Dominant dystrophic epidermolysis bullosa is associated with glycolytically active GATA3+ T helper 2 cells which may contribute to pruritus in lesional skin.

BACKGROUND: Dominant dystrophic epidermolysis bullosa (DDEB) is characterized by trauma-induced blisters and, in some individuals, intense pruritus. Precisely what causes itch in DDEB and optimal ways to reduce it have not been fully determined. OBJECTIVES: To characterize DDEB skin transcriptomes to identify therapeutic targets to reduce pruritus in patients. METHODS: Using bulk RNA sequencing, we evaluated affected and unaffected skin biopsy samples from six patients with DDEB (all with the very itchy pruriginosa subtype) and four healthy individuals. Single-cell transcriptomes of affected (n = 2) and unaffected (n = 1) DDEB skin and healthy skin (n = 2) were obtained. Dupilumab treatment was provided for three patients. RESULTS: The skin bulk transcriptome showed significant enrichment of T helper (Th)1/2 and Th17 pathways in affected DDEB skin compared with nonlesional DDEB skin and healthy skin. Single-cell transcriptomics showed an association of glycolytically active GATA3+ Th2 cells in affected DDEB skin. Treatment with dupilumab in three people with DDEB led to significantly reduced visual analogue scale (VAS) itch scores after 12 weeks (mean VAS 3.83) compared with pretreatment (mean VAS 7.83). Bulk RNAseq and quantitative polymerase chain reaction showed that healthy skin and dupilumab-treated epidermolysis bullosa (EB) pruriginosa skin have similar transcriptomic profiles and reduced Th1/Th2 and Th17 pathway enrichment. CONCLUSIONS: Single-cell RNAseq helps define an enhanced DDEB-associated Th2 profile and rationalizes drug repurposing of anti-Th2 drugs in treating DDEB pruritus.

Dominant dystrophic epidermolysis bullosa (DDEB) is a rare inherited skin disease that causes fragile skin that blisters easily, often triggered by minor injuries. These blisters are accompanied by intense itching, which can be distressing. The underlying cause of DDEB lies in genetic mutations in a gene called COL7A1. This gene encodes 'type VII collagen', a protein crucial for attaching the outer skin layer (epidermis) to the layer beneath (dermis). Although the genetic basis of DDEB is understood, the causes of itch are not known. As well as this, effective treatments for DDEB are lacking, which has driven scientists to explore innovative approaches like repurposing existing drugs. Drug repurposing involves using medications that have already been approved for other health conditions. One such drug is dupilumab, which is used for severe atopic dermatitis (eczema). Dupilumab targets immune cells called Th2 cells, which play a role in inflammation and allergies. While dupilumab has shown promise in relieving DDEB itching, the way it works in this condition is unclear. This study, carried out by a group of researchers in Taiwan, looked at gene expression in DDEB-affected and unaffected skin, and compared it to gene expression in healthy skin samples. We found heightened activity in Th2 immune cells and abnormal gene signals related to itching, similar to atopic dermatitis. These findings support using dupilumab and other anti-inflammatory drugs to alleviate itching in DDEB. Clinical trials will be crucial to evaluate the effectiveness of these drugs for managing DDEB symptoms. This research opens doors for enhanced treatment options and improving the quality of life of people living with DDEB.

Immunological mechanisms underlying progression of chronic wounds in recessive dystrophic epidermolysis bullosa.

Hereditary epidermolysis bullosa (EB) is a mechanobullous skin fragility disorder characterized by defective epithelial adhesion, leading to mechanical stress-induced skin blistering. Based on the level of tissue separation within the dermal-epidermal junction, EB is categorized into simplex (EBS), junctional (JEB), dystrophic (DEB) and Kindler syndrome. There is no cure for EB, and painful chronic cutaneous wounds are one of the major complications in recessive (RDEB) patients. Although RDEB is considered a cutaneous disease, recent data support the underlying systemic immunological defects. Furthermore, chronic wounds are often colonized with pathogenic microbiota, leading to excessive inflammation and altered wound healing. Consequently, patients with RDEB suffer from a painful sensation of chronic, cutaneous itching/burning and an endless battle with bacterial infections. To improve their quality of life and life expectancy, it is important to prevent cutaneous infections, dampen chronic inflammation and stimulate wound healing. A clear scientific understanding of the immunological events underlying the maintenance of chronic poorly healing wounds in RDEB patients is necessary to improve disease management and better understand other wound healing disorders. In this review, we summarize current knowledge of the role of professional phagocytes, such as neutrophils, macrophages and dendritic cells, the role of T-cell-mediated immunity in lymphoid organs, and the association of microbiota with poor wound healing in RDEB. We conclude that RDEB patients have an underlying immunity defect that seems to affect antibacterial immunity.

