Chronic activation of Toll-like receptor 2 induces an ichthyotic skin phenotype.

BACKGROUND: Ichthyosis defines a group of chronic conditions that manifest phenotypically as a thick layer of scales, often affecting the entire skin. While the gene mutations that lead to ichthyosis are well documented, the actual signalling mechanisms that lead to scaling are poorly characterized; however, recent publications suggest that common mechanisms are active in ichthyotic tissue and in analogous models of ichthyosis. OBJECTIVES: To determine common mechanisms of hyperkeratosis that may be easily targeted with small-molecule inhibitors. METHODS: We combined gene expression analysis of gene-specific short hairpin RNA (shRNA) knockdowns in rat epidermal keratinocytes (REKs) of two genes mutated in autosomal recessive congenital ichthyosis (ARCI), Tgm1 and Alox12b, and proteomic analysis of skin scale from patients with ARCI, as well as RNA sequencing data from rat epidermal keratinocytes treated with the Toll-like receptor 2 (TLR2) agonist Pam3CSK4. RESULTS: We identified common activation of the TLR2 pathway. Exogenous TLR2 activation led to increased expression of important cornified envelope genes and, in organotypic culture, caused hyperkeratosis. Conversely, blockade of TLR2 signalling in keratinocytes from patients with ichthyosis and our shRNA models reduced the expression of keratin 1, a structural protein overexpressed in ichthyosis scale. A time course of TLR2 activation in REKs revealed that although there was rapid initial activation of innate immune pathways, this was rapidly superseded by widespread upregulation of epidermal differentiation-related proteins. Both nuclear factor kappa B phosphorylation and GATA3 upregulation was associated with this switch, and GATA3 overexpression was sufficient to increase keratin 1 expression. CONCLUSIONS: Taken together, these data define a dual role for TLR2 activation during epidermal barrier repair that may be a useful therapeutic modality in treating diseases of epidermal barrier dysfunction.

Treatment Effect of Omalizumab on Severe Pediatric Atopic Dermatitis: The ADAPT Randomized Clinical Trial.

Importance: Systemic treatments for severe childhood atopic dermatitis have limited evidence and/or are unlicensed. Despite the efficacy of anti-IgE medication (omalizumab) in the treatment of atopy, no large randomized studies in childhood atopic dermatitis have been published. Objective: To determine the effectiveness of omalizumab in treating severe atopic dermatitis in children. Design, Setting, and Participants: The Atopic Dermatitis Anti-IgE Pediatric Trial (ADAPT) was a 24-week single-center, double-blind, placebo-controlled randomized clinical trial with a 24-week follow-up. Conducted from November 20, 2014, to August 31, 2017, at Guy's and St Thomas' Hospital NHS Foundation Trust and King's College London in the United Kingdom, this trial recruited participants after a screening visit. Eligible participants (n = 62) were aged 4 to 19 years and had severe eczema (with objective Scoring Atopic Dermatitis [SCORAD] index >40) that was unresponsive to optimum therapy. Statistical analysis was conducted using the intention-to-treat principle. Interventions: Subcutaneous omalizumab or placebo for 24 weeks. The drug manufacturer's dosing tables were used to determine the dosage based on total IgE (30-1500 IU/mL) and body weight (in kilograms) at randomization. Main Outcomes and Measures: Objective SCORAD index after 24 weeks of treatment. Results: In total, 62 children (mean [SD] age, 10.3 [4.2] years; 32 (52%) were male) were randomized to either omalizumab (n = 30) or placebo (n = 32). Five participants withdrew from treatment (4 [13%] from the placebo group, and 1 [3%] from the omalizumab group). Follow-up attendance was 97% at week 24 and 98% at week 48. After adjustment for baseline objective SCORAD index, age, and IgE level, the mean difference in objective SCORAD index improvement between groups at week 24 was -6.9 (95% CI, -12.2 to -1.5; P = .01), significantly favoring omalizumab therapy and reflecting the results in other assessments of atopic dermatitis severity. Improved quality-of-life scores were seen in the omalizumab group, as measured by the Children's Dermatology Life Quality Index/Dermatology Life Quality Index (-3.5; 95% CI, -6.4 to -0.5) and Pediatric Allergic Disease Quality of Life Questionnaire score (-0.5; 95% CI, -0.9 to -0.0). Improvements in disease severity occurred despite lower potent topical corticosteroid use in the omalizumab group compared with the placebo group (median [interquartile range (IQR)] percentage of body surface area covered, 16% [10%-46%] vs 31% [14%-55%]; median [IQR] number of days of use, 109 [34-164] days vs 161 [82-171] days). Conclusions and Relevance: This randomized clinical trial found that omalizumab significantly reduced atopic dermatitis severity and improved quality of life in a pediatric population with atopy and severe eczema despite highly elevated total IgE levels at baseline. The result was associated with a potent topical corticosteroid sparing effect and may suggest that omalizumab is a treatment option for difficult-to-manage severe eczema in children with atopy. Trial Registration: ClinicalTrials.gov identifier: NCT02300701.

