Interleukin-15 Is Associated with Severity and Mortality in Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis

The Role of IL-13, IL-15 and Granulysin in the Pathogenesis of Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis

Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN) are Severe Cutaneous Adverse Reactions (SCARS) characterized by fever and mucocutaneous lesions leading to necrosis and sloughing of the epidermis. Conjunctival lesions are reported in 85% of patients. The pathogenesis of SJS/TEN/SCARS is not completely understood. It is hypothesized that IL-13, IL-15 and Granulysin expressed in plasma and skin may play a role. We measured the circulating levels of these cytokines in the plasma using ELISA and their expression in the skin using immunofluorescence microscopy. A total of 12 SJS/TEN skin biopsy samples (8 SJS, 2 SJS/TEN overlap and 2 TEN) were analyzed. Biopsy samples from patients with Lichen Planus (an inflammatory condition of the skin and mucous membranes) served as controls. Studies were also performed in human corneal epithelial cells where expression of these cytokines were measured following a challenge with TNF-α (0, 1, 10 and 100 ng/ml). The intensity of immunofluorescence was measured Using Imaris® software. The results showed significantly increased expression of these cytokines in the skin biopsy samples as measured by the average intensities of IL-13 (6.1 x 133.0 ± 4.231 x 10^8), and Granulysin (4.2 x 123.0 ± 4.231 x 10^8) compared to Lichen planus control (3.0 x 123.0 ±1.62 x 10^5). Increased expression of IL-13 and IL-15 were noted in cell culture studies and in the plasma samples when compared to Normal Human Plasma as controls. It is concluded that IL-13, IL-15 and Granulysin play a role in the pathogenesis of SJS/TEN.

An Updated Review of the Diagnostic Methods in Delayed Drug Hypersensitivity

Delayed drug hypersensitivity reactions are clinically diverse reactions that vary from isolated benign skin conditions that remit quickly with no or symptomatic treatment, drug discontinuation or even continued drug treatment, to the other extreme of severe cutaneous adverse reactions (SCARs) that are associated with presumed life-long memory T-cell responses, significant acute and long-term morbidity and mortality. Diagnostic "in clinic" approaches to delayed hypersensitivity reactions have included patch testing (PT), delayed intradermal testing (IDT) and drug challenges for milder reactions. Patch and IDT are, in general, performed no sooner than 4-6 weeks after resolution of the acute reaction at the maximum non-irritating concentrations. Functional in vitro and ex vivo assays have largely remained the province of research laboratories and include lymphocyte transformation test (LTT) and cytokine release enzyme linked ImmunoSpot (ELISpot) assay, an emerging diagnostic tool which uses cytokine release, typically IFN-γ, after the patient's peripheral blood mononuclear cells are stimulated with the suspected drug(s). Genetic markers such as human leukocyte antigen have shown recent promise for both pre-prescription screening as well as pre-emptive and diagnostic testing strategies.

Elevated serum level of interleukin-15 in vitiligo patients and its correlation with disease severity but not activity

BACKGROUND

Vitiligo is a common acquired disorder of depigmentation. Its pathogenesis entails a T helper (Th) 1-cytotoxic T (cT) lymphocytes mediated autoimmune melanocyte destruction. Interleukin (IL)-15 is one of the IL-2 family of cytokines and shares several actions with IL-2. IL-15 enhances survival, maturation, and functional activity of natural killer, neutrophils, and dendritic cells. Furthermore, it potentiates survival, maturation, and cytotoxicity of memory cT cells. IL-15 has been shown to play a crucial role in the pathogenesis of several autoimmune diseases but was poorly investigated in patients with vitiligo.

AIMS

The study aimed at evaluating IL-15 level in the sera of patients with vitiligo and its association with vitiligo severity and activity.

PATIENTS AND METHODS

The study included 30 patients with nonsegmental vitiligo and 30 healthy controls. Vitiligo Extent Score (VES) and Vitiligo Disease Activity (VIDA) score were used to assess vitiligo severity and activity, respectively. Serum level of IL-15 was assessed by enzyme-linked immune-sorbent assay.

RESULTS

Serum IL-15 level, in patients with vitiligo, was significantly higher in comparison with the control group (P = .001). A significant positive correlation was found between serum IL-15 level and VES score (P = .001), whereas there was no significant correlation between IL-15 level and VIDA score as well as the disease duration.

CONCLUSION

IL-15 level was elevated in the sera of patients with vitiligo. IL-15 may therefore have a significant impact on vitiligo autoimmune pathogenesis, and further identification of its molecular roles may highlight new therapeutic strategies for vitiligo.

Detecting Lesional Granulysin Levels for Rapid Diagnosis of Cytotoxic T lymphocyte-Mediated Bullous Skin Disorders

BACKGROUND

Bullous skin disorders are induced by different pathomechanisms and several are emergent, including Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Rapid diagnostic methods for SJS/TEN or cytotoxic T-lymphocyte (CTL)-mediated bullous disorders are crucial for early treatment. Granulysin, primarily expressed by CTLs, is a specific cytotoxic protein responsible for SJS/TEN and similar skin reactions.