Diversity of Mechanisms Underlying Latent TGF-ß Activation in Recessive Dystrophic Epidermolysis Bullosa.

Injury- and inflammation-driven progressive dermal fibrosis is a severe manifestation of recessive dystrophic epidermolysis bullosa-a genetic skin blistering disease caused by mutations in COL7A1. TGF-ß activation plays a prominent part in progressing dermal fibrosis. However, the underlying mechanisms are not fully elucidated. TGF-ß is secreted in a latent form, which has to be activated for its biological functions. In this study, we determined that recessive dystrophic epidermolysis bullosa fibroblasts have an enhanced capacity to activate the latent form. Mechanistic and functional assessment demonstrated that this process depends on multiple latent TGF-ß activators, including TSP-1, RGD-binding integrins, matrix metalloproteinases, and ROS, which act in concert, in a self-perpetuating feedback loop to progress fibrosis. Importantly, our study also disclosed keratinocytes as prominent facilitators of fibrosis in recessive dystrophic epidermolysis bullosa. They stimulate microenvironmental latent TGF-ß activation through enhanced production of the above mediators. Collectively, our study provides data on the molecular mechanism behind dysregulated TGF-ß signaling in recessive dystrophic epidermolysis bullosa, which are much needed for the development of evidence-based fibrosis-delaying treatments.

Aberrant recruitment of leukocytes defines poor wound healing in patients with recessive dystrophic epidermolysis bullosa.

BACKGROUND: Poorly healing wounds are one of the major complications in patients suffering from recessive dystrophic epidermolysis bullosa (RDEB). At present, there are no effective means to analyze changes in cellular and molecular networks occurring during RDEB wound progression to predict wound outcome and design betted wound management approaches. OBJECTIVES: To better define mechanisms influencing RDEB wound progression by evaluating changes in molecular and cellular networks. METHODS: We developed a non-invasive approach for sampling and analysis of wound-associated constituents using wound-covering bandages. Cellular and molecular components from seventy-six samples collected from early, established and chronic RDEB wounds were evaluated by FACS-based immuno-phenotyping and ELISA. RESULTS: Our cross-sectional analysis determined that progression of RDEB wounds to chronic state is associated with the accumulation (up to 90 %) of CD16+CD66b+ mature neutrophils, loss of CD11b+CD68+ macrophages, and a significant increase (up to 50 %) in a number of CD11c+CD80+CD86+ activated professional antigen presenting cells (APC). It was also marked by changes in activated T cells populations including a reduction of CD45RO+ peripheral memory T cells from 80 % to 30 % and an increase (up to 70 %) in CD45RA+ effector T cells. Significantly higher levels of MMP9, VEGF-A and cathepsin G were also associated with advancing of wounds to poorly healing state. CONCLUSIONS: Our data demonstrated that wound-covering bandages are useful for a non-invasive sampling and analysis of wound-associated constituents and that transition to poorly healing wounds in RDEB patients as associated with distinct changes in leukocytic infiltrates, matrix-remodeling enzymes and pro-angiogenic factors at wound sites.

Bone marrow transplant with post-transplant cyclophosphamide for recessive dystrophic epidermolysis bullosa expands the related donor pool and permits tolerance of nonhaematopoietic cellular grafts.

