Recent progress of Stevens-Johnson syndrome/toxic epidermal necrolysis: Diagnosis criteria, pathogenesis and therapy.

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) represent a severe spectrum of rare mucocutaneous reactions, primarily drug-induced and characterized by significant morbidity and mortality. These conditions manifest through extensive skin detachment, distinguishing them from other generalized skin eruptions. The rarity and severity of SJS/TEN underscore the importance of accurate diagnostic criteria and effective treatments, which are currently lacking consensus. This review proposes new diagnostic criteria to improve specificity and global applicability. Recent advancements in understanding the immunopathogenesis of SJS/TEN are explored, emphasizing the role of drug-specific T cell responses and HLA polymorphisms in disease onset. The review also addresses current therapeutic approaches, including controversies surrounding the use of immunosuppressive agents and the emerging role of TNF-α inhibitors. Novel therapeutic strategies targeting specific pathogenic mechanisms, such as necroptosis and specific immune cell pathways, are discussed. Furthermore, the development of new drugs based on these insights, including targeted monoclonal antibodies and inhibitors, are examined. The review concludes by advocating for more robust and coordinated efforts across multidisciplinary medical fields to develop effective treatments and diagnostic tools for SJS/TEN, with the aim of improving patient outcomes and understanding of the disease and its mechanisms.

EGFR ligands synergistically increase IL-17A-induced expression of psoriasis signature genes in human keratinocytes via IκBζ and Bcl3.

Various epidermal growth factor receptor (EGFR) ligands are highly expressed in the epidermis of psoriasis lesions, and abnormal EGFR activation appears to be involved in the pathogenesis of psoriasis. However, how EGFR signaling contributes to the development of psoriasis is unclear. Interleukin (IL)-17A, a critical effector of the IL-23/IL-17A pathway, increases the expression of psoriasis signature genes in keratinocytes and plays an essential role in the pathogenesis of psoriasis by inducing IκBζ, a critical transcriptional regulator in psoriasis. In this study, we stimulated primary human keratinocytes with IL-17A and various EGFR ligands to investigate whether EGFR ligands regulate the expression of psoriasis signature genes. In cultured normal human keratinocytes and a living skin equivalent, EGFR ligands did not induce psoriasis-related gene expression, but significantly enhanced the IL-17A-mediated induction of various psoriasis signature genes, including antimicrobial peptides, cytokines, and chemokines. This was dependent on an EGFR activation-mediated synergistic increase in IL-17A-induced IκBζ expression and was partially mediated by the EGFR-dependent upregulation of Bcl3. Therefore, EGFR ligands can act as synergistic agents of IL-17A signaling by stimulating the epidermal production of psoriasis signature genes in psoriasis lesions. This study reveals a potential mechanism by which EGFR signaling contributes to the pathogenesis of psoriasis.

A retrospective study on the incidence, management and risk factors of skin rash in patients with advanced prostate cancer in Japan.

