Dystrophic Epidermolysis Bullosa Patients Research Articles

240 Efficient base editing to correct COL7A1 nonsense mutations in primary recessive dystrophic epidermolysis bullosa patient keratinocytes

240 Efficient base editing to correct COL7A1 nonsense mutations in primary recessive dystrophic epidermolysis bullosa patient keratinocytes

Molecular profiling of an Indian EB cohort - a single centre experience.

Epidermolysis bullosa (EB) encompasses rare hereditary skin conditions marked by skin fragility, nail dystrophy, and minor trauma-induced skin blisters. This study aims to identify genetic variants in Indian EB patients and examine the relationship between genotypic and phenotypic manifestations. EB patients seen consecutively over a period of 5 years at Outpatient Department of Dermatology. Baseline demographic data, birth history, family history, skin manifestation at birth, past medical history, current cutaneous manifestations, and the evolution of the disease were assessed and recorded. Genetic variants were identified using targeted gene panel sequencing of 23 EB-related genes, and a genetic-phenotype analysis was performed. Our study included 65 patients with EB. Among 65 EB patients, 38 dystrophic EB cases (58.46%), 12 junctional EB (18.46%), 12 epidermolysis bullosa simplex (18.46%), and 3 Kindler EB (4.62%) were reported. Dominant and recessive forms of dystrophic EB accounted for 16.92% and 41.4%, respectively. We identified 75 unique genetic variants, 58.67% newly discovered and 41.33% previously reported. Compound heterozygous variations were more frequent (55.55%) than homozygous ones (44.44%) in recessive dystrophic EB patients. Junctional EB patients harboured LAMB3 gene mutations more frequently, while epidermolysis bullosa simplex patients showed KRT5 and KRT14 gene missense heterozygous mutations. Kindler EB patients had homozygous mutations in the FERTM1 gene. Our study unveiled several novel genetic variants; severe phenotypes associated with nonsense genetic variants. These findings offer valuable insights for future clinical assessments and tailored management strategies.

Dystrophic Epidermolysis Bullosa (DEB): How Can Pregnancy Alter the Course of This Rare Disease? An Updated Literature Review on Obstetrical Management with an Additional Italian Experience.

Epidermolysis Bullosa (EB) is an extremely rare and disabling inherited genetic skin disease with a predisposition to develop bullous lesions on the skin and inner mucous membranes, occurring after mild friction or trauma, or even spontaneously. Within the spectrum of EB forms, dystrophic EB (DEB) represents the most intriguing and challenging in terms of clinical management, especially with regard to pregnancy, due to the highly disabling and life-threatening phenotype. Disappointingly, in the literature little focus has been directed towards pregnancy and childbirth in DEB patients, resulting in a lack of sound evidence and guidance for patients themselves and clinicians. The current study aims to contribute to the DEB literature with an updated summary of the existing evidence regarding the obstetrical and anesthesiological management of this rare disease. Furthermore, this literature review sought to answer the question of whether, and if so, in which way, the pregnancy condition may alter the course of the underlying dermatologic skin disease. Having all this information is indispensable when counseling a patient with DEB who desires a child or is expecting one. Finally, we reported own experience with a pregnant woman with a recessive DEB whom we recently managed, with a favorable outcome.

Surgical Management of Psudosyndactyly in Recessive Dystrophic Epidermolysis Bullosa: About Three Case Reports

Recessive dystrophic epidermolysis bullosa (RDEB) is defined as a congenital disorder resulting from mutations in the COL7A1 gene, often resulting in hand contractures and pseudosyndactyly. While multiple treatments exist to improve hand malformations, there are currently still no radical cures for this disease because of its high recurrence rate. This paper reports our experience of management of hand deformities in three cases of Recessive dystrophic epidermolysis bullosa patients with surgical management and postoperative skin dressings. Hand function was significantly improved after the complete release of pseudosyndactyly and the achievement of satisfying digital web spaces. Patients were followed up for one year and showed good results after functional hand training activities.

Splicing Modulation via Antisense Oligonucleotides in Recessive Dystrophic Epidermolysis Bullosa.

