Blistering Skin Disease Research Articles

Understanding host's response to staphylococcal scalded skinsyndrome.

The aim of this review was to summarise the current knowledge on host-related factors that contribute to the development and severity of staphylococcal scalded skin syndrome (SSSS) in children. A comprehensive assessment and analysis of the existing literature on SSSS clinical features, pathogenesis and susceptibility factors. SSSS is a blistering skin disease caused by circulating exfoliative toxins (ETs) of Staphylococcus aureus (S. aureus), almost exclusively affecting infants, young children and immunocompromised individuals. ETs possess serine protease activity and target desmoglein-1 (Dsg-1) in the superficial epidermis. While the role of S. aureus ETs and site of action are well-described, other host factors such as impaired immune responses to ETs, poor renal clearance and genetic factors are crucial for the onset of and/or the severity of SSSS in children. The fate of desmosomal fractions after cleavage by ETs, as well as the role of dermal inflammatory cell infiltrates remain to be elucidated.

Unbiased screening identifies regulators of cell-cell adhesion and treatment options in pemphigus

Cell-cell junctions, and specifically desmosomes, are crucial for robust intercellular adhesion. Desmosomal function is compromised in the autoimmune blistering skin disease pemphigus vulgaris. We combine whole-genome knockout screening and a promotor screen of the desmosomal gene desmoglein 3 in human keratinocytes to identify novel regulators of intercellular adhesion. Kruppel-like-factor 5 (KLF5) directly binds to the desmoglein 3 regulatory region and promotes adhesion. Reduced levels of KLF5 in patient tissue indicate a role in pemphigus vulgaris. Autoantibody fractions from patients impair intercellular adhesion and reduce KLF5 levels in in vitro and in vivo disease models. These effects were dependent on increased activity of histone deacetylase 3, leading to transcriptional repression of KLF5. Inhibiting histone deacetylase 3 increases KLF5 levels and protects against the deleterious effects of autoantibodies in murine and human pemphigus vulgaris models. Together, KLF5 and histone deacetylase 3 are regulators of desmoglein 3 gene expression and intercellular adhesion and represent potential therapeutic targets in pemphigus vulgaris.

Novel readthrough agent suppresses nonsense mutations and restores functional type VII collagen and laminin 332 in epidermolysis bullosa

Recessive Dystrophic Epidermolysis Bullosa (RDEB) and Junctional Epidermolysis Bullosa (JEB) are lethal blistering skin disorders resulting from mutations in genes coding for type VII collagen (COL7A1) and laminin 332 (LAMA3, LAMB3, or LAMC2), respectively. In RDEB, 25% of patients harbor nonsense mutations causing premature termination codons (PTCs). In JEB, a majority of mutations in LAMB3 are nonsense mutations (80%). ELX-02, an aminoglycoside analog, has demonstrated superior PTC readthrough activity and lower toxicity compared to gentamicin in various genetic disorders. This study investigated ELX-02's ability to suppress PTCs and promote the expression of C7 and laminin 332 in primary RDEB keratinocytes/fibroblasts and primary JEB keratinocytes harboring nonsense mutations. ELX-02 induced a dose-dependent production of C7 or laminin β3 that surpassed the results achieved with gentamicin. ELX-02 reversed RDEB and JEB cellular hypermotility and improved poor cell-substratum adhesion in JEB cells. Importantly, ELX-02-induced C7 and laminin 332 localized to the dermal-epidermal junction. This is the first study demonstrating that ELX-02 can induce PTC readthrough and restore functional C7 and laminin 332 in RDEB and JEB caused by nonsense mutations. Therefore, ELX-02 may offer a novel and safe therapy for RDEB, JEB, and other inherited skin diseases caused by nonsense mutations.

Assessing the ChatGPT aptitude: A competent and effective Dermatology doctor?