BACKGROUND: Worldwide, prostate cancer (PC) is the second most diagnosed cancer and the fifth leading cause of cancer death in men. Hormonal therapies, commonly used for PC, are associated with a range of treatment-emergent adverse events (TEAEs). The population from Japan seems to be at higher risk of developing TEAEs of skin rash compared to the overall global population. This study was conducted to get a better insight into the incidence, management, and risk factors for skin rash during active treatment for advanced PC in Japan. METHODS: A retrospective cohort of PC patients was identified and subsequently categorized, into non-metastatic and metastatic castration-resistant prostate cancer patients (nmCRPC and mCRPC), and metastatic castration-naïve prostate cancer patients (mCNPC). The analysis was based on a dataset from the Medical Data Vision (MDV) database. Descriptive statistics were determined, and a multivariate Cox proportional hazards model was used to the associated risk factors for the onset of rash. RESULTS: Overall, 1,738 nmCRPC patients, 630 mCRPC patients, and 454 mCNPC patients were included in this analysis. The median age was 78 years old and similar across the three cohorts. The skin rash incidence was 19.97% for nmCRPC cohort, 28.89% for mCRPC cohort, and 28.85% for mCNPC cohort. The median duration of skin rash ranged from 29 to 42 days. Statistically significant risk factors for developing skin rash included a history of allergy or hypersensitivity (all cohorts), increased age (nmCRPC and mCRPC), a body mass index (BMI) of < 18.5 (nmCRPC and mCRPC), and a PSA level higher than the median (nmCRPC). Skin rash was commonly managed with systemic and topical corticosteroids which ranged from 41.76% to 67.03% for all cohorts. Antihistamines were infrequently used. CONCLUSION: This study provides a better understanding of the real-world incidence, onset, duration, management and risk factors of skin rash in patients on active PC treatment in Japan. It was observed that approximately 20-30% of PC patients experience skin rash. Development of skin rash was associated with previous allergy or hypersensitivity, BMI of < 18.5, increased age and higher PSA levels, and was usually treated with corticosteroids.

Bcl-3 induced by IL-22 via STAT3 activation acts as a potentiator of psoriasis-related gene expression in epidermal keratinocytes.

IL-22 induces STAT3 phosphorylation and mediates psoriasis-related gene expression. However, the signaling mechanism leading from pSTAT3 to the expression of these genes remains unclear. We focused on Bcl-3, which is induced by STAT3 activation and mediates gene expression. In cultured human epidermal keratinocytes, IL-22 increased Bcl-3, which was translocated to the nucleus with p50 via STAT3 activation. The increases in CXCL8, S100As and human ß-defensin 2 mRNA expression caused by IL-22 were abolished by siRNA against Bcl-3. Although CCL20 expression was also augmented by IL-22, the knockdown of Bcl-3 increased its level. Moreover, the combination of IL-22 and IL-17A enhanced Bcl-3 production, IL-22-induced gene expression, and the expression of other psoriasis-related genes, including those encoding IL-17C, IL-19, and IL-36γ. The expression of these genes (except for CCL20) was also suppressed by the knockdown of Bcl-3. Bcl-3 overexpression induced CXCL8 and HBD2 expression but not S100As expression. We also compared Bcl-3 expression between psoriatic skin lesions and normal skin. Immunostaining revealed strong signals for Bcl-3 and p50 in the nucleus of epidermal keratinocytes from psoriatic skin. The IL-22-STAT3-Bcl-3 pathway may be important in the pathogenesis of psoriasis.

A case of woolly hair nevus, multiple linear pigmentation, and epidermal nevi with somatic HRAS p.G12S mutation.

Woolly hair nevus is a rare syndrome that presents as woolly hair in restricted areas of the scalp and may be associated with pigmented macules or epidermal nevus on the body. Here, we report a case of woolly hair nevus, linear pigmentation, and multiple epidermal nevi with a somatic HRAS c.34G>A(p.G12S) mutation.

Heparinoid suppresses Der p-induced IL-1ß production by inhibiting ERK and p38 MAPK pathways in keratinocytes.

Epidermal keratinocytes initiate skin inflammation by activating immune cells. The skin barrier is disrupted in atopic dermatitis (AD) and epidermal keratinocytes can be exposed to environmental stimuli, such as house dust mite (HDM) allergens. We showed previously that HDM allergens activate the NLRP3 inflammasome of keratinocytes, thereby releasing pro-inflammatory cytokines. Heparinoid is an effective moisturizer for atopic dry skin. However, a recent report showed that heparinoid treatment can improve inflammation of lichen planus. Therefore, we hypothesized that it acts on epidermal keratinocytes not only as a moisturizer, but also as a suppressant of the triggers of skin inflammation. We found that HDM allergen-induced interleukin (IL)-1ß release from keratinocytes was inhibited significantly by heparinoid pretreatment without affecting cell viability. However, heparinoid did not affect caspase-1 release, suggesting that heparinoid did not affect HDM allergen-induced inflammasome activation. Heparinoid treatment not only decreased intracellular levels of pro-IL-1ß, but also suppressed IL-1ß messenger RNA (mRNA) expression in keratinocytes. Among the intracellular signalling pathways, the activation of extracellular signal-regulated kinase and p38 pathways, which are required for IL-1ß expression in keratinocytes, was inhibited by heparinoid treatment. The inhibitory effect of heparinoid on IL-1ß mRNA expression was also confirmed with living skin equivalents. Our results demonstrated that heparinoid suppresses the initiation of keratinocyte-mediated skin inflammation.