Antisense oligonucleotides (ASOs) represent an emerging therapeutic platform for targeting genetic diseases by influencing various aspects of (pre-)mRNA biology, such as splicing, stability, and translation. In this study, we investigated the potential of modulating the splicing pattern in recessive dystrophic epidermolysis bullosa (RDEB) patient cells carrying a frequent genomic variant (c.425A > G) that disrupts splicing in the COL7A1 gene by using short 2'-O-(2-Methoxyethyl) oligoribo-nucleotides (2'-MOE ASOs). COL7A1-encoded type VII collagen (C7) forms the anchoring fibrils within the skin that are essential for the attachment of the epidermis to the underlying dermis. As such, gene variants of COL7A1 leading to functionally impaired or absent C7 manifest in the form of extensive blistering and wounding. The severity of the disease pattern warrants the development of novel therapies for patients. The c.425A > G variant at the COL7A1 exon 3/intron 3 junction lowers the efficiency of splicing at this junction, resulting in non-functional C7 transcripts. However, we found that correct splicing still occurs, albeit at a very low level, highlighting an opportunity for intervention by modulating the splicing reaction. We therefore screened 2'-MOE ASOs that bind along the COL7A1 target region ranging from exon 3 to the intron 3/exon 4 junction for their ability to modulate splicing. We identified ASOs capable of increasing the relative levels of correctly spliced COL7A1 transcripts by RT-PCR, sqRT-PCR, and ddPCR. Furthermore, RDEB-derived skin equivalents treated with one of the most promising ASOs exhibited an increase in full-length C7 expression and its accurate deposition along the basement membrane zone (BMZ).

Simple and affordable soft brace application in dystrophic epidermolysis bullosa patients.

Dystrophic epidermolysis bullosa (DEB) is a hereditary disease characterized by increased fragility of the epidermis and mucosa and is accompanied by blister formation following minor trauma. Repeated injuries cause contracture and scar formation, which can further result in hand deformity, leading to a decline in hand ability and a lower quality of life. In this study, after the scar release of patients' hands, we developed a new and practical portable soft support, and evaluated its efficacy in delaying the scar contracture of hands after operation. According to the hand function scores, the patients were divided into two groups. Those with excellent and good grades were assigned to the open hand function group, and those with poor grades were allocated to the restricted hand function group. The primary conditions, the use of a postoperative soft brace, and some common factors in the two groups were compared to determine whether these parameters influence postoperative hand function. There were no significant differences in age, gender, body mass index, ADL assessment index, albumin concentration, hemoglobin concentration, fasting blood glucose level, prothrombin time, and activated partial thromboplastin time between the two groups (p > 0.05). In contrast, there was a significant difference between the two groups in the use of soft braces following the operation (p < 0.05). The odds ratio of patients fixed with a brace compared with patients not fixed with soft braces was 11.01. Soft brace is a critical factor impacting the hand function of patients with dystrophic epidermolysis bullosa after scar contracture release in both hands. Indeed, a hand brace worn after the operation can delay the recurrence of scar contracture in both hands and offer patients a longer time to use their hands effectively. In addition, by restoring the appearance of patients' hands and some hand functions, patients' mental state and quality of life have been greatly improved.

Efficacy of oral JAK1 or JAK1/2 inhibitor for treating refractory pruritus in dystrophic epidermolysis bullosa: A retrospective case series.

Refractory pruritus is the most distressing, disease-related symptom in patients with dystrophic epidermolysis bullosa (DEB), inducing an itch-scratch-blister cycle. Chronic inflammation is a hallmark of DEB, thus upregulation of inflammatory cytokines and Janus kinase (JAK) signaling may play a role in DEB-related pruritus. We retrospectively reviewed the medical records of DEB patients with refractory pruritus who were treated with either baricitinib, a JAK1/2 inhibitor, or upadacitinib, a selective JAK1 inhibitor. Patients received baricitinib (4 mg) or upadacitinib (15 mg) once a day for 2-32 weeks. A total of 12 DEB patients (six recessive DEB and six dominant DEB) were included in this study. The mean±SD baseline pruritus visual analog scale (VAS) score was 7.5 ± 1.7. Upadacitinib or baricitinib treatment resulted in a rapid and sustained decrease in itch. Four out of 12 patients (33.3%) and seven out of 10 patients (70%) showed a decrease of at least 3 points in the pruritus VAS score from baseline at weeks 2 and 4, respectively. The mean percentage changes from baseline in pruritus VAS scores at weeks 2 and 4 were -42.9% and -52.7%, respectively. Subgroup analysis showed greater reductions in the pruritus VAS score in the baricitinib group (n = 5) compared to the upadacitinib group (n = 7), and in patients with epidermolysis bullosa pruriginosa (n = 3) compared to other subtypes of DEB (n = 9); however, these differences did not reach statistical significance. Three out of 10 (33.3%) patients showed at least a 2-point reduction in pain intensity from baseline at week 4. Eight out of 12 patients (66.7%) also showed a reduction in the number of new blisters, which correlated with a reduction in the pruritus score. No patient discontinued treatment because of serious adverse events. Our results suggest that JAK1 or JAK1/2 inhibitors could be a promising treatment option for DEB-related pruritus. Long-term safety should be assessed in future studies.

