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Background The effectiveness of biologics for psoriasis shows heterogeneity among patients. With pharmacogenetic markers, it might be possible to predict treatment response. Objectives We aimed to test the association between genetic markers and the response to biologics in psoriasis (etanercept, adalimumab, ustekinumab) in a prospective cohort. Methods We investigated the copy number variation in the LCE3B and LCE3C genes, and eight single-nucleotide polymorphisms ( SNPs) in HLA-C*06, CD84, IL12B, IL23R, TRAF3 IP2, ERAP1, IFIH1 and TNFAIP3. The decrease in Psoriasis Area and Severity Index ( PASI) was calculated as ∆ PASI (absolute PASI decrease compared with baseline) and PASI 75 (proportion of patients with ≥ 75% improvement vs. baseline). Associations between genetic variants and treatment outcome were assessed using multivariable linear regression analysis (∆ PASI corrected for baseline PASI, primary analysis) and Pearson's χ2-test or Fisher's exact test ( PASI 75, secondary analysis). Results We included 348 treatment episodes in 234 patients. Patients heterozygous ( GA) for the SNP in CD84 (rs6427528) had a better ∆ PASI response to etanercept after 3 months ( P = 0·025) than the homozygous reference group ( GG). In addition, patients heterozygous ( CT) for the IL12B variant showed a better response (∆ PASI) to ustekinumab ( P = 0·017) than the reference group ( CC). Patients homozygous ( GG) for the SNP in TNFAIP3 showed a worse response (∆ PASI) to ustekinumab ( P = 0·031) than the reference group ( TT). The associations with ustekinumab resulting from the primary analysis were not confirmed in the secondary ( PASI 75) analysis. Conclusions We demonstrated a strong association between etanercept use in psoriasis and variations in CD84, a gene that was previously found to be a predictor of response to etanercept in rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

A letter to the editor on a research study on Autoinflammatory Disorders (AID) characterized by an unprovoked innate immune response, resulting in recurrent or ongoing systemic inflammation and fever, is presented.

Background Schnitzler's syndrome (SchS) is an autoinflammatory disease characterized by a chronic urticarial rash, a monoclonal component and signs of systemic inflammation. Interleukin ( IL)-1β is pivotal in the pathophysiology. Objectives Here we investigated the cellular source of proinflammatory mediators in the skin of patients with SchS. Methods Skin biopsies of lesional and nonlesional skin from eight patients with SchS and healthy controls, and patients with cryopyrin-associated periodic syndrome ( CAPS), delayed-pressure urticaria ( DPU) and cold-contact urticaria ( CCU) were studied. We studied in vivo IL-1β, IL-17 and antimicrobial protein ( AMP) expression in resident skin cells and infiltrating cells. In addition we investigated the in vitro effect of IL-1β, IL-17 and polyinosinic-polycytidylic acid (poly: IC) stimulation on cultured epidermal keratinocytes. Results Remarkably, we found IL-1β-positive dermal mast cells in both lesional and nonlesional skin of patients with SchS, but not in healthy control skin and CCU, and fewer in CAPS. IL-17-positive neutrophils were observed only in lesional SchS and DPU skin. In lesional SchS epidermis, mRNA and protein expression levels of AMPs were strongly increased compared with nonlesional skin and that of healthy controls. When exposed to IL-1β, poly: IC or IL-17, patient and control primary human keratinocytes produced AMPs in similar amounts. Conclusions Dermal mast cells of patients with SchS produce IL-1β. This presumably leads to activation of keratinocytes and neutrophil influx, and further amplification of inflammation by IL-17 (from neutrophils and mast cells) and epidermal AMP production leading to chronic histamine-independent neutrophilic urticarial dermatosis. [ABSTRACT FROM AUTHOR]

Background Psychosocial stress can be a risk factor for the maintenance and exacerbation of chronic inflammatory diseases, such as psoriasis and rheumatoid arthritis ( RA). Objectives To gain insight into the specificity of the psychophysiological stress response during chronic inflammation, we assessed autonomic and neuroendocrine responses to stress in different chronic inflammatory diseases. Methods Thirty patients with psoriasis (nine women, mean age 58·5 years ± 12·4), 34 patients with RA (16 women, mean age 60·8 years ± 9·2) and 25 healthy controls (16 women, mean age 55·6 years ± 8·7) underwent a standardized psychosocial stress task ( Trier Social Stress Test). Salivary levels of α-amylase and cortisol and self-reported tension levels were measured before and after the stress test. Results The cortisol response to stress was heightened in patients with psoriasis compared with patients with RA and healthy controls, whereas there were no differences in the autonomic and self-reported measures. Conclusions The altered neuroendocrine stress response in patients with psoriasis suggests that stressful events might have different physiological consequences for specific patient groups with chronic inflammatory conditions, possibly adversely affecting disease status. [ABSTRACT FROM AUTHOR]

