T-cell receptor diversity and allergen sensitivity in childhood asthma and atopic dermatitis.

BACKGROUND: Childhood allergies of asthma and atopic dermatitis (AD) involve an overactive T-cell immune response triggered by allergens. However, the impact of T-cell receptor (TCR) repertoires on allergen sensitization and their role in mediating different phenotypes of asthma and AD in early childhood remains unclear. METHODS: A total of 78 children, comprising 26 with asthma alone, 26 with AD alone, and 26 healthy controls (HC), were enrolled. TCR repertoire profiles were determined using a unique molecular identifier system for next-generation sequencing. Integrative analyses of their associations with allergen-specific IgE levels and allergies were performed. RESULTS: The diversity in TCR alpha variable region (TRAV) genes of TCR repertoires and complementarity determining region 3 (CDR3) clonality in TRAV/TRBV (beta) genes were significantly higher in children with AD compared with those with asthma and HC (p < .05). Compared with HC, the expression of TRAV13-1 and TRAV4 genes was significantly higher in both asthma and AD (p < .05), with a significant positive correlation with mite-specific IgE levels (p < .01). In contrast, TRBV7-9 gene expression was significantly lower in both asthma and AD (p < .01), with this gene showing a significant negative correlation with mite-specific IgE levels (p < .01). Furthermore, significantly higher TRAV8-3 gene expression, positively correlated with food-specific IgE levels, was found in children with AD compared with those with asthma (p < .05). CONCLUSION: Integrated TCR repertoires analysis provides clinical insights into the diverse TCR genes linked to antigen specificity, offering potential for precision immunotherapy in childhood allergies.

Clinical characteristics and genetic HLA marker for patients with oxaliplatin-induced adverse drug reactions.

BACKGROUND: Oxaliplatin is commonly used to treat gastrointestinal malignancies. However, its applications are limited due to potential adverse drug reactions (ADRs), particularly severe anaphylactic shock. There is no method to predict or prevent ADRs caused by oxaliplatin. Therefore, we aimed to investigate the genetic HLA predisposition and immune mechanism of oxaliplatin-induced ADRs. METHODS: A retrospective review was performed for 154 patients with ADRs induced by oxaliplatin during 2016-2021 recorded in our ADR notification system. HLA genotyping was conducted for 47 patients with oxaliplatin-induced ADRs, 1100 general population controls, and 34 oxaliplatin-tolerant controls in 2019-2023. The in vitro basophil activation test (BAT) was performed and oxaliplatin-specific IgE levels were determined. RESULTS: The incidence of oxaliplatin-induced ADRs and anaphylactic shock in our cohort was 7.1% and 0.15%, respectively. Of the 154 patients, 67.5% suffered rash/eruption; 26.0% of the patients who could not undergo oxaliplatin rechallenge were considered to show oxaliplatin-induced immune-mediated hypersensitivity reactions (HRs). The genetic study found that the HLA-DRB∗12:01 allele was associated with oxaliplatin-induced HRs compared to the general population controls (sensitivity = 42.9%; odds ratio [OR] = 3.4; 95% CI = 1.4-8.2; P = 0.008) and tolerant controls (OR = 12; 95% CI = 2.3-63.7; P = 0.001). The in vitro BAT showed higher activation of CD63+ basophils in patients with oxaliplatin-induced HRs compared to the tolerant controls (P < 0.05). Only four patients (8.5%) with oxaliplatin-induced ADRs were positive for oxaliplatin-specific IgE. CONCLUSIONS: This study found that 26.0% of patients with oxaliplatin-induced ADRs could not undergo oxaliplatin rechallenge. HLA-DRB∗12:01 is regarded as a genetic marker for oxaliplatin-induced hypersensitivity.

Clinical characteristics and immune profiles of patients with immune-mediated alopecia associated with COVID-19 vaccinations.