Clinical and molecular features in a cohort of Middle Eastern patients with epidermolysis bullosa.

Epidermolysis bullosa (EB) features skin and mucosal fragility due to pathogenic variants in genes encoding components of the cutaneous basement membrane. Based on the level of separation within the dermal-epidermal junction, EB is sub-classified into four major types including EB simplex (EBS), junctional EB (JEB), dystrophic EB (DEB), and Kindler EB (KEB) with 16 EB-associated genes reported to date. We ascertained a cohort of 151 EB patients of various Middle Eastern ethnic backgrounds. The cohort was comprised of EBS (64%, 97/151), DEB (21%, 31/151), JEB (12%, 18/151), and KEB (3%, 5/151). KRT14 and KRT5 variants were most common among EBS patients with 43% (42/97) and 46% (45/97) of EBS patients carrying mutations in either of these two genes, respectively. Truncal involvement was more common in KRT14-associated EBS as compared to EBS due to KRT5 mutations (p < .05). Mutations in COL17A1 and laminin 332-encoding genes were identified in 55% (10/18) and 45% (8/18) of JEB patients. Scarring alopecia, caries, and EB nevi were most common among JEB patients carrying COL17A1 mutations as compared to laminin 332-associated JEB (p < .05). Abnormal nails were evident in most DEB and JEB patients while poikiloderma was exclusively observed in KEB (p < .001). EB patients of Middle Eastern origin were found to feature specific phenotype-genotype correlations of relevance to the diagnosis and genetic counseling of patients in this region.

Metformin shows anti-neoplastic properties by inhibition of oxidative phosphorylation and glycolysis in epidermolysis bullosa-associated aggressive cutaneous squamous cell carcinoma.

While most cutaneous squamous cell carcinomas (cSCCs) are treatable, certain high-risk cSCCs, such as those in recessive dystrophic epidermolysis bullosa (RDEB) patients, are particularly aggressive. Owing to repeated wounding, inflammation and unproductive healing, RDEB patients have a 68% cumulative risk of developing life-threatening cSCCs by the age of 35, and a 70% risk of death by the age of 45. Despite aggressive treatment, cSCC represents the leading cause of premature mortality in these patients, highlighting an unmet clinical need. Increasing evidence points to a role of altered metabolism in the initiation and maintenance of cSCC, making metabolism a potential therapeutic target. We sought to determine the feasibility of targeting tumour cell energetics as a strategy to selectively hinder the growth advantage of aggressive cSCC. We evaluated the cell energetics profiles of RDEB-SCC cells by analysing available gene expression data against multiple gene signatures and single-gene targets linked to metabolic reprogramming. Additionally, we employed real-time metabolic profiling to measure glycolysis and respiration in these cells. Furthermore, we investigated the anti-neoplastic properties of the metformin against human and murine high-risk cSCCs in vitro and in vivo. Gene expression analyses highlighted a divergence in cell energetics profiles between RDEB-SCC and non-malignant RDEB keratinocytes, with tumour cells demonstrating enhanced respiration and glycolysis scores. Real-time metabolic profiling supported these data and additionally highlighted a metabolic plasticity of RDEB-SCC cells. Against this background, metformin exerted an anti-neoplastic potential by hampering both respiration and glycolysis, and by inhibiting proliferation in vitro. Metformin treatment in an analogous model of fast-growing murine cSCC resulted in delayed tumour onset and slower tumour growth, translating to a 29% increase in median overall survival. Our data indicate that metformin exerts anti-neoplastic properties in aggressive cSCCs that exhibit high-risk features by interfering with respiration and glycolytic processes.

Herpes simplex virus gene therapy for dystrophic epidermolysis bullosa (DEB)

The FDA has recently approved Krystal biotech's beremagene geperpavec (B-VEC, Vyjuvek) to treat the wounds of dystrophic epidermolysis bullosa (DEB) patients. This represents a giant step, not only toward the treatment of this devastating disease, but also for the whole field of non-replicative (nr) recombinant HSV-1 vectors for gene therapy. To view this Bench to Bedside, open or download the PDF.