OBJECTIVE

To assess granulysin levels in blister fluids to differentiate SJS/TEN and similar CTL-mediated bullous reactions from other autoimmune bullous disorders.

METHODS

Using ELISA, we measured granulysin in blister fluids from patients with bullous skin disorders, including SJS/TEN, erythema multiforme major, bullous fixed-drug eruption, bullous lupus erythematosus, paraneoplastic pemphigus, pemphigus vulgaris, bullous pemphigoid, purpura fulminans-related bullae, and hand-foot syndrome/hand-foot-skin reactions. We compared serum and blister granulysin levels in patients with SJS/TEN presenting varying severity, monitoring serial granulysin levels from acute to late stages.

RESULTS

Overall, 144 patients presenting with bullous skin disorders were enrolled. Blister granulysin levels (mean ± SD) in CTL-mediated disorders, including TEN (n = 28; 3938.7 ± 3475.7), SJS-TEN overlapping (n = 22; 1440.4 ± 1179.6), SJS (n = 14; 542.0 ± 503.2), erythema multiforme major (n = 7; 766.3 ± 1073.7), generalized bullous fixed-drug eruption (n = 10; 720.4 ± 858.3), and localized bullous fixed-drug eruption (n = 16; 69.0 ± 56.4), were significantly higher than in non-CTL-mediated bullous disorders (P < .0001), including bullous lupus erythematosus (n = 3; 22.7 ± 20.1), paraneoplastic pemphigus (n = 3; 20.3 ± 8.6), pemphigus vulgaris (n = 3; 4.4 ± 2.8), bullous pemphigoid (n = 18; 4.0 ± 2.7), purpura fulminans (n = 4; 5.9 ± 5.5), and hand-foot syndrome/hand-foot-skin reactions (n = 6; 4.6 ± 3.5). Blister granulysin levels correlated with clinical severity of SJS/TEN (P < .0001).

CONCLUSIONS

Determination of blister granulysin levels is a noninvasive and useful tool for rapid differential diagnosis of SJS/TEN and other similar CTL-mediated bullous skin disorders for treatment selection.

Clinical and pathogenic aspects of the severe cutaneous adverse reaction epidermal necrolysis (EN)

The severe cutaneous adverse reaction epidermal necrolysis (EN) which includes toxic epidermal necrolysis and the milder Stevens-Johnson syndrome is characterized by epidermal loss due to massive keratinocyte apoptosis and/or necroptosis. EN is often caused by a drug mediating a specific TCR-HLA interaction via the (pro)hapten, pharmacological interaction or altered peptide loading mechanism involving a self-peptide presented by keratinocytes. (Memory) CD8 + T cells are activated and exhibit cytotoxicity against keratinocytes via the perforin/granzyme B and granulysin pathway and Fas/FasL interaction. Alternatively drug-induced annexin release by CD14 + monocytes can induce formyl peptide receptor 1 death of keratinocytes by necroptosis. Subsequent keratinocyte death stimulates local inflammation, activating other immune cells producing pro-inflammatory molecules and downregulating regulatory T cells. Widespread epidermal necrolysis and inflammation can induce life-threatening systemic effects, leading to high mortality rates. Research into genetic susceptibility aims to identify risk factors for eventual prevention of EN. Specific HLA class I alleles show the strongest association with EN, but risk variants have also been identified in genes involved in drug metabolism, cellular drug uptake, peptide presentation and function of CD8 + T cells and other immune cells involved in cytotoxic responses. After the acute phase of EN, long-term symptoms can remain or arise mainly affecting the skin and eyes. Mucosal sequelae are characterized by occlusions and strictures due to adherence of denuded surfaces and fibrosis following mucosal inflammation. In addition, systemic pathology can cause acute and chronic hepatic and renal symptoms. EN has a large psychological impact and strongly affects health-related quality of life among EN survivors.

Toxic Epidermal Necrolysis and Steven-Johnson Syndrome: A Comprehensive Review

Significance: Toxic epidermal necrolysis (TEN) and Steven-Johnson syndrome (SJS) are potentially fatal acute mucocutaneous vesiculobullous disorders. Evidence to date suggests that outcomes for patients with both TEN and SJS are largely dependent on stopping the causative agent, followed by supportive care and appropriate wound management in a specialized burns unit. These are life-threatening conditions characterized by widespread full-thickness cutaneous and mucosal necrosis. This article outlines the approach to holistic management of such patients, in a specialized unit, highlighting various practical aspects of wound care to prevent complications such as infection, mucosal and adhesions, and ocular scaring. Recent Advances: There is improved understanding of pain and morbidity with regard to the type and frequency of dressing changes. More modern dressings, such as nanocrystalline, are currently favored as they may be kept in situ for longer periods. The most recent evidence on systemic agents, such as corticosteroids and cyclosporine, and novel treatments, are also discussed. Critical Issues: Following cessation of the culprit trigger, management in a specialized burns unit is the most important management step. It is now understood that a multidisciplinary team is essential in the care of these patients. Following admission of such patients, dermatology, ear, nose, and throat surgery, ophthalmology, urology, colorectal surgery, and gynecology should all be consulted to prevent disease sequelae. Future Directions: Looking forward, research is aimed at achieving prospective data on the efficacy of systemic immunomodulating agents and dressing types. Tertiary centers with burns units should develop policies for such patients to ensure that the relevant teams are consulted promptly to avoid mucocutaneous complications.