BACKGROUND: The clinical characteristics and pathomechanism for immune-mediated alopecia following COVID-19 vaccinations are not clearly characterized. OBJECTIVE: We investigated the causality and immune mechanism of COVID-19 vaccines-related alopecia areata (AA). STUDY DESIGN: 27 new-onset of AA patients after COVID-19 vaccinations and 106 vaccines-tolerant individuals were enrolled from multiple medical centers for analysis. RESULTS: The antinuclear antibody, total IgE, granulysin, and PARC/CCL18 as well as peripheral eosinophil count were significantly elevated in the patients with COVID-19 vaccines-related AA compared with those in the tolerant individuals (P = 2.03 × 10-5-0.039). In vitro lymphocyte activation test revealed that granulysin, granzyme B, and IFN-γ released from the T cells of COVID-19 vaccines-related AA patients could be significantly increased by COVID-19 vaccine excipients (polyethylene glycol 2000 and polysorbate 80) or spike protein (P = 0.002-0.04). CONCLUSIONS: Spike protein and excipients of COVID-19 vaccines could trigger T cell-mediated cytotoxicity, which contributes to the pathogenesis of immune-mediated alopecia associated with COVID-19 vaccines.

Zinc deficiency associated with cutaneous toxicities induced by epidermal growth factor receptor tyrosine kinase inhibitor therapy in patients with lung adenocarcinoma.

PURPOSE: Cutaneous toxicities are common adverse effects following epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) therapy. Zinc deficiency causes diverse diseases, including skin toxicities. Therefore, this study aimed to investigate the role of zinc deficiency in patients with EGFR-TKI-induced skin toxicities. EXPERIMENTAL DESIGN: This retrospective study enrolled 269 patients with diverse skin disorders who visited our hospital between January 2016 and December 2017. The skin toxicity severities and plasma zinc levels of 101 EGFR-TKI-treated cancer patients were analysed and compared with those of 43 non-EGFR-TKI-treated cancer patients and 125 patients without cancer but presenting cutaneous manifestations. Additionally, the role of zinc in erlotinib-induced skin eruptions was established in a 14-day-murine model. Clinical features were further evaluated following systemic zinc supplementation in EGFR-TKI-treated cancer patients. RESULTS: EGFR-TKI-treated patients demonstrated severe cutaneous manifestations and a significant decrease in plasma zinc levels than those of the control groups. The serum zinc level and Common Terminology Criteria for Adverse Events (CTCAE) 5.0 grading of EGFR-TKI-induced skin toxicities showed a significant negative correlation (r = -0.29; p < 0.0001). Moreover, erlotinib treatment decreased the plasma zinc levels and induced periorificial dermatitis in rats confirming zinc deficiency following EGFR-TKI treatment. Zinc supplementation to the EGFR-TKI-treated cancer patients showed a significant decrease in the CTCEA grading (p < 0.0005 for mucositis and p < 0.0.0001 for all other cases) after 8 weeks. CONCLUSIONS: Skin impairment following EGFR-TKI therapy could be ameliorated through zinc supplementation. Thus, zinc supplementation should be considered for cancer patients undergoing EGFR-TKI therapy.

Whole genome sequencing identifies genetic variants associated with co-trimoxazole hypersensitivity in Asians.

