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Staphylococcus aureus is a human pathogen of growing clinical significance, owing to its increasing levels of resistance to most antibiotics. Infections range from mild wound infections to severe infections such as endocarditis, osteomyelitis and septic shock. Adherence of S. aureus to human host cells is an important step, leading to colonization and infection. Adherence is mediated by a multiplicity of proteins expressed on the bacterial surface, including clumping factor B. In this study, we aimed to identify new targets of clumping factor B in human keratinocytes by undertaking a genome-wide yeast two-hybrid screen of a human keratinocyte cDNA library. We show that clumping factor B is capable of binding cytokeratin 8 (CK8), a type II cytokeratin. Using a domain-mapping strategy we identified amino acids 437-464 as necessary for this interaction. Recombinantly expressed fragments of both proteins were used in pull-down experiments and confirmed the yeast two-hybrid studies. Analysis with S. aureus strain Newman deficient in clumping factor B showed the clumping factor B-dependence of the interaction with CK8. We postulate that the clumping factor B-CK8 interaction is a novel factor in S. aureus infections. DOI 10.1099/mic.0.034413-0

Finally, residual expression of LAMB3 protein in perilesional and uninvolved patient skin, as detected by western blot, further supports the presence of RM in these clinically restored skin areas (Fig. Common molecular mechanisms of phenotypic alleviation in genetic diseases include loss of heterozygosity (LOH), gene deletion, nondisjunction mutations, as well as nonsense codon readthrough and RNA I trans i -splicing. All authors declare to have no conflicts of interest or affiliations with organizations or entities with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript and that this information is accurate, complete and up-to-date. [Extracted from the article]

Summary: Background: Several new genes and clinical subtypes have been identified since the publication in 2014 of the report of the last International Consensus Meeting on Epidermolysis Bullosa (EB). Objectives: We sought to reclassify disorders with skin fragility, with a focus on EB, based on new clinical and molecular data. Methods: This was a consensus expert review. Results: In this latest consensus report, we introduce the concept of genetic disorders with skin fragility, of which classical EB represents the prototype. Other disorders with skin fragility, where blisters are a minor part of the clinical picture or are not seen because skin cleavage is very superficial, are classified as separate categories. These include peeling skin disorders, erosive disorders, hyperkeratotic disorders, and connective tissue disorders with skin fragility. Because of the common manifestation of skin fragility, these 'EB‐related' disorders should be considered under the EB umbrella in terms of medical and socioeconomic provision of care. Conclusions: The proposed classification scheme should be of value both to clinicians and researchers, emphasizing both clinical and genetic features of EB. What is already known about this topic? Epidermolysis bullosa (EB) is a group of genetic disorders with skin blistering.The last updated recommendations on diagnosis and classification were published in 2014. What does this study add? We introduce the concept of genetic disorders with skin fragility, of which classical EB represents the prototype.Clinical and genetic aspects, genotype–phenotype correlations, disease‐modifying factors and natural history of EB are reviewed.Other disorders with skin fragility, e.g. peeling skin disorders, erosive disorders, hyperkeratotic disorders, and connective tissue disorders with skin fragility are classified as separate categories; these 'EB‐related' disorders should be considered under the EB umbrella in terms of medical and socioeconomic provision of care. Linked Comment:Pope. Br J Dermatol 2020; 183:603. Linked Comment:Pope. Br J Dermatol 2020; 183:603. Plain language summary available online [ABSTRACT FROM AUTHOR]

Background: Primary melanoma ulceration is an unfavourable prognostic factor included in current staging systems. Yet, the immunological and molecular alterations responsible for this adverse outcome have not been fully elucidated. Objectives: We aimed to identify immunological differences between ulcerated and non‐ulcerated primary melanomas concerning both innate and adaptive immunity and to correlate these with clinical outcome. Methods: Formalin‐fixed paraffin‐embedded primary melanomas from 112 patients (pts) were analysed by immunohistochemistry. The expression of various markers identifying tumour‐infiltrating lymphocytes, macrophages and dendritic cells was evaluated semi‐quantitatively by three independent investigators. Tumour cell expression of programmed death‐ligand 1 (PD‐L1), transporter of antigen processing 1 and the MxA protein was also analysed. Results: Recurrence occurred in 21/56 pts (37.5%) with ulcerated vs. 14/56 pts (25.0%) with non‐ulcerated tumours (P = 0.15). Tumour ulceration was associated with more frequent development of brain metastasis (17.6 vs. 3.6% of pts, P = 0.015). Immunohistochemistry showed an association of ulceration with the presence of intratumoural CD68+ macrophages (P = 0.028) as well as with increased numbers of intratumoural CD11c+ dendritic cells (P = 0.014) and CD163+ macrophages (P = 0.001). PD‐L1 positivity (expression in >1% of tumour cells) was more frequent in ulcerated than non‐ulcerated tumours [40 (72.7%) vs. 25 (44.6%), P = 0.003]. A positive correlation between intratumoural CD11c+ (Spearman's correlation coefficient ρ: 0.42) and CD163+ (ρ: 0.31) cell count and frequency of tumour cell PD‐L1 expression was detected. Conclusions: Our results confirm the adverse clinical outcome associated with primary melanoma ulceration, particularly concerning the risk of recurrence and subsequent development of brain metastases. The observed immunological differences suggest a conceivable role of increased intratumoural macrophage and dendritic cell counts associated with enhanced tumour cell PD‐L1 expression potentially contributing to the immunosuppressive, growth‐promoting microenvironment of ulcerated primary melanomas. [ABSTRACT FROM AUTHOR]