Generation and Clinical Application of Gene-Modified Autologous Epidermal Sheets in Netherton Syndrome: Lessons Learned from a Phase 1 Trial.

Netherton syndrome (NS) is a rare autosomal recessive skin disorder caused by mutations in SPINK5. It is a debilitating condition with notable mortality in the early years of life. There is no curative treatment. We undertook a nonrandomized, open-label, feasibility, and safety study using autologous keratinocytes transduced with a lentiviral vector encoding SPINK5 under the control of the human involucrin promoter. Six NS subjects were recruited, and gene-modified epithelial sheets were successfully generated in three of five subjects. The sheets exhibited expression of correctly sized lympho-epithelial Kazal-type-related inhibitor (LEKTI) protein after modification. One subject was grafted with a 20 cm2 gene-modified graft on the left anterior thigh without any adverse complications and was monitored by serial sampling for 12 months. Recovery within the graft area was compared against an area outside by morphology, proviral copy number and expression of the SPINK5 encoded protein, LEKTI, and its downstream target kallikrein 5, which exhibited transient functional correction. The study confirmed the feasibility of generating lentiviral gene-modified epidermal sheets for inherited skin diseases such as NS, but sustained LEKTI expression is likely to require the identification, targeting, and engraftment of long-lived keratinocyte stem cell populations for durable therapeutic effects. Important learning points for the application of gene-modified epidermal sheets are discussed.

Persistent kallikrein 5 activation induces atopic dermatitis-like skin architecture independent of PAR2 activity.

BACKGROUND: Upregulation of kallikreins (KLKs) including KLK5 has been reported in atopic dermatitis (AD). KLK5 has biological functions that include degrading desmosomal proteins and inducing proinflammatory cytokine secretion through protease-activated receptor 2 (PAR2). However, due to the complex interactions between various cells in AD inflamed skin, it is difficult to dissect the precise and multiple roles of upregulated KLK5 in AD skin. OBJECTIVE: We investigated the effect of upregulated KLK5 on the expression of epidermal-related proteins and cytokines in keratinocytes and on skin architecture. METHODS: Lesional and nonlesional AD skin biopsies were collected for analysis of morphology and protein expression. The relationship between KLK5 and barrier-related molecules was investigated using an ex vivo dermatitis skin model with transient KLK5 expression and a cell model with persistent KLK5 expression. The influence of upregulated KLK5 on epidermal morphology was investigated using an in vivo skin graft model. RESULTS: Upregulation of KLK5 and abnormal expression of desmoglein 1 (DSG1) and filaggrin, but not PAR2 were identified in AD skin. PAR2 was increased in response to transient upregulation of KLK5, whereas persistently upregulated KLK5 did not show this effect. Persistently upregulated KLK5 degraded DSG1 and stimulated secretion of IL-8, IL-10, and thymic stromal lymphopoietin independent of PAR2 activity. With control of higher KLK5 activity by the inhibitor sunflower trypsin inhibitor G, restoration of DSG1 expression and a reduction in AD-related cytokine IL-8, thymic stromal lymphopoietin, and IL-10 secretion were observed. Furthermore, persistently elevated KLK5 could induce AD-like skin architecture in an in vivo skin graft model. CONCLUSIONS: Persistently upregulated KLK5 resulted in AD-like skin architecture and secretion of AD-related cytokines from keratinocytes in a PAR2 independent manner. Inhibition of KLK5-mediated effects may offer potential as a therapeutic approach in AD.