BackgroundThe efficacy and adeptness of ChatGPT 3.5 and ChatGPT 4.0 in the precise diagnosis and management of conditions like atopic dermatitis and Autoimmune blistering skin diseases (AIBD) remain to be elucidated. So this study examined the accuracy and effectiveness of the ChatGPT responses related to understanding, therapies, and specific cases of these two conditions. MethodFirstly, the responses provided by ChatGPTs to a set of 50 questionnaires underwent evaluation by five distinct dermatologists, with complete adjudication of the third-party reviewer. The comparative analysis included the evaluative efficacy of both ChatGPT3.5 and ChatGPT4.0 against the diagnostic abilities exhibited by three distinct cohorts of qualified clinical professionals. And then, an examination was conducted to assess the diagnostic proficiency of ChatGPT3.5 and ChatGPT4.0 in the context of diagnosing specific instances of skin blistering autoimmune diseases. ResultsIn assessing the proficiency of ChatGPTs in generating responses related to fundamental knowledge about AD it is noteworthy that both versions of ChatGPTs, despite their lack of specialized training on medical databases, exhibited a commendable capacity to yield solutions that exhibited a substantial degree of concurrence with evidence-based medical information. Accordingly we observed that the performance of ChatGPT-4.0 beyond that of the ChatGPT-3.5. However, it it crucial to emphasize that ChatGPT-4.0 did not show the ability to offer answers surpassing those provided by associate senior, and senior medical professionals. In the assessment designed to determine the proficiency of ChatGPTs in recognizing particular type of AIBD, it is evident that both ChatGPT-4 and ChatGPT-3.5 demonstrated inadequacy in providing responses that are both precise and accurate for each individual occurrence of this skin condition. ConclusionBoth ChatGPT-3.5 and ChatGPT-4.0 satisfactory for addressing fundamental inquiries related to atopic dermatitis, however they prove insufficient for diagnosing AIBD. The progress of ChatGPT in achieving utility within the professional medical domain remains a considerable journey ahead.

Pemphigus vulgaris autoantibodies induce an ER stress response.

Desmosomes are intercellular junctions that mediate cell-cell adhesion and are essential for maintaining tissue integrity. Pemphigus vulgaris (PV) is an autoimmune epidermal blistering disease caused by autoantibodies (IgG) targeting desmoglein 3 (Dsg3), a desmosomal cadherin. PV autoantibodies cause desmosome disassembly and loss of cell-cell adhesion, but the molecular signaling pathways that regulate these processes are not fully understood. Using high-resolution time-lapse imaging of live keratinocytes, we found that ER tubules make frequent and persistent contacts with internalizing Dsg3 puncta in keratinocytes treated with PV patient IgG. Biochemical experiments demonstrated that PV IgG activated ER stress signaling pathways, including both IRE1⍺ and PERK pathways, in cultured keratinocytes. Further, ER stress transcripts were upregulated in PV patient skin. Pharmacological inhibition of ER stress protected against PV IgG-induced desmosome disruption and loss of keratinocyte cell-cell adhesion, suggesting that ER stress may be an important pathomechanism and therapeutically targetable pathway for PV treatment. These data support a model in which desmosome adhesion is integrated with ER function to serve as a cell adhesion stress sensor that is activated in blistering skin disease.

Human leukocyte antigen class II (DRB1 and DQB1) alleles frequencies in patients with bullous pemphigoid, Stevens–Johnson syndrome and toxic epidermal necrolysis in Russian population

BACKGROUND: Bullous pemphigoid is known to be an autoimmune, life-threatening blistering skin disorder characterized by subepidermal blister formation. In bullous pemphigoid activation of B-cell immunity depends on the interaction between T-cell receptors and classic HLA II molecules. Similar interrelation has been revealed in a vast variety of studies on severe allergic reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis. It was also suggested that Stevens-Johnson syndrome and toxic epidermal necrolysis might be associated both with HLA I and II classes. AIM: To assess the prevalence of HLA-DRB1 and DQB1 alleles at a low and high-resolution levels in patients with bullous pemphigoid and Stevens-Johnson syndrome / toxic epidermal necrolysis. MATERIALS AND METHODS: 29 Bullous pemphigoid, 14 Stevens-Johnson syndrome / toxic epidermal necrolysis patients and 92 health volunteers were included in the study. HLA-DRB1 and DQB1 alleles were assessed by polymerase chain reaction using specific primers. RESULTS: At a low-resolution level, HLA-DRB1*4 (p 0.02) and DRB1*14 (p 0.0015) alleles were statistically significantly revealed in bullous pemphigoid patients compared to health controls. Additionally, at the high-resolution level the predisposing to bullous pemphigoid HLA-DRB1*04:02 allele was also identified (p 0.01). At the low-resolution level of HLA-DQB1 typing we displayed protective and predisposing to bullous pemphigoid alleles HLA-DQB1*1 (p 0.01) and HLA-DQB1*2 (p 0.039) respectively. At the low-resolution level of HLA-DQB1 typing, the chances to obtain DQB1*03:02 allele were 3.71 times higher compared to healthy volunteers (p 0.01). In patients with Stevens-Johnson syndrome / toxic epidermal necrolysis, HLA-DRB1*4 allele was shown to be predisposing (p 0.03). For all other types of HLA alleles (DRB1 and DQB1) at the high-resolution level no any statistically significant results have been observed in these patients. CONCLUSION: We identified HLA-DRB1*4, DRB1*14, DRB1*04:02 alleles predisposing to the development of bullous pemphigoid, with the HLA-DQB1*1 allele being protective for the development of bullous pemphigoid and HLA-DRB1*4 allele predisposing to the development of severe drug reactions of Stevens-Johnson syndrome / toxic epidermal necrolysis. No any protective alleles in Stevens-Johnson syndrome / toxic epidermal necrolysis patients were detected.

