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Experimental Dermatology

Wiley

Preprints posted in the last 90 days, ranked by how well they match Experimental Dermatology's content profile, based on 10 papers previously published here. The average preprint has a 0.01% match score for this journal, so anything above that is already an above-average fit.

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Health-related quality of life in mild-moderate patchy alopecia areata: Results from the first controlled Phase 2 clinical trial in this population with STS01 (dithranol/ProSilic) and challenges for the future

Fleet, D. M.; Messenger, A.; Bryden, A.; Harris, M. J.; Holmes, S.; Farrant, P.; Leaker, B.; Takwale, A.; Oakford, M.; Kaur, M.; Mowbray, M.; Macbeth, A.; Gangwani, P.; Gkini, M. A.; Jolliffe, V.

2026-04-04 dermatology 10.64898/2026.04.02.26349940 medRxiv
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A phase 2, randomised, double-blind, placebo controlled trial has been conducted in mild to moderate patchy alopecia areata (AA). This demonstrated significant and dose related improvements in hair regrowth with STS01, a controlled release, topical formulation of dithranol. Here we report the results of the Alopecia Areata Symptom Impact Scale (AASIS) that assesses the severity of symptoms, daily functioning and feelings. Similar to trials in severe AA, significant improvements in hair regrowth did not translate into significant health-related quality of life (HRQoL) improvements, even in patients with complete hair regrowth, although there was some treatment-related correlation between changes in AASIS scores from baseline and clinical assessment SALT scores. The use of current HRQoL methods or indeed new measures in development for future trials, will have considerable challenges: patients may not have a true baseline at entry, may develop coping mechanisms, and there may be a delay between physical and psychological improvement.

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Hair follicle-derived epithelial sheet has potential in vitiligo treatment

Li, J.; Chen, J.; Ling, L.; Tan, Z. L.; Sun, T.; Lin, J.; Chen, S.; Uyama, T.; Zhang, Q.; Liu, Q.; Wu, F.; Wu, W.

2026-03-30 dermatology 10.64898/2026.03.24.26349027 medRxiv
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Vitiligo is an acquired pigmentary disorder of the skin and mucus membranes. Previous study has demonstrated that autologous cultured epithelial grafts (ACEG) is an effective treatment for stable vitiligo. However, extraction of full-thickness skin might result in scar formation at donor site, which have hindered the wider application of this technology, especially for patients requiring large-area transplantation. Hair follicle as a source of keratinocyte and melanocyte, could be potential source of cells for preparation of autologous cultured sheet. Through culture system optimization, we have demonstrated maintenance of undifferentiated hair follicle-derived cells in feeder-independent culture system. After expansion, the hair follicle cells were directed to differentiate into a multi-layered, epidermis-like sheet. Cell identity, viability, purity, genomic stability, and antiseptic testing for hair follicle-derived epithelial sheet (HFES) were evaluated to ensure its safety. Immunofluorescence staining showed that basal keratinocytes were the main cell type of the autologous HFES. Optimization of culture conditions leads to increased melanocyte proliferation and functionality. Transcriptomic analysis confirmed upregulation of melanosome maturation genes. The proportions of cells are also similar to composition of cells under physiological conditions. Transplantation of HFES to depigmented areas in patients with stable vitiligo results in skin repigmentation. This technology provides a novel therapeutic option for vitiligo management.

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Advancing Hair Loss Assessment in Alopecia Areata: The Mathematical Case for Centralised, Standardised Imaging

Fleet, D. M.; Messenger, A.; Bryden, A.; Harris, M. j.; Holmes, S.; Farrant, P.; Leaker, B.; Takwale, A.; Oakford, M.; Kaur, M.; Mowbray, M.; Macbeth, A.; Gangwani, P.; Gkini, M. a.; Jolliffe, V.

2026-04-04 dermatology 10.64898/2026.04.02.26349939 medRxiv
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Background In clinical trials for alopecia areata (AA) the treatment effect (percentage of hair loss) is estimated using the Severity of Alopecia Tool (SALT) score. Trials in patients with severe AA (>=50% hair loss) employed a local rating of the SALT score performed at trial sites by different investigators. However, in mild-to-moderate AA (<= 50% hair loss) where SALT scores are lower, potential inter rater variability and margin of error may compromise the results. Objectives To compare Centralised and Local measurement of hair loss in mild moderate AA. Methods In a Phase 2 clinical trial a centralised measurement of hair loss was performed from photographic images taken using a standardised protocol and professional camera equipment. Local scoring was also undertaken at screening/baseline for eligibility. We assessed: the repeatability of the central system (screening vs baseline values), the reproducibility of the central versus the local rating system and the potential impact of each method on the endpoints using a Monte-Carlo simulation method. Results There was good agreement and consistency of scoring with Central rating. This provided much smaller margins of error, 50% lower than Local rating. The simulations demonstrated that substituting Local rating for Central rating would result in a reduction of the likelihood of a statistically significant outcome by at least 50% depending on the SALT score defined clinical response endpoint. Conclusions Central rating is most appropriate in the Phase 2 learning stage of clinical development and provides an accurate representation of the quantity of hair loss, minimising error and ensuring consistency in measurements.

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Efficacy, safety and dose response of STS01, a topical controlled release nanoparticle formulation (dithranol/Prosilic), in adults with mild to moderate patchy alopecia areata: A randomised, double-blind, multicentre, phase 2 trial

Fleet, D.; Messenger, A.; Bryden, A.; Harris, M. J.; Holmes, S.; Farrant, P.; Leaker, B.; Takwale, A.; Oakford, M.; Kaur, M.; Mowbray, M.; MacBeth, A.; Gangwani, P.; Gkini, M. A.; Jolliffe, V.