Infantile haemangioma.

With a prevalence of 4·5%, infantile haemangiomas are the most common benign tumours of infancy, arising in the first few weeks of life and exhibiting a characteristic sequence of growth and spontaneous involution. Most infantile haemangiomas do not require therapy. However, to identify at-risk haemangiomas, close follow-up is crucial in the first weeks of life; 80% of all haemangiomas reach their final size by 3 months of age. The main indications for treatment are life-threatening infantile haemangioma (causing heart failure or respiratory distress), tumours posing functional risks (eg, visual obstruction, amblyopia, or feeding difficulties), ulceration, and severe anatomic distortion, especially on the face. Oral propranolol is now the first-line treatment, which should be administered as early as possible to avoid potential complications. Haemangioma shrinkage is rapidly observed with oral propranolol, but a minimum of 6 months of therapy is recommended.

A mechanistic target of rapamycin complex 1/2 (mTORC1)/V-Akt murine thymoma viral oncogene homolog 1 (AKT1)/cathepsin H axis controls filaggrin expression and processing in skin, a novel mechanism for skin barrier disruption in patients with atopic dermatitis.

BACKGROUND: Filaggrin, which is encoded by the filaggrin gene (FLG), is an important component of the skin's barrier to the external environment, and genetic defects in FLG strongly associate with atopic dermatitis (AD). However, not all patients with AD have FLG mutations. OBJECTIVE: We hypothesized that these patients might possess other defects in filaggrin expression and processing contributing to barrier disruption and AD, and therefore we present novel therapeutic targets for this disease. RESULTS: We describe the relationship between the mechanistic target of rapamycin complex 1/2 protein subunit regulatory associated protein of the MTOR complex 1 (RAPTOR), the serine/threonine kinase V-Akt murine thymoma viral oncogene homolog 1 (AKT1), and the protease cathepsin H (CTSH), for which we establish a role in filaggrin expression and processing. Increased RAPTOR levels correlated with decreased filaggrin expression in patients with AD. In keratinocyte cell cultures RAPTOR upregulation or AKT1 short hairpin RNA knockdown reduced expression of the protease CTSH. Skin of CTSH-deficient mice and CTSH short hairpin RNA knockdown keratinocytes showed reduced filaggrin processing, and the mouse had both impaired skin barrier function and a mild proinflammatory phenotype. CONCLUSION: Our findings highlight a novel and potentially treatable signaling axis controlling filaggrin expression and processing that is defective in patients with AD.

Treatment of infantile haemangiomas: recommendations of a European expert group.

UNLABELLED: With a prevalence of 2.6-4.5 %, infantile haemangiomas (IH) represent the most common tumour of infancy. While the majority of IH does not require therapy and regresses spontaneously, about 10 % of IH exhibit complications such as obstruction, ulceration or disfigurement. With the advent of oral propranolol, many conventional treatment options have become obsolete. This paper summarizes current recommendations for management of complicated IH. These recommendations have been written by an expert group after a consensus process including bibliographic review, several drafts of synthesis, meetings with quantitative voting system and redaction of an approved final manuscript. CONCLUSION: Oral propranolol is the first-line agent for the treatment of complicated IH. WHAT IS KNOWN: • Infantile haemangiomas (IH) are the most common tumours of infancy. Within a very short period after its discovery and long before the publication of randomized controlled trials, propranolol has become the number one agent for the treatment of complicated IH. What is New: • We report IH treatment recommendations of an international, interdisciplinary team of experts, based on an up-to-date review of the literature.