Hailey-Hailey Disease: Case Series and Review of Systemic Medications.

Hailey-Hailey disease (HHD) is a rare inherited blistering skin disorder characterized by a chronic relapsing course. While it does not pose a serious threat to the patient's health, the quality of life can change. Unfortunately, there is currently no standard treatment for this condition. In this observational retrospective cohort study, our aim was to discover the demographic characteristics and treatment strategies for managing HHD. In this retrospective cohort study, we documented the demographic, clinical, and histopathological characteristics beside various treatment employed options of patients diagnosed with HHD at Razi Hospital over the past 14 years. A total of 32 patients with HHD were enrolled in the study (15 male and 17 female). The mean age of patients was 50.41 ± 13.15 (22-77) years. The average age of disease onset was 37.31 ± 11.88 (15-60) years. Among the participants, 16 individuals (50%) affirm a positive family history of some kind of pemphigoid blisters. The most common site of disease activity was the inguinal area, observed in 14 patients (33.33%). Histopathological examination discovered the existence of suprabasal acantholysis in all of the specimens. Worthily, direct immunofluorescence analysis showed negative results in all skin biopsies. All patients received topical steroids and either topical or systemic antimicrobial agents. In cases of flares, systemic steroids were the most popular and favorable treatment choice during flares. Indeed, Hailey-Hailey disease, characterized by its chronic inflammatory and rare nature with a relapsing and remitting course, poses a significant challenge for dermatologists. The treatment of HHD has been less than satisfactory and it often presents a challenge and could be misdiagnosed. Among the available treatment options, topical steroids and antimicrobial agents are the most administered therapies.

Chondroitin sulfate proteoglycan 4 (CSPG4) increases invasion of recessive dystrophic epidermolysis bullosa-associated cutaneous squamous cell carcinoma by modifying TGFβ signaling.

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare genetic skin-blistering disorder often progressing to metastatic cutaneous squamous cell carcinoma (cSCC) at chronic wound sites. Chondroitin sulfate proteoglycan 4 (CSPG4) is a cell-surface proteoglycan that is an oncoantigen in multiple malignancies, where it modulates oncogenic signaling, drives epithelial-to-mesenchymal transition (EMT), and enables cell motility. To evaluate CSPG4 expression and function in RDEB-cSCC. RDEB-cSCC cell lines were used to assess CSPG4-dependent changes in invasive potential, TGFβ1-stimulated signal activation, and clinically relevant cytopathology metrics in an in vitro full-thickness tumor model. CSPG4 expression in RDEB-cSCC and non-RDEB cSCC tumors was analyzed via immunohistochemistry and single-cell RNA sequencing (scRNA-seq), respectively. Inhibiting CSPG4 expression reduced invasive potential in multiple RDEB-cSCC cell lines and altered membrane-proximal TGFβ signal activation through changes in SMAD3 phosphorylation. CSPG4 expression was uniformly localized to basal-layer keratinocytes in fibrotic RDEB skin and tumor cells at the tumor/stroma interface at the invasive front in RDEB-cSCC tumors in vivo. Analysis of published scRNA-seq data revealed that CSPG4 expression was correlated with an enhanced EMT transcriptomic signature in cells at the tumor/stroma interface of non-RDEB cSCC tumors. Cytopathological metrics, like nucleus:cell area ratio, were influenced by CSPG4 expression in in vitro tumor models. We determined that CSPG4 expression in RDEB-cSCC cell lines enhanced invasive potential. Mechanistically, CSPG4 was found to enhance membrane-proximal TGFβ-stimulated signaling through SMAD3, which is a key mediator of EMT in RDEB-cSCC. The implication of these studies is that CSPG4 may represent a therapeutic target that can be leveraged for clinical management in patients with RDEB-cSCC.