Summary: Background: Generalized severe epidermolysis bullosa simplex (EBS‐gen sev) is a genetic blistering skin disease in which autosomal dominant mutations in either the keratin KRT5 or KRT14 genes lead to impaired function of the intermediate filament cytoskeleton in the basal epidermis. Here we present an ex vivo RNA trans‐splicing‐based therapeutic approach to correct the phenotype. Objectives: To correct a mutation within exon 1 of the KRT14 gene, using a 5′‐trans‐splicing approach, where any mutation within the first seven exons could be replaced by a single therapeutic molecule. Methods: A therapeutic RNA trans‐splicing molecule containing wild‐type exons 1–7 was stably transduced into an EBS patient‐derived keratinocyte line. Trans‐splicing was confirmed via reverse‐transcriptase polymerase chain reaction, Western blotting and immunofluorescence microscopy. Skin equivalents generated from corrected keratinocytes were grafted onto nude mice and analysed about 8 weeks post‐transplantation for regular epidermal stratification, trans‐splicing‐induced green fluorescent protein expression and blistering. Results: Transplanted skin equivalents generated from trans‐splicing‐corrected patient keratinocytes showed a stable and blister‐free epidermis. KRT14 correction disrupted EBS‐gen sev‐associated proinflammatory signalling, as shown at the mRNA and protein levels. Disruption of the pathogenic feedback loop in addition to overall downregulation of KRT14 expression highlighted the effect of KRT14 correction on the EBS pathomechanism. Conclusions: Our data demonstrate that trans‐splicing‐mediated mRNA therapy is an effective method for the correction of dominantly inherited KRT14 mutations at the transcriptional level. This results in the rescue of the EBS‐gen sev phenotype and stabilization of the epidermis in a xenograft mouse model. What's already known about this topic? RTM163, described in this study, was previously used in a transient in vitro transfection system, where the ability to correct KRT14 at the mRNA level was demonstrated. What does this study add? In this study, we stably transduced RTM163 in a second patient‐derived keratinocyte line.Successful trans‐splicing was confirmed in this cell line.The expression of disease‐related marker genes, which are characteristically deregulated in epidermolysis bullosa simplex, were analysed.For the first time this study showed that RNA trans‐splicing molecule‐transduced patient keratinocytes can differentiate into a phenotypically normal and blister‐free epidermis in a xenograft mouse model. What is the translational message? This study shows the feasibility of using spliceosome‐mediated RNA trans‐splicing to generate a stable and blister‐free epidermis in vivo.Combined with pre‐existing ex vivo gene therapeutic methods, this might be a valid option for future treatments of dominantly inherited genodermatoses. Linked Comment: Bremer and van den Akker. Br J Dermatol 2019; 180:17–19. [ABSTRACT FROM AUTHOR]

As a response to changing profiles of the Asian population in the United States, this study examines the demographic, human capital, and acculturation factors that are associated with the official poverty status of Asian immigrant householders by their U.S. citizenship status. From the 1990 Census Public Use Microdata Sample (Census of Population and Housing, 1990a), responses from 229,004 Asian householders are analyzed using hierarchical bivariate logistic regression. The results suggests that high levels of human capital and acculturation reduce the odds of Asian householders living below the official poverty threshold, regardless of their citizenship status. The degree to which the selected variables are associated with poverty status varies by citizenship status.

Linked Article: Ebens et al. Br J Dermatol 2021; 184:1161–1169. [ABSTRACT FROM AUTHOR]

