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Lack of reliable measures of cutaneous chronic graft-versus-host disease (cGVHD) remains a significant challenge. Non-expert assistance in marking photographs of active disease could aid the development of automated segmentation algorithms, but validated metrics to evaluate training effects are lacking. We studied absolute and relative error of marked body surface area (BSA), redness, and the Dice index as potential metrics of non-expert improvement. Three non-experts underwent an extensive training program led by a board-certified dermatologist to mark cGVHD in photographs. At the end of the 4-month training, the dermatologist confirmed that each trainee had learned to accurately mark cGVHD. The trainees' inter- and intra-rater intraclass correlation coefficient estimates were "substantial" to "almost perfect" for both BSA and total redness. For fifteen 3D photos of patients with cGVHD, the trainees' median absolute (relative) BSA error compared to expert marking dropped from 20 cm

Skin ulceration is an important cause of morbidity in systemic sclerosis and can occur at anytime during disease progression. Incident disease cohorts are important for understanding whether skin ulceration represents active vasculopathy versus resultant damage. Biomarkers for skin ulcer pathogenesis, both serum and imaging, are under investigation to elucidate the functional consequences of the structural abnormalities. Novel therapeutics for the treatment of vasculopathy benefit from reliable biomarkers able to predict the disease evolution remains an important unmet need. Nonetheless, a diagnostic approach that captures early skin ulceration and treatments that restore vascular and immune homeostasis is critical for effective systemic sclerosis (SSc) vasculopathy management.

A feature issue is being presented by a team of guest editors containing papers based on studies presented at the Optica Biophotonics Congress: Biomedical Optics held on April 24–27, 2022 in Fort Lauderdale, Florida, USA.

Chronic graft-versus-host disease (GVHD) commonly occurs after allogeneic hematopoietic cell transplantation (HCT) despite standard prophylactic immune suppression. Intensified universal prophylaxis approaches are effective but risk possible overtreatment and may interfere with the graft-versus-malignancy immune response. Here we summarize conceptual and practical considerations regarding preemptive therapy of chronic GVHD, namely interventions applied after HCT based on evidence that the risk of developing chronic GVHD is higher than previously appreciated. This risk may be anticipated by clinical factors or risk assignment biomarkers or may be indicated by early signs and symptoms of chronic GVHD that do not fully meet National Institutes of Health diagnostic criteria. However, truly preemptive, individualized, and targeted chronic GVHD therapies currently do not exist. In this report, we (1) review current knowledge regarding clinical risk factors for chronic GVHD, (2) review what is known about chronic GVHD risk assignment biomarkers, (3) examine how chronic GVHD pathogenesis intersects with available targeted therapeutic agents, and (4) summarize considerations for preemptive therapy for chronic GVHD, emphasizing trial development, including trial design and statistical considerations. We conclude that robust risk assignment models that accurately predict chronic GVHD after HCT and early-phase preemptive therapy trials represent the most urgent priorities for advancing this novel area of research.

ImportancePrior studies have demonstrated an association between cutaneous chronic graft-vs-host disease (cGVHD) and mortality. Assessment of the prognostic value of different measures of disease severity would assist in risk stratification.ObjectiveTo compare the prognostic value of body surface area (BSA) and National Institutes of Health (NIH) Skin Score on survival outcomes stratified by erythema and sclerosis subtypes of cGVHD.Design, Setting, and ParticipantsMulticenter prospective cohort study from the Chronic Graft-vs-Host Disease Consortium including 9 medical centers in the US, enrolled from 2007 through 2012 and followed until 2018. Participants were adults and children with a diagnosis of cGVHD requiring systemic immunosuppression and with skin involvement during the study period, who had longitudinal follow-up. Data analysis was performed from April 2019 to April 2022.ExposuresPatients underwent continuous BSA estimation and categorical NIH Skin Score grading of cutaneous cGVHD at enrollment and every 3 to 6 months thereafter.Main Outcomes and MeasuresNonrelapse mortality (NRM) and overall survival (OS), compared between BSA and NIH Skin Score longitudinal prognostic models, adjusted for age, race, conditioning intensity, patient sex, and donor sex.ResultsOf 469 patients with cGVHD, 267 (57%) (105 female [39%]; mean [SD] age, 51 [12] years) had cutaneous cGVHD at enrollment, and 89 (19%) developed skin involvement subsequently. Erythema-type disease had earlier onset and was more responsive to treatment compared with sclerosis-type disease. Most cases (77 of 112 [69%]) of sclerotic disease occurred without prior erythema. Erythema-type cGVHD at first follow-up visit was associated with NRM (hazard ratio, 1.33 per 10% BSA increase; 95% CI, 1.19-1.48; P P 2, 5.9; P = .05). Conversely, NIH Skin Score collected at the same intervals lost significant prognostic information (likelihood ratio test χ2, 14.7; P Conclusions and RelevanceIn this prospective cohort study, erythema-type cutaneous cGVHD was associated with increased risk of mortality. Erythema BSA collected at baseline and follow-up predicted survival more accurately than the NIH Skin Score in patients requiring immunosuppression. Accurate assessment of erythema BSA may assist in identifying patients with cutaneous cGVHD at high risk for mortality.