Role of auto-antibodies in the mechanisms of dengue pathogenesis and its progression: a comprehensive review.

A complex interaction among virulence factors, host-genes and host immune system is considered to be responsible for dengue virus (DENV) infection and disease progression. Generation of auto-antibodies during DENV infection is a major phenomenon that plays a role in the pathophysiology of dengue hemorrhagic fever and dengue shock syndrome. Hemostasis, thrombocytopenia, hepatic endothelial dysfunction, and autoimmune blistering skin disease (pemphigus) are different clinical manifestations of dengue pathogenesis; produced due to the molecular mimicry of DENV proteins with self-antigens like coagulation factors, platelets and endothelial cell proteins. This review elaborately describes the current advancements in auto-antibody-mediated immunopathogenesis which inhibits coagulation cascade and promotes hyperfibrinolysis. Auto-antibodies like anti-endothelial cell antibodies-mediated hepatic inflammation during severe DENV infection have also been discussed. Overall, this comprehensive review provides insight to target auto-antibodies that may act as potential biomarkers for disease severity, and a ground for the development of therapeutic strategy against DENV.

Single-Cell Profiling Unveils the Inflammatory Heterogeneity within Cutaneous Lesions of Bullous Pemphigoid

Bullous pemphigoid (BP) is a subepidermal blistering skin disease with a complex pathogenesis involving various immune cells. However, the transcriptional features of these cells remain poorly defined. In this study, we constructed a comprehensive and single-cell resolution atlas of various immune cells within BP skin lesions through integrative single-cell analysis, flow cytometry, and multiplex immunohistochemistry. We observed prominent expansion and transcriptional changes in mast cells, macrophages, basophils, and neutrophils within BP lesions. Mast cells within the lesions adopted an active state and exhibited an elevated capacity for producing proinflammatory mediators. We observed an imbalance of macrophages/dendritic cells within BP lesions. Two macrophage subpopulations (NLRP3+ and C1q+) with distinct transcriptional profiles were identified and upregulated effector programs. T-peripheral helper-like T helper 2 cells were expanded in skin lesions and peripheral blood of patients with BP and were capable of promoting B-cell responses. In addition, we observed clonally expanded granzyme B-positive CD8+ T cells within BP lesions. Chemokine receptor mapping revealed the potential roles of macrophages and mast cells in recruiting pathogenic immune cells and underlying mechanisms within BP lesions. Thus, this study reveals key immune pathogenic features of BP lesions, thereby providing valuable insights for potential therapeutic interventions in this disease.

Elevated expression of interleukin-6 (IL-6) and serum amyloid A (SAA) in the skin and the serum of recessive dystrophic epidermolysis bullosa: Skin as a possible source of IL-6 through Toll-like receptor ligands and SAA.

The effect of persistent skin inflammation on extracutaneous organs and blood is not well studied. Patients with recessive dystrophic epidermolysis bullosa (RDEB), a severe form of the inherited blistering skin disorder, have widespread and persistent skin ulcers, and they develop various complications including anaemia, hyperglobulinaemia, hypoalbuminaemia and secondary amyloidosis. These complications are associated with the bioactivities of IL-6, and the development of secondary amyloidosis requires the persistent elevation of serum amyloid A (SAA) level. We found that patients with RDEB had significantly higher serum levels of IL-6 and SAA compared to healthy volunteers and patients with psoriasis or atopic dermatitis. Both IL-6 and SAA were highly expressed in epidermal keratinocytes and dermal fibroblasts of the skin ulcer lesions. Keratinocytes and fibroblasts surrounding the ulcer lesions are continuously exposed to Toll-like receptor (TLR) ligands, pathogen-associated and damage-associated molecular pattern molecules. Invitro, TLR ligands induced IL-6 expression via NF-κB in normal human epidermal keratinocytes (NHEKs) and dermal fibroblasts (NHDFs). SAA further induced the expression of IL-6 via TLR1/2 and NF-κB in NHEKs and NHDFs. The limitation of this study is that NHEKs and NHDFs were not derived from RDEB patients. These observations suggest that TLR-mediated persistent skin inflammation might increase the risk of IL-6-related systemic complications, including RDEB.