Propranolol for infantile haemangiomas: single centre experience of 250 cases and proposed therapeutic protocol.

OBJECTIVE: To assess the safety and efficacy of systemic propranolol for the treatment of complicated infantile haemangiomas. DESIGN: Retrospective review of case notes of paediatric patients treated with propranolol for complicated infantile haemangiomas. SETTING: Tertiary care children's hospital. PATIENTS: All paediatric patients with complicated infantile haemangiomas who commenced treatment with propranolol from July 2008 to December 2011 and have completed treatment for at least 3 months. RESULTS: 250 patients were treated with propranolol; 34.4% were premature and 5.6% postmature. Indications for propranolol included: vision compromise (42.0%), bleeding and/or ulceration (30.4%) airway obstruction (8.8%), feeding difficulty (8.4%), risk of permanent disfigurement (4.4%) and other (6%) (nasal obstruction, auditory canal obstruction, large haemangioma, compression of neck structure and spinal cord). Median age at beginning of treatment was 4.5 months. Median age at end of treatment was 16.7 months. Median length of therapy was 11.8 months. Adverse effects (such as wheezing, worsening of ulceration, sleep disturbance, diarrhoea) occurred in 38 patients (15.2%), leading to modifications in management in 26 patients (10.4%). 240 patients (96%) had good to excellent response to treatment. 20 patients (8%) experienced regrowth of the haemangioma on cessation of propranolol and six patients (2.4%) required propranolol to be restarted. CONCLUSIONS: In appropriately selected patients, propranolol is a safe and effective treatment for infantile haemangiomas.

Epithelial inflammation resulting from an inherited loss-of-function mutation in EGFR.

Epidermal growth factor receptor (EGFR) signaling is fundamentally important for tissue homeostasis through EGFR/ligand interactions that stimulate numerous signal transduction pathways. Aberrant EGFR signaling has been reported in inflammatory and malignant diseases, but thus far no primary inherited defects in EGFR have been recorded. Using whole-exome sequencing, we identified a homozygous loss-of-function missense mutation in EGFR (c.1283 G>A; p.Gly428Asp) in a male infant with lifelong inflammation affecting the skin, bowel, and lungs. During the first year of life, his skin showed erosions, dry scale, and alopecia. Subsequently, there were numerous papules and pustules--similar to the rash seen in patients receiving EGFR inhibitor drugs. Skin biopsy demonstrated an altered cellular distribution of EGFR in the epidermis with reduced cell membrane labeling, and in vitro analysis of the mutant receptor revealed abrogated EGFR phosphorylation and EGF-stimulated downstream signaling. Microarray analysis on the patient's skin highlighted disturbed differentiation/premature terminal differentiation of keratinocytes and upregulation of several inflammatory/innate immune response networks. The boy died at the age of 2.5 years from extensive skin and chest infections as well as electrolyte imbalance. This case highlights the major mechanism of epithelial dysfunction following EGFR signaling ablation and illustrates the broader impact of EGFR inhibition on other tissues.

A genome-wide association study of atopic dermatitis identifies loci with overlapping effects on asthma and psoriasis.

