Stevens-Johnson syndrome secondary to massive inflammatory hyperplasia of bilateral lingual margins: a case report and literature review.

Stevens-Johnson syndrome (SJS), also known as the multifactorial erythematous drug eruption, is a class of adverse reactions of the skin and mucous membranes primarily caused by drug allergy often involving the oral cavity, eyes, and external genital mucosa, generally accompanied by fever, and can be life-threatening in severe cases. In February 2022, the Department of Stomatology, the First Affiliated Hospital of Zhengzhou University admitted a patient with huge inflammatory hyperplasia of bilateral lingual margins secondary to SJS. Upon admission, no other obvious symptoms were observed except for tongue hyperplasia. The patient suffered from a severe adverse drug reaction caused by acetaminophen 2 months ago and was complicated by liver dysfunction and pulmonary infection. After 1 month of treatment and rehabilitation, he developed a secondary tongue mass and was subsequently admitted to Dept. of Oral and Maxillofacial Surgery Ward 2, the First Affiliated Hospital of Zhengzhou University. After completing the examination, the tongue mass was surgically removed. After a follow-up of 11 months, the patient's condition was satisfactory and no temporary discomfort was observed. The case of tongue mass secondary to SJS is extremely rare. If a stomatologist encounters a similar case, we should carefully inquire about the drug allergy history and recent medication history, and be alert to whether or not they had adverse drug reactions recently.

Delayed localized hypersensitivity reactions to COVID-19 mRNA vaccines: a 6-month retrospective study.

Several individuals have developed delayed localized cutaneous vaccine reactions to the two novel mRNA Covid-19 vaccines. Clinical and histopathologic results of this case series study confirm that the localized injection-site reactions to the mRNA COVID-19 vaccines are delayed hypersensitivity reactions that, unlike immediate hypersensitivity reactions, are not a contraindication to vaccination.

The Multifaceted Mas-Related G Protein-Coupled Receptor Member X2 in Allergic Diseases and Beyond.

Recent research on mast cell biology has turned its focus on MRGPRX2, a new member of the Mas-related G protein-coupled subfamily of receptors (Mrgprs), originally described in nociceptive neurons of the dorsal root ganglia. MRGPRX2, a member of this group, is present not only in neurons but also in mast cells (MCs), specifically, and potentially in other cells of the immune system, such as basophils and eosinophils. As emerging new functions for this receptor are studied, a variety of both natural and pharmacologic ligands are being uncovered, linked to the ability to induce receptor-mediated MC activation and degranulation. The diversity of these ligands, characterized in their human, mice, or rat homologues, seems to match that of the receptor's interactions. Natural ligands include host defense peptides, basic molecules, and key neuropeptides such as substance P and vasointestinal peptide (known for their role in the transmission of pain and itch) as well as eosinophil granule-derived proteins. Exogenous ligands include MC secretagogues such as compound 48/80 and mastoparan, a component of bee wasp venom, and several peptidergic drugs, among which are members of the quinolone family, neuromuscular blocking agents, morphine, and vancomycin. These discoveries shed light on its capacity as a multifaceted participant in naturally occurring responses within immunity and neural stimulus perception, as in responses at the center of immune pathology. In host defense, the mice Mrgprb2 has been proven to aid mast cells in the detection of peptidic molecules from bacteria and in the release of peptides with antimicrobial activities and other immune mediators. There are several potential actions described for it in tissue homeostasis and repair. In the realm of pathologic response, there is evidence to suggest that this receptor is also involved in chronic inflammation. Furthermore, MRGPRX2 has been linked to the pathophysiology of non-IgE-mediated immediate hypersensitivity drug reactions. Different studies have shown its possible role in other allergic diseases as well, such as asthma, atopic dermatitis, contact dermatitis, and chronic spontaneous urticaria. In this review, we sought to cover its function in physiologic processes and responses, as well as in allergic and nonallergic immune disease.

Potential mechanisms of anaphylaxis to COVID-19 mRNA vaccines.

Anaphylaxis to vaccines is historically a rare event. The coronavirus disease 2019 pandemic drove the need for rapid vaccine production applying a novel antigen delivery system: messenger RNA vaccines packaged in lipid nanoparticles. Unexpectedly, public vaccine administration led to a small number of severe allergic reactions, with resultant substantial public concern, especially within atopic individuals. We reviewed the constituents of the messenger RNA lipid nanoparticle vaccine and considered several contributors to these reactions: (1) contact system activation by nucleic acid, (2) complement recognition of the vaccine-activating allergic effector cells, (3) preexisting antibody recognition of polyethylene glycol, a lipid nanoparticle surface hydrophilic polymer, and (4) direct mast cell activation, coupled with potential genetic or environmental predispositions to hypersensitivity. Unfortunately, measurement of anti-polyethylene glycol antibodies in vitro is not clinically available, and the predictive value of skin testing to polyethylene glycol components as a coronavirus disease 2019 messenger RNA vaccine-specific anaphylaxis marker is unknown. Even less is known regarding the applicability of vaccine use for testing (in vitro/vivo) to ascertain pathogenesis or predict reactivity risk. Expedient and thorough research-based evaluation of patients who have suffered anaphylactic vaccine reactions and prospective clinical trials in putative at-risk individuals are needed to address these concerns during a public health crisis.