Intravenous gentamicin therapy induces functional type VII collagen in patients with recessive dystrophic epidermolysis bullosa: an open-label clinical trial.

Recessive dystrophic epidermolysis bullosa (RDEB) is an incurable widespread blistering skin disorder caused by mutations in the gene encoding for type VII collagen (C7), the major component of anchoring fibrils. To evaluate the efficacy and safety of intravenous (IV) gentamicin readthrough therapy in patients with RDEB harbouring nonsense mutations. The primary outcomes were increased expression of C7 in patients' skin and safety assessments (ototoxicity, nephrotoxicity, autoimmune response); secondary outcomes included measuring wound healing in target wounds and assessment by a validated Epidermolysis Bullosa Disease Activity and Scarring Index (EBDASI) scoring system. An open-label pilot trial to assess two different IV gentamicin regimens between August 2018 and March 2020 with follow-up through to 180 days post-treatment was carried out. Three patients with RDEB with confirmed nonsense mutations in COL7A1 in either one or two alleles and decreased baseline expression of C7 at the dermal-epidermal junction (DEJ) of their skin participated in the study. Three patients received gentamicin 7.5 mg kg-1 daily for 14 days and two of the three patients further received 7.5 mg kg-1 IV gentamicin twice weekly for 12 weeks. Patients who had pre-existing auditory or renal impairment, were currently using ototoxic or nephrotoxic medications, or had allergies to aminoglycosides or sulfate compounds were excluded. After gentamicin treatment, skin biopsies from all three patients (age range 18-28 years) exhibited increased C7 in their DEJ. With both regimens, the new C7 persisted for at least 6 months post-treatment. At 1 and 3 months post-treatment, 100% of the monitored wounds exhibited > 85% closure. Both IV gentamicin infusion regimens decreased EBDASI total activity scores. Of the patients assessed with the EBDASI, all exhibited decreased total activity scores 3 months post-treatment. All three patients completed the study; no adverse effects or anti-C7 antibodies were detected. IV gentamicin induced the readthrough of nonsense mutations in patients with RDEB and restored functional C7 in their skin, enhanced wound healing and improved clinical parameters. IV gentamicin may be a safe, efficacious, low-cost and readily available treatment for this population of patients with RDEB.

Is It Time to Reconsider Rituximab Dosing Regimens for Pemphigus Vulgaris?

Rituximab is currently approved for patients affected by moderate-to-severe pemphigus vulgaris, a severe autoimmune blistering skin disease that can be life-threatening. The standard rituximab dosing regimens, originally established for B-cell non-Hodgkin's lymphomas, have been recognized to exceed the effective dose required for inducing B-cell depletion, considering that the B-cell burden in pemphigus vulgaris is considerably lower than in lymphoproliferative disorders. We herein report our experience with very ultra-low-dose rituximab in two patients affected by pemphigus vulgaris.

Monocyte populations are involved in the pathogenesis of experimental epidermolysis bullosa acquisita.