BACKGROUND: Co-trimoxazole, a sulfonamide antibiotic, is used to treat a variety of infections worldwide, and it remains a common first-line medicine for prophylaxis against Pneumocystis jiroveci pneumonia. However, it can cause severe cutaneous adverse reaction (SCAR), including Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms. The pathomechanism of co-trimoxazole-induced SCAR remains unclear. OBJECTIVE: We aimed to investigate the genetic predisposition of co-trimoxazole-induced SCAR. METHODS: We conducted a multicountry case-control association study that included 151 patients with of co-trimoxazole-induced SCAR and 4631 population controls from Taiwan, Thailand, and Malaysia, as well as 138 tolerant controls from Taiwan. Whole-genome sequencing was performed for the patients and population controls from Taiwan; it further validated the results from Thailand and Malaysia. RESULTS: The whole-genome sequencing study (43 case patients vs 507 controls) discovered that the single-nucleotide polymorphism rs41554616, which is located between the HLA-B and MICA loci, had the strongest association with co-trimoxazole-induced SCAR (P = 8.2 × 10-9; odds ratio [OR] = 7.7). There were weak associations of variants in co-trimoxazole-related metabolizing enzymes (CYP2D6, GSTP1, GCLC, N-acetyltransferase [NAT2], and CYP2C8). A replication study using HLA genotyping revealed that HLA-B∗13:01 was strongly associated with co-trimoxazole-induced SCAR (the combined sample comprised 91 case patients vs 2545 controls [P = 7.2 × 10-21; OR = 8.7]). A strong HLA association was also observed in the case patients from Thailand (P = 3.2 × 10-5; OR = 3.6) and Malaysia (P = .002; OR = 12.8), respectively. A meta-analysis and phenotype stratification study further indicated a strong association between HLA-B∗13:01 and co-trimoxazole-induced drug reaction with eosinophilia and systemic symptoms (P = 4.2 × 10-23; OR = 40.1). CONCLUSION: This study identified HLA-B∗13:01 as an important genetic factor associated with co-trimoxazole-induced SCAR in Asians.

Metabolomics reveals microbial-derived metabolites associated with immunoglobulin E responses in filaggrin-related atopic dermatitis.

BACKGROUND: Filaggrin (FLG) gene mutation and immunoglobulin E (IgE)-mediated sensitization are the most important predictors of atopic dermatitis (AD). However, a metabolomics-based approach to address the metabolic impact of FLG mutations on allergic IgE responses for AD is still lacking. We, though, determine the relationships of metabolic profiles in AD with FLG mutations and allergic responses. METHODS: Eighty-one children with adolescent AD (n = 58) and healthy controls (n = 23) were prospectively enrolled. Mutations in the filaggrin gene were identified using whole-exome sequencing, and plasma metabolic profiles were determined using 1 H-nuclear magnetic resonance (NMR) spectroscopy. Integrative analyses of their associations related to total serum IgE levels were performed, and further metabolic functional pathways for AD were also assessed. RESULTS: Metabolites contributed to the separation between AD and controls were identified using the supervised partial least squares discriminant analysis (Q2 /R2  = 0.90, Ppermutation <0.001). Nitrogen and amino acid metabolisms for energy production, and microbe-related methane and propanoate metabolisms were significantly associated with AD compared with healthy controls (FDR-adjusted p < .05). Five of fifteen metabolites related to FLG mutations were positively correlated with total serum IgE levels. Among them, dimethylamine and isopropanol were strongly associated with methane metabolism and propanoate metabolism, respectively, in AD with FLG mutations (FDR-adjusted p < .01). CONCLUSION: A strong correlation of microbial-derived metabolites, dimethylamine and isopropanol, with FLG mutations and IgE allergic reactions provides the influence of host genetics on the microbiome to regulate susceptibility to allergic responses in the pathogenesis of AD.

Disseminated intravascular coagulation in Stevens-Johnson syndrome and toxic epidermal necrolysis.

BACKGROUND: Patients with Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) have high mortality rates. Disseminated intravascular coagulation has been reported in SJS/TEN patients. The influence of this lethal complication in patients with SJS/TEN is not well known. OBJECTIVE: This study aimed to investigate the risk and outcomes of disseminated intravascular coagulation in patients with SJS/TEN. METHODS: We analyzed the disseminated intravascular coagulation profiles of patients receiving a diagnosis of SJS/TEN between 2010 and 2019. RESULTS: We analyzed 150 patients with SJS/TEN (75 with SJS, 22 with overlapping SJS/TEN, and 53 with TEN) and their complete disseminated intravascular coagulation profiles. Disseminated intravascular coagulation was diagnosed in 32 patients (21.3%), primarily those with TEN. It was significantly associated with systemic complications, including gastrointestinal bleeding, respiratory failure, renal failure, liver failure, infection, and bacteremia. Additionally, SJS/TEN patients with disseminated intravascular coagulation had elevated procalcitonin levels. Among patients with SJS/TEN, disseminated intravascular coagulation was associated with a greater than 10-fold increase in mortality (78.1% vs 7%). LIMITATIONS: The study limitations include small sample size and a single hospital system. CONCLUSION: Disseminated intravascular coagulation is a potential complication of SJS/TEN and associated with higher mortality. Early recognition and appropriate management of this critical complication are important for patients with SJS/TEN.