BACKGROUND: Recessive dystrophic epidermolysis bullosa (RDEB) is a severe systemic genodermatosis lacking therapies beyond supportive care for its extensive, life-limiting manifestations. OBJECTIVES: To report the safety and preliminary responses of 10 patients with RDEB to bone marrow transplant (BMT) with post-transplant cyclophosphamide (PTCy BMT) after reduced-intensity conditioning with infusions of immunomodulatory donor-derived mesenchymal stromal cells (median follow-up 16 months). METHODS: BMT toxicities, donor blood and skin engraftment, skin biopsies, photographic and dynamic assessments of RDEB disease activity were obtained at intervals from pre-BMT to 1 year post-BMT. RESULTS: Related donors varied from haploidentical (n = 6) to human leucocyte antigen (HLA)-matched (n = 3), with one HLA-matched unrelated donor. Transplant complications included graft failure (n = 3; two pursued a second PTCy BMT), veno-occlusive disease (n = 2), posterior reversible encephalopathy (n = 1) and chronic graft-versus-host disease (n = 1; this patient died). In the nine ultimately engrafted patients, median donor chimerism at 180 days after transplant was 100% in peripheral blood and 27% in skin. Skin biopsies showed stable (n = 7) to improved (n = 2) type VII collagen protein expression by immunofluorescence and gain of anchoring fibril components (n = 3) by transmission electron microscopy. Early signs of clinical response include trends toward reduced body surface area of blisters/erosions from a median of 49·5% to 27·5% at 100 days after BMT (P = 0·05), with parental measures indicating stable quality of life. CONCLUSIONS: PTCy BMT in RDEB provides a means of attaining immunotolerance for future donor-derived cellular grafts (ClinicalTrials.gov identifier NCT02582775). What's already known about this topic? Severe, generalized recessive dystrophic epidermolysis bullosa (RDEB) is marked by great morbidity and early death. No cure currently exists for RDEB. Bone marrow transplant (BMT) is the only described systemic therapy for RDEB. What does this study add? The first description of post-transplant cyclophosphamide (PTCy) BMT for RDEB. PTCy was well tolerated and provided excellent graft-versus-host disease prophylaxis, replacing long courses of calcineurin inhibitors in patients receiving human leucocyte antigen-matched sibling BMT. What is the translational message? The PTCy BMT platform permits identification of a suitable related donor for most patients and for subsequent adoptive transfer of donor nonhaematopoietic cells after establishment of immunological tolerance.

Murine type VII collagen distorts outcome in human skin graft mouse model for dystrophic epidermolysis bullosa.

Human skin graft mouse models are widely used to investigate and develop therapeutic strategies for the severe generalized form of recessive dystrophic epidermolysis bullosa (RDEB), which is caused by biallelic null mutations in COL7A1 and the complete absence of type VII collagen (C7). Most therapeutic approaches are focused on reintroducing C7. Therefore, C7 and anchoring fibrils are widely used as readouts in therapeutic research with skin graft models. In this study, we investigated the expression pattern of human and murine C7 in a grafting model, in which human skin is reconstituted out of in vitro cultured keratinocytes and fibroblasts. The model revealed that murine C7 was deposited in both human healthy control and RDEB skin grafts. Moreover, we found that murine C7 is able to form anchoring fibrils in human grafts. Therefore, we advocate the use of human-specific antibodies when assessing the reintroduction of C7 using RDEB skin graft mouse models.

Impaired lymphoid extracellular matrix impedes antibacterial immunity in epidermolysis bullosa.

Genetic loss of collagen VII causes recessive dystrophic epidermolysis bullosa (RDEB), a skin fragility disorder that, unexpectedly, manifests also with elevated colonization of commensal bacteria and frequent wound infections. Here, we describe an unprecedented systemic function of collagen VII as a member of a unique innate immune-supporting multiprotein complex in spleen and lymph nodes. In this complex, collagen VII specifically binds and sequesters the innate immune activator cochlin in the lumen of lymphoid conduits. In genetic mouse models, loss of collagen VII increased bacterial colonization by diminishing levels of circulating cochlin LCCL domain. Intraperitoneal injection of collagen VII, which restored cochlin in the spleen, but not in the skin, reactivated peripheral innate immune cells via cochlin and reduced bacterial skin colonization. Systemic administration of the cochlin LCCL domain was alone sufficient to diminish bacterial supercolonization of RDEB mouse skin. Human validation demonstrated that RDEB patients displayed lower levels of systemic cochlin LCCL domain with subsequently impaired macrophage response in infected wounds. This study identifies an intrinsic innate immune dysfunction in RDEB and uncovers a unique role of the lymphoid extracellular matrix in systemic defense against bacteria.

Epidermolysis Bullosa (EB) Acquisita in an Adult Patient with Previously Unrecognized Mild Dystrophic EB and Biallelic COL7A1 Mutations.