The 2022 mpox outbreak has rapidly emerged onto the global medical scene while the world continues to grapple with the COVID-19 pandemic. Unlike COVID-19, however, most patients with mpox present with skin findings, the evolving clinical presentation of which may be mistaken for other common skin diseases, particularly sexually transmitted infections. This Special Communication provides an overview of the evolution of mpox skin findings from its initial description in humans in 1970 to the present-day multinational outbreak.

IMPORTANCE: Hematopoietic cell transplantation (HCT) is a potential cure for hematologic cancer but is associated with a risk of relapse and death. Dynamic biomarkers to predict relapse and inform treatment decisions after HCT are a major unmet clinical need. OBJECTIVE: To identify a quantitative characteristic of leukocyte-endothelial interactions after HCT and test its associations with patient outcomes. DESIGN, SETTING, AND PARTICIPANTS: In this prospective single-center cohort study from June 2017 to January 2020, patients of any age, sex, race, and ethnicity who had HCT for hematologic cancer were referred by health care professionals as either suspected of having symptoms or not having symptoms of acute graft-vs-host disease between 25 and 161 days after HCT. Patients underwent noninvasive skin videomicroscopy. Videos of dermal microvascular flow were recorded with a reflectance confocal microscope. Two blinded observers (J.R.P. and Z.Z.) counted leukocytes adherent to and rolling along the vessel wall per hour (A&R). Of 57 enrolled patients, 1 relapsed before imaging and was excluded, resulting in 56 patients included in analyses. MAIN OUTCOMES AND MEASURES: Relapse of cancer, relapse-free survival, and overall survival. RESULTS: Among the 56 patients (median age, 59 years; 38 [68%] male) who underwent imaging a median of 40 days after HCT, 21 had high A&R and 35 had low A&R. After correcting for the revised Disease Risk Index, patients with high A&R had higher rates of relapse (hazard ratio [HR], 4.24; 95% CI, 1.32-13.58; P = .02), reduced relapse-free survival (HR, 3.29; 95% CI, 1.26-8.55; P = .02), and reduced overall survival (HR, 3.06, 95% CI, 1.02-9.19; P = .05). These associations were preserved after correcting for possible confounders, steroid treatment, and acute graft-vs-host disease status. In the prognostic adequacy calculation by using Cox models, the new imaging biomarker (A&R) accounted for 82% to 95% of the prognostic information to predict each outcome. By contrast, the best existing clinical predictor routinely available, the revised Disease Risk Index, accounted for 10% to 28% of the prognostic information in the same model. CONCLUSIONS AND RELEVANCE: In this cohort study, leukocyte-endothelial interactions, visualized directly in skin after HCT, were associated with the patient outcomes of relapse, relapse-free survival, and overall survival. Assessing this dynamic marker could help patients at high risk for relapse who may benefit from interventions, such as early withdrawal of immunosuppression.