Genetic variants of PPAR-gamma coactivator 1B augment NLRP3-mediated inflammation in gouty arthritis.

Objective: Gout is characterized by recurrent attacks of arthritis with hyperuricaemia and urate crystal-induced inflammation. Although urate transporters are known as risk factors, the immunogenetics of gouty inflammation remains unclear. This study aimed to investigate the genetic association between immune/metabolism regulators and gout. Methods: We enrolled 448 gout patients and 943 population controls from Taiwan; all were Han Chinese. We screened association between gout and 22 variants of candidate genes, including NLRP3 , caspase 1, peroxisome proliferator-activated receptor-γ, proliferator-activated receptor-γ coactivator 1α ( PPARGC1A ) and 1ß ( PPARGC1B ). The association was validated by replication and combined-sample analyses. Functional assays were performed by quantitative PCR, ELISA, siRNA knockdown and transfection using THP-1 cells, peripheral blood mononuclear cells and synovial cells from patients. Results: Gouty arthritis exhibited significant association with variants of peroxisome PPARGC1B , which included a missense single nucleotide polymorphism, rs45520937 [P = 6.66 × 10 -9 ; odds ratio (95% CI): 1.85 (1.51, 2.28)]. Expression of PPARGC1B and NLRP3 was induced in urate crystal-activated THP-1, peripheral blood mononuclear cells and synovial cells from gout patients in acute stage. siRNA knockdown of PPARGC1B upregulated NLRP3 in urate crystal-activated macrophages. Compared with the wild-type carriers, patients with the risk A allele of rs45520937 showed statistically increased NLRP3 (P = 0.044) and plasma IL-1ß (P = 0.006). Transfection of PPARGC1B cDNA with rs45520937 A allele to macrophages significantly augmented the expression of NLRP3 and IL-1ß. Conclusion: Genetic variants of PPARGC1B are significantly associated with gout, and a missense single nucleotide polymorphism, rs45520937, augments NLRP3 and IL-1ß expression. These data suggest that variants of PPARGC1B , a regulator of metabolism and inflammation, contribute to the pathogenesis of gouty arthritis.

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.

Evolving models of the immunopathogenesis of T cell-mediated drug allergy: The role of host, pathogens, and drug response.

Immune-mediated (IM) adverse drug reactions (ADRs) are an underrecognized source of preventable morbidity, mortality, and cost. Increasingly, genetic variation in the HLA loci is associated with risk of severe reactions, highlighting the importance of T-cell immune responses in the mechanisms of both B cell-mediated and primary T cell-mediated IM-ADRs. In this review we summarize the role of host genetics, microbes, and drugs in IM-ADR development; expand on the existing models of IM-ADR pathogenesis to address multiple unexplained observations; discuss the implications of this work in clinical practice today; and describe future applications for preclinical drug toxicity screening, drug design, and development.

Severe Cutaneous Adverse Reactions: The Pharmacogenomics from Research to Clinical Implementation.

Severe cutaneous adverse reactions (SCARs), previously thought to be idiosyncratic or unpredictable, are a deadly form of adverse drug reactions with skin manifestations. Current pharmacogenomic studies of SCARs have made important strides, as the prevention of SCARs, to some extent, appears attainable with the identification of genetic variants for genes encoding drug-metabolizing enzymes and human leukocyte antigens (HLAs). Despite the improvement of incidence, a treatment guideline for this devastating condition is still unavailable, highlighting the inadequacy of contemporary accepted therapeutic interventions. As such, prompt withdrawal of causative drugs is believed to be a priority of patient management. In this review, we discuss recent cutting-edge findings concerning the discovery of biomarkers for SCARs and their clinical utilities in the better prediction and early diagnosis of this disease. The knowledge compiled herein provides clues for future investigations on deciphering additional genetic markers for SCARs and the design of clinical trials for the prospective identification of subjects at genetic risk for this condition, ultimately personalizing the medicine.