Introduction: Tenascin-X (TNX) is an extracellular matrix (ECM) glycoprotein, the absence of which in humans leads to a recessive form of Ehlers-Danlos syndrome (EDS), a group of inherited connective tissue disorders characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. A mouse model of TNX-deficient type EDS has been used to characterize the dermatological, orthopedic, and obstetrical features. The growing insight in the clinical overlap between myopathies and inherited connective tissue disorders asks for a study of the muscular characteristics of inherited connective tissue diseases. Therefore, this study aims to define the muscular phenotype of TNX knockout (KO) mice. Materials and methods: We performed a comprehensive study on the muscular phenotype of these TNX KO mice, consisting of standardized clinical assessment, muscle histology, and gene expression profiling of muscle tissue. Furthermore, peripheral nerve composition was studied by histology and electron microscopy. Results: The main findings are the presence of mild muscle weakness, mild myopathic features on histology, and functional upregulation of genes encoding proteins involved in ECM degradation and synthesis. Additionally, sciatic nerve samples showed mildly reduced collagen fibril density of endoneurium. Discussion: The muscular phenotype of TNX KO mice consists of mild muscle weakness with histological signs of myopathy and of increased turnover of the ECM in muscle. Furthermore, mildly reduced diameter of myelinated fibers and reduction of collagen fibril density of endoneurium may correspond with polyneuropathy in TNX-deficient EDS patients. This comprehensive assessment can serve as a starting point for further investigations on neuromuscular function in TNX KO mice. [ABSTRACT FROM AUTHOR]

Tenascin-X is a large extracellular matrix glycoprotein that is widely distributed within connective tissues and is associated with an autosomal recessive type of Ehlers-Danlos syndrome (EDS). Tenascin-X represents the first EDS susceptibility gene that does not code for a fibrillar collagen or collagen-processing enzyme. We describe a paediatric case of tenascin-X deficiency and review the literature. [ABSTRACT FROM AUTHOR]

Background The antiprotease activity of cystatin M/E regulates skin barrier formation, as it inhibits the activity of cathepsin V, cathepsin L and legumain, thereby controlling the processing of transglutaminase 3. Misregulation of this pathway by unrestrained protease activity, as seen in cystatin M/E-deficient mice, leads to abnormal stratum corneum and hair follicle formation, and severe disturbance of skin barrier function. Objectives Our major aim was to make a quantitative analysis of the expression of all players of this pathway in the epidermis of patients with inflammatory skin diseases. A second aim was to determine if reconstructed human skin could be used as an in vitro model system to investigate this pathway. Methods Autopsy material from normal human tissues, biopsies from normal skin of healthy volunteers, and lesional skin from patients with atopic dermatitis and psoriasis were used to study the expression of the above-mentioned molecules at the mRNA level by quantitative real-time polymerase chain reaction. Localization of the protein was performed by immunofluorescence microscopy, and expression was quantitated by image analysis. Results In skin, cystatin M/E is expressed at relatively higher levels than its target proteases, when compared with other tissues, which emphasizes its prominent role in cutaneous biology. We found decreased expression of cystatin M/E and cathepsin V in lesional atopic dermatitis and psoriasis epidermis at the mRNA level as well as the protein level. Cathepsin L and transglutaminase 3 were increased at the transcriptional level; however, this was not reflected by higher protein levels. Interestingly, the expression of all these molecules in reconstructed skin was qualitatively and quantitatively similar to the in vivo situation. Conclusions Disturbance of the cystatin M/E – cathepsin pathway could contribute to the dysregulated skin barrier function observed in inflammatory dermatoses. Human reconstructed skin appears to be a valuable model to study this novel biochemical pathway in vitro. [ABSTRACT FROM AUTHOR]

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Basal keratinocytes of human epidermis strongly express the cell surface glycoprotein β1-integrin, and putatively harbour epidermal stem cells. Selective sorting and culturing of keratinocyte stem cells forms the basis for studies on the role of these cells as targets for therapeutic intervention and gene therapy. Here we have studied variables which affect cell surface labelling for β1-integrin, flow sorting and subsequent culturing of β1-integrin-positive and β1-integrin-negative keratinocytes. Keratinocytes were derived from small human skin punch biopsies (3 or 4 mm in diameter), and we tested a number of variables such as choice of proteolytic enzyme for cell isolation, cell concentration, fixation, storage of fixed cell suspensions and labelling conditions. In contrast to thermolysin treatment for cell isolation, trypsin treatment left most cell surface β1-integrin molecules intact. Ethanol and paraformaldehyde fixation interfered with β1-integrin detection, and unfixed cells gave the best results. Optimisation of all the individual steps resulted in a labelling protocol for reproducible staining and sorting of the cells. Sorted cells were seeded in 96-well plates (300 cells/well) and colonies were obtained in more than 50% of the wells with β1-integrin-positive keratinocytes. In plates with β1-integrin-negative cells, only 10% of the wells contained keratinocyte colonies. Flow sorted keratinocytes obtained by trypsin formed numerous colonies in cell culture experiments. In cell suspensions obtained with thermolysin, only sparse colonies were formed. We conclude that our methodology permits the use of small human tissue samples for cell labelling and sorting, while preserving the clonogenic potential. [Copyright &y& Elsevier]