The current revolution of digital health technology and machine learning offers enormous potential to improve patient care. Nevertheless, it is essential to recognize that dermatology requires an approach different from those of other specialties. For many dermatological conditions, there is a lack of standardized methodology for quantitatively tracking disease progression and treatment response (clinimetrics). Furthermore, dermatological diseases impact patients in complex ways, some of which can be measured only through patient reports (psychometrics). New tools using digital health technology (e.g., smartphone applications, wearable devices) can aid in capturing both clinimetric and psychometric variables over time. With these data, machine learning can inform efforts to improve health care by, for example, the identification of high-risk patient groups, optimization of treatment strategies, and prediction of disease outcomes. We use the term personalized, data-driven dermatology to refer to the use of comprehensive data to inform individual patient care and improve patient outcomes. In this paper, we provide a framework that includes data from multiple sources, leverages digital health technology, and uses machine learning. Although this framework is applicable broadly to dermatological conditions, we use the example of a serious inflammatory skin condition, chronic cutaneous graft-versus-host disease, to illustrate personalized, data-driven dermatology.

Objective To develop a guideline that reliably identifies cutaneous adherent and rolling leukocytes from mimicking scenarios via in vivo reflectance confocal videomicroscopy. Methods We used a clinical reflectance confocal microscope, the VivaScope 1500, to acquire 1522 videos of the upper dermal microcirculation from 12 healthy subjects and 60 patients after allogeneic hematopoietic cell transplantation. Blinded to clinical information, two trained raters independently counted the number of adherent and rolling leukocytes in 88 videos. Based on discrepancies in the initial assessments, we developed a guideline to identify both types of leukocyte-endothelial interactions via a modified Delphi method (without anonymity). To test the guideline's ability to improve the inter-rater reliability, the two raters assessed the remaining 1434 videos by using the guideline. Results We demonstrate a guideline that consists of definitions, a step-by-step flowchart, and corresponding visuals of adherent and rolling leukocytes and mimicking scenarios. The guideline improved the inter-rater reliability of the manual assessment of both interactions. The intraclass correlation coefficient (ICC) of adherent leukocyte counts increased from 0.056 (95% confidence interval: 0-0.236, n = 88 videos, N = 10 subjects) to 0.791 (0.770-0.809, n = 1434, N = 67). The ICC of rolling leukocyte counts increased from 0.385 (0.191-0.550, n = 88, N = 10) to 0.626 (0.593-0.657, n = 1434, N = 67). Intra-rater ICC post-guideline was 0.953 (0.886-0.981, n = 20, N = 12) and 0.956 (0.894-0.983, n = 20, N = 12) for adherent and rolling, respectively. Conclusion The guideline aids in the manual identification of adherent and rolling leukocytes via in vivo reflectance confocal videomicroscopy.

Chronic graft-versus-host disease (cGVHD), a potentially debilitating complication of hematopoietic cell transplantation, confers increased risk for mortality. Whereas treatment decisions rely on an accurate assessment of disease activity/severity, validated methods of assessing cutaneous cGVHD activity/severity appear to be limited. In this study, we aimed to identify and evaluate current data on the assessment of disease activity/severity in cutaneous cGVHD. Using modified PRISMA methods, we performed a critical literature review for relevant articles. Our literature search identified 1741 articles, of which 1635 were excluded as duplicates or failure to meet inclusion criteria. Of the included studies (n = 106), 39 (37%) addressed clinical and/or histopathologic parameters, 53 (50%) addressed serologic parameters, 8 (7.5%) addressed imaging parameters, and 6 (5.5%) addressed computer-based technologies. The only formally validated metric of disease activity/severity assessment in cutaneous cGVHD is the National Institutes of Health consensus scoring system, which is founded on clinical assessment alone. The lack of an objective marker for cGVHD necessitates further studies. An evaluation of the potential contributions of serologic, imaging, and/or computer-based technologies is warranted.