Insights into the poor prognosis of allopurinol-induced severe cutaneous adverse reactions: the impact of renal insufficiency, high plasma levels of oxypurinol and granulysin.

OBJECTIVE: Allopurinol, an antihyperuricaemic agent, is one of the common causes of life-threatening severe cutaneous adverse reactions (SCAR), including drug rash with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS) and toxic epidermal necrosis (TEN). The prognostic factors for allopurinol-related SCAR remain unclear. This study aimed to investigate the relationship of dosing, renal function, plasma levels of oxypurinol and granulysin (a cytotoxic protein of SJS/TEN), the disease severity and mortality in allopurinol-SCAR. METHODS: We prospectively enrolled 48 patients with allopurinol-SCAR (26 SJS/TEN and 22 DRESS) and 138 allopurinol-tolerant controls from 2007 to 2012. The human leucocyte antigen (HLA)-B*58:01 status, plasma concentrations of oxypurinol and granulysin were determined. RESULTS: In this cohort, HLA-B*58:01 was strongly associated with allopurinol-SCAR (p<0.001, OR (95% CI) 109 (25 to 481)); however, the initial/maintenance dosages showed no relationship with the disease. Poor renal function was significantly associated with the delayed clearance of plasma oxypurinol, and increased the risk of allopurinol-SCAR (p<0.001, OR (95% CI) 8.0 (3.9 to 17)). Sustained high levels of oxypurinol after allopurinol withdrawal correlated with the poor prognosis of allopurinol-SCAR. In particular, the increased plasma levels of oxypurinol and granulysin linked to the high mortality of allopurinol-SJS/TEN (p<0.01), and strongly associated with prolonged cutaneous reactions in allopurinol-DRESS (p<0.05). CONCLUSIONS: Impaired renal function and increased plasma levels of oxypurinol and granulysin correlated with the poor prognosis of allopurinol-SCAR. Allopurinol prescription is suggested to be avoided in subjects with renal insufficiency and HLA-B*58:01 carriers. An early intervention to increase the clearance of plasma oxypurinol may improve the prognosis of allopurinol-SCAR.

Severe cutaneous adverse reactions related to systemic antibiotics.

BACKGROUND: Systemic antibiotics are a major cause of severe cutaneous adverse reactions (SCARs). The selection of alternative antibiotics and management for SCARs patients with underlying infections can be challenging. METHODS: We retrospectively analyzed 74 cases of SCARs, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug rash with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP), related to use of systemic antibiotics in Taiwan from January 2006 to January 2012. We analyzed the causative antibiotics, clinical features, organ involvements, and mortality. We also assessed patient tolerability to alternative antibiotics after the development of antibiotic-related SCARs. RESULTS: The most common causes of SCARs were penicillins and cephalosporins for SJS/TEN and AGEP; glycopeptides for DRESS. Fatality was more frequent in the SJS/TEN group. In patients with SJS/TEN, higher mortality was associated with old age and underlying sepsis before the development of SCARs. The majority of patients with penicillin- or cephalosporin-related SCARs were able to tolerate quinolones, glycopeptides, and carbapenems. CONCLUSIONS: Complicated underlying conditions and infections may increase mortality in patients with antibiotic-related SCARs. The selection of structurally different alternative drugs is important to avoid recurrence.

Carbamazepine-induced toxic effects and HLA-B*1502 screening in Taiwan.