2026-04-04 dermatology 10.64898/2026.04.02.26349934 medRxiv
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Background There are no licensed treatments for patients with mild to moderate patchy alopecia areata (AA). Objectives To evaluate the efficacy, safety and dose response of STS01, a novel nanoparticle controlled release, topical formulation of dithranol/Prosilic. Methods In a phase 2, double blind study, adult patients with mild to moderate AA (guideline 10% to 50% of scalp hair loss) were randomly assigned to STS01 at doses of 0.25%, 0.5%, 1%, 2% or placebo, daily for 6 months. The primary endpoints included the proportion of patients achieving a >=30% improvement in Severity of Alopecia Tool (SALT) score, and percentage change from baseline in SALT score. This minimum level of improvement is generally accepted as an indicator of the population likely to progress to complete regrowth Results A total of 155 patients were randomized and treated (placebo, n=32; STS01 groups, n=30 to 31). STS01 1% met the primary efficacy endpoint of >=30% SALT score improvement compared to placebo: 75.9% (95% CI, 60.3 to 91.4%) vs 36.7% (95% CI, 19.4 to 53.9%) at 6 months; p=0.0037. The least squares (LS) mean percentage change in SALT score from baseline to end of treatment showed a clear dose response relationship; STS01 0.5% was the minimally effective dose and 2% the maximum tolerated dose, and there was a statistically significant improvement in the STS01 1% group (minus 55.0% vs +0.6% with placebo; p<0.01). Significant improvements (p<0.05) in LS mean percentage changes from baseline in SALT scores were demonstrated in the STS01 1% group at 2 months (-28.6% vs 12.8%), 4 months (-57.2% vs 1.5%), and 6 months (minus 67.0% vs 0.6%). Clinical Global Impression improvement was reported in 72.0% of patients with STS01 1% vs 41.7% with placebo (p<0.05). The most commonly reported treatment emergent adverse events were skin irritation reactions, but were mostly mild (STS01: 56.7% to 71.0%; placebo: 21.9%) or moderate (STS01:13.3% to 35.5%; placebo: 0%) and manageable by reduced frequency of application. There were 15 skin-related discontinuations with STS01 (12.2%) and 2 (6.3%) with placebo. Conclusions STS01 demonstrated a clear dose response, with STS01 1% dose optimally more effective than placebo for hair regrowth with minimal tolerance concerns in mild to moderate patchy AA. Skin irritation reactions were generally manageable and there were no new safety signals. Further characterisation of the STS01 1% dose is planned in a phase 3 study. Chief Investigator AGM reports fees from Soterios Ltd. Chief Statistician DMF is an employee of Soterios Ltd. All other authors were Principal Investigators in the trial and their clinics were reimbursed for the work involved. Most also had sponsorship in the form of consultancies, investigational roles or lecturing roles on behalf of other Dermatological pharmaceutical companies

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Patient Perspectives and Satisfaction: Educational Needs and Communication Barriers in Dermatology Clinics in Saudi Arabia - A Cross-Sectional Survey

Alshammarie, F.; Alhobera, A.; Alshammari, M.

2026-03-12 dermatology 10.64898/2026.03.11.26348118 medRxiv
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PurposeUnderstanding patient perspectives is essential to improving quality and satisfaction of care in dermatology clinics. In Saudi Arabia, limited national data exist on patients educational needs and communication barriers. This study aimed to assess patient satisfaction, identify educational gaps, and explore communication challenges in dermatology clinics across Saudi Arabia. Patients and methodsA national cross-sectional survey was conducted among 976 dermatology patients. A structured questionnaire evaluated demographics, perceived knowledge, satisfaction with information provided, communication barriers, and preferred educational methods. Descriptive statistics and chi-square tests were used for analysis. ResultsAmong participants who had attended dermatology clinics (n = 795), 61.6% reported frequent or occasional confusion about their condition, and only 45.4% demonstrated high self-reported knowledge. Overall satisfaction was moderate, with 58.3% satisfied or very satisfied, while 9.9% reported dissatisfaction. The most reported communication barriers were limited consultation time (25.2%) and patient anxiety about asking questions (15.3%). Patients felt least informed about treatment options (22.6%), diagnosis (20.3%), and potential side effects (19.3%). Most participants (70.6%) preferred language communication to be in Arabic, and 78% favored the physical method of face-to-face education consultation. Patient knowledge, barriers and preferences significantly differed with age, gender, and condition complexity (p < 0.05). ConclusionDermatology patients in Saudi Arabia report moderate satisfaction with substantial educational needs and communication barriers. Addressing consultation time constraints, fostering supportive communication environments, and providing patient-centered, language-appropriate education; particularly through direct face-to-face interactions will aid to enhance understanding, satisfaction, and engagement in for an overall better provider-patient dermatologic care.

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Healthcare Equity in Vitiligo Management: A Comparative Cross-Sectional Analytical Study of Patients Profiles, Clinical Outcomes, and Quality of Life in Public versus Private Hospitals in Kandahar, Afghanistan

Farooqi, K.; Rahimi, B. A.; Hirman, A. R.; Tarin, Z.; Sharma, S. K.