Atopic dermatitis (AD) is the most common dermatological disease of childhood. Many children with AD have asthma and AD shares regions of genetic linkage with psoriasis, another chronic inflammatory skin disease. We present here a genome-wide association study (GWAS) of childhood-onset AD in 1563 European cases with known asthma status and 4054 European controls. Using Illumina genotyping followed by imputation, we generated 268 034 consensus genotypes and in excess of 2 million single nucleotide polymorphisms (SNPs) for analysis. Association signals were assessed for replication in a second panel of 2286 European cases and 3160 European controls. Four loci achieved genome-wide significance for AD and replicated consistently across all cohorts. These included the epidermal differentiation complex (EDC) on chromosome 1, the genomic region proximal to LRRC32 on chromosome 11, the RAD50/IL13 locus on chromosome 5 and the major histocompatibility complex (MHC) on chromosome 6; reflecting action of classical HLA alleles. We observed variation in the contribution towards co-morbid asthma for these regions of association. We further explored the genetic relationship between AD, asthma and psoriasis by examining previously identified susceptibility SNPs for these diseases. We found considerable overlap between AD and psoriasis together with variable coincidence between allergic rhinitis (AR) and asthma. Our results indicate that the pathogenesis of AD incorporates immune and epidermal barrier defects with combinations of specific and overlapping effects at individual loci.

A functional IL-6 receptor (IL6R) variant is a risk factor for persistent atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) is a common inflammatory skin disease. Previous studies have revealed shared genetic determinants among different inflammatory disorders, suggesting that markers associated with immune-related traits might also play a role in AD. OBJECTIVE: We sought to identify novel genetic risk factors for AD. METHODS: We examined the results of all genome-wide association studies from a public repository and selected 318 genetic markers that were significantly associated with any inflammatory trait. These markers were considered candidates and tested for association with AD in a 3-step approach including 7 study populations with 7130 patients with AD and 9253 control subjects. RESULTS: A functional amino acid change in the IL-6 receptor (IL-6R Asp358Ala; rs2228145) was significantly associated with AD (odds ratio [OR], 1.15; P = 5 × 10(-9)). Interestingly, investigation of 2 independent population-based birth cohorts showed that IL-6R 358Ala specifically predisposes to the persistent form of AD (ORpersistent AD = 1.22, P = .0008; ORtransient AD = 1.04, P = .54). This variant determines the balance between the classical membrane-bound versus soluble IL-6R signaling pathways. Carriers of 358Ala had increased serum levels of soluble IL-6R (P = 4 × 10(-14)), with homozygote carriers showing a 2-fold increase. Moreover, we demonstrate that soluble IL-6R levels were higher in patients with AD than in control subjects (46.0 vs 37.8 ng/mL, P = .001). Additional AD risk variants were identified in RAD50, RUNX3, and ERBB3. CONCLUSION: Our study supports the importance of genetic variants influencing inflammation in the etiology of AD. Moreover, we identified a functional genetic variant in IL6R influencing disease prognosis and specifically predisposing to persistent AD.

Human involucrin promoter mediates repression-resistant and compartment-specific LEKTI expression.

Gene-modified skin grafts, produced through gene transfer to human keratinocyte stem cells, offer the possibility of therapeutic benefit for inherited skin diseases. We have previously described efficient lentiviral vector-mediated gene transfer to keratinocyte stem cells and the generation of human skin grafts for the inherited skin disease, Netherton syndrome, which arises due to mutations in serine protease inhibitor Kazal-type 5 (SPINK5). Vectors incorporating an internal murine retroviral-derived promoter [spleen focus-forming virus (SFFV)] in combination with a codon-optimized SPINK5 transgene supported high levels of reconstitution and robust correction of skin architecture. Subsequent longer-term experiments have uncovered unanticipated silencing phenomena, with loss of SPINK5 gene expression over time. The inadvertent introduction of CpG sites during codon optimization appears to have rendered vectors susceptible to silencing due to methylation across the promoter-transgene boundary. Substitution of the methylation-susceptible SFFV promoter with a 572-bp minimal human involucrin promoter (INVOp), which encodes very few CpG sites, prevented repression of the SPINK5 transgene and resulted in durable and highly compartment-specific reconstitution of lympho-epithelial Kazal-type-related inhibitor (LEKTI) in human skin grafted onto immunodeficient mice. We conclude that skin grafts modified with lentiviral vectors encoding INVOp offer a suitable platform for therapeutic gene therapy in Netherton syndrome, and our experience highlights unanticipated effects of transgene codon optimization.