BACKGROUND: Carbamazepine, an anticonvulsant and a mood-stabilizing drug, is the main cause of the Stevens-Johnson syndrome (SJS) and its related disease, toxic epidermal necrolysis (TEN), in Southeast Asian countries. Carbamazepine-induced SJS-TEN is strongly associated with the HLA-B*1502 allele. We sought to prevent carbamazepine-induced SJS-TEN by using HLA-B*1502 screening to prospectively identify subjects at genetic risk for the condition. METHODS: From 23 hospitals in Taiwan, we recruited 4877 candidate subjects who had not taken carbamazepine. We genotyped DNA purified from the subjects' peripheral blood to determine whether they carried the HLA-B*1502 allele. Those testing positive for HLA-B*1502 (7.7% of the total) were advised not to take carbamazepine and were given an alternative medication or advised to continue taking their prestudy medication; those testing negative (92.3%) were advised to take carbamazepine. We interviewed the subjects by telephone once a week for 2 months to monitor them for symptoms. We used the estimated historical incidence of SJS-TEN as a control. RESULTS: Mild, transient rash developed in 4.3% of subjects; more widespread rash developed in 0.1% of subjects, who were hospitalized. SJS-TEN did not develop in any of the HLA-B*1502-negative subjects receiving carbamazepine. In contrast, the estimated historical incidence of carbamazepine-induced SJS-TEN (0.23%) would translate into approximately 10 cases among study subjects (P<0.001). CONCLUSIONS: The identification of subjects carrying the HLA-B*1502 allele and the avoidance of carbamazepine therapy in these subjects was strongly associated with a decrease in the incidence of carbamazepine-induced SJS-TEN. (Funded by the National Science Council of Taiwan and the Taiwan Drug Relief Foundation.).

A new nucleic acid-based agent inhibits cytotoxic T lymphocyte-mediated immune disorders.

BACKGROUND: Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and graft-versus-host disease (GVHD) are distinct immune reactions elicited by drugs or allogeneic antigens; however, they share a pathomechanism with the activation of cytotoxic T lymphocytes (CTLs). CTLs produce cytotoxic proteins, cytokines, chemokines, or immune alarmins, such as granulysin (GNLY), leading to the extensive tissue damage and systemic inflammation seen in patients with SJS/TEN or GVHD. Currently, there is no effective therapeutic agent specific for CTL-mediated immune disorders. OBJECTIVES: By targeting GNLY(+) CTLs, we aimed to develop a nucleic acid-based agent consisting of an anti-CD8 aptamer with GNLY small interfering RNA (siRNA). METHODS: We performed systematic evolution of ligands using exponential enrichment to select and identify effective anti-CD8 aptamers. We developed an aptamer-siRNA chimera using a "sticky bridge" method by conjugating the aptamer with siRNA. We analyzed the inhibitory effects of the aptamer-siRNA chimera on CTL responses in patients with SJS/TEN or GVHD. RESULTS: We identified a novel DNA aptamer (CD8AP17s) targeting CTLs. This aptamer could be specifically internalized into human CTLs. We generated the CD8AP17s aptamer-GNLY siRNA chimera, which showed a greater than 79% inhibitory effect on the production of GNLY by drug/alloantigen-activated T cells. The CD8AP17s aptamer-GNLY siRNA chimera decreased cytotoxicity in in vitro models of both SJS/TEN (elicited by drug-specific antigen) and GVHD (elicited by allogeneic antigens). CONCLUSIONS: Our results identified a new nucleic acid-based agent (CD8 aptamer-GNLY siRNA chimera) that can significantly inhibit CTL-mediated drug hypersensitivity, such as that seen in patients with SJS/TEN, as well as the alloreactivity seen in patients with GVHD. This study provides a novel therapeutic strategy for CTL-mediated immune disorders.

Genetic variants associated with phenytoin-related severe cutaneous adverse reactions.