Circulating anti-type VII collagen autoantibodies are frequently detected in patients with recessive dystrophic epidermolysis bullosa (RDEB). However, evidence supporting their pathogenic role in inducing epidermolysis bullosa acquisita (EBA) has been provided for only one individual with dominant dystrophic epidermolysis bullosa (DDEB). We describe here a patient who presented with dystrophic toenails since early childhood and developed trauma-induced skin blisters and oral erosions at age 26 years. Direct immunofluorescence showed IgG deposits with a u-serrated pattern along the cutaneous basement membrane zone, while no change in the expression of collagen VII could be detected by antigen mapping. High-titre anti-collagen VII antibodies were detected by enzyme-linked immunoassay (ELISA). In parallel, sequencing of epidermolysis bullosa (EB) genes identified compound heterozygous COL7A1 missense c.410G>A (p.Arg137Gln) and splicing c.3674C>T (p.Ala1225_Gln1241del) mutations, previously unrecognized in dystrophic epidermolysis bullosa (DEB). Thus, our patient had RDEB "nails-only" and developed mechanobullous EBA in adulthood. These data support a pathogenic role of circulating autoantibodies to collagen VII in inducing EBA in selected patients with DEB. Unforeseen worsening of skin symptoms in DEB should prompt laboratory investigations for EBA.

Pseudosyndactyly - an inflammatory and fibrotic wound healing disorder in recessive dystrophic epidermolysis bullosa.

BACKGROUND: A genetic blistering skin disease, recessive dystrophic epidermolysis bullosa (RDEB), is marked by severe wound healing defects and finger contractures. The purpose of this investigation was to elucidate the mechanisms of impaired wound healing and pseudosyndactyly occurring in RDEB patients by studying the role of known inflammation and fibrosis markers in RDEB pseudosyndactyly tissue. PATIENTS AND METHODS: We studied the expression of the fibrosis and/or inflammation markers tenascin-C, α-smooth muscle actin, transforming growth factor-ß1, interleukin-1ß, and interleukin-6 in scarring and nonscarring tissue from healthy donors and RDEB patients by semiquantitative real time-PCR and, where applicable, by immunoblots. Furthermore, the distribution pattern of α-smooth muscle actin and tenascin-C were assessed by immunofluorescence microscopy. RESULTS: Based on mRNA and protein analysis, we found upregulation of tenascin-C, interleukin-1ß, and interleukin-6 - but not of transforming growth factor-ß1 - in recessive dystrophic epidermolysis bullosa scar samples taken from pseudosyndactyly hands. Unexpectedly, α-smooth muscle actin was not upregulated. CONCLUSIONS: Our results confirm inflammation and fibrosis in recessive dystrophic epidermolysis bullosa, especially in scars, suggesting major roles for these processes in pseudosyndactyly. Our data therefore suggests the potential use of antiinflammatory and antifibrotic drugs in the prevention of pseudosyndactyly.

High Local Concentrations of Intradermal MSCs Restore Skin Integrity and Facilitate Wound Healing in Dystrophic Epidermolysis Bullosa.

Dystrophic epidermolysis bullosa (DEB) is an incurable skin fragility disorder caused by mutations in the COL7A1 gene, coding for the anchoring fibril protein collagen VII (C7). Life-long mechanosensitivity of skin and mucosal surfaces is associated with large body surface erosions, chronic wounds, and secondary fibrosis that severely impede functionality. Here, we present the first systematic long-term evaluation of the therapeutic potential of a mesenchymal stromal cell (MSC)-based therapy for DEB. Intradermal administration of MSCs in a DEB mouse model resulted in production and deposition of C7 at the dermal-epidermal junction, the physiological site of function. The effect was dose-dependent with MSCs being up to 10-fold more potent than dermal fibroblasts. MSCs promoted regeneration of DEB wounds via normalization of dermal and epidermal healing and improved skin integrity through de novo formation of functional immature anchoring fibrils. Additional benefits were gained by MSCs' anti-inflammatory effects, which led to decreased immune cell infiltration into injured DEB skin. In our setting, the clinical benefit of MSC injections lasted for more than 3 months. We conclude that MSCs are viable options for localized DEB therapy. Importantly, however, the cell number needed to achieve therapeutic efficacy excludes the use of systemic administration.

[Immunofluorescence mapping for diagnosis of congenital epidermolysis bullosa]. / Mapeo por inmunofluorescencia para el diagnóstico de epidermólisis ampollosa congénita.

