Background Allergic contact dermatitis (ACD) is the most common occupational disease. Although murine contact hypersensitivity provides a framework for understanding ACD, it carries important ...differences from its human counterpart. Unlike the contact hypersensitivity model, which is induced by potent sensitizers (ie, dinitrofluorobenzene), human ACD is induced by weak-to-moderate sensitizers (ie, nickel), which cannot induce reactions in mice. Distinct hapten-specific immune-polarizing responses to potent inducers were suggested in mice, with unclear relevance to human ACD. Objective We explored the possibility of distinct T-cell polarization responses in skin to common clinically relevant ACD allergens. Methods Gene-expression and cellular studies were performed on common allergens (ie, nickel, fragrance, and rubber) compared with petrolatum-occluded skin, using RT-PCR, gene arrays, and immunohistochemistry. Results Despite similar clinical reactions in all allergen groups, distinct immune polarizations characterized different allergens. Although the common ACD transcriptome consisted of 149 differentially expressed genes across all allergens versus petrolatum, a much larger gene set was uniquely altered by individual allergens. Nickel demonstrated the highest immune activation, with potent inductions of innate immunity, TH 1/TH 17 and a TH 22 component. Fragrance, and to a lesser extent rubber, demonstrated a strong TH 2 bias, some TH 22 polarization, and smaller TH 1/TH 17 contributions. Conclusions Our study offers new insights into the pathogenesis of ACD, expanding the understanding of T-cell activation and associated cytokines in allergen-reactive tissues. It is the first study that defines the common transcriptome of clinically relevant sensitizers in human skin and identifies unique pathways preferentially activated by different allergens, suggesting that ACD cannot be considered a single entity.
Objective
To our knowledge, there is no broad genomic analysis comparing skin and synovium in psoriatic arthritis (PsA). Also, there is little understanding of the relative levels of cytokines and ...chemokines in skin and synovium. The purpose of this study was to better define inflammatory pathways in paired lesional skin and affected synovial tissue in patients with PsA.
Methods
We conducted a comprehensive analysis of cytokine and chemokine activation and genes representative of the inflammatory processes in PsA. Paired PsA synovial tissue and skin samples were obtained from 12 patients on the same day. Gene expression studies were performed using Affymetrix HGU133 Plus 2.0 arrays. Confirmatory quantitative real‐time polymerase chain reaction (PCR) was performed on selected transcripts. Cell populations were assessed by immunohistochemistry and immunofluorescence.
Results
Globally, gene expression in PsA synovium was more closely related to gene expression in PsA skin than to gene expression in synovium in other forms of arthritis. However, PsA gene expression patterns in skin and synovium were clearly distinct, showing a stronger interleukin‐17 (IL‐17) gene signature in skin than in synovium and more equivalent tumor necrosis factor (TNF) and interferon‐γ gene signatures in both tissues. These results were confirmed with real‐time PCR.
Conclusion
This is the first comprehensive molecular comparison of paired lesional skin and affected synovial tissue samples in PsA. Our results support clinical trial data showing that PsA skin and joint disease are similarly responsive to TNF antagonists, while IL‐17 antagonists have better results in PsA skin than in PsA joints. Genes selectively expressed in PsA synovium might direct future therapies for PsA.
Atopic dermatitis (AD) is the most common inflammatory skin disease, but treatment options for moderate‐to‐severe disease are limited. Ustekinumab is an IL‐12/IL‐23p40 antagonist that suppresses Th1, ...Th17 and Th22 activation, commonly used for psoriasis patients. We sought to assess efficacy and safety of ustekinumab in patients with moderate‐to‐severe AD. In this phase II, double‐blind, placebo‐controlled study, 33 patients with moderate‐to‐severe AD were randomly assigned to either ustekinumab (n=16) or placebo (n=17), with subsequent crossover at 16 weeks, and last dose at 32 weeks. Background therapy with mild topical steroids was allowed to promote retention. Study endpoints included clinical (SCORAD50) and biopsy‐based measures of tissue structure and inflammation, using protein and gene expression studies. The ustekinumab group achieved higher SCORAD50 responses at 12, 16 (the primary endpoint) and 20 weeks compared to placebo, but the difference between groups was not significant. The AD molecular profile/transcriptome showed early robust gene modulation, with sustained further improvements until 32 weeks in the initial ustekinumab group. Distinct and more robust modulation of Th1, Th17 and Th22 but also Th2‐related AD genes was seen after 4 weeks of ustekinumab treatment (i.e. MMP12, IL‐22, IL‐13, IFN‐γ, elafin/PI3, CXCL1 and CCL17; P<.05). Epidermal responses (K16, terminal differentiation) showed faster (4 weeks) and long‐term regulation (32 weeks) from baseline in the ustekinumab group. No severe adverse events were observed. Ustekinumab had clear clinical and molecular effects, but clinical outcomes might have been obscured by a profound “placebo” effect, most likely due to background topical glucocorticosteroids and possibly insufficient dosing for AD.