2026-02-02 dermatology 10.64898/2026.01.30.26345190 medRxiv
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BackgroundHealthcare system disparities have a significant impact on chronic disease management in conflict-affected settings. Vitiligo, a stigmatizing dermatological condition, requires sustained care, yet limited evidence exists regarding how healthcare sector differences affect patient outcomes in Afghanistan. This study addresses this critical knowledge gap in a post-conflict, resource-limited setting. The main objectives of this study were to compare socio-demographic profiles, clinical characteristics, psychological burden, and health-related quality of life (HRQoL) between vitiligo patients attending public versus private hospitals in Kandahar, Afghanistan. MethodsA cross-sectional analytical study was conducted from March 2023 to January 2024 with 402 vitiligo patients (153 [38.1%] from three public hospitals and 249 [61.9%] from five private hospitals). Comprehensive assessment included socio-demographic variables, clinical severity (Vitiligo Area Severity Index [VASI]), psychological distress (General Health Questionnaire-12 [GHQ-12]), anxiety (Hamilton Anxiety Rating Scale [HAM-A]), depression (Quick Inventory of Depressive Symptomatology [QIDS-SR16]), and HRQoL (Dermatology Life Quality Index [DLQI]). Stratified analyses, multivariable linear regression, and interaction testing were performed. ResultsCompared to public hospitals, patients visiting private hospitals were younger (69.3% aged 18- 29 years, {chi}2=21.4, p<0.001), more rural (65.5%, {chi}2=12.7, p<0.001), and less educated (63.9% illiterate, {chi}2=15.2, p<0.001). However, clinical severity (VASI: public M=6.58{+/-}7.47; private M=6.84{+/-}4.64; t=-0.427, p=0.670), psychological burden, and HRQoL showed no significant differences between sectors. Interaction analyses revealed moderating effects: disease severity impacted HRQoL more strongly in public hospitals (VASIxhospital type: B=-0.168, 95%CI: - 0.258 to -0.077, p<0.001, {beta}=-0.515), while psychological distress affected HRQoL more in private settings (GHQxhospital type: B=0.440, 95%CI: 0.094 to 0.785, p=0.013, {beta}=0.442). ConclusionWhile demographic disparities exist in healthcare access, clinical and psychological outcomes are similar across sectors. However, pathways to HRQoL impairment differ significantly, suggesting sector-specific mechanisms requiring tailored interventions. These findings highlight the need for equitable, context-sensitive vitiligo care that addresses both universal and sector-specific determinants of patient well-being in conflict-affected settings.

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Diagnostic accuracy of two-photon fluorescence microscopy in the Mohs micrographic surgical margins of squamous cell carcinoma

Huang, C. Z.; Ching-Roa, V. D.; Heckman, C. M.; Mould, K.; Sipprell, W. H.; Smoller, B. R.; Ibrahim, S. F.; Giacomelli, M. G.

2026-02-24 dermatology 10.64898/2026.02.21.26346787 medRxiv
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Cutaneous squamous cell carcinoma (SCC) can be time-consuming to treat with Mohs micrographic surgery (MMS) due to the need for intraoperative frozen section (FS) preparation. Two-photon fluorescence microscopy (TPFM) can generate H&E-equivalent images from fresh tissue specimens in a fraction of this time. To determine the accuracy of TPFM for the evaluation of squamous cell carcinoma in MMS margins compared to conventional FS Mohs slide preparation. TPFM was used to image 144 first stage MMS margins from patients being treated for SCC. A Mohs surgeon reviewed 44 training images and then evaluated 100 margins. After a delay, the same surgeon evaluated the corresponding FS slides. Pairs of TPFM and FS slides were reviewed by an expert dermatopathologist to form a consensus diagnosis. Agreement with consensus diagnosis as assessed by an independent dermatopathologist. 3 margins (3%) unequivocally disagreed with the consensus on TPFM and 2 margins (2%) disagreed on FS. The sensitivity and specificity of TPFM were 95.1% and 98.2%, respectively. This study demonstrates that slide-free histology can be interpreted equivalently to conventional Mohs slide processing by both MMS surgeons and dermatopathologists with minimal training.

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Cancer Cell Line Encyclopedia Data Suggest that Ligands for ERBB Family Receptors May Drive BRAF-WT Melanomas

Wilson, E.; Conway, A.; Riese, D. J.

2026-03-18 cancer biology 10.64898/2026.03.16.712185 medRxiv
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I.Cutaneous skin melanomas with wild-type BRAF alleles ("BRAF-WT melanomas") remain relatively difficult to treat, even though they typically possess driver mutations in a RAS gene or NF1. For example, these tumors respond relatively poorly to combinations of MEK and BRAF inhibitors, and their response to ICIs is muted compared to the response of BRAF-mutant melanomas. ERBB2 and ERBB4, which encode receptor tyrosine kinase genes, are necessary and sufficient for the proliferation of multiple BRAF-WT melanoma cell lines. Consequently, we have postulated that ERBB4-ERBB2 heterodimerization drives BRAF-WT melanomas. This mechanism is consistent with the observation that elevated ERBB4 transcription or ERBB4 mutations are found in a significant fraction of BRAF-WT melanoma tumor samples. Moreover, a subset of ERBB4 mutations found in BRAF-WT melanoma samples increases proliferation in a BRAF-WT melanoma cell line. Because the elevated ERBB4 transcription observed in BRAF- WT melanomas is typically insufficient to cause ligand-independent ERBB4 signaling, we have postulated that ligands for ERBB family receptors drive the elevated ERBB4-ERBB2 heterodimerization responsible for the proliferation of BRAF-WT melanoma cell lines. We have explored this hypothesis by analyzing data found in the Broad Institutes Cancer Cell Line Encyclopedia. These data suggest that some EGF family hormones are required for the proliferation of BRAF-WT melanoma cell lines. Likewise, the G11/Gq pathway, which can stimulate cleavage and maturation of EGF family hormones, is also required for the proliferation of BRAF-WT melanoma cell lines. Thus, these data suggest additional therapeutic targets in BRAF-WT melanomas. Moreover, because many uveal (ocular) melanomas possess elevated G11/Gq signaling, these data suggest that ligand stimulation of ERBB receptor signaling may contribute to uveal melanomagenesis or progression.