The added value of H2 antagonists in premedication regimens during paclitaxel treatment.

BACKGROUND: Ranitidine, a histamine 2 blocker, is the standard of care to prevent hypersensitivity reactions (HSRs) caused by paclitaxel infusion. However, the added value of ranitidine in this premedication regimen is controversial. Therefore, we compared the incidence of HSRs during paclitaxel treatment between a standard regimen including ranitidine and a regimen without ranitidine. METHODS: This prospective, pre-post interventional, non-inferiority study compared the standard premedication regimen (N = 183) with dexamethasone, clemastine and ranitidine with a premedication regimen without ranitidine (N = 183). The primary outcome was the incidence of HSR grade ≥3. Non-inferiority was determined by checking whether the upper bound of the two-sided 90% confidence interval (CI) for the difference in HSR rates excluded the +6% non-inferiority margin. RESULTS: In both the pre-intervention (with ranitidine) and post-intervention (without ranitidine) group 183 patients were included. The incidence of HSR grade ≥3 was 4.4% (N = 8) in the pre-intervention group and 1.6% (N = 3) in the post-intervention group: difference -2.7% (90% CI: -6.2 to 0.1). CONCLUSIONS: As the upper boundary of the 90% CI does not exceed the predefined non-inferiority margin of +6%, it can be concluded that a premedication regimen without ranitidine is non-inferior to a premedication regimen with ranitidine. CLINICAL TRIAL REGISTRATION: www.trialregister.nl ; NL8173.

Association of Multiple Gene Polymorphisms Including Homozygous NUDT15 R139C With Thiopurine Intolerance During the Treatment of Acute Lymphoblastic Leukemia.

Although thiopurine is a crucial drug for treating acute lymphoblastic leukemia, individual variations in intolerance are observed due to gene polymorphisms. A 3-year-old boy with B-cell precursor acute lymphoblastic leukemia who was administered thiopurine developed mucositis, sepsis, and hemophagocytic lymphohistiocytosis due to prolonged hematologic toxicity, chronic disseminated candidiasis, and infective endocarditis that triggered multiple brain infarctions. The patient was found to harbor 3 gene polymorphisms associated with thiopurine intolerance including homozygous NUDT15 R139C, heterozygous ITPA C94A, and homozygous MTHFR C677T and heterozygous RFC1 G80A. Thus, the combined effect of intolerance via multiple gene polymorphisms should be considered in case of unexpected adverse reactions.

A group of cationic amphiphilic drugs activates MRGPRX2 and induces scratching behavior in mice.

BACKGROUND: Mas gene-related G protein-coupled receptors (MRGPRs) are a G protein-coupled receptor family responsive to various exogenous and endogenous agonists, playing a fundamental role in pain and itch sensation. The primate-specific family member MRGPRX2 and its murine orthologue MRGPRB2 are expressed by mast cells mediating IgE-independent signaling and pseudoallergic drug reactions. OBJECTIVES: Our aim was to increase knowledge about the function and regulation of MRGPRX2/MRGPRB2, which is of major importance in prevention of drug hypersensitivity reactions and drug-induced pruritus. METHODS: To identify novel MRGPR (ant)agonists, we screened a library of pharmacologically active compounds by utilizing a high-throughput calcium mobilization assay. The identified hit compounds were analyzed for their pseudoallergic and pruritogenic effects in mice and human. RESULTS: We found a class of commonly used drugs activating MRGPRX2 that, to a large extent, consists of antidepressants, antiallergic drugs, and antipsychotics. Three-dimensional pharmacophore modeling revealed structural similarities of the identified agonists, classifying them as cationic amphiphilic drugs. Mast cell activation was investigated by using the 3 representatively selected antidepressants clomipramine, paroxetine, and desipramine. Indeed, we were able to show a concentration-dependent activation and MRGPRX2-dependent degranulation of the human mast cell line LAD2 (Laboratory of Allergic Diseases-2). Furthermore, clomipramine, paroxetine, and desipramine were able to induce degranulation of human skin and murine peritoneal mast cells. These substances elicited dose-dependent scratching behavior following intradermal injection into C57BL/6 mice but less so in MRGPRB2-mutant mice, as well as wheal-and-flare reactions following intradermal injections in humans. CONCLUSION: Our results contribute to the characterization of structure-activity relationships and functionality of MRGPRX2 ligands and facilitate prediction of adverse reactions such as drug-induced pruritus to prevent severe drug hypersensitivity reactions.