Comparing COL7A1 gene expression in fibroblast cells of dystrophic epidermolysis bullosa patients with clinical responses to autologous fibroblasts transplantation

Objectives: This clinical research aimed to establish autologous fibroblasts transplantation as a possible treatment for patients with DEJ. The COL7A1 gene expression was also evaluated.&#x0D; Methods: Six patients (3M and 3F), 4 with no recurrent wounds and 2 with recurrent wounds after surgery, and 15 healthy subjects were included in the study as controls. Quantitative real-time polymerase chain reaction (real-time PCR) analysis of the COL7A1 gene was performed using an oligonucleotide primer pair designed to amplify across the exon/exon junction.&#x0D; Results: The COL7A1 expression level was down-regulated at exons 26-27, 47-48, 96-97, and 116-117 in all patients′ fibroblasts compared with the healthy controls. However, the expression of the COL7A1 gene in the fibroblasts of the patients with a positive response to the treatment was not significantly changed compared with the patients with the poor response. (ClinicalTrials.gov NCT01908088)&#x0D; Conclusion: In this study the mRNA expression levels of COL7A1 were significantly less in the patients when compared with healthy controls. However the COL7A1 expression after autologous fibroblasts transplantation was not different between the two groups of patients, and further examination is needed to elucidate the mechanism of the treatment.

Oral health status in patients with inherited epidermolysis bullosa: a comparative multicenter study.

Epidermolysis bullosa (EB) is a rare genetic mucocutaneous disorder characterized by epithelial fragility leading to blister formation on skin and mucous membranes with even minor mechanical trauma. Most EB oral health publications give fragmented information, focusing on only one oral health aspect or one EB type. The aim of this study was to expand the knowledge of the overall oral health status of individuals with dystrophic, junctional, and simplex EB. A comparative multicenter study, including a control group, and based on questionnaires and clinical examinations, was undertaken in three EB expert centers. Most EB (90.2%) participants brushed their teeth at least once a day despite the pain. The prevalence of enamel defects and caries experience did not differ between the 42 EB participants and the 42 age-/sex-matched healthy controls. Gingival inflammation unrelated to dental plaque accumulation was found in EB participants. Blisters, erythema, and erosion/ulceration mainly involved gingiva, buccal mucosa, lips, and palate, with different topographic patterns according to EB type. EB patients whatever the age showed a similar lesion distribution. Simplex and dystrophic EB patients under 12 years old displayed higher lesion severity than junctional EB ones. Only dystrophic type exhibited microstomia and ankyloglossia. Oral health status seemed to benefit from a close collaboration between dental practitioner and dermatologist, and from regular dental examination, starting at a young age and with a focus on prevention. The new appreciation of oral health involvement highlighted by this study is essential for EB patients care, regarding comorbidities and quality of life.

Inherited epidermolysis bullosa dystrophica and squamous cell carcinoma- A case report

Epidermolysis bullosa dystrophica (EBD) is an inherited disease of the structural proteins in the upper dermis, characterized by blister formation at the site of trauma followed by scarring. Skin fragility and blistering are the hallmarks of this disease. Cutaneous squamous cell carcinoma (cSCC) is a dreadful complication in the epidermolysis bullosa (EB) patients and common cause of death. The recent advances in distinct tumor microenvironment explain the aggressive nature of SCC in recessive Recessive Dystrophic Epidermolysis Bullosa (RDEB) patients and the use of collagen VII re-expression as a possible therapeutic measure. Regular follow-up is a must in preventing complications.

Preclinical model for phenotypic correction of dystrophic epidermolysis bullosa by in vivo CRISPR-Cas9 delivery using adenoviral vectors

Recessive dystrophic epidermolysis bullosa, a devastating skin fragility disease characterized by recurrent skin blistering, scarring, and a high risk of developing squamous cell carcinoma is caused by mutations in COL7A1, the gene encoding type VII collagen, which is the major component of the anchoring fibrils that bind the dermis and epidermis. Ex vivo correction of COL7A1 by gene editing in patients’ cells has been achieved before. However, in vivo editing approaches are necessary to address the direct treatment of the blistering lesions characteristic of this disease. We have now generated adenoviral vectors for CRISPR-Cas9 delivery to remove exon 80 of COL7A1, which contains a highly prevalent frameshift mutation in Spanish patients. For in vivo testing, a humanized skin mouse model was used. Efficient viral transduction of skin was observed after excisional wounds generated with a surgical punch on regenerated patient skin grafts were filled with the adenoviral vectors embedded in a fibrin gel. Type VII collagen deposition in the basement membrane zone of the wounded areas treated with the vectors correlated with restoration of dermal-epidermal adhesion, demonstrating that recessive dystrophic epidermolysis bullosa (RDEB) patient skin lesions can be directly treated by CRISPR-Cas9 delivery in vivo.