Background Patients with recessive dystrophic epidermolysis bullosa (RDEB) have an increased risk of developing rapidly progressive and metastatic cutaneous squamous cell carcinomas (SCC). It is unclear why these SCC behave more aggressively than sporadic SCC. Matrix metalloproteinases (MMP) are a family of endopeptidases that contribute to growth, invasion and metastasis of SCC. The role of MMP in RDEB-associated SCC is not known. Objectives To investigate the expression of MMP-7, MMP-13 and MMP-9 in RDEB-associated SCC in comparison with sporadic SCC and Bowen’s disease. Methods Immunohistochemical analysis of 25 RDEB-associated SCC, 61 sporadic SCC and 28 sporadic lesions of Bowen’s disease was carried out using monoclonal antibodies for MMP-7, MMP-9, MMP-13 and E-cadherin and syndecan-1. Results MMP-7 was detected in all RDEB-associated SCC, in tumour cells within the invasive edge, where E-cadherin and syndecan-1 were markedly diminished or absent. MMP-7 expression was also observed in 98% of sporadic SCC and in 68% of Bowen’s diseases. MMP-7 staining was significantly stronger in RDEB-associated SCC than in sporadic SCC, and was most abundant in poorly differentiated tumours. MMP-13 was detected in tumour cells in 96% of RDEB-associated SCC and in all sporadic cutaneous SCC. MMP-9 was detected in the inflammatory cells in all SCC examined. Conclusions These results identify MMP-7 and MMP-13 as tumour cell-specific markers for SCC progression and as potential therapeutic targets in RDEB-associated SCC. The pattern of immunolabelling suggests that MMP-7 may shed E-cadherin and syndecan-1 from the SCC cell surface. [ABSTRACT FROM AUTHOR]

Background: Kindler's syndrome is a rare genodermatosis mainly characterized by the onset of skin blistering in early childhood, web formation of fingers and toes, photosensitivity, and progressive poikiloderma. There is still debate whether this disease represents a distinctive entity in the spectrum of congenital bullous poikilodermas or a variant of dystrophic epidermolysis bullosa. Objective: To evaluate the recently proposed and debated characteristic immunohistochemical and ultrastructural features of Kindler's syndrome. Patient/methods: Immunofluorescence (IF) antigen mapping and transmission electron microscopy (TEM) were performed on a skin specimen from non-sun-exposed inner aspect of the upper arm of a 49-year-old patient with characteristic clinical features of Kindler's syndrome. Results: IF studies revealed focally an extensively broadened, partly reticular staining pattern in the dermoepidermal basement membrane zone (BMZ) with antibodies against laminin-5 and type IV as well as type VII collagen. Anti-α6 and β4 integrin staining revealed small gaps in the linear reactivity in the BMZ. Abundant keratin bodies, as detected by anti-immunoglobulin M (IgM) staining, were focally present in the dermis, indicating prominent epidermal apoptosis. This was verified by a histochemical apoptosis stain [terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) reaction]. Transmission electron microscopic examination showed manifold reduplications of the lamina densa (with attached anchoring fibrils) as well as a keratin body surrounded by a fibroblast in the upper dermis. Conclusion: We present characteristic immunohistochemical and ultrastructural features of Kindler's syndrome identical to those described by Shimizu et al. (Arch Dermatol 1997; 133: 1111) and provide evidence that Kindler's syndrome might primarily be an apoptotic disorder of basal keratinocytes. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented regarding the effect of increased levels of matrix metalloproteinase-9 (MMP-9) and interleukin-8 (IL-8) in blister fluids of patients with dystrophic and junctional epidermolysis bullosa.

Epidermolysis bullosa acquisita (EBA) is an autoimmune bullous disease with frequent ocular involvement, but visual loss is rare. In contrast, EBA patients with predominant IgA autoantibodies more frequently develop severe ocular involvement, which tends to be refractory to therapy. We report two patients with ‘IgA–EBA’ with ocular involvement. Both initially presented with a generalized bullous disease, and direct immunofluorescence microscopy demonstrated IgA in the basement membrane zone of the skin, and in the conjunctiva and cornea of patient 1. On salt-split patient skin, IgA was found predominantly on the dermal side of the artificial split in both patients. Direct immunoelectron microscopy demonstrated IgA below the lamina densa in close association with the anchoring fibrils in both patients. In patient 1, who had a prolonged course of the disease, the skin disorder responded well to treatment with cyclosporin, but the ocular involvement ended in bilateral blindness despite repeated surgical treatment. In patient 2, the blister formation and scarring conjunctivitis was stopped by a combination of prednisolone and colchicine. These patients show that in subepithelial blistering diseases, early delineation of disease nosology is critical to detect subtypes with severe ocular involvement such as ‘IgA–EBA’. In addition, colchicine may be a valuable alternative in the treatment of EBA with ocular involvement. [ABSTRACT FROM AUTHOR]

Linked Article: Condorelli et al. Br J Dermatol 2019; 181:1017–1027. [ABSTRACT FROM AUTHOR]

The article presents a case study of a one-month-old girl presented with nail dystrophy, oral leukoplakia and multiple subungual haematomas on both hands. Topics include laryngeal stenosis with an altered inspiratory stridor and horse cry as the most remarkable symptom, diagnosis of e autosomal recessive genodermatosis, laryngo-onycho-cutaneous syndrome (LOC), and suffering from LOC variant based on a plectin gene (PLEC) mutation, expressed in variety of tissues causing pleiotropic phenotypes.