The microbiome of the "sterile" pustules in palmoplantar pustulosis.

The skin microbiome influences skin pathophysiology. Palmoplantar pustulosis (PPP) is a chronic skin disease characterized by infectious-like pustules on the palms and soles. These pustules are thought to be sterile because bacterial cultures obtained from the pustules are negative. However, culture methods are limited in their ability to identify all bacteria on the skin. We hypothesized that the "sterile" pustules of PPP do not lack bacteria, but rather contain a microbiome. To test this hypothesis, we identified bacteria in "sterile" pustules using non-culture methods. We conducted Sanger and 16S rRNA sequencing using primers specific to the V1-V2 region in PPP-pustulovesicles (PVs) (n = 43) and pompholyx vesicle fluids (n = 15). Sanger sequencing identified some Staphylococcus, Propionibacterium, Streptococcus and Pyrinomonas species in PPP-PVs but failed to identify any bacteria in most of the pompholyx vesicles. 16S rRNA sequencing of PPP-PVs indicated the presence of a microbiome that included various phyla, including Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes. At the genus level, smokers had higher levels of Staphylococcus in PPP-PVs compared with non-smokers. These results indicate that a microbiome exists in "sterile" pustules of PPP and that PPP smokers had higher levels of Staphylococcus in pustules. It is therefore necessary to reconsider the pathogenesis of PPP from the perspective of the microbiome.

Epidermal keratinocytes sense dsRNA via the NLRP3 inflammasome, mediating interleukin (IL)-1ß and IL-18 release.

Skin epidermis, in addition to its barrier function, is able to actively sense harmful pathogens using pattern recognition receptors. In immune cells, the nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain containing 3 (NLRP3) inflammasome can mediate innate immunity against viral infection via a mechanism involving viral dsRNA recognition. Epidermal keratinocytes express NLRP3 inflammasome, which can sense contact sensitizers and mite allergens, leading to pro-interleukin (IL)-1ß and pro-IL-18 cleavage into their active forms. Skin often faces viral infection. However, it is unknown whether viral dsRNA can be detected by the keratinocyte NLRP3 inflammasome. We transfected polyinosinic:polycytidylic acid (poly I:C), a synthetic viral dsRNA analogue, into cultured primary human keratinocytes at the aid of Lipofectamine 2000, and found that transfected poly I:C activated caspase-1 and induced caspase-1-dependent release of IL-1ß and IL-18, which were suppressed on transfection with NLRP3 siRNA. The activation of keratinocyte NLRP3 inflammasome by transfected poly I:C was dependent on dsRNA-induced protein kinase (PKR) activation, and priming with type I interferons upregulated NLRP3 inflammasome activation through promoting PKR activation in poly I:C-transfected keratinocytes. In conclusion, the NLRP3 inflammasome can act as a sensor of dsRNA in epidermal keratinocytes, which may be important in both skin innate immune defense against viral infection and skin inflammation.

Fulminant type 1 diabetes caused by DIHS could be affected by the reactivation of HHV-6.