Acute pancreatic injuries: A complication of Stevens-Johnson syndrome/toxic epidermal necrolysis associated with cytotoxic immunocell activation

BACKGROUND

Complications involving internal organs are usually present in Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). However, pancreatic complications are rarely reported and studied.

OBJECTIVE

To summarize clinical characteristics of SJS/TEN-associated acute pancreatic injuries and to investigate underlying inflammatory mechanisms.

METHODS

Clinical records of 124 inpatients with SJS/TEN were reviewed. Serum levels of tumor necrosis factor α, interleukin (IL) 6, IL-18, IL-15, IL-12p70, and soluble CD56 were determined in 18 healthy donors and 17 patients with SJS/TEN, including 3 with acute pancreatic injuries.

RESULTS

Acute pancreatic injury was diagnosed in 7.3% of patients (9/124) in the SJS/TEN cohort. Elevation of serum transaminase level and hypoalbuminemia occurred more frequently in patients with acute pancreatic injuries compared with those without pancreatic symptoms (P = .004 and <.001, respectively). Although acute pancreatic injury did not alter mortality rate of SJS/TEN, it was associated with longer hospitalization stays (P = .008). Within the serum cytokines whose levels were elevated in SJS/TEN, only IL-18 was found to be selectively increased in patients with acute pancreatic injuries compared with those without them (P = .03).

LIMITATIONS

Cohort was small.

CONCLUSION

Acute pancreatic injury is a gastrointestinal complication of SJS/TEN in which hepatotoxicity is more likely to occur. Overexpression of IL-18 might be involved in this unique entity.

Drug-Induced liver Injury Associated with Severe Cutaneous Hypersensitivity Reactions: A Complex Entity in Need of a Multidisciplinary Approach

Idiosyncratic drug-induced liver injury (DILI) occasionally occurs in the setting of severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) and drug reaction with eosinophilia and systemic symptoms (DRESS). This strengthens the proposed immunologic mechanism associated with this adverse reaction. DRESS exhibits the most common association with DILI. SCARs have a wide spectrum of heterogeneous clinical presentations and severity, and genetic predisposition has been identified. In the context of SCARs, DILI present a different clinical picture, ranging from mild injury to acute liver failure. Elucidating the role of DILI in the clinical presentation and outcome of SCARs represents a challenge due to limited information from published studies and the lack of consensus on definitions. The cholestatic and mixed pattern of liver damage typically predominates in the case of DILI associated with SCARs, which is different from DILI without SCARs where hepatocellular is the most common injury pattern. Only a few drugs have been associated with both DILI and SCARs. Is this article, the criteria used for DILI recognition among SCARS have been revised and discussed, along with the drugs most commonly involved in these syndromes as well as the outcome, prognostic factors and the need for a multidisciplinary approach to improve the management of DILI in the context of SCARs.

Recent advances in managing and understanding Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening diseases characterized by detachment of the epidermis and mucous membrane. SJS/TEN are considered to be on the same spectrum of diseases with different severities. They are classified by the percentage of skin detachment area. SJS/TEN can also cause several complications in the liver, kidneys, and respiratory tract. The pathogenesis of SJS/TEN is still unclear. Although it is difficult to diagnose early stage SJS/TEN, biomarkers for diagnosis or severity prediction have not been well established. Furthermore, optimal therapeutic options for SJS/TEN are still controversial.

Several drugs, such as carbamazepine and allopurinol, are reported to have a strong relationship with a specific human leukocyte antigen (HLA) type. This relationship differs between different ethnicities. Recently, the usefulness of HLA screening before administering specific drugs to decrease the incidence of SJS/TEN has been investigated.

Skin detachment in SJS/TEN skin lesions is caused by extensive epidermal cell death, which has been considered to be apoptosis via the Fas-FasL pathway or perforin/granzyme pathway. We reported that necroptosis, i.e. programmed necrosis, also contributes to epidermal cell death. Annexin A1, released from monocytes, and its interaction with the formyl peptide receptor 1 induce necroptosis. Several diagnostic or prognostic biomarkers for SJS/TEN have been reported, such as CCL-27, IL-15, galectin-7, and RIP3.

Supportive care is recommended for the treatment of SJS/TEN. However, optimal therapeutic options such as systemic corticosteroids, intravenous immunoglobulin, cyclosporine, and TNF-α antagonists are still controversial. Recently, the beneficial effects of cyclosporine and TNF-α antagonists have been explored. In this review, we discuss recent advances in the pathophysiology and management of SJS/TEN.

Cytokines/Chemokines: Novel Biomarkers Associated with Severe Cutaneous Adverse Reactions

Although the incidence of severe cutaneous adverse reactions (SCARs) is very low, if it is not diagnosed and treated in time, it can not only cause skin and mucous membrane involvement, but can also cause multiple organ failure and even death. The diagnostic criteria and treatment guidelines for severe drug eruptions have not been unified. Many medical centers have used human leukocyte antigen alleles to diagnose SCARs. Some prospective studies have shown that susceptibility gene testing can prevent SCARs as early as possible, but the widespread implementation of its technology is limited by being ethnically specific. With the unique advantages of cytokine detection technology, cytokines are increasingly important for the diagnosis and treatment of SCARs. Related cytokines/chemokines involved in the pathogenesis, adjuvant diagnosis, and treatment of SCARs are discussed.