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Grading of Erythema and Visual Attributes in Atopic Dermatitis across Diverse Skin Tones Using a Vision AI Pipeline

Abdolahnejad, M.; Kyremeh, M.; Smith, J.; Fang, G.; Chan, H. O.; Joshi, R.; Hong, C.

2026-03-31 dermatology 10.64898/2026.03.30.26349755 medRxiv
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Background: Atopic dermatitis (AD) is a prevalent chronic inflammatory skin disease associated with clinical, psychosocial, and economic burden. Accurate severity assessment is essential for guiding treatment escalation and monitoring disease activity, yet clinician-based scoring systems such as the Eczema Area and Severity Index (EASI) are limited by subjectivity and considerable inter- and intra-rater variability. Erythema, a key driver of AD severity grading, is particularly prone to inconsistent evaluation due to differences in ambient lighting, device quality, skin tone, and rater experience, underscoring the need for objective, reproducible assessment tools. Objective: To develop and validate an artificial intelligence (AI) pipeline for grading erythema, excoriation, and lichenification severity in AD from clinical photographs. The study evaluated the level of agreement between AI severity ratings in each category against dermatologists, non-specialists, and a consensus reference standard, with erythema as the primary outcome of interest. Methods: A two-stage AI pipeline was developed using EfficientNet B7 convolutional neural networks (CNNs). The first CNN was trained as a binary AD classifier on 451 AD and 601 non-AD images for lesion detection and segmentation. The second CNN was trained on 173 dermatologist-annotated AD images which were scored on a 0-3 ordinal scale for erythema, excoriation, and lichenification. This CNN had a downstream feature extraction algorithms such red channel contrast for erythema, Law's E5L5 for excoriation, and S5L5 texture maps for lichenification. In a cross-sectional validation study, 41 independent test images were scored by two blinded dermatologists and two blinded physicians. AI predictions were compared to individual rater groups and mode-derived consensus scores using weighted Cohen's kappa, classification accuracy, confusion matrices, and error direction analyses. Results: On internal validation, the severity CNN achieved 84% overall accuracy (averaged across all three attributes), 86% sensitivity, 87% specificity, and a macro-averaged area under the receiver operating characteristic curve (AUC) of 0.90. In the external comparison with blinded human raters, erythema agreement between the AI and dermatologist consensus was substantial (accuracy 80.7%; kappa = 0.68), with no large (>2-point) misclassifications. Physician consensus agreement was lower (accuracy 54.8%; kappa = 0.34), reflecting greater variability among primary care physicians (non-specialists). For excoriation, AI-dermatologist agreement was moderate (accuracy 72.4%; kappa = 0.62); for lichenification, agreement was similar (accuracy 71.4%; kappa = 0.59). Across all features, disagreements were predominantly between adjacent severity categories. The AI was able to generate erythema severity grades for images of darker skin tones that dermatologists typically would not rate and were marked as "unable to assess". Limitations: The validation set was small (41 images), severe cases (score 3) were underrepresented, one rater participated in both training annotation and validation scoring, and sample size was insufficient for robust stratification by skin tone or body site. Conclusion: The AI pipeline demonstrated dermatologist-level accuracy for erythema scoring, consistent moderate agreement for excoriation and lichenification, and a potential advantage in assessing erythema on darker skin tones. These findings support its potential as a standardized, objective tool for AD severity assessment. Prospective validation in larger, more diverse cohorts is warranted.

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Global Disparities in Access to Dermatological Care: the Skin Health Observatory

Freeman, E. E.; Yardman-Frank, J. M.; Kilmer, J.; Pacheco, A.; Su, K.; McMahon, D. E.; Li, C.; Anwar, S.; Barger, K.; Qian, Y.; Strahan, A.; Westby, S.; Bhat, R.; El Sayed, M.; Enbiale, W.; Galvan-Casas, C.; Gao, X.; Gondokaryono, S. P.; Kibbi, A. G.; Lee, A.; Ly, F.; Ocampo-Candiani, J.; Richard, M.-A.; Romiti, R.; Lim, H. W.; Takeshita, J.; Kerob, D.; Chuberre, B.; de Lambert, G.; Fuller, L. C.; Griffiths, C. E. M.; Dlova, N. C.