Cutaneous erythema is used in diagnosis and response assessment of cutaneous chronic graft-versus-host disease (cGVHD). The development of objective erythema evaluation methods remains a challenge. We used a pre-trained neural network to segment cGVHD erythema by detecting changes relative to a patient’s registered baseline photo. We fixed this change detection algorithm on human annotations from a single photo pair, by using either a traditional approach or by marking definitely affected (“Do Not Miss”, DNM) and definitely unaffected skin (“Do Not Include”, DNI). The fixed algorithm was applied to each of the remaining 47 test photo pairs from six follow-up sessions of one patient. We used both the Dice index and the opinion of two board-certified dermatologists to evaluate the algorithm performance. The change detection algorithm correctly assigned 80% of the pixels, regardless of whether it was fixed on traditional (median accuracy: 0.77, interquartile range 0.62–0.87) or DNM/DNI segmentations (0.81, 0.65–0.89). When the algorithm was fixed on markings by different annotators, the DNM/DNI achieved more consistent outputs (median Dice indices: 0.94–0.96) than the traditional method (0.73–0.81). Compared to viewing only rash photos, the addition of baseline photos improved the reliability of dermatologists’ scoring. The inter-rater intraclass correlation coefficient increased from 0.19 (95% confidence interval lower bound: 0.06) to 0.51 (lower bound: 0.35). In conclusion, a change detection algorithm accurately assigned erythema in longitudinal photos of cGVHD. The reliability was significantly improved by exclusively using confident human segmentations to fix the algorithm. Baseline photos improved the agreement among two dermatologists in assessing algorithm performance.

Through vertex component analysis of hyperspectral imaging data in the visible spectral range, we differentiated erythematous and pigmented areas in patients with cutaneous chronic graft-versus-host disease. We explored the feasibility of hyperspectral imaging in combination with unsupervised learning algorithms to differentiate active disease from inactive post-inflammatory skin changes, a fundamental practice gap in caring for these patients. We compared erythema and pigment maps to the visual assessment by a dermatologist as the ground truth.

To evaluate the effect of illumination, camera orientation, and camera distance on color consistency of different skin tones, several swatches from a Pantone SkinTone Guide deck were selected and photographed at varying distances, illuminations, and angles. The RGB values from each selected swatch from each image were converted to LAB units and compared with the converted “true” values provided by Pantone. The ability of various color references to correct different skin tones was tested by comparing color values from a subject’s forearm skin to “true” color values of the closest Pantone SkinTone swatch found by visual comparison.

Robust 3D pose tracking of an object is a critical technique for various mobile sensing applications. Computer vision-based pose tracking method provides a cost-effective solution, but it is sensitive to occlusion and illumination change issues. In this work, we propose a novel visual-inertial sensor fusion framework and demonstrate the real-time implementation of a tightly-coupled sensor fusion algorithm: inertial perspective-n-point (IPNP) algorithm. With measurements from an inertial measurement unit (IMU), the prototype system only needs to detect two keypoints to track all six degrees of freedom of a planar object, e.g., a mobile X-ray detector, a 50% reduction on required number of keypoints, compared with the vision-based perspective-n-point algorithm.

A recently developed non-destructive method was used to investigate the stress build-up in chemically strengthened lithium aluminosilicate glass. We utilized an updated version of the gradient scattered light method, which now enables more precise determination of the depth coordinates, recovering a more detailed stress profile around the knee. The main motivation of the work was to characterize and optimize the development of the knee-shaped breaking point in stress profile in lithium aluminosilicate glass using Saunders-Kubichan method of 1-step strengthening in a mixture of KNO(3)+NaNO(3) molten salt bath. In the industry, a 2-step process is still commonly used to build such a stress profile. 1-step strengthening will simplify the process as well as save the cost. Compared to previous studies, which used a destructive method based on transmitted light photoelasticity, we found that in the samples ion-exchanged for 24h the knee-shaped breaking points were situated two times deeper whereas the case-depths were 28% shallower. The measured stress profiles were validated by stress equilibrium and by comparison to Na(+) ion concentration profiles.

We explore the potential of reflectance confocal video microscopy of human skin microvasculature to noninvasively track immune cell activity following hematopoietic cell transplantation. In three patients, we tracked leukocyte-endothelial interactions over time.