IMPORTANCE: The antiepileptic drug phenytoin can cause cutaneous adverse reactions, ranging from maculopapular exanthema to severe cutaneous adverse reactions, which include drug reactions with eosinophilia and systemic symptoms, Stevens-Johnson syndrome, and toxic epidermal necrolysis. The pharmacogenomic basis of phenytoin-related severe cutaneous adverse reactions remains unknown. OBJECTIVE: To investigate the genetic factors associated with phenytoin-related severe cutaneous adverse reactions. DESIGN, SETTING, AND PARTICIPANTS: Case-control study conducted in 2002-2014 among 105 cases with phenytoin-related severe cutaneous adverse reactions (n=61 Stevens-Johnson syndrome/toxic epidermal necrolysis and n=44 drug reactions with eosinophilia and systemic symptoms), 78 cases with maculopapular exanthema, 130 phenytoin-tolerant control participants, and 3655 population controls from Taiwan, Japan, and Malaysia. A genome-wide association study (GWAS), direct sequencing of the associated loci, and replication analysis were conducted using the samples from Taiwan. The initial GWAS included samples of 60 cases with phenytoin-related severe cutaneous adverse reactions and 412 population controls from Taiwan. The results were validated in (1) 30 cases with severe cutaneous adverse reactions and 130 phenytoin-tolerant controls from Taiwan, (2) 9 patients with Stevens-Johnson syndrome/toxic epidermal necrolysis and 2869 population controls from Japan, and (3) 6 cases and 374 population controls from Malaysia. MAIN OUTCOMES AND MEASURES: Specific genetic factors associated with phenytoin-related severe cutaneous adverse reactions. RESULTS: The GWAS discovered a cluster of 16 single-nucleotide polymorphisms in CYP2C genes at 10q23.33 that reached genome-wide significance. Direct sequencing of CYP2C identified missense variant rs1057910 (CYP2C9*3) that showed significant association with phenytoin-related severe cutaneous adverse reactions (odds ratio, 12; 95% CI, 6.6-20; P=1.1 × 10(-17)). The statistically significant association between CYP2C9*3 and phenytoin-related severe cutaneous adverse reactions was observed in additional samples from Taiwan, Japan, and Malaysia. A meta-analysis using the data from the 3 populations showed an overall odds ratio of 11 (95% CI, 6.2-18; z=8.58; P < .00001) for CYP2C9*3 association with phenytoin-related severe cutaneous adverse reactions. Delayed clearance of plasma phenytoin was detected in patients with severe cutaneous adverse reactions, especially CYP2C9*3 carriers, providing a functional link of the associated variants to the disease. CONCLUSIONS AND RELEVANCE: This study identified CYP2C variants, including CYP2C9*3, known to reduce drug clearance, as important genetic factors associated with phenytoin-related severe cutaneous adverse reactions.

Clinicopathologic analysis of coxsackievirus a6 new variant induced widespread mucocutaneous bullous reactions mimicking severe cutaneous adverse reactions.

BACKGROUND: The cutaneous manifestations of human enterovirus (HEV) infection are usually limited, such as hand-foot-mouth disease. By comparison, Stevens-Johnson syndrome (SJS) is a life-threatening severe cutaneous adverse reaction (SCAR), mainly caused by drugs. During the HEV outbreaks in 2010-2012 in Taiwan, we identified 21 patients who developed widespread blistering mucocutaneous reactions without any suspected drug causality. METHODS: We screened possible pathogen(s) for detecting human herpes virus (HHV1-HHV7), HEV, or Mycoplasma pneumoniae infections using throat swab virus cultures, real-time PCR, DNA sequencing, immunochemistry and electron microscopy analyses. RESULTS: Coxsackievirus A6 (CVA6) DNA was identified in the blistering skin lesions in 6 of 21 patients. Cytotoxic T lymphocytes and natural killer cells expressing granulysin predominantly infiltrated into the skin lesions, sharing the histopathological features with SJS. Intact CVA6 viral particles were identified in the blister fluids and skin lesions by electron microscopy. The phylogenetic analysis of the viral genome showed the CVA6 DNA sequence sharing higher similarity (97.6%-98.1%) to CVA6 strains reported from Finland at 2008. CONCLUSIONS: This study identifies a new variant of CVA6 as the causative agent for severe mucocutaneous blistering reactions mimicking SCAR. An awareness of this unusual presentation of HEV infection is needed in the epidemic area.