Monocytes play a significant role in the pathogenesis of most inflammatory diseases, including autoimmune diseases. Herein, different subpopulations of monocytes often play differential, partially antagonistic roles, in the regulation of tissue populations. Pemphigoid diseases constitute a group of autoimmune blistering skin diseases featuring a marked infiltration of the dermis with immune cells, including monocytes. The monocyte subsets infiltrating the skin, however, have largely remained elusive. Monocyte adhesion and recruitment into the inflamed tissues are regulated by chemokine receptors, most prominently by CCR2 and CX3CR1. To delineate the involvement of monocyte populations in autoimmune blistering skin diseases, we spatiotemporally monitored the dynamic spectrum of monocyte populations that infiltrate the inflamed skin using multiphoton intravital imaging and reporter mice for chemokine receptors. Experimental epidermolysis bullosa acquisita (EBA) was induced by injection of anti-murine type VII collagen (amCOLVII) IgG into the Csf1rEGFP-reporter mice, where circulating myeloid cells, such as monocytes and neutrophils, express an EGFP. EGFP+ cells, including neutrophils and monocytes, were present in the skin, immediately after the deposition of the amCOLVII antibody at the dermal-epidermal junction. To investigate the recruitment and involvement of different monocyte-derived cell populations in the disease course further, EBA was induced in CCR2RFP/+-reporter and CX3CR1GFP/+-reporter mice. A comparable distribution of red fluorescent protein (RFP)+ or green fluorescent protein (GFP)+ was found in both diseased mice and their respective controls over time, indicating the similar recruitment of monocytes into the skin following the binding of autoantibodies. Experiments were extended to the CCR2RFP/RFP-deficient and CX3CR1GFP/GFP-deficient mice to determine whether monocyte recruitment and disease severity are compromised in the absence of the receptor. A comparable pattern was seen in the recruitment of monocytes into the skin in both reporter and deficient mice. However, in contrast to similar disease severity between CX3CR1-deficient and reporter mice, CCR2-deficient mice developed significantly less disease than CCR2-reporter mice, as indicated by the percentage of affected area of ears. Collectively, our observations indicate that while CCR2 and CX3CR1 receptors are not involved in the recruitment of monocytes into the skin, CCR2 deficiency is associated with improved disease outcomes in experimental EBA in mice.

Successful Management of Visphota Kustha (Blistering Skin Diseases) through Multimodality Treatment of Ayurveda - A Case Study

Successful Management of Visphota Kustha (Blistering Skin Diseases) through Multimodality Treatment of Ayurveda - A Case Study

Beremagene geperpavec (B-VEC) gene therapy for the treatment of cutaneous wounds in patients with dystrophic epidermolysis bullosa: a critically appraised research paper.

Dystrophic epidermolysis bullosa (DEB) is a rare inherited blistering skin disease that causes lifelong, slow-to-heal wounds, which predispose patients to chronic inflammation, scarring and an increased risk of developing squamous cell carcinoma. Management is largely supportive with no approved corrective therapies currently available. We critically appraise the phase III clinical trial reported by Guide et al., investigating the topical application of beremagene geperpavec on cutaneous wounds in DEB.

Inflammation-mediated fibroblast activation and immune dysregulation in collagen VII-deficient skin.

Inflammation is known to play a critical role in all stages of tumorigenesis; however, less is known about how it predisposes the tissue microenvironment preceding tumor formation. Recessive dystrophic epidermolysis bullosa (RDEB), a skin-blistering disease secondary to COL7A1 mutations and associated with chronic wounding, inflammation, fibrosis, and cutaneous squamous cell carcinoma (cSCC), models this dynamic. Here, we used single-cell RNA sequencing (scRNAseq) to analyze gene expression patterns in skin cells from a mouse model of RDEB. We uncovered a complex landscape within the RDEB dermal microenvironment that exhibited altered metabolism, enhanced angiogenesis, hyperproliferative keratinocytes, infiltration and activation of immune cell populations, and inflammatory fibroblast priming. We demonstrated the presence of activated neutrophil and Langerhans cell subpopulations and elevated expression of PD-1 and PD-L1 in T cells and antigen-presenting cells, respectively. Unsupervised clustering within the fibroblast population further revealed two differentiation pathways in RDEB fibroblasts, one toward myofibroblasts and the other toward a phenotype that shares the characteristics of inflammatory fibroblast subsets in other inflammatory diseases as well as the IL-1-induced inflammatory cancer-associated fibroblasts (iCAFs) reported in various cancer types. Quantitation of inflammatory cytokines indicated dynamic waves of IL-1α, TGF-β1, TNF, IL-6, and IFN-γ concentrations, along with dermal NF-κB activation preceding JAK/STAT signaling. We further demonstrated the divergent and overlapping roles of these cytokines in inducing inflammatory phenotypes in RDEB patients as well as RDEB mouse-derived fibroblasts together with their healthy controls. In summary, our data have suggested a potential role of inflammation, driven by the chronic release of inflammatory cytokines such as IL-1, in creating an immune-suppressed dermal microenvironment that underlies RDEB disease progression.