Understanding the socioeconomic costs of dystrophic epidermolysis bullosa in Europe: a costing and health-related quality of life study

BackgroundDystrophic epidermolysis bullosa (EB) is a family of rare genetic dermatological conditions. Recent evidence indicated that in addition to its detrimental implications on patient health-related quality of life (HRQoL), there are substantial socioeconomic cost implications, especially regarding direct non-medical costs. This study aims to understand the burden of dystrophic EB (DEB) in Europe, using a primary EB patient-level dataset.MethodsA bottom-up, cross-sectional, study design was adopted for non-institutionalised patients diagnosed with EB who received outpatient care across EU5 countries: France, Germany, Italy, Spain, and the United Kingdom. A prevalence-based approach was used to estimate resource utilisation from a societal perspective, including direct (medical and non-medical) and indirect costs for patients and caregivers. Patient and caregiver outcomes were obtained using the EQ-5D questionnaire.ResultsA sample of 91 DEB patients was analysed. Overall, average EU5 annual cost per patient was estimated at €53,359, ranging from €18,783 (France) to €79,405 (Germany). Average EU5 annual direct medical costs were estimated at €8357 (15.7% of total), ranging from €5658 (France) to €12,576 (Germany); average direct non-medical costs were estimated at €41,353 (77.5% of total), ranging from €11,961 (France) to €57,000 (Germany); and average indirect costs were estimated at €3649 (6.8% of total), ranging from €1025 (Italy) to €9930 (United Kingdom). Costs varied across patients with different disability but also between children and adults. The mean EQ-5D index score for adult DEB patients ranged between 0.304 (United Kingdom) and 0.541 (Germany), with an EU5 average of 0.456, whereas the mean EQ-5D visual analogue scale score ranged between 47.5 (Germany) and 70.0 (France), with an EU5 average of 61.9. Limitations included potential patient selection bias, recall bias, and exclusion of bandaging and related costs.ConclusionsThe study revealed a substantial socioeconomic burden for DEB in Europe, attributable mostly to high direct non-medical costs, with the majority of patients requiring support from caregivers at home. Compared to the average economic burden of the overall EB patient population, costs for DEB patients are higher across all components of direct medical, direct non-medical and indirect costs.

Analysis of COL7A1 pathogenic variants in a large cohort of dystrophic epidermolysis bullosa patients from Argentina reveals a new genotype-phenotype correlation.

Dystrophic epidermolysis bullosa (DEB) is a clinically heterogeneous heritable skin disorder, characterized by blistering of the skin and mucous membranes following minor trauma. Dominant (DDEB) and recessive (RDEB) forms are caused by pathogenic variants in COL7A1 gene. Argentina's population has a heterogeneous genetic background, and little is known about the molecular basis of DEB in our country or in native South American populations. In this study, we present the prevalence and geographical distribution of pathogenic variants found in 181 patients from 136 unrelated families (31 DDEB and 105 RDEB). We detected 95 different variants, 59 of them were previously reported in the literature and 36 were novel, nine of which were detected in more than one family. The most prevalent pathogenic variants were identified in exon 73 in DDEB patients and in exon 3 in RDEB patients. We also report a new phenotype-genotype correlation found in 10 unrelated families presenting mild blistering and severe mucosal involvement. Molecular studies in populations with an unexplored genetic background like ours revealed a diversity of pathogenic variants, and we hope that these findings will contribute to the definition of targets for new gene therapies.

Longitudinal study of wound healing status and bacterial colonisation of Staphylococcus aureus and Corynebacterium diphtheriae in epidermolysis bullosa patients.