SJS/TEN 2019: From science to translation

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are potentially life-threatening, immune-mediated adverse reactions characterized by widespread erythema, epidermal necrosis, and detachment of skin and mucosa. Efforts to grow and develop functional international collaborations and a multidisciplinary interactive network focusing on SJS/TEN as an uncommon but high burden disease will be necessary to improve efforts in prevention, early diagnosis and improved acute and long-term management. SJS/TEN 2019: From Science to Translation was a 1.5-day scientific program held April 26-27, 2019, in Vancouver, Canada. The meeting successfully engaged clinicians, researchers, and patients and conducted many productive discussions on research and patient care needs.

Mechanisms of Severe Cutaneous Adverse Reactions: Recent Advances

Cutaneous adverse drug reactions are unpredictable and include various different skin conditions of varying degrees of severity. The most concerning are usually referred to as severe cutaneous adverse reactions (SCARs) and include acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS), also known as drug-induced hypersensitivity syndrome (DiHS) or hypersensitivity syndrome (HSS), Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). All are delayed type IV hypersensitivity reactions in which a T-cell-mediated drug-specific immune response is responsible for causing the disease. Nonetheless, specific T-cell subpopulations develop in response to certain environmental conditions and produce cytokines that orchestrate the various phenotypes. Cytotoxic T lymphocytes (CTLs), T-helper type 1 (Th1), Th2, Th17, and regulatory T cells (Treg), among other T-cell subpopulations, participate in the development of SCAR phenotypes. Cell subpopulations belonging to the innate immune system, comprising natural killer cells, innate lymphoid cells, monocytes, macrophages and dendritic cells, can also participate in shaping specific immune responses in various clinical conditions. Additionally, tissue-resident cells, including keratinocytes, can contribute to epidermal damage by secreting chemokines that attract pro-inflammatory immunocytes. The final phenotypes in each clinical entity result from the complex interactions between a variety of cell lineages, their products, soluble mediators and genetic and environmental factors. Although the pathophysiology of these reactions is not fully understood, intensive research in recent years has led to major progress in our understanding of the contribution of certain cell types and soluble mediators to the variability of SCAR phenotypes.

Attenuation of Wnt/β-catenin signaling in patients with Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrosis (TEN) are rare but life-threatening severe cutaneous adverse reactions. Current studies have suggested that the pathobiology of drug-mediated SJS/TEN involves a dysregulation of cellular immunity with overwhelming activation of cytotoxic T lymphocytes. The canonical Wnt signaling pathway plays important roles in T cell development and activation, which may provide potential avenues for alleviating dysregulated immunity in SJS/TEN. In this study, we aimed to assess the implication of Wnt signaling in drug-reactive T cells in SJS/TEN. We showed downregulation of Wnt signaling components, including T cell factor 1 (TCF-1)/lymphoid enhancer binding factor 1 (LEF-1) transcription factors, in SJS/TEN patients, suggesting that canonical Wnt signaling is regulated during cytotoxic T cell responses in SJS/TEN. Further analyses demonstrated that engagement of the T cell receptor by antigen encounter and treatment of a prognostic marker of SJS/TEN, IL-15, in vitro led to the downregulation of LEF-1 and TCF-1 expression in CD8+ T cells. Enhancement of Wnt signaling by adding the Wnt activators attenuated ex vivo activation of drug-specific T cells from SJS/TEN patients, indicating a functional involvement of Wnt signaling in the pathomechanism of SJS/TEN. These findings provide additional insight into the immunopathogenesis and therapeutic intervention of this devastating condition.

Serum and blister-fluid elevation and decreased epidermal content of high-mobility group box 1 protein in drug-induced Stevens-Johnson syndrome/toxic epidermal necrolysis

BACKGROUND

High-mobility group box 1 (HMGB1) is a damage-associated molecular-pattern protein. Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) are serious, immune-mediated skin-blistering conditions.

OBJECTIVES

To determine serum and/or blister-fluid total HMGB1 levels in SJS/TEN cohorts, and HMGB1 expression in formalin-fixed, paraffin-embedded (FFPE) SJS/TEN skin vs. healthy and maculopapular exanthema (MPE) skin. Methods Serum HMGB1 was quantified in Malawian nevirapine-induced hypersensitivity, Taiwanese SJS/TEN and Spanish SJS/TEN cohorts. FFPE skin (healthy skin, MPE, SJS/TEN) was stained and assessed for HMGB1 expression.