Importance The use of artificial intelligence (AI) is accelerating in all aspects of medicine and has the potential to transform clinical care and dermatology workflows. However, to develop image-based algorithms for dermatology applications, comprehensive criteria establishing development and performance evaluation standards are required to ensure product fairness, reliability, and safety. Objective To consolidate limited existing literature with expert opinion to guide developers and reviewers of dermatology AI. Evidence review In this consensus statement, the 19 members of the International Skin Imaging Collaboration AI working group volunteered to provide a consensus statement. A systematic PubMed search was performed of English-language articles published between December 1, 2008, and August 24, 2021, for "artificial intelligence" and "reporting guidelines," as well as other pertinent studies identified by the expert panel. Factors that were viewed as critical to AI development and performance evaluation were included and underwent 2 rounds of electronic discussion to achieve consensus. Findings A checklist of items was developed that outlines best practices of image-based AI development and assessment in dermatology. Conclusions and relevance Clinically effective AI needs to be fair, reliable, and safe; this checklist of best practices will help both developers and reviewers achieve this goal.

We report a case of noninfectious vacuolar interface dermatitis associated with colonic and perianal ulceration in a patient with acquired immunodeficiency syndrome (AIDS), which responded to immunosuppressive treatment. Our findings suggest that interface dermatitis in the setting of AIDS may warrant further gastrointestinal evaluation and may respond to immunosuppression.

Skin biomechanical parameters (dynamic stiffness, frequency, relaxation time, creep, and decrement) measured using a myotonometer (MyotonPRO) could inform the management of sclerotic disease. To determine which biomechanical parameter(s) can accurately differentiate patients with sclerotic chronic graft-versus-host disease from post–hematopoietic cell transplant controls, 15 patients with sclerotic chronic graft-versus-host disease and 11 post–hematopoietic cell transplant controls were measured with the myotonometer on 18 anatomic sites. Logistic regression and two machine learning algorithms (least absolute shrinkage and selection operator regression and random forest) were developed to classify subjects. In univariable analysis, frequency had the highest overfit-corrected area under the curve (0.91). Backward stepwise selection and random forest machine learning identified frequency and relaxation time as the optimal parameters for differentiating patients with sclerotic chronic graft-versus-host disease from post–hematopoietic cell transplant controls. Least absolute shrinkage and selection operator regression selected the combination of frequency and relaxation time (overfit-corrected area under the curve = 0.87). Discriminatory ability was maintained when only the sites accessible while the patient is supine (12 sites) were used. We report the distribution of values for these highly discriminative biomechanical parameters, which could inform the assessment of disease severity in future quantitative biomechanical studies of sclerotic chronic graft-versus-host disease.

miR-146a inhibits inflammatory responses in human keratinocytes and in different mouse models of skin inflammation. Little is known about the role of miR-146b in the skin. In this study, we confirmed the increased expression of miR-146a and miR-146b (miR-146a/b) in the lesional skin of patients with psoriasis. The expression of miR-146a was approximately twofold higher than that of miR-146b in healthy human skin, and it was more strongly induced by stimulation of proinflammatory cytokines in keratinocytes and fibroblasts. miR-146a/b target genes regulating inflammatory responses or proliferation were altered in the skin of patients with psoriasis, among which FERMT1 was verified as a direct target of miR-146a. In silico analysis of genome-wide data from >4,000 psoriasis cases and >8,000 controls confirmed a moderate association between psoriasis and genetic variants in the miR-146a encoding gene. Transfection of miR-146a/b suppressed and inhibition enhanced keratinocyte proliferation and the expression of psoriasis-related target genes. Enhanced expression of miR-146a/b-influenced genes was detected in cultured keratinocytes from miR-146a−/− and skin fibroblasts from miR-146a−/− and miR-146b−/− mice stimulated with psoriasis-associated cytokines as compared with wild-type mice. Our results indicate that besides miR-146a, miR-146b is expressed and might be capable of modulation of inflammatory responses and keratinocyte proliferation in psoriatic skin.