2026-02-09 dermatology 10.64898/2026.02.06.26345759 medRxiv
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BackgroundSkin disease affects 4.7-4.9 billion individuals globally; however, little is known about access to dermatological care. MethodsWe conducted a multinational, cross-sectional survey of dermatological care across 194 WHO member states and three additional geographic areas in 2024-2025. Primary outcomes included dermatologist density per 100,000 population and number of dermatologists globally. Secondary outcomes included training programme density, workforce distribution, perceived access to care, and health system characteristics. Descriptive statistics and nonparametric tests compared outcomes across World Bank Income (WBI) levels and WHO regions. FindingsResponses were obtained from 158 countries. Mean dermatologist density was 2.66 per 100,000, ranging from 0.37 in low-income (LICs) to 5.05 in high-income countries (HICs). There are estimated 175,633 dermatologists globally (95% CI: 173,598-177,668). Forty-two percent of countries reported inadequate or extremely poor access to dermatological care. There was significant variation (p < 0.001) in access to all types of subspecialty care (paediatric, surgical, dermatopathology) across WBI levels, with consistently worse access in lower-income countries. Dermatologists are primarily based in urban centres (79%). Twenty-one percent of countries lack dermatology training programs, with training varying by WBI level (p < 0.001). Non-dermatologist healthcare workers bear a substantial responsibility for management of skin disease. InterpretationSignificant global disparities exist in access to dermatological care, particularly in lower resource settings. Achieving skin health equity will require global commitment to expanding/funding training programmes, incentivizing decentralization of dermatology practice, and optimizing alternative care delivery including upskilling front-line healthcare workers. FundingInternational League of Dermatological Societies and LOreal Dermatological Beauty.

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Copy Number Analysis in Congenital Nevi: Concordance and Diagnostic Limitations of aCGH, sWGS, and Methylation Profiling

Karelin, A.; Brecht, I. B.; Pogoda, M.; Demidov, G.; Abele, M.; Schneider, D. T.; Aldea, D.; Etchevers, H. C.; Puig, S.; Hahn, M.; Forchhammer, S.

2026-03-03 dermatology 10.64898/2026.03.03.26347388 medRxiv
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BackgroundDistinguishing benign proliferative nodules (PNs) from melanoma arising within congenital melanocytic nevi remains a major diagnostic challenge. Copy number alteration (CNA) analysis is widely used to support classification, but current criteria were developed using array comparative genomic hybridization (aCGH). The performance of alternative platforms such as shallow whole-genome sequencing (sWGS) and methylation arrays in this setting is poorly defined. ObjectivesThe objective of this study is to compare CNA profiles obtained from aCGH, sWGS, and methylation arrays in atypical nodules arising within congenital nevi, and to correlate these molecular findings with clinical outcomes. MethodsSixteen samples from fourteen patients were retrospectively analyzed using all three platforms. CNAs were cataloged, concordance across methods was quantified using the Jaccard index, and molecular classifications were compared. Clinical follow-up was reviewed to provide clinical context. ResultsaCGH detected 39 CNAs, sWGS 60, and methylation profiling 66. Concordance was highest between sWGS and methylation (mean Jaccard 0.67), followed by aCGH versus sWGS (0.64) and aCGH versus methylation (0.49). Cases with high aneuploidy demonstrated strong cross-platform agreement, whereas low-burden lesions exhibited greater variability between methods. Divergent molecular classifications were observed in six cases. ConclusionsWhile all methods reliably detect broad chromosomal changes, sWGS and methylation arrays identify many additional focal CNAs that may not align with CGH-based diagnostic criteria. Until platform-specific thresholds are established, aCGH remains the most conservative and clinically validated approach for evaluating proliferative nodules in congenital nevi. SIGNIFICANCEAccurate molecular classification of melanocytic proliferations in congenital nevi is essential but challenging, particularly in patients with multiple proliferative nodules. This study provides the first systematic comparison of aCGH, sWGS, and methylation-based CNA profiling in this setting. We show that higher-resolution platforms detect substantially more focal aberrations, which can lead to discordant and potentially overcalled malignancy assessments when applying CGH-derived criteria. Our findings highlight the need for platform-adapted diagnostic frameworks and support continued use of CGH as the most conservative and clinically validated method for risk stratification. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=118 HEIGHT=200 SRC="FIGDIR/small/26347388v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1d7b155org.highwire.dtl.DTLVardef@1bb7081org.highwire.dtl.DTLVardef@d72e3forg.highwire.dtl.DTLVardef@11d3f0b_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Multi-omics Analyses of Facial Skin in Acne Identify Distinct Microbial and Metabolic Features at Lesional and Non-lesional Sites

Chen, Y.; De Pessemier, B.; Myers, T.; Zuffa, S.; Zemlin, J.; Pourhamidi, S.; Dal Belo, S. E.; Woo, A.; Moreau, M.; Idkowiak-Baldys, J.; Kalcheva, I.; Gomes, P. W. P.; Lieng, C.; Almoughrabie, S.; Dan Nguyen, A.; Espinoza, J. L.; Dupont, C. L.; Van de Wiele, T.; Callewaert, C.; McDonald, D.; Zengler, K.; Bartko, A.; Aguilar, L.; Barbarat, P.; Gallo, R. L.; Dorrestein, P. C.; Zheng, Q.; Bouslimani, A.; Song, S. J.; Knight, R.

2026-02-10 microbiology 10.64898/2026.02.10.702622 medRxiv
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The microbial and biochemical landscape of clinically normal-appearing skin in individuals with acne remains uncharacterized. Here, we performed longitudinal multi-omics profiling of facial skin from 10 individuals with moderate acne and 10 healthy controls, integrating 16S rRNA gene sequencing, shotgun metagenomics, and untargeted metabolomics across lesional and non-lesional sites. Compositional tensor factorization revealed that non-lesional acne skin occupies a distinct intermediate state between healthy and lesional skin in both the microbiome and the metabolome. Machine learning models distinguished healthy from non-lesional acne skin with 70% accuracy, demonstrating that molecular dysbiosis occurs in areas of the skin without visible lesions. Non-lesional sites exhibited reduced microbial diversity, strain-level shifts in Corynebacterium and Lawsonella correlating with disease severity, and metabolic alterations, including elevated lipids and perturbed amino acid and dipeptide profiles. Microbe-metabolite co-occurrence network analyses revealed that healthy skin is enriched for protective metabolites such as urocanic acid, while acne-associated skin shows distinct co-occurrence patterns. These findings establish that acne represents a field effect disorder, with molecular alterations extending beyond visible lesions to encompass the entire facial skin ecosystem. This molecular signature of pre-lesional skin provides potential biomarkers for early intervention and suggests that effective acne treatment may require holistic approaches targeting the broader skin environment rather than individual lesions alone.