Inflammatory skin and bowel disease linked to ADAM17 deletion.

We performed genetic and immunohistochemical studies in a sister and brother with autosomal recessive neonatal inflammatory skin and bowel lesions. The girl died suddenly at 12 years of age from parvovirus B19-associated myocarditis; her brother had mild cardiomyopathy. We identified a loss-of-function mutation in ADAM17, which encodes a disintegrin and metalloproteinase 17 (also called tumor necrosis factor α [TNF-α]-converting enzyme, or TACE), as the probable cause of this syndrome. Peripheral-blood mononuclear cells (PBMCs) obtained from the brother at 17 years of age showed high levels of lipopolysaccharide-induced production of interleukin-1ß and interleukin-6 but impaired release of TNF-α. Despite repeated skin infections, this young man has led a relatively normal life. (Funded by Barts and the London Charity and the European Commission Seventh Framework Programme.).

Mediastinal involvement in lymphangiomatosis: a previously unreported MRI sign.

BACKGROUND: Multifocal lymphangiomatosis is a rare systemic disorder affecting children. Due to its rarity and wide spectrum of clinical, histological and imaging features, establishing the diagnosis of multifocal lymphangiomatosis can be challenging. OBJECTIVES: The purpose of this study was to describe a new imaging sign in this disorder: paraspinal soft tissue and signal abnormality at MRI. MATERIALS AND METHODS: We retrospectively reviewed the imaging, clinical and histopathological findings in a cohort of eight children with thoracic involvement from this condition. RESULTS: Evidence of paraspinal chest disease was identified at MRI and CT in all eight of these children. The changes comprise heterogeneous intermediate-to-high signal parallel to the thoracic vertebrae on T2-weighted sequences at MRI, with abnormal paraspinal soft tissue at CT and plain radiography. CONCLUSION: Multifocal lymphangiomatosis is a rare disorder with a broad range of clinicopathological and imaging features. MRI allows complete evaluation of disease extent without the use of ionising radiation and has allowed us to describe a previously unreported imaging sign in this disorder, namely, heterogeneous hyperintense signal in abnormal paraspinal tissue on T2-weighted images.

A proposal for classification of entities combining vascular malformations and deregulated growth.

BACKGROUND: Agreement on terminology and nomenclature is fundamental and essential for effective exchange of information between clinicians and researchers. An adequate terminology to describe all patients showing vascular malformations combined with deregulated growth is at present not available. OBJECTIVES: To propose a classification of patients with vascular malformations, not restricted to the face, and growth disturbances based on simple, clinically visible characteristics, on which clinicians and researchers can comment and which should eventually lead to an internationally accepted classification. METHODS: Rooted in our joint experience we established a classification of vascular malformation not limited to the face, with growth disturbances. It is based on the nature and localization of the vascular malformations; the nature, localization and timing of growth disturbances; the nature of co-localization of the vascular malformations and growth disturbances; the presence or absence of other features. Subsequently a mixed (experienced and non-experienced) group of observers evaluated 146 patients (106 from the Netherlands; 40 from the UK) with vascular malformations and disturbed growth, using the classification. Inter-observer variability was assessed by estimating the Intra-Class Correlation (ICC) coefficient and its 95% confidence interval. RESULTS: We defined 6 subgroups within the group of entities with vascular malformation-deregulated growth. Scoring the patients using the proposed classification yielded a high inter-observer reproducibility (ICC varying between 0.747 and 0.895 for all levels of flow). CONCLUSIONS: The presently proposed classification was found to be reliable and easy to use for patients with vascular malformations with growth disturbances. We invite both clinicians and researchers to comment on the classification, in order to improve it further. This way we may obtain our final aim of an internationally accepted classification of patients, which should facilitate both clinical treatment and care of, as well as research into the molecular background of entities combining vascular malformation and deregulated growth.

Ex-vivo gene therapy restores LEKTI activity and corrects the architecture of Netherton syndrome-derived skin grafts.