Psoriasis is a common immune‐mediated disease that affects 2%‐4% of individuals in North America and Europe. In the past decade, advances in research have led to an improved understanding of immune ...pathways involved in the pathogenesis of psoriasis and has spurred the development of targeted therapeutics. Recently, three psoriasis autoantigens have been described: cathelicidin (LL37), a disintegrin and metalloprotease domain containing thrombospondin type 1 motif‐like 5 (ADAMTSL5), and lipid antigens generated by phospholipase A2 (PLA2) group IVD (PLA2G4D). It is important to establish the expression, regulation and therapeutic modulation of these psoriasis autoantigens. In this study, we performed immunohistochemistry and two‐colour immunofluorescence on non‐lesional and lesional psoriasis skin to characterize ADAMTSL5 and LL37, and their co‐expression with T cells, dendritic cells, neutrophils and macrophages, which are the main immune cells that drive this disease. Our results showed that ADAMTSL5 and LL37 are significantly (P<.05) increased in lesional skin and are co‐expressed by many dendritic cells, macrophages and some T cells in the dermis. Gene expression analysis showed significant (P<.05) upregulation of LL37 in lesional skin and significant downregulation following treatment with etanercept. ADAMTSL5 and LL37 are also significantly decreased by IL‐17 or TNF‐α blockade, suggesting feed‐forward induction of psoriasis autoantigens by disease‐related cytokines.
Alopecia areata (AA) is a common inflammatory disease targeting the anagen‐stage hair follicle. Different cytokines have been implicated in the disease profile, but their pathogenic role is not yet ...fully determined. We studied biopsies of pretreatment lesional and non‐lesional (NL) scalp and post‐treatment (intra‐lesional steroid injection) lesional scalp of 6 patchy patients with AA using immunohistochemistry and gene expression analysis. Immunohistochemistry showed increases in CD3+, CD8+ T cells, CD11c+ dendritic cells and CD1a+ Langerhans cells within and around hair follicles of pretreatment lesional scalp, which decreased upon treatment. qRT‐PCR showed in pretreatment lesional scalp (compared to NL) significant increases (P < 0.05) in expression of inflammatory markers (IL‐2, IL‐2RA, JAK3, IL‐15), Th1 (CXCL10 and CXCL9), Th2 (IL‐13, CCL17 and CCL18), IL‐12/IL‐23p40 and IL‐32. Among these, we observed significant downregulation with treatment in IL‐12/IL‐23p40, CCL18 and IL‐32. We also observed significant downregulation of several hair keratins in lesional scalp, with significant upregulation of KRT35, KRT75 and KRT86 in post‐treatment lesional scalp. This study shows concurrent activation of Th1 and Th2 immune axes as well as IL‐23 and IL‐32 cytokine pathways in lesional AA scalp and defined a series of response biomarkers to corticosteroid injection. Clinical trials with selective antagonists coupled with cytokine‐pathway biomarkers will be necessary to further dissect pathogenic immunity.