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TYK2 Inhibition with Deucravacitinib Improves Clinical Outcomes and Resolves Interferon-Driven Inflammation in Lichen Planopilaris

Stockard, A.; Leibovit-Reiben, Z.; Hu, B.; Jiang, R.; Roberts, B. T.; Penner, S.; Li, X.; Ramirez, Z.; Stewart, K.; Fox, J.; Bogle, R.; Zhang, N.; Shao, S.; Borges Da Silva, H.; DiCaudo, D. J.; Zunich, S.; Pincelli, T. P.; Tsoi, L. C.; Pittelkow, M. R.; Sluzevich, J.; Gudjonsson, J. E.; Mangold, A. R.

2026-03-22 dermatology 10.64898/2026.03.13.26348272 medRxiv
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Lichen Planopilaris (LPP) is a lymphocyte-mediated scarring alopecia characterized by progressive follicular destruction and fibrosis. In this clinical trial, patients with biopsy proven LPP were treated with deucravacitinib (an oral inhibitor of tyrosine kinase 2 (TYK2)) 6 mg BID for 24 weeks (NCT-06091956). Bulk and single-cell RNA sequencing was performed on paired pre- and post-treatment scalp biopsies from baseline and week 4. Patients (N=10) demonstrated improvements in PGA (88.9%, p=0.008), LPPAI (-2.3 points, SD 1.1, p=0.002) and Skindex-16 (-21.0 points, SD 22.1, p=0.014) scores at week 24. Bulk transcriptomic analysis of untreated LPP revealed upregulation of type I Interferon (IFN)-stimulated genes and pathways related to inflammation, immune activation, keratinization, and extracellular matrix remodelling, with downregulation of immune and inflammatory pathways following treatment. Single-cell RNA-seq of LPP was characterized by enrichment of CD8+GZMK+ T cells which showed downregulation of T-cell receptor signaling as well as antiviral pathways with treatment. Basal keratinocytes exhibited reduced cytokine and interferon signaling and decreased communication with NK cells following treatment. CCL19+ fibroblasts were prominent in untreated disease was attenuated after treatment, with downregulation of type I IFN signaling. Selective TYK2 inhibition with deucravacitinib effectively suppresses these inflammatory circuits in LPP and represents a promising therapeutic strategy.

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Knowledge, Attitudes, and Practices (KAP) Regarding Photoprotection Among Medical Students at a Nicaraguan University: A Cross-Sectional Study

Montes, J.; Noguera, B.; Obregon, A.; Rivas, A.; Whynot, H.; Poveda, R.; Blandon, V.

2026-02-26 dermatology 10.64898/2026.02.24.26347045 medRxiv
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BackgroundMedical students represent a critical population for photoprotection education, as future physicians responsible for skin cancer prevention counseling. However, no previous studies have characterized knowledge, attitudes, and practices (KAP) regarding photoprotection among medical students in Central America or the Caribbean. ObjectiveTo assess KAP related to photoprotection and identify associated factors among medical students at a Nicaraguan university. MethodsA cross-sectional study was conducted among 133 medical students at the Universidad Iberoamericana de Ciencias y Tecnologia (UNICIT), Managua, Nicaragua. An ad hoc questionnaire assessed sociodemographic characteristics, knowledge, attitudes, and photoprotective practices. Domain-specific and global KAP scores were calculated. Bivariate analyses examined associations with sex, academic year, skin phototype, and age. ResultsParticipants were predominantly female (73.7%), with a median age of 20 years (IQR: 18-21). Although 97.0% knew what sunscreen is and 88.0% correctly identified adequate sunscreen characteristics, only 33.1% knew the minimum recommended SPF for daily use, and 21.8% understood endogenous photoprotective mechanisms. Regular sunscreen use was reported by 39.1%, while 24.8% reported never using it. Women demonstrated significantly higher scores across all domains, with moderate effect sizes for practice (d = 0.56) and global KAP (d = 0.60). No improvements were observed across academic years (p > 0.05). Age showed weak negative correlations with practice ({rho} = -0.237; p = 0.006) and global KAP ({rho} = -0.204; p = 0.018). The primary barrier to sunscreen use was forgetfulness (49.6%). ConclusionsThis first KAP study among medical students in Nicaragua reveals a substantial gap between photoprotection knowledge and practice. Current medical training appears insufficient to promote sustained protective behaviors. Findings support integrating practical, behavior-oriented photoprotection education into medical curricula and establish a regional baseline for future interventions.

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The stem cell compartment in human oral mucosa and its activation in oral lichen planus.

Schreurs, O. J. F.; Fedele, S.; Porter, S.; Kjolle, G. K.; Schenck, K.; Soland, T. M.; Walko, G.