RESULTS

Serum total HMGB1 was not significantly elevated in patients with nevirapine-induced SJS/TEN (3·98 ± 2·17 ng mL^-1 ), MPE (3·92 ± 2·75 ng mL^-1 ) or drug reaction with eosinophilia and systemic symptoms (4·73 ± 3·00 ng mL^-1 ) vs. tolerant controls (2·97 ± 3·00 ng mL^-1 ). HMGB1 was significantly elevated in Taiwanese patients with SJS/TEN, highest during the acute phase (32·6 ± 26·6 ng mL^-1 ) vs. the maximal (19·7 ± 23·2 ng mL^-1 ; P = 0·007) and recovery (24·6 ± 25·3 ng mL^-1 ; P = 0·027) phases. In blister fluid from Spanish patients with SJS/TEN, HMGB1 (486·8 ± 687·9 ng mL^-1 ) was significantly higher than in serum (8·8 ± 7·6 ng mL^-1 ; P <0·001). Preblistered SJS/TEN skin showed decreased epidermal nuclear HMGB1 expression in upper epidermis vs. healthy or MPE skin but retained basal/suprabasal expression.

CONCLUSIONS

Epidermal HMGB1 expression was decreased in SJS/TEN skin. Retained basal/suprabasal epidermal HMGB1 expression may exacerbate localized injury in SJS/TEN.

Clinical features, outcomes and treatment in children with drug induced Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), which can be considered a late-onset allergic reaction, can cause serious long-term sequelae. SJS/TEN are considered a spectrum of life-threatening adverse drug reactions. They have the same clinical manifestations and the only difference is in the extent of epidermal detachment. These conditions are associated with high mortality, although incidence of SJS/TEN is rare in children. SJS/TEN is an adverse drug reaction influenced by genes that involve pharmacokinetics, pharmacodynamics and immune response. Infective agents are additional influencing factors. Anticonvulsants and antibiotics, and especially sulphonamides and non-steroidal anti-inflammatory drugs, are among the drugs that were predominantly suspected of triggering SJS/TEN. No evidence-based standardized treatment guidelines for SJS or TEN are currently available. The usual treatment is mainly founded on the withdrawal of the suspected causative agent and supportive therapy. In pediatric patients, the specific therapeutic strategies are controversial and comprise systemic corticosteroids and the use of intravenous immunoglobulin (IVIG). More recently, new therapeutic approaches have been used, such as immunosuppressive therapies, including cyclosporine and TNF-α inhibitors. (www.actabiomedica.it)

Serum Interleukin-15 is a Marker of Alopecia Areata Severity

Background:

Interleukin-15 (IL-15) is a cytokine that is involved in many inflammatory and autoimmune diseases. Although alopecia areata (AA) is an autoimmune disease, serum levels of IL-15 have not been studied well in AA patients.

Aim of the Work:

We aims at evaluating the serum levels of IL-15 in active AA.

Subject and Methods:

This case-control study included 40 AA patients and 40 apparently healthy matched controls. Written informed consents were obtained from all the participants. The scalp was examined to assess sites, number, and size of alopecia patches, and the severity of AA lesions was assessed using the Severity of Alopecia Tool score (SALT score) which determine the percentage of hair loss in the scalp. The body was carefully examined to detect any alopecia patches in any hairy area. Nail examination was carried out to detect any nail involvement. Serum IL-15 levels were measured using an ELISA kits.

Results:

Serum levels of IL-15 in patients were significantly higher than those in the control group (P < 0.001). Serum levels in alopecia totalis were significantly higher than those with one or two patches, and serum levels in patients with both scalp and body involvement were significantly elevated than the levels of patients with either scalp or body involvement. There was a statistically significant positive correlation between SALT score and serum levels of IL-15 (P < 0.001).

Conclusion:

Serum IL-15 may be a marker of AA severity.

The skin as a metabolic and immune-competent organ: Implications for drug-induced skin rash

Current advances in the study of cutaneous adverse drug reactions can be attributed to the recent understanding that the skin is both a metabolically and immunologically competent organ. The ability of the skin to serve as a protective barrier with limited drug biotransformation ability, yet highly active immune function, has provided insights into its biological capability. While the immune response of the skin to drugs is vastly different from that of the liver due to evolutionary conditioning, it frequently occurs in response to various drug classes and manifests as a spectrum of hypersensitivity reactions. The skin is a common site of adverse and idiosyncratic drug reactions; drug-specific T-cells, as well as involvement of an innate immune response, appear to be key mechanistic drivers in such scenarios. Association of other factors such as human leukocyte antigen (HLA) polymorphisms may play a significant role for particular drugs. This review aims to integrate emerging findings into proposed mechanisms of drug metabolism and immunity in the skin that are likely responsible for rashes and other local allergic responses. These unique biological aspects of the skin, and their translation into implications for drug development and the use of animal models, will be discussed.