Keloids are benign fibroproliferative tumors more frequently found among African Americans. Until now, keloid etiopathogenesis is not fully understood. To characterize keloids in African Americans, ...we performed transcriptional profiling of biopsies from large chronic keloids, adjacent non‐lesional (NL) skin (n=3) and a newly formed keloid lesion using Affymetrix HGU133 2.0 plus arrays. Quantitative RT‐PCR (qRT‐PCR) and immunohistochemistry (IHC) staining were performed to confirm increased expression of relevant genes. We identified 1202 upregulated and 961 downregulated differentially expressed genes (DEGs) between keloid and NL skin; 1819 up‐ and 1867 downregulated DEGs between newly formed keloid and NL skin; and 492 up‐ and 775 downregulated DEGs between chronic and newly formed keloid (fold change >2, false discovery rate <0.05). Many of the top upregulated DEGs between chronic keloid and NL skin and between newly formed keloid and NL skin are involved in bone/cartilage formation including Fibrillin 2 (FBN2), Collagen type X alpha 1, Asporin (ASPN), Cadherin 11 (CDH11), Bone morphogenic protein 1 (BMP1), Secreted phosphoprotein 1 and Runt‐related transcription factor 2 (RUNX2). qRT‐PCR confirmed significant (P<.05) upregulation of BMP1, RUNX2, CDH11 and FBN2 in chronic keloid compared to NL skin. IHC staining showed increased protein expression of ASPN, CDH11, BMP1 and RUNX2 on chronic and newly formed keloid compared to NL skin. Our study shows that large keloids in African Americans represent a dysplasia of cutaneous connective tissue towards immature cartilage or bone differentiation. The phenotype is potentially regulated by overexpression of RUNX2. This knowledge may give insights to guide the development of better treatment for the disease in the future.
Background Psoriasis and atopic dermatitis (AD) are common, complex inflammatory skin diseases. Both diseases display immune infiltrates in lesions and epidermal growth/differentiation alterations ...associated with a defective skin barrier. An incomplete understanding of differences between these diseases makes it difficult to compare human disease pathology to animal disease models. Objective To characterize differences between these diseases in expression of genes related to epidermal growth/differentiation and inflammatory circuits. Methods We performed genomic profiling of mRNA in chronic psoriasis (n = 15) and AD (n = 18) skin lesions compared with normal human skin (n = 15). Results As expected, clear disease classifications could be constructed on the basis of expected immune polarity (TH 1, TH 2, TH 17) differences. However, even more striking differences were identified in epidermal differentiation programs that could be used for precise disease classifications. Although both psoriasis and AD skin lesions displayed regenerative epidermal hyperplasia, which is a general alteration in epidermal growth, keratinocyte terminal differentiation was differentially polarized. In AD, we found selective defects in expression of multiple genes encoding the cornified envelope, with the largest alteration in loricrin (expressed at 2% of the level of normal skin). At the ultrastructural level, the cornified envelope in AD was broadly defective with highly decreased compaction of corneocytes and reduced intercellular lipids. Hence, the entire keratinocyte terminal differentiation program (cytoplasmic compaction, cornification, and lipid release) is defective in AD, potentially underlying the immune differences. Conclusion Our study shows that although alterations in barrier responses exist in both diseases, epidermal differentiation is differentially polarized, with major implications for primary disease pathogenesis.
Physician rating of cutaneous erythema is central to clinical dermatological assessment as well as quantification of outcome measures in clinical trials in a number of dermatologic conditions. ...However, issues with inter‐rater reliability and variability in the setting of higher Fitzpatrick skin types make visual erythema assessment unreliable. We developed and validated a computer‐assisted image‐processing algorithm (EQscore) to reliably quantify erythema (across a range of skin types) in the dermatology clinical setting.
Our image processing algorithm evaluated erythema based upon green light suppression differentials between affected and unaffected skin. A group of four dermatologists used a 4‐point Likert scale as a human evaluation of similar erythematous patch tests. The algorithm and dermatologist scores were compared across 164 positive patch test reactions. The intra‐class correlation coefficient of groups and the correlation coefficient between groups were calculated. The EQscore was validated on and independent image set of psoriasis, minimal erythema dose testing and steroid‐induced blanching images. The reliability of the erythema quantification method produced an intra‐class correlation coefficient of 0.84 for the algorithm and 0.67 for dermatologists. The correlation coefficient between groups was 0.85. The EQscore demonstrated high agreement with clinical scoring and superior reliability compared with clinical scoring, avoiding the pitfalls of erythema underrating in the setting of pigmentation. The EQscore is easily accessible (http://lab.rockefeller.edu/krueger/EQscore), user‐friendly, and may allow dermatologists to more readily and accurately rate the severity of dermatological conditions and the response to therapeutic treatments.
