a more aggressive approach with systemic antibody targeted therapy including mogamulizumab, brentuximab vedotin, or alemtuzumab. A retrospective cohort case series of 27 patients from Aarhus University Hospital, Denmark is presented, evaluating real-world outcomes of patients with cutaneous T-cell lymphomas treated with intravenous systemic targeted therapies from 2013 to 2023. The median age was 72 and the majority had Sézary syndrome or mycosis fungoides. All patients had relapsed/refractory advanced stage cutaneous T-cell lymphoma. Six patients received mogamulizumab, 12 patients received brentuximab vedotin, and 15 patients received alemtuzumab. Six patients received more than 1 of the systemic targeted treatments. Overall response rates were 78% for mogamulizumab, 65% for brentuximab vedotin, and 61% for alemtuzumab. Median time to progression was 2.5, 4, and 11 months, respectively. In conclusion, this paper offers a unique perspective on the complexities of clinical practice when managing advanced-stage cutaneous T-cell lymphomas and demonstrates the effectiveness of the therapies described, with particular emphasis on the promising results observed with alemtuzumab administered in a low-dose protocol.

HSP90, a molecular chaperone, has been identified as a drug target in inflammatory skin diseases. However, 4 different HSP90 isoforms (HSP90α, HSP90β, GRP94, and TRAP1) exist. Therefore, this study aimed to evaluate the functional role of the HSP90 isoforms in skin inflammation. Selective knockdown of the HSP90 isoforms revealed different inflammatory effects in stimulated keratinocytes. TRAP1 knockdown significantly downregulated the expression of the measured inflammatory genes (IL1B, IL6, IL17C, IL23A, IL19, IL36G, CXCL8, CCL5, CCL17, CCL20). Selective and combined knockdown of HSP90α and HSP90β showed a trend toward increased inflammatory activity. Selective GRP94 knockdown and combined knockdown of the organelle-specific isoforms (GRP94 + TRAP1) or all 4 isoforms resulted in inconsistent effects. In addition, a selective TRAP1 inhibitor (gamitrinib) suppressed the inflammatory gene expression in keratinocytes and fibroblasts (IL17C, IL23A, IL36G) and in hidradenitis suppurativa skin cultured ex vivo (IL1B, IL6, CXCL8, IL17A, IL36G). In conclusion, selective and simultaneous knockdown of the HSP90 isoforms mediated different inflammatory effects, revealing that the HSP90 isoforms have distinct roles in skin inflammation. In addition, we discovered that inhibition of TRAP1 exerted consistent anti-inflammatory effects, suggesting that TRAP1 inhibitors may represent a topical therapeutic strategy for inflammatory skin diseases.