Background Through noninvasive imaging of live, individual immune cells of patients post allogeneic hematopoietic cell transplantation (HCT), we characterized differences in microvasculature among patients with cutaneous acute graft-versus-host disease (aGVHD) compared to post-HCT patients without any organ aGVHD (controls). Traditional histopathology is often non-specific for cutaneous aGVHD. We present parameters characteristic of cell motion within upper dermal capillaries, which could enable noninvasive tracking of disease development. Objective Test the feasibility of eight quantitative parameters extracted from reflectance confocal videos to distinguish between patients with and without cutaneous aGVHD following HCT. Methods We used a clinical reflectance confocal microscope to noninvasively image left volar forearm dermal capillaries of 5 cutaneous aGVHD patients and 5 post-HCT controls prior to topical and systemic therapies. All diagnoses were retrospectively confirmed on day 100 by a transplant physician (MB) based on initiation and response to therapy. Two raters (JRP, IS) independently estimated capillary density and size, and the number and size of paused (temporarily stopping), adherent (stationary for 30+ sec), and rolling leukocytes. The mean value per two raters was calculated for further analysis. Due to the small sample size, descriptive statistics were used. Results Patients in both study groups were similarly distributed in terms of gender (40% female), age (median 63 and 63, respectively), days post-HCT (median 44 and 41), and underlying disease (60% and 40% acute myeloid leukemia; the rest: myelodysplastic syndrome). 4 patients had only skin involvement: grade 1 (N=1 patient), grade 2 (N=3), whereas one patient had grade 2 cutaneous with symptoms of chronic ocular GVHD. One patient required therapy with systemic steroids. We found an increased number of rolling (median: 2 vs 1), adherent (3 vs 1) and paused (2 vs 1) leukocytes in aGVHD patients, compared to post-HCT controls (Figure 1). The average time of a leukocyte being paused was higher in aGVHD patients (6±7 seconds) than post-HCT controls (2±3 seconds). The size of paused leukocytes was greater in aGVHD patients (9±2¼m) compared to controls (6±4¼m) (Figure 2). Capillary size (8±2 vs. 8±2¼m) and density (4±1 vs. 3±2 capillaries) were similar among both groups. Conclusion In similar-sized capillaries, we observed increased leukocyte interactions with the endothelium in aGVHD patients compared to post-HCT controls. Despite similar sized rolling and adherent leukocytes, the size of paused leukocytes was larger in aGVHD patients. Future studies could evaluate the change of these parameters over time.

Background miR-10a-5p has been shown to regulate cancer cell proliferation and invasiveness and endothelial cell inflammatory responses. The function of miR-10a-5p in the skin has not been previously studied. The aim of the current study was to examine miR-10a-5p expression, regulation, and function in keratinocytes (KCs) in association with atopic dermatitis (AD). Methods The expression of miR-10a-5p and its target genes was analyzed using RT-qPCR, mRNA array analysis, in situ hybridization, and immunofluorescence. The transfection of miRNA mimics, cell cycle distribution analysis, and luciferase assays was used to study miR-10a-5p functions in human primary KCs. Results miR-10a-5p was found to be upregulated in lesional skin from patients with AD and in proliferating KCs. Array and pathway analysis of IL-1β-stimulated KCs revealed that miR-10a-5p inhibited many genes that affect cell cycle progression and only a few inflammation-related genes. Accordingly, fewer cells in S-phase and reduced proliferation were detected as characteristics of miR-10a-5p-transfected KCs. The influence of miR-10a-5p on cell proliferation was also evident in KCs induced by AD-related cytokines, including IL-4, IL-17, and IL-1β, as measured by the capacity to strongly suppress the expression of the proliferation marker Ki-67. Among AD-related putative direct target genes, we verified hyaluronan synthase 3, a damage-associated positive regulator of KC migration and proliferation, as a direct target of miR-10a-5p. Conclusions miR-10a-5p inhibits KC proliferation and directly targets hyaluronan synthase 3 and thereby may modulate AD-associated processes in the skin.

Objective To describe upper dermal microvasculature of healthy human skin in terms of density and size of cutaneous blood vessels, leukocyte velocity, and leukocyte interactions with the endothelium. Methods We used a reflectance confocal microscope, the VivaScope 1500, to acquire videos of individual cell motion. Results We found no rolling leukocytes in the upper microvasculature of ten healthy subjects. We observed "paused" leukocytes, that is, leukocytes that temporarily stop, coinciding with the simultaneous stopping of the rest of the blood flow. We imaged more paused (median: 1.0 per subject) and adherent (1.5) leukocytes in the forearm than in the chest (median 0 paused and 0 adherent per subject) per 5 minutes of videos per body site. Leukocytes were paused for a median of 7 seconds in the forearm and 3 seconds in the chest, and we found no correlation between this parameter and the blood vessel or leukocyte size. We visualized blood flow change direction. Flowing leukocyte velocities followed a lognormal distribution and were on average higher in the chest (117 µm/s) than in the forearm (66 µm/s). Conclusion The proposed method and reported values in healthy skin provide new insights into intact human skin microcirculation.