2026-03-06 cell biology 10.64898/2026.03.04.709521 medRxiv
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In mice, oral epithelial stem cells (OESCs) are essential for oral mucosal homeostasis and repair. Less is known regarding the role of OESCs in the human oral mucosa. Here, we studied the behaviour of OESCs and their contribution to tissue maintenance and repair in oral lichen planus (OLP). OLP is a chronic T cell-mediated disease characterized by basal keratinocyte degeneration, epithelial atrophy, acanthosis, and hyperkeratosis. Using immunohistological techniques and semi-automated image analysis, we observed that in OLP proliferative activity was increased in the normally largely quiescent basal cell compartment. In areas of OLP mucosa with intact basal cell layer, expression of NGFR, KRT15, and KRT19-markers of slowly cycling reserve OESCs, was strongly reduced or absent. In contrast, expression of CSPG4, a marker for actively cycling stem cells, was increased in OLP basal cells. Tissue compartmentalization, as evaluated by keratin expression, was strongly disturbed. Taken together, our findings indicate that the inflammation in OLP leads to activation and proliferation of OESCs that give rise to a population of cells with an aberrant differentiation programme. Along with the well-documented epithelial up-regulation of anti-apoptotic proteins in OLP, this likely reflects an attempt by the epithelium to avoid overt ulceration.

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Photodynamic priming with Vitamin D and ALA-based PDT induces intratumoral immune cell recruitment and signaling pathway activation in murine cutaneous squamous cell carcinoma

Shen, A. S.; Anand, S.; Cheng, C.-E.; Kovacic, B.; Powers, J.; Diaz, C. M.; Hasan, T.; Maytin, E. V.

2026-02-06 cancer biology 10.64898/2026.02.04.703788 medRxiv
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Photodynamic therapy (PDT) is effective for early epithelial pre-cancers, yet its efficacy in fully-developed cutaneous squamous cell carcinoma (SCC) is limited by immunosuppression in the tumor microenvironment. Vitamin D (VitD) has emerged as a potential neoadjuvant to enhance photodynamic priming in several cancers. Here, we investigated how VitD pretreatment modulates local and systemic immune responses to aminolevulinic acid-based PDT in two immunocompetent murine SCC models (chronic UV-induced SCC, and subcutaneously implanted PDVC57B cells). VitD combined with PDT significantly amplified hallmarks of immunogenic cell death, including calreticulin and HMGB1 expression, and increased recruitment of neutrophils, macrophages, dendritic cells, and CD8 T cells into tumors. Importantly, VitD+PDT produced a higher M1/M2 macrophage ratio, and reduced the number of exhausted (PD-1 expressing) T cells compared to PDT alone. Immune profiling of blood demonstrated enhanced T-cell activation (CD69) and reduced TIM-3 expression on cytotoxic T cells. Transcriptomic analysis revealed pathway enrichment for interferon-/{gamma} signaling and suppression of pro-tumorigenic epithelial-mesenchymal transition and of angiogenesis after VitD+PDT. Collectively, these findings demonstrate that VitD reprograms the immune response to PDT by enhancing cytotoxic immunity while limiting immunosuppressive features. This suggests an immune-priming strategy to consider, possibly alongside immune checkpoint blockade, for treating cutaneous SCC.

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Normative Reference Values for the FACE-Q Skin Cancer Module: Patient Preoperative Scores and Comparison With Healthy Partners

Ottenhof, M. J.

2026-02-16 surgery 10.64898/2026.02.12.26345805 medRxiv
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BackgroundThe FACE-Q Skin Cancer Module is a condition-specific patient-reported outcome measure for facial skin cancer. While its psychometric properties have been established, normative reference values that enable score interpretation in clinical practice and research are lacking. ObjectiveTo establish normative reference values for the FACE-Q Skin Cancer Module using preoperative patient data and to validate these values by comparison with a demographically matched cohort of healthy partners. MethodsTwo cohorts were analyzed: 287 patients with facial skin cancer (preoperative scores) and 82 healthy partners of skin cancer patients (same-age population without facial skin cancer). Both cohorts completed the Appearance (9 items) and Psychosocial Distress (8 items) scales. Patients additionally completed the Cancer Worry scale (10 items) and Sun Protection scale (5 items). Scores were transformed to a 0-100 scale. Normative values were expressed as percentiles overall and stratified by sex and age group. Group comparisons used independent t-tests, Mann-Whitney U tests, and Cohens d. Internal consistency was assessed with Cronbachs alpha. ResultsPatient and partner cohorts were well matched for age (68.6{+/-}11.9 vs 68.4{+/-}13.0, p=0.902) and sex (46.7% vs 41.5% female, p=0.476). Surprisingly, preoperative facial appearance scores were virtually identical between patients and partners (55.6{+/-}14.0 vs 56.6{+/-}13.6, p=0.590, d=-0.08), as were psychosocial distress scores (14.3{+/-}12.0 vs 14.4{+/-}13.3, p=0.942, d=-0.01). This equivalence held across age groups. A significant sex interaction was identified: female patients scored lower on appearance than female partners (54.3 vs 59.9, p=0.048, d=-0.40), whereas no difference existed among males (56.9 vs 53.1, p=0.168). Internal consistency was excellent in both cohorts (Cronbachs 0.82-0.93). Patients reported marginally higher sun protection behaviors than partners (38.0 vs 33.6, p=0.050). ConclusionsPreoperative FACE-Q Skin Cancer scores in patients are equivalent to those of demographically matched healthy individuals, confirming that these scores serve as valid normative references. The established percentile norms enable clinicians and researchers to interpret individual patient scores in context. The sex-specific difference in appearance scores warrants further investigation.