Background Tofacitinib is an oral Janus kinase inhibitor being investigated for psoriasis. Objective We sought to elucidate the molecular mechanisms underlying the clinical efficacy of tofacitinib in ...patients with psoriasis. Methods Twelve patients with plaque psoriasis were randomized (3:1) to receive 10 mg of tofacitinib or placebo twice daily for 12 weeks. Biopsy specimens were taken from nonlesional (baseline) and lesional (baseline, days 1 and 3, and weeks 1, 2, 4, and 12) skin. Biopsy specimens were examined for psoriatic epidermal features (thickness, Ki67+ keratinocytes and keratin 16 KRT16 mRNA expression, and phosphorylated signal transducer and activator of transcription pSTAT+ nuclei) and T-cell and dendritic cell (DC) subsets by using immunohistochemistry, and mRNA transcripts were quantified by using a microarray. Results In lesional skin keratinocyte pSTAT1 and pSTAT3 staining was increased at baseline but reduced after 1 day of tofacitinib (baseline, median of 1290 pSTAT1+ cells/μm2 ; day 1, median of 332 pSTAT1+ cells/μm2 ; and nonlesional, median of 155 pSTAT1+ cells/μm2 ). Epidermal thickness and KRT16 mRNA expression were significantly and progressively reduced after days 1 and 3 of tofacitinib administration, respectively (eg, KRT16 decreased 2.74-fold, day 3 vs baseline, P = .016). Decreases in DC and T-cell numbers were observed after weeks 1 and 2, respectively. At week 4, significant decreases in IL-23/TH 17 pathways were observed that persisted through week 12. Improvements in clinical and histologic features were strongly associated with changes in expression of psoriasis-related genes and reduction in IL-17 gene expression. Conclusions Tofacitinib has a multitiered response in patients with psoriasis: (1) rapid attenuation of keratinocyte Janus kinase/STAT signaling; (2) removal of keratinocyte-induced cytokine signaling, leading to reductions in pathologic DC and T-cell numbers to nonlesional levels; and (3) inhibition of the IL-23/TH 17 pathway.
Background Atopic dermatitis (AD) and psoriasis pathogeneses involve skin barrier impairment and immune dysregulation; however, the contribution of B-cell imbalances to these diseases has not yet ...been determined. Objective We sought to quantify B-cell populations and antibody-secreting cells in the blood of patients with AD, patients with psoriasis, and control subjects. Methods We studied 34 adults with moderate-to-severe AD (mean SCORAD score, 65), 24 patients with psoriasis (mean Psoriasis Area and Severity Index score, 16), and 27 healthy subjects using an 11-color flow cytometric antibody panel. IgD/CD27 and CD24/CD38 core gating systems were used to determine frequencies of plasmablasts and naive, memory, transitional, and activated B cells. Results We measured increased CD19+ CD20+ B-cell counts in the skin and blood of patients with AD ( P < .01). Significantly higher frequencies of chronically activated CD27+ memory and nonswitched memory B cells were observed in patients with AD ( P < .05), with lower values of double-negative populations (4% for patients with AD vs 7% for patients with psoriasis P = .001 and 6% for control subjects P = .02). CD23 expression was highest in patients with AD and correlated with IgE levels ( P < .01) and disease severity ( r = 0.6, P = .0002). Plasmablast frequencies and IgE expression were highest in all memory subsets of patients with AD ( P < .01). Finally, CD19+ CD24++ CD38++ transitional and CD19+ CD24− CD38− new memory B-cell counts were higher in patients with AD versus those in patients with psoriasis (2.8% vs 1.4% P = .001 and 9.2% vs 5.7% P = .02, respectively). Conclusions AD is accompanied by systemic expansion of transitional and chronically activated CD27+ memory, plasmablast, and IgE-expressing memory subsets. These data create a critical basis for the future understanding of this debilitating skin disease.
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