Current Perspectives on Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are considered a delayed-type hypersensitivity reaction to drugs. They represent true medical emergencies and an early recognition and appropriate management is decisive for the survival. SJS/TEN manifest with an "influenza-like" prodromal phase (malaise, fever), followed by painful cutaneous and mucous membrane (ocular, oral, and genital) lesions, and other systemic symptoms. The difference between SJS, SJS/TEN overlap, and TEN is defined by the degree of skin detachment: SJS is defined as skin involvement of < 10%, TEN is defined as skin involvement of > 30%, and SJS/TEN overlap as 10-30% skin involvement. The diagnosis of different degrees of epidermal necrolysis is based on the clinical assessment in conjunction with the corresponding histopathology. The mortality rates for SJS and TEN have decreased in the last decades. Today, the severity-of-illness score for toxic epidermal necrolysis (SCORTEN) is available for SJS/TEN severity assessment. Drugs with a high risk of causing SJS/TEN are anti-infective sulfonamides, anti-epileptic drugs, non-steroidal anti-inflammatory drugs of the oxicam type, allopurinol, nevirapine, and chlormezanone. Besides conventional drugs, herbal remedies and new biologicals should be considered as causative agents. The increased risk of hypersensitivity reactions to certain drugs may be linked to specific HLA antigens. Our understanding of the pathogenesis of SJS/TEN has improved: drug-specific T cell-mediated cytotoxicity, genetic linkage with HLA- and non-HLA-genes, TCR restriction, and cytotoxicity mechanisms were clarified. However, many factors contributing to epidermal necrolysis still have to be identified, especially in virus-induced and autoimmune forms of epidermal necrolysis not related to drugs. In SJS/TEN, the most common complications are ocular, cutaneous, or renal. Nasopharyngeal, esophageal, and genital mucosal involvement with blisters, erosions as well as secondary development of strictures also play a role. However, in the acute phase, septicemia is a leading cause of morbidity and fatality. Pulmonary and hepatic involvement is frequent. The acute management of SJS/TEN requires a multidisciplinary approach. Immediate withdrawal of potentially causative drugs is mandatory. Prompt referral to an appropriate medical center for specific supportive treatment is of utmost importance. The most frequently used treatments for SJS/TEN are systemic corticosteroids, immunoglobulins, and cyclosporine A.

Antibiotics with Interleukin-15 Inhibition Reduce Joint Inflammation and Bone Erosions but Not Cartilage Destruction in Staphylococcus aureus-Induced Arthritis

Staphylococcus aureus-induced arthritis causes rapid joint destruction, often leading to disabling joint damage despite antibiotics. We have previously shown that interleukin-15 (IL-15) inhibition without antibiotics is beneficial in S. aureus-induced arthritis. We therefore hypothesized that the inhibition of IL-15, in combination with antibiotics, might represent a useful therapy that would reduce inflammation and joint destruction but preserve the host's ability to clear the infection. Female wild-type C57BL/6 mice were intravenously inoculated with the toxic shock syndrome toxin 1 (TSST-1)-producing LS-1 strain of S. aureus with 0.8 × 10⁸ CFU S. aureus LS-1/mouse. Three days later, treatment consisting of cloxacillin, followed by flucloxacillin, together with either anti-IL-15 antibodies (aIL-15ab) or control antibodies, was started. Studied outcomes included survival, weight change, bacterial clearance, and joint damage. The addition of aIL-15ab to antibiotics in S. aureus-induced arthritis reduced synovitis and bone erosions compared to controls. The number of bone-resorbing osteoclasts in the joints was reduced, whereas cartilage destruction was not significantly altered. Importantly, the combination therapy did not adversely affect the clinical outcome of S. aureus-induced arthritis, such as survival or weight change, or compromise the host's ability to clear the infection. Since the clinical outcome of S. aureus-induced arthritis was not affected, the addition of aIL-15ab to antibiotics ought to be safe. Taken together, the combination of aIL-15ab and antibiotics is a beneficial, but not optimal, treatment of S. aureus-induced arthritis since it reduces synovitis and bone erosions but has a limited effect on cartilage destruction.

Diverse expression of TNF-α and CCL27 in serum and blister of Stevens-Johnson syndrome/toxic epidermal necrolysis

Background

The pathogenesis of Stevens–Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) is not fully understood. Our previous study reported that chemokine CCL27 was overexpressed in serum of SJS/TEN patients. The objective of this study was to investigate the levels of CCL27 and TNF-α in serum and blister fluid from patients with SJS/TEN during the acute stage or resolution phase.

Methods

A total of 27 patients with SJS/TEN and 39 healthy donors were recruited to the study. Serum and vesicular levels of CCL27 and TNF-α were determined by enzyme-linked immunosorbent assays.

Results

Serum levels of CCL27 and TNF-α were significantly elevated in patients with SJS/TEN during the acute stage as compared to the resolution phase and also compared with levels observed in normal controls (P = 0.001/< 0.001; P = 0.012/< 0.001). Serum TNF-α levels were significantly higher in patients with SJS/TEN during the resolution phase compared with normal controls (P < 0.001). Serum CCL27 levels were positively correlated with TNF-α levels during the acute stage (r_s = 0.660; P < 0.001). Blister fluid exhibited much lower CCL27 levels than serum did during the acute stage (P = 0.008). TNF-α levels were much higher in vesicles in contrast to serum from acute stage (P = 0.040) as well as serum from resolution phase (P = 0.029).

Conclusions

Our study demonstrated roles of CCL27 and TNF-α in promoting the course of SJS/TEN. CCL27 may act early in the course of disease, via the circulation, whereas TNF-α acts throughout the course of disease, in skin lesions.