Inflammatory tissue response is one of the first and most common manifestations of acute graft-versus-host disease (aGVHD), a potentially deadly immune-mediated disease that occurs in 30-60% of patients after stem cell transplantation. A fundamental challenge in developing effective treatment strategies for aGVHD is the lack of tools to study disease biology in real-time in post-transplant patients. The inflammatory tissue response causes increased expression of specialized endothelial proteins on vessel walls making leukocytes to roll, adhere and eventually extravasate into the tissue at a higher rate than in normal conditions. Although the importance of leukocyte-endothelial interactions to detect and track inflammation has been well shown in murine models, there are no published clinical studies in humans. In this study, we explore the feasibility to detect presence of aGVHD in post-transplant patients through the imaging of in vivo leukocyte motion. We used a clinical confocal microscope (Vivascope 1500) to acquire videos of 5 aGVHD patients and 5 controls (no aGVHD) within 50±30 days post-transplant. The microscope is capable of real-time imaging of individual cells in the postcapillary vessels at 9 frames per second. Through video analysis, we extracted five quantitative parameters: number and velocity of rolling leukocytes, number of adherent leukocytes (stationary >30 s), blood flow velocity, and number of vessels. In a limited number of subjects, we show that parameters characteristic of the dynamic motion in skin capillaries can be observed noninvasively in post-transplant patients. Further studies are needed to test the diagnostic potential of these parameters.

Leukocyte-endothelial interactions have been well-characterized by intravital microscopy in mice. Quantitative parameters descriptive of these dynamic processes, e.g. the level of leukocyte rolling, adhesion and extravasation, can detect and track inflammation. Despite technology available to study individual cell motion noninvasively in human skin, we are not aware of any published exploratory or clinical studies. In this preliminary study, we explore the feasibility to extract parameters characteristic of individual cell motion in the postcapillary vessels of healthy human skin from videos taken by a noninvasive clinical confocal microscope (Vivascope 1500). The microscope is capable of real-time imaging of individual cells at 9 frames per second. We took videos of ten cutaneous vessels per each of two body sites (volar forearm and upper anterior chest) of ten healthy subjects. We then characterized the dynamic motion of cells via subsequent video analysis by extracting the following parameters: blood flow velocity, number of adherent leukocytes (stationary

The skin is a difficult to access tissue for efficient delivery of large and/or charged macromolecules, including therapeutic DNA and RNA oligonucleotides. Cell-penetrating peptide PepFect6 (PF6) has been shown to be suitable transport vehicle for siRNAs in cell culture and systemically in vivo in mice. MiR-146a is known as anti-inflammatory miRNA that inhibits multiple factors from the nuclear factor (NF)-κB pathway in various cell types, including keratinocytes. In this study, PF6 was shown to form unimodal nanocomplexes with miR-146a mimic that entered into human primary keratinocytes, where miR-146a inhibited the expression of its direct targets from the NF-κB pathway and the genes known to be activated by NF-κB, C-C motif ligand (CCL)5 and interleukin (IL)-8. The transfection of miR-146a mimic with PF6 was more efficient in sub-confluent keratinocyte cultures, affected keratinocyte proliferation less and had similar effect on cell viability when compared with a lipid based agent. Subcutaneous pre-administration of PF6-miR-146a nanocomplexes attenuated ear-swelling and reduced the expression of pro-inflammatory cytokines and chemokines IL-6, CCL11, CCL24 and C-X-C motif ligand 1 (CXCL1) in a mouse model of irritant contact dermatitis. Our data demonstrates that PF6-miR-146a nanoparticles might have potential in the development of therapeutics to target inflammatory skin diseases.