CONTEXT: In the previous issue of this journal, we reported that the incidence of fulminant type 1 diabetes (FT1D) due to the drug-induced hypersensitivity syndrome (DIHS) in Japan is higher than that in the general population and is associated with HLAB62. On the other hand, the reactivation of human herpesvirus 6 (HHV-6), which has been reported to be associated with DIHS, was observed at a higher frequency, but its association with the development of FT1D was unclear. OBJECTIVE: We aimed to clarify the relationship between the onset of FT1D and the reactivation of HHV-6. METHODS: We conducted a literature search for cases of DIHS-induced FT1D in addition to previously reported cases, and investigated the changes in the HHV-6 antibody titer before and after the onset of FT1D. RESULTS: The HHV-6 antibody titer was increased just before or after the onset of FT1D in all 8 cases. In one case, HHV-6 DNA was also identified shortly before the onset of FT1D. CONCLUSION: These results indicate for the first time that the reactivation of HHV-6 is associated with the onset of FT1D caused by DIHS.　.

Improvement of the Ocular Prognosis of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: A National Survey in Japan.

PURPOSE: To investigate the incidence and prognostic factors of ocular sequelae in Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) cases arising between 2016 and 2018 in Japan, and compare the findings with those presented in the previous 2005-2007 survey. DESIGN: Retrospective, national trend survey. METHODS: Dermatologic case report forms (CRFs) (d-CRFs) were sent to 257 institutions that treated at least 1 SJS/TEN case, and 508 CRFs were collected from 160 institutions. Ophthalmologic CRFs (o-CRFs) regarding patient demographic data, onset date, ocular findings (first appearance, day of worst severity, and final follow-up), topical treatment (betamethasone), outcome (survival or death), and ocular sequelae (visual disturbance, eye dryness) were sent to the ophthalmologists in those 160 institutions. The results of this survey were then compared with that of the previous 2005-2007 survey. RESULTS: A total of 240 cases (SJS/TEN: 132/108) were included. The incidence of ocular sequelae incidence was 14.0%, a significant decrease from the 39.2% in the previous survey (SJS/TEN: 87/48). In 197 (82.1%) of the cases, systemic treatment was initiated within 3 days after admission, an increase compared to the previous survey (ie, treatment initiated in 82 [60.7%] of 135 cases). Of the 85 cases with an Acute Ocular Severity Score of 2 and 3, 62 (72.9%) received corticosteroid pulse therapy and 73 (85.9%) received 0.1% betamethasone therapy; an increase compared to the 60.0% and 70.8%, respectively, in the previous survey. Ocular-sequelae-associated risk factors included Acute Ocular Severity Score (P < .001) and specific year in the survey (P < .001). CONCLUSIONS: The ophthalmologic prognosis of SJS/TEN has dramatically improved via early diagnosis, rapid assessment of acute ocular severity, and early treatment.

Prospective observational study of zinc deficiency symptoms during first-line chemotherapy for gastric and colorectal cancer.

Background: Zinc deficiency during long-term chemotherapy and its related symptoms, including skin rash, taste disorders, and oral mucositis, have not been sufficiently investigated. Methods: This prospective observational study enrolled patients with gastric and colorectal cancer who underwent standard first-line chemotherapy. According to the Practice Guidelines for Zinc Deficiency, zinc deficiency is defined as a serum level of <60 µg/dL. Serum zinc levels were measured before and after (1, 3, and 6 months) chemotherapy, and symptoms were assessed using the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events version 1.0. Repeated measures were analyzed using a generalized linear mixed model. Results: Of the 61 enrolled patients, 48 who underwent standard first-line chemotherapy with fluoropyrimidine plus oxaliplatin were analyzed. Zinc deficiency was observed in 18 patients (38%) before chemotherapy. The least-squares means of serum zinc levels significantly decreased at 3 and 6 months of chemotherapy in 30 patients without zinc deficiency at the start of chemotherapy (both P<0.01) but not in 18 with zinc deficiency at the beginning. Changes in serum zinc levels during chemotherapy negatively correlated with changes in taste, rash, and itching (all P<0.04) in patients without zinc deficiency before treatment initiation. Conclusions: Serum zinc levels decreased during chemotherapy in zinc-non-deficient patients at the beginning of chemotherapy and correlated with taste changes, skin rash, and itching. Therefore, investigating whether zinc supplementation ameliorates these symptoms is necessary.