The Function of HLA-B*13:01 Involved in the Pathomechanism of Dapsone-Induced Severe Cutaneous Adverse Reactions

Dapsone-induced hypersensitivity reactions may cause severe cutaneous adverse reactions, such as drug reaction with eosinophilia and systemic symptoms (DRESS). It has been reported that HLA-B*13:01 is strongly associated with dapsone-induced hypersensitivity reactions among leprosy patients. However, the phenotype specificity and detailed immune mechanism of HLA-B*13:01 remain unclear. We investigated the genetic predisposition, HLA-B*13:01 function, and cytotoxic T cells involved in the pathogenesis of dapsone-induced severe cutaneous adverse reactions. We enrolled patients from Taiwan and Malaysia with DRESS and maculopapular eruption with chronic inflammatory dermatoses. Our results showed that the HLA-B*13:01 allele was present in 85.7% (6/7) of patients with dapsone DRESS (odds ratio = 49.64, 95% confidence interval = 5.89-418.13; corrected P = 2.92 × 10^-4) but in only 10.8% (73/677) of general population control individuals in Taiwan. The level of granulysin, the severe cutaneous adverse reaction-specific cytotoxic protein released from cytotoxic T cells, was increased in both the plasma of DRESS patients (36.14 ± 9.02 ng/ml, P < 0.05) and in vitro lymphocyte activation test (71.4%, 5/7 patients) compared with healthy control individuals. Furthermore, dapsone-specific cytotoxic T cells were significantly activated when co-cultured with HLA-B*13:01-expressing antigen presenting cells in the presence of dapsone (3.9-fold increase, compared with cells with no HLA-B*13:01 expression; P < 0.01). This study indicates that HLA-B*13:01 is strongly associated with dapsone DRESS and describes a functional role for the HLA-restricted immune mechanism induced by dapsone.

An Updated Review of the Molecular Mechanisms in Drug Hypersensitivity

Drug hypersensitivity may manifest ranging from milder skin reactions (e.g., maculopapular exanthema and urticaria) to severe systemic reactions, such as anaphylaxis, drug reactions with eosinophilia and systemic symptoms (DRESS)/drug-induced hypersensitivity syndrome (DIHS), or Stevens–Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN). Current pharmacogenomic studies have made important strides in the prevention of some drug hypersensitivity through the identification of relevant genetic variants, particularly for genes encoding drug-metabolizing enzymes and human leukocyte antigens (HLAs). The associations identified by these studies are usually drug, phenotype, and ethnic specific. The drug presentation models that explain how small drug antigens might interact with HLA and T cell receptor (TCR) molecules in drug hypersensitivity include the hapten theory, the p-i concept, the altered peptide repertoire model, and the altered TCR repertoire model. The broad spectrum of clinical manifestations of drug hypersensitivity involving different drugs, as well as the various pathomechanisms involved, makes the diagnosis and management of it more challenging. This review highlights recent advances in our understanding of the predisposing factors, immune mechanisms, pathogenesis, diagnostic tools, and therapeutic approaches for drug hypersensitivity.

The Epidemiology of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis in China

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are life-threatening disease. However, there are only few epidemiologic studies of SJS/TEN from China. To analyze the clinical characteristics, causality, and outcome of treatment for SJS/TEN in China, we reviewed case reports of patients with SJS/TEN from the China National Knowledge Infrastructure (CNKI) and Wanfang database from 2006 to 2016 and patients with SJS/TEN who were admitted to the First Affiliated Hospital of Fujian Medical University during the same period. There were 166 patients enrolled, including 70 SJS, 2 SJS/TEN overlap, and 94 TEN. The most common offending drugs were antibiotics (29.5%) and anticonvulsants (24.1%). Carbamazepine, allopurinol, and penicillins were the most common single offending drugs (17.5%, 9.6%, and 7.2%). Chinese patent medicines accounted for 5.4%. There were 76 (45.8%) patients receiving systemic steroid and intravenous immunoglobulin (IVIG) in combination therapy, especially for TEN (80.3%), and others were treated with systemic steroids alone. Mortality rate of combination treatment comparing with steroid alone in TEN patients had no statistical significance. In conclusion, carbamazepine and allopurinol were the leading causative drugs for SJS/TEN in China. Combination of IVIG and steroids is a common treatment for TEN, but its efficacy in improving mortality needs further investigation.