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Establishment of Stable Immortalized Human Choroidal Melanocytes for Ocular Research

Fuentes-Rodriguez, A.; Mitchell, A.; Gelinas, V.; Coutant, K.; Droit, A.; Landreville, S.

2026-02-17 cell biology 10.64898/2026.02.16.706000 medRxiv
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PurposeThe short lifespan of primary normal choroidal melanocytes (NCMs) in vitro represents a major barrier to mechanistic, functional, and translational studies of choroid biology and uveal melanoma (UM). This study aimed to establish and characterize immortalized human NCM lines that retain melanocytic function, maintain a non-cancerous profile, and are amenable to gene editing. MethodsNCMs from four donors were immortalized by lentiviral transduction of Cyclin-dependent kinase 4 (CDK4R24C), Cyclin D1, and human Telomerase reverse transcriptase (hTERT), establishing NCM-K4DT lines. Their morphology, melanocytic marker expression, proliferation and functional properties (melanin synthesis, tyrosinase activity) were evaluated. Genomic stability was assessed by targeted mutation profiling, karyotyping, and copy number variation analysis. The tumorigenicity was tested in immunodeficient mice. Plasmid-based CRISPR/Cas9 editing was performed to determine their suitability for gene editing. ResultsNCM-K4DT lines retained dendritic-shaped morphology, pigmentation, and expression of PMEL, TYRP1, Melan-A, and SOX10. Cells exhibited enhanced proliferative capacity with preserved cell cycle regulation. Melanin production and tyrosinase activity were comparable to primary NCMs. Genomic profiling confirmed the absence of UM-associated driver mutations and chromosomal abnormalities. In vivo growth assays demonstrated no tumorigenic potential. Notably, NCM-K4DT cells were efficiently edited by CRISPR/Cas9. ConclusionsNCM-K4DT lines represent stable, non-cancerous, and genetically tractable models for studying choroidal melanocyte biology, modeling UM-associated mechanisms, and advancing therapeutic development in ocular research.

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Methicillin-Susceptible Staphylococcus aureus ST398 in atopic dermatitis in Portugal displays pathogenic traits associated with impaired skin barrier function

Caieiro, D.; Faria, N. A.; Botelho, A.; Araujo, M.; Ramos, L.; Calvao, J.; Goncalo, M.; Miragaia, M.

2026-02-18 dermatology 10.64898/2026.02.17.26346495 medRxiv
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Staphylococcus aureus plays a central role in the exacerbation of atopic dermatitis (AD), but the population structure and pathogenic determinants of strains colonizing AD patients remain poorly understood. It is unclear whether these strains mirror those circulating in the general community or whether specific clonal lineages are selectively adapted to the AD skin microenvironment. Data addressing this question are scarce, particularly in Portugal. In this study, we investigated the molecular epidemiology and pathogenic traits of S. aureus colonizing skin lesions in adult patients with AD in Portugal. We found that lesion-associated isolates belonged predominantly to the methicillin-susceptible S. aureus MSSA-ST398 clonal type, a lineage that is widely circulating in the Portuguese community, particularly among vulnerable populations, and that has also been implicated in severe human infections. Notably, isolates from this clonal type in AD harboured specific pathogenicity traits associated with skin barrier disruption, including hemolysin and urease production, which may contribute to their success as colonizers in AD. Our findings highlight that S. aureus colonization in AD arises from a dynamic interplay between community-level molecular epidemiology and disease-specific selective pressures. While circulating lineages provide the genetic background diversity, the AD skin microenvironment appears to shape which clones ultimately become dominant. Such an integrated perspective may help to inform future geographically tailored strategies aimed at limiting bacterial burden and preventing disease exacerbation in AD.

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Evaluation of the Anti-Inflammatory and Wound-Healing Potentials of Nigella sativa Extract in Dermal Injury Models

Sowunmi, K. S.; Ibrahim, M. O.

2026-01-29 cell biology 10.64898/2026.01.28.702240 medRxiv
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Skin repair depends on balanced inflammation, oxidative control, and growth-factor signalling. Disruption of these events delays healing and leads to chronic wounds. Nigella sativa (black seed) contains bioactive compounds such as thymoquinone with anti-inflammatory and antioxidant activity, but its integrated effect on dermal repair remains unclear. This study evaluated the anti-inflammatory and wound-healing properties of N. sativa extract in a full-thickness excision wound model in rats. Animals were divided into control, standard (1% silver sulfadiazine), and N. sativa ointment-treated (10% w/w) groups. Wound contraction, histological organisation, antioxidant enzymes, inflammatory cytokines, and expression of pro-repair genes were assessed. Topical N. sativa significantly accelerated wound closure (97.5 {+/-} 1.2 % vs. 84.7 {+/-} 2.1 % in controls, p < 0.001) and improved epithelial regeneration and collagen deposition. Treatment enhanced superoxide dismutase and catalase activities by over 35%, reduced malondialdehyde by 38%, and lowered TNF-, IL-1{beta}, and IL-6 levels by 33-46%. VEGF and PDGF gene expression increased 2.7- and 2.2-fold, respectively, compared with untreated wounds. These results demonstrate that N. sativa extract promotes healing through concurrent modulation of inflammation, oxidative balance, and angiogenic signalling. The findings support its potential as a natural, biocompatible therapeutic for managing dermal injuries and cosmetic skin repair. Further work should optimise formulation, dosage, and clinical application to translate these benefits to human wound management.