Development and Validation of a Novel Score to Predict Mortality in Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: CRISTEN.

BACKGROUND: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening, severe mucocutaneous adverse reactions. Severity prediction at early onset is urgently required for treatment. However, previous prediction scores have been based on data of blood tests. OBJECTIVE: This study aimed to present a novel score that predicts mortality in patients with SJS/TEN in the early stages based on only clinical information. METHODS: We retrospectively evaluated 382 patients with SJS/TEN in a development study. A clinical risk score for TEN (CRISTEN) was created according to the association of potential risk factors with death. We calculated the sum of these risk factors using CRISTEN, and this was validated in a multinational survey of 416 patients and was compared with previous scoring systems. RESULTS: The significant risk factors for death in SJS/TEN comprised 10 items, including patients' age of ≥65 years, ≥10% body surface area involvement, the use of antibiotics as culprit drugs, the use of systemic corticosteroid therapy before the onset, and mucosal damage affecting the ocular, buccal, and genital mucosa. Renal impairment, diabetes, cardiovascular disease, malignant neoplasm, and bacterial infection were included as underlying diseases. The CRISTEN model showed good discrimination (area under the curve [AUC] = 0.884) and calibration. In the validation study, the AUC was 0.827, which was statistically comparable to those of previous systems. CONCLUSION: A scoring system based on only clinical information was developed to predict mortality in SJS/TEN and was validated in an independent multinational study. CRISTEN may predict individual survival probabilities and direct the management and therapy of patients with SJS/TEN.

Mite allergen is a danger signal for the skin via activation of inflammasome in keratinocytes.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disorder caused by multiple factors. Among them, house dust mite (HDM) allergens are important in the development of AD. In airway allergy, HDM allergens activate innate immunity. However, information regarding the activation of innate immunity by HDM allergens in the skin is limited. OBJECTIVES: The inflammasome is a key regulator of pathogen recognition and inflammation. We investigated whether HDM allergens activate the inflammasome in epidermal keratinocytes. METHODS: Keratinocytes were stimulated with Dermatophagoides pteronyssinus, and the activation of caspase-1 and secretion of IL-1ß and IL-18 were examined. Formation of the inflammasome was studied by analyzing the subcellular distributions of inflammasome proteins. The importance of specific inflammasome proteins was studied by knocking down their expression through transfection of keratinocytes with lentiviral particles carrying short hairpin RNAs (shRNAs). RESULTS: D pteronyssinus activated caspase-1 and induced caspase-1-dependent release of IL-1ß and IL-18 from keratinocytes. Moreover, D pteronyssinus stimulated assembly of the inflammasome by recruiting apoptosis-associated specklike protein containing a caspase-recruitment domain (ASC), caspase-1, and nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin-domain containing 3 (NLRP3) to the perinuclear region. Finally, infection with lentiviral particles carrying ASC, caspase-1, or NLRP3 shRNAs suppressed the release of IL-1ß and IL-18 from the keratinocytes. Activation of the NLRP3 inflammasome by D pteronyssinus was dependent on cysteine protease activity. CONCLUSION: House dust mite allergens are danger signals for the skin. In addition, HDM-induced activation of the NLRP3 inflammasome may play a pivotal role in the pathogenesis of AD.

Immunohistological analysis of pathogenic infiltrates in the epidermis and liver of a patient with toxic epidermal necrolysis accompanied by vanishing bile duct syndrome.