Biomarkers of adverse drug reactions

Adverse drug reactions can be caused by a wide range of therapeutics. Adverse drug reactions affect many bodily organ systems and vary widely in severity. Milder adverse drug reactions often resolve quickly following withdrawal of the casual drug or sometimes after dose reduction. Some adverse drug reactions are severe and lead to significant organ/tissue injury which can be fatal. Adverse drug reactions also represent a financial burden to both healthcare providers and the pharmaceutical industry. Thus, a number of stakeholders would benefit from development of new, robust biomarkers for the prediction, diagnosis, and prognostication of adverse drug reactions. There has been significant recent progress in identifying predictive genomic biomarkers with the potential to be used in clinical settings to reduce the burden of adverse drug reactions. These have included biomarkers that can be used to alter drug dose (for example, Thiopurine methyltransferase (TPMT) and azathioprine dose) and drug choice. The latter have in particular included human leukocyte antigen (HLA) biomarkers which identify susceptibility to immune-mediated injuries to major organs such as skin, liver, and bone marrow from a variety of drugs. This review covers both the current state of the art with regard to genomic adverse drug reaction biomarkers. We also review circulating biomarkers that have the potential to be used for both diagnosis and prognosis, and have the added advantage of providing mechanistic information. In the future, we will not be relying on single biomarkers (genomic/non-genomic), but on multiple biomarker panels, integrated through the application of different omics technologies, which will provide information on predisposition, early diagnosis, prognosis, and mechanisms. Impact statement • Genetic and circulating biomarkers present significant opportunities to personalize patient therapy to minimize the risk of adverse drug reactions. ADRs are a significant heath issue and represent a significant burden to patients, healthcare providers, and the pharmaceutical industry. • This review details the current state of the art in biomarkers of ADRs (both genetic and circulating). There is still significant variability in patient response which cannot be explained by current knowledge of genetic risk factors for ADRs; however, we discussed how specific advances in genomics have the potential to yield better and more predictive models. • Many current clinically utilized circulating biomarkers of tissue injury are valid biomarkers for a number of ADRs. However, they often give little insight into the specific cell or tissue subtype which may be affected. Emerging circulating biomarkers with potential to provide greater information on the etiology/pathophysiology of ADRs are described.

SJS/TEN 2017: Building Multidisciplinary Networks to Drive Science and Translation

Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) is a life-threatening, immunologically mediated, and usually drug-induced disease with a high burden to individuals, their families, and society with an annual incidence of 1 to 5 per 1,000,000. To effect significant reduction in short- and long-term morbidity and mortality, and advance clinical care and research, coordination of multiple medical, surgical, behavioral, and basic scientific disciplines is required. On March 2, 2017, an investigator-driven meeting was held immediately before the American Academy of Dermatology Annual meeting for the central purpose of assembling, for the first time in the United States, clinicians and scientists from multiple disciplines involved in SJS/TEN clinical care and basic science research. As a product of this meeting, this article summarizes the current state of knowledge and expert opinion related to SJS/TEN covering a broad spectrum of topics including epidemiology and pharmacogenomic networks; clinical management and complications; special populations such as pediatrics, the elderly, and pregnant women; regulatory issues and the electronic health record; new agents that cause SJS/TEN; pharmacogenomics and immunopathogenesis; and the patient perspective. Goals include the maintenance of a durable and productive multidisciplinary network that will significantly further scientific progress and translation into prevention, early diagnosis, and management of SJS/TEN.

[What's new in dermatological research?]

This manuscript provides a selection of dermatological research manuscripts published from September 2016 to August 2017. It is not an exhaustive review but rather a selection of manuscripts susceptible to modify the dermatological practice or affording new pathophysiologic mechanisms and new therapeutic approaches. The following areas of interest are concerned: recognition of dermatological images by artificial intelligence, new concepts in atopic dermatitis, wound repair and hair growth cycle. New data concerning melanomagenesis, epidermolysis bullosa simplex and drug eruption are also highlighted.

Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: Associations, Outcomes, and Pathobiology-Thirty Years of Progress but Still Much to Be Done

Although rare, Stevens-Johnson syndrome and toxic epidermal necrolysis remain among the most devastating of acute conditions involving the skin. In the past 30 years, tremendous progress has been made in understanding the causes and pathobiology of this often life-threatening condition. Su et al demonstrate associations between IL 15 serum levels and the outcome of patients with Stevens-Johnson syndrome and toxic epidermal necrolysis. Their findings provide ideas for further investigations that may help us better understand the role of cytokines in this T-cell mediate disease and provides clues to possible new therapies.

Methotrexate-induced epidermal necrosis: A case series of 24 patients

BACKGROUND

Methotrexate-induced epidermal necrosis (MEN) is a rare but life-threatening cutaneous reaction that mimics Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN).

OBJECTIVES

To investigate the clinicopathology, risk factors, and prognostic factors of MEN.

METHODS

We enrolled 24 patients with MEN and 150 controls and analyzed the demographics, pathology, and plasma concentrations of methotrexate (MTX).

RESULTS

Patients with MEN showed extensive skin necrosis (mean, 33.2% total body surface area) but no target lesions. The histopathology displayed keratinocyte dystrophy. Early signs of MEN included painful skin erosions, oral ulcers, and leukopenia/thrombocytopenia. Although 79.2% patients received leucovorin treatment, there was 16.7% mortality. Risk factors for MEN included older age (>60 years), chronic kidney disease, and high initial dosage of MTX without folic acid supplementation. Renal insufficiency delayed MTX clearance. Severe renal disease and leukopenia predicted poor prognosis in MEN, but none of the SCORe of Toxic Epidermal Necrosis criteria were associated with mortality of MEN.

LIMITATIONS

The study was limited by the small sample size.

CONCLUSION

MEN exhibited distinct clinicopathologic features from SJS/TEN. Recognition of the early signs and prognostic factors is important, because the rapid institution of leucovorin may be helpful. To reduce the risk of MEN, physicians should avoid prescribing MTX to high-risk patients and titrate the dosage slowly upward with folic acid supplementation.