Netherton syndrome (NS) is a debilitating congenital skin disorder caused by mutations in the SPINK5 gene encoding the lymphoepithelial Kazal-type-related inhibitor (LEKTI). It is characterized by defective keratinization, recurrent infections, and hypernatraemic dehydration with a mortality rate of about 10% in the first year of life. Currently, there are no curative treatments for NS. We have developed a HIV-1 based, self-inactivating lentiviral vector to express SPINK5 in keratinocytes as part of an ex-vivo gene therapy strategy for NS. High transduction efficiency was achieved in NS keratinocytes and reconstitution of LEKTI expression was confirmed in previously deficient cells. These genetically corrected keratinocytes were further tested in an in vitro organotypic culture (OTC) system and in vivo mouse/human skin engraftment model. Results showed correction of epidermal architecture in both OTCs and regenerated skin grafts. Importantly, the results from corrected skin grafts indicated that even where detectable LEKTI expression was restored to a limited numbers of cells, a wider bystander benefit occurred around these small populations. As LEKTI is a secreted protein, the genetically modified graft may provide not only an immediate local protective barrier, but also act as a source of secreted LEKTI providing a generalized benefit following ex-vivo gene therapy.

A genome-wide analysis of loss of heterozygosity and chromosomal copy number variation in Proteus syndrome using high-density SNP microarrays.

Excessive cell proliferation and genetic changes such as loss of an allele (loss of heterozygosity (LOH)) or amplifications or deletions of parts of chromosomes (copy number variations (CNV)) are common findings in cancers. It is unknown whether these changes are also present in patients with overgrowth syndromes, although the presence of small-scale CNVs (such as duplication of 11p15 in Beckwith-Wiedemann syndrome), excessive cell proliferation and an increased frequency of tumors have all been reported in these patients. We present results of a genome-wide scan for LOH and CNV in Proteus syndrome (PS), a severely disfiguring overgrowth syndrome. We investigated CNV and LOH in DNA derived from affected and normal tissue samples from six PS patients using Affymetrix GeneChip Mapping 250 K Nsp high-density single-nucleotide polymorphism microarrays. Analysis revealed that LOH and CNVs were not common in PS. We attempted to validate selected CNVs detected by microarray analysis using quantitative genomic PCR, but the observed changes were not confirmed. These results suggest that large-scale genome-wide CNVs and LOH as seen in cancer syndromes are not characteristic findings in PS, although we cannot rule out the possibility that newer arrays with a higher number of probes could uncover smaller CNVs not detected in this study.

Interleukin-1 alpha blockade prevents hyperkeratosis in an in vitro model of lamellar ichthyosis.

The autosomal recessive congenital ichthyoses are a family of related diseases, causing a severe defect in the barrier function of the epidermis. Neonates are usually born as collodion babies, but later form scales characteristic of the disease, due to a combination of thickening of the cornified layer and an increase in the production of non-polar lipids. Current treatments of choice are exfoliative creams and moisturizing agents and the use of oral retinoids. The skin condition and treatment impact significantly on quality of life and, with oral retinoids, there are potential complications associated with long-term use. A greater understanding of the mechanisms that result in scaling should lead to better directed therapies, not only for the inherited ichthyoses, but also other hyperkeratotic disorders. Using siRNA knockdown of the principle gene mutated in lamellar ichthyosis (LI), transglutaminase-1, in rat keratinocytes, we created an in vitro organotypic culture model that closely mimics the disease. Interleukin-1 alpha (IL1A) expression was increased and there was a lack of loricrin cross-linking. All LI patients tested had an increased IL1A and treatment of wild-type organotypic cultures with IL1A was sufficient to induce hyperkeratosis. Treatment of disease mimic organotypic cultures with IL-1 receptor antagonist led to a dose-dependent decrease in hyperkeratosis without a reduction in non-polar lipids in the cornified layer, which has the potential to reduce scaling without the requirement to constantly apply emollients.