The tools for diagnosis of epidermolysis bullosa have advanced greatly since Hintner's group introduced antigen mapping as a diagnostic test for this family of genodermatoses. Monoclonal or polyclonal antibodies raised against some of the specific proteins found in the epidermis and basement membrane of the epidermis have allowed 4 types of epidermolysis bullosa de be identified and all variants to be classified. When a newborn baby presents with blisters, many conditions are implicated in the differential diagnosis. Examination under an optical microscope can suggest epidermolysis bullosa, but immunofluorescence mapping and electron microscopy are required for confirmation of the diagnosis and further classification of congenital epidermolysis bullosa. This article explains the importance of immunofluorescence antigen mapping and describes the methods employed for classification and subclassification of epidermolysis bullosa.

Immune reactivity to type VII collagen: implications for gene therapy of recessive dystrophic epidermolysis bullosa.

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe genodermatosis caused by loss-of-function mutations in COL7A1 encoding type VII collagen, the component of anchoring fibrils. As exogenous type VII collagen may elicit a deleterious immune response in RDEB patients during upcoming clinical trials of gene therapies or protein replacement therapies, we developed enzyme-linked immunosorbent assay (ELISA) and enzyme-linked immunosorbent spot (ELISPOT) assays to analyze B- and T-cell responses, to the full-length type VII collagen. The ELISA was highly sensitive and specific when tested against sera from 41 patients with epidermolysis bullosa acquisita (EBA), and the IFN-gamma ELISPOT detected a cellular response that correlated with ongoing EBA manifestations. Both tests were next applied to assess the risk of an immune response to type VII collagen in seven RDEB patients with a range of type VII collagen expression profiles. Immune responses against type VII collagen were dependent on the expression of type VII collagen protein, and consequently on the nature and position of the respective COL7A1 mutations. These immunologic tests will be helpful for the selection of RDEB patients for future clinical trials aiming at restoring type VII collagen expression, and in monitoring their immune response to type VII collagen after treatment.

Autoimmunity to type VII collagen: epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is an acquired, mechanobullous disease characterized by autoimmunity to type VII collagen. Type VII collagen makes anchoring fibrils, structures that connect the epidermis and its underlying basement membrane zone to the papillary dermis. EBA patients exhibit skin fragility, blisters, scars and milia formation reminiscent of genetic dystrophic epidermolysis bullosa (DEB). DEB patients have diminutive or absent anchoring fibrils due to a genetic defect in the gene encoding type VII collagen. EBA patients have a decrease in normally functioning anchoring fibrils secondary to an abnormality in their immune system in which they produce 'pathogenic' IgG anti-type VII collagen antibodies. The pathogenicity of these autoantibodies has been demonstrated by passive transfer animal models, in which anti-type VII collagen antibodies injected into a mouse produced an EBA-like blistering disease in the animal. EBA has several distinct clinical presentations. It can present with features similar to DEB, bullous pemphigoid, cicatricial pemphigoid, Brunsting-Perry pemphigoid or IgA bullous dermatosis. Treatment for EBA is unsatisfactory, however, some therapeutic success has been reported with colchicine, dapsone, photophoresis, infliximab and intravenous immunoglobulin.

High frequency of the 425A-->G splice-site mutation and novel mutations of the COL7A1 gene in central Europe: significance for future mutation detection strategies in dystrophic epidermolysis bullosa.

BACKGROUND: Mutations in the type VII collagen gene (COL7A1) are responsible for dominant and recessive forms of dystrophic epidermolysis bullosa (DEB). These mutations are usually specific for individual families; only a few cases of recurring mutations have been identified. OBJECTIVES: Forty-three unrelated Hungarian and German patients with different DEB phenotypes were screened for novel and recurrent COL7A1 mutations. METHODS: All patients were classified based on clinical and genetic findings, skin immunofluorescent antigen mapping, and electron microscopic studies. Mutation analysis was performed by amplification of genomic DNA with polymerase chain reaction using COL7A1-specific primers, heteroduplex analysis, and direct nucleotide sequencing. Restriction endonuclease digestion was used for family screening and mutation verification. Results In this group of patients, the splice-site mutation 425A-->G was observed frequently, in 11 of 86 alleles (12.8%), once in homozygous form and in nine cases in heterozygous form. One of 100 control alleles from clinically unaffected individuals also carried the mutation. We also identified three novel mutations: the 976-3C-->A splice-site mutation, and the 4929delT and 8441-15del20 deletions. CONCLUSIONS: High recurrence of the splice-site mutation 425A-->G in central European patients with DEB should be taken into account when designing COL7A1 mutation detection strategies. Reporting of three novel COL7A1 mutations in this study further emphasizes the molecular heterogeneity of DEB and provides more information for studies on genotype-phenotype correlations in different DEB subtypes.