Toxic epidermal necrolysis (TEN) is a severe cutaneous adverse drug reaction characterized by extensive epidermal detachment, which is reportedly mediated by drug-specific cytotoxic CD8+ T cells, inflammatory monocytes, and neutrophils. Besides the skin, TEN often damages other organs, and it remains unknown whether they are mediated by similar pathogenic cells that cause epidermal damage. We experienced a case who developed TEN complicated with vanishing bile duct syndrome. Immunohistological analysis revealed the infiltration of CD8+ T cells, inflammatory monocytes, and neutrophil extracellular trap-forming neutrophils in the lesions of both the skin and liver with different degree of infiltration of these cells. These data suggest a difference of dominant pathogenic cells between skin and liver of patients with TEN.

Serum Soluble OX40 as a Diagnostic and Prognostic Biomarker for Drug-Induced Hypersensitivity Syndrome/Drug Reaction with Eosinophilia and Systemic Symptoms.

BACKGROUND: Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS) is a severe adverse drug reaction commonly associated with the reactivation of human herpesvirus 6 (HHV-6). There are currently no adequate biomarkers for the early diagnosis and detection of DIHS/DRESS. Notably, OX40 (CD134) has an important role in allergic inflammation and functions as a cellular receptor for HHV-6 entry. We previously reported that the membrane-bound form of OX40 in CD4+ T cells was upregulated in DIHS/DRESS. OBJECTIVE: We sought to investigate the clinical significance of serum soluble OX40 (sOX40) in DIHS/DRESS. METHODS: Serum sOX40 levels in patients with DIHS/DRESS (n = 39), maculopapular exanthema/erythema multiforme (n = 17), Stevens-Johnson syndrome/toxic epidermal necrolysis (n = 13), or autoimmune bullous diseases (n = 5), and levels in healthy volunteers (n = 5) were examined by enzyme-linked immunosorbent assay. Copy numbers of HHV-6, HHV-7, and cytomegalovirus in peripheral blood mononuclear cells were quantified using real-time PCR. RESULTS: Serum sOX40 levels in patients with DIHS/DRESS in the acute stage were elevated in parallel with high OX40 expression on CD4+ T cells. Serum sOX40 levels were significantly positively correlated with disease severity and serum levels of thymus and activation-regulated chemokine, IL-5, and IL-10. Human herpesvirus 6-positive patients had higher sOX40 levels than did HHV-6-negative patients, and serum sOX40 levels were correlated with HHV-6 DNA loads. CONCLUSIONS: Serum sOX40 levels can be a useful diagnostic marker for DIHS/DRESS that reflect disease severity. Elevated serum sOX40 levels also predict HHV-6 reactivation in patients with DIHS/DRESS.

Risk factors for sepsis and effects of pretreatment with systemic steroid therapy for underlying condition in SJS/TEN patients: Results of a nationwide cross-sectional survey in 489 Japanese patients.

BACKGROUND: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening severe cutaneous adverse reactions (SCARs). Sepsis has been shown to be the main cause of death in SJS/TEN. The European SCAR study reported that 14.8 % of SJS/TEN patients were receiving systemic steroid therapy for their underlying condition prior to onset. However, it remained unclear whether this factor affected the mortality rate. OBJECTIVE: This study was performed to identify risk factors for sepsis in SJS/TEN patients. In addition, we compared patients who had and had not received systemic steroid therapy for their underlying condition. METHODS: A primary survey regarding the numbers of SJS/TEN patients between 2016 and 2018 was sent to 1205 institutions in Japan. A secondary survey seeking more detailed information was sent to institutions reporting SJS/TEN patients. We analyzed 315 SJS patients and 174 TEN patients using a logistic regression model, Wilcoxon's rank-sum test, χ2 test, and Fisher's exact test. RESULTS: Significant risk factors for sepsis included TEN, diabetes, and intensive care unit (ICU) admission. The mortality rate was significantly higher among patients with sepsis. Patients who had received systemic steroid therapy had a lower incidence of fever, and showed a higher mortality rate. CONCLUSION: Based on a nationwide epidemiological survey of SJS/TEN in Japan, we identified risk factors for sepsis and found that patients who had received steroid therapy for their underlying condition had a lower incidence of fever and a higher mortality rate.