Plectin Deficiency in Fibroblasts Deranges Intermediate Filament and Organelle Morphology, Migration, and Adhesion

Plectin, a highly versatile and multifunctional cytolinker, has been implicated in several multisystemic disorders. Most sequence variations in the human plectin gene (PLEC) cause epidermolysis bullosa simplex with muscular dystrophy (EBS-MD), an autosomal recessive skin-blistering disorder associated with progressive muscle weakness. In this study, we performed a comprehensive cell biological analysis of dermal fibroblasts from three different patients with EBS-MD, where PLEC expression analyses revealed preserved mRNA levels in all cases, whereas full-length plectin protein content was significantly reduced or completely absent. Downstream effects of pathogenic PLEC sequence alterations included massive bundling of vimentin intermediate filament networks, including the occurrence of ring-like nuclei-encasing filament bundles, elongated mitochondrial networks, and abnormal nuclear morphologies. We found that essential fibroblast functions such as wound healing, migration, or orientation upon cyclic stretch were significantly impaired in the cells of patients with EBS-MD. Finally, EBS-MD fibroblasts displayed reduced adhesion capacities, which could be attributed to smaller focal adhesion contacts. Our study not only emphasizes plectin's functional role in human skin fibroblasts, it also provides further insights into the understanding of EBS-MD-associated disease mechanisms.

P18 Epidermolysis bullosa acquisita in children: report of three cases

Abstract Epidermolysis bullosa acquisita (EBA) is an acquired, subepidermal blistering skin disease characterized by autoantibodies against type VII collagen, which links the epidermis to the dermis at the dermo-epidermal junction. Clinically, patients have skin fragility and blisters over trauma-prone sites, scarring, milia and onychodystrophy. The diagnosis can be challenging as it shares clinical and histopathological features with other immunobullous diseases. Although exceptionally rare in children, we report three paediatric patients with EBA and variable disease severity. The main clinical features were blisters (n = 3), milia (n = 3), scarring (n = 2), oral erosions (n = 2) and onychodystrophy (n = 1). Histological findings were nonspecific, showing a subepidermal blister with various inflammatory infiltrates. On direct immunofluorescence a bright deposit of IgG was seen, and the antibodies adhered to the dermal side of the salt-split in two cases. ELISA analysis confirmed circulating autoantibodies against type VII collagen in one patient. All received a course of oral corticosteroids alongside steroid-sparing agents such as dapsone, azathioprine and rituximab depending on clinical response and shared favourable prognosis. Early use of topical steroids can help but high-dose oral corticosteroids are often required as well as steroid-sparing agents such as dapsone, methotrexate, azathioprine, ciclosporin, mycophenolate mofetil, cyclophosphamide and rituximab. In our experience, although the treatment approaches have been different, all the patients had favourable outcomes.

The landscape of the immunoglobulin repertoire in endemic pemphigus foliaceus.

Primarily driven by autoreactive B cells, pemphigus foliaceus (PF) is an uncommon autoimmune blistering skin disease of sporadic occurrence worldwide. However, PF reaches a prevalence of 3% in the endemic areas of Brazil, the highest ever registered for any autoimmune disease, which indicates environmental factors influencing the immune response in susceptible individuals. We aimed to provide insights into the immune repertoire of patients with PF living in the endemic region of the disease, compared to healthy individuals from the endemic region and a non-endemic area. We characterized the B-cell repertoire in i) nontreated patients (n=5); ii) patients under immunosuppressive treatment (n=5); iii) patients in remission without treatment (n=6); and two control groups iv) from the endemic (n=6) and v) non-endemic areas in Brazil (n=4). We used total RNA extracted from peripheral blood mononuclear cells and performed a comprehensive characterization of the variable region of immunoglobulin heavy chain (IGH) in IgG and IgM using next-generation sequencing. Compared to individuals from a different area, we observed remarkably lower clonotype diversity in the B-cell immune repertoire of patients and controls from the endemic area (p < 0.02), suggesting that the immune repertoire in the endemic area is under geographically specific and intense environmental pressure. Moreover, we observed longer CDR3 sequences in patients, and we identified differential disease-specific usage of IGHV segments, including increased IGHV3-30 and decreased IGHV3-23 in patients with active disease (p < 0.04). Finally, our robust network analysis discovered clusters of CDR3 sequences uniquely observed in patients with PF. Our results indicate that environmental factors, in addition to disease state, impact the characteristics of the repertoire. Our findings can be applied to further investigation of the environmental factors that trigger pemphigus and expand the knowledge for identifying new targeted and more effective therapies.