Epidermolysis bullosa (EB) is an inherited disorder characterised by skin fragility and the appearance of blisters and wounds. Patient wounds are often colonised or infected with bacteria, leading to impaired healing, pain and high risk of death by sepsis. Little is known about the impact of bacterial composition and susceptibility in wound resolution, and there is a need for longitudinal studies to understand healing outcomes with different types of bacterial colonisation. A prospective longitudinal study of 70 wounds from 15 severe EB patients (Junctional and Recessive Dystrophic EB) from Chile. Wounds were selected independently of their infected status. Wound cultures, including bacterial species identification, composition and Staphylococcus aureus (SA) antibiotic susceptibility were registered. Wounds were separated into categories according to their healing capacity, recognising chronic, and healing wounds. Hundred-one of the 102 wound cultures were positive for bacterial growth. From these, 100 were SA-positive; 31 were resistant to Ciprofloxacin (31%) and only seven were methicillin-resistant SA (7%). Ciprofloxacin-resistant SA was found significantly predominant in chronic wounds (**P < .01). Interestingly, atoxigenic Corynebacterium diphtheriae (CD) was identified and found to be the second most abundant recovered bacteria (31/101), present almost always in combination with SA (30/31). CD was only found in Recessive Dystrophic EB patients and not related to wound chronicity. Other less frequent bacterial species found included Pseudomonas aeruginosa, Streptococus spp. and Proteus spp. Infection was negatively associated with the healing status of wounds.

713 The RNA-based reprogramming of renal epithelial cells derived from recessive dystrophic epidermolysis bullosa patients into induced pluripotent stem cells

No effective therapies are available for recessive dystrophic epidermolysis bullosa (RDEB) at this time. Reprogramming adult cells into induced pluripotent stem cells (iPSCs) may allow for the development of new therapies for RDEB. iPSCs can be derived from many cell types, such as fibroblasts, keratinocytes, and blood cells. The isolation of fibroblasts and keratinocytes requires a skin biopsy, an invasive procedure commonly associated with scarring and inflammation, and venipuncture is potentially traumatic for RDEB patients due to the fragility of their skin.

102 Citrullinated histone H3, a marker for neutrophil extracellular traps, is associated with poorer prognosis in recessive dystrophic epidermolysis bullosa patients with cutaneous squamous cell carcinoma

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe hereditary skin disease characterized by skin and mucosa fragility with blister formation due to type VII collagen deficiency. The major complication in RDEB patients is the development of squamous cell carcinoma (SCC) leading to premature mortality. Our study aims to correlate the immune profiles of SCCs with clinico-histopathological features in a cohort of RDEB patients. The immune cell profile was assessed by immunohistochemical analyses on 33 SCCs from 19 RDEB patients included between March 2016 and December 2021.

T-cell activation and bacterial infection in skin wounds of recessive dystrophic epidermolysis bullosa patients.

Recessive dystrophic epidermolysis bullosa (RDEB) patients develop poorly healing skin wounds that are frequently colonized with microbiota. Because T cells play an important role in clearing such pathogens, we aimed to define the status of adaptive T cell‐mediated immunity in RDEB wounds. Using a non‐invasive approach for sampling of wound‐associated constituents, we evaluated microbial contaminants in cellular fraction and exudates obtained from RDED wounds. Infectivity and intracellular trafficking of inactivated Staphylococcus aureus was accessed in RDEB keratinocytes. S. aureus and microbial antigen‐specific activation of RDEB wound‐derived T cells were investigated by fluorescence‐activated cell sorting‐based immune‐phenotyping and T‐cell functional assays. We found that RDEB wounds and epithelial cells are most frequently infected with Staphylococcus sp. and Pseudomonas sp. and that S. aureus essentially infects more RDEB keratinocytes and RDEB‐derived squamous cell carcinoma cells than keratinocytes from healthy donors. The RDEB wound‐associated T cells contain populations of CD4+ and CD8+ peripheral memory T cells that respond to soluble microbial antigens by proliferating and secreting interferon gamma (IFNγ). Moreover, CD8+ cytotoxic T lymphocytes recognize S. aureus‐infected RDEB keratinocytes and respond by producing interleukin‐2 (IL‐2) and IFNγ and degranulating and cytotoxically killing infected cells. Prolonged exposure of RDEB‐derived T cells to microbial antigens in vitro does not trigger PD‐1‐mediated T‐cell exhaustion but induces differentiation of the CD4high population into CD4highCD25+FoxP3+ regulatory T cells. Our data demonstrated that adaptive T cell‐mediated immunity could clear infected cells from wound sites, but these effects might be inhibited by PD‐1/Treg‐mediated immuno‐suppression in RDEB.