HCP5 rs2395029 is a rapid and inexpensive alternative to HLA-B*57:01 genotyping to predict abacavir hypersensitivity reaction in Spain.

Abacavir (ABC) is an HIV nucleotide-analogue reverse transcriptase inhibitor that can produce a severe hypersensitivity reaction (ABC-HSR) in about 5% of the patients. The HLA-B*57:01 allele is associated with the development of ABC-HSR. Therefore, HLA-B*57:01 genotyping is required prior to the prescription of ABC. The technique routinely used in our laboratory is the sequence-specific oligonucleotide probes (SSOP) reverse hybridization method followed by Sanger sequencing. This technique is time-consuming and expensive. The single-nucleotide polymorphism (SNP) HCP5 rs2395029 was described to be in complete linkage disequilibrium with HLA-B*57:01. In this study, we aimed to assess the linkage disequilibrium between HCP5 rs2395029 and HLA-B*57:01 in patients receiving medical assistance at our hospital. We selected 226 HIV-infected patients from our hospital who had been routinely genotyped since 2009 with the SSOP and Sanger sequencing method: 49 HLA-B*57:01 positives and 177 negatives. We genotyped them for HCP5 rs2395019 by real time PCR (qPCR). We exploratory performed two copy number variation assays flanking HCP5 rs2395019 to explore possible deletions that could break the linkage disequilibrium with HLA-B*57:01. The concordance between HLA-B*57:01 and the HCP5 rs2395029 G allele was absolute, with a specificity and sensitivity of 100% (95% confidence interval: 93.0-100.0% and 98.0-100.0%, respectively) and estimated positive and negative predictive values of 84.4% (48.1-93.9%) and 99.9% (99.4-100.0%), respectively. No deletions were found at HCP5 flanking regions. The duration and cost of the SSOP-based method was considerably higher than the SNP-based method. Therefore, the HCP5 rs2395029 genotyping method may be alternatively used in the clinical practice.

Accuracy of penicillin allergy diagnostic tests: A systematic review and meta-analysis.

BACKGROUND: Having a penicillin allergy label associates with a higher risk for antibiotic resistance and increased health care use. OBJECTIVE: We sought to assess the accuracy of skin tests and specific IgE quantification in the diagnostic evaluation of patients reporting a penicillin/ß-lactam allergy. METHODS: We performed a systematic review and diagnostic accuracy meta-analysis, searching on MEDLINE, Scopus, and Web of Science. We included studies conducted in patients reporting a penicillin allergy and in whom skin tests and/or specific IgE quantification were performed and compared with drug challenge results. We quantitatively assessed the accuracy of diagnostic tests with bivariate random-effects meta-analyses. Meta-regression and subgroup analyses were performed to explore causes of heterogeneity. Studies' quality was evaluated using QUADAS-2 criteria. RESULTS: We included 105 primary studies, assessing 31,761 participants. Twenty-seven studies were assessed by bivariate meta-analysis. Skin tests had a summary sensitivity of 30.7% (95% CI, 18.9%-45.9%) and a specificity of 96.8% (95% CI, 94.2%-98.3%), with a partial area under the summary receiver-operating characteristic curve of 0.686 (I2 = 38.2%). Similar results were observed for subanalyses restricted to patients reporting nonimmediate maculopapular exanthema or urticaria/angioedema. Specific IgE had a summary sensitivity of 19.3% (95% CI, 12.0%-29.4%) and a specificity of 97.4% (95% CI, 95.2%-98.6%), with a partial area under the summary receiver-operating characteristic curve of 0.420 (I2 = 8.5%). Projected predictive values mainly reflect the low frequency of true penicillin allergy. CONCLUSIONS: Skin tests and specific IgE quantification appear to have low sensitivity and high specificity. Because current evidence is insufficient for assessing the role of these tests in stratifying patients for delabeling, we identified key requirements needed for future studies.

Neutrophilic drug reactions.

Neutrophilic drug reactions are unique eruptions that can affect hospitalized patients and share a common pathophysiology with neutrophils as the key mediators of inflammation. They range in clinical presentation from papules and plaques to bullae and erosions to pustules. Although there is some overlap in presentation, each has distinguishing features that aid the clinician in differentiation from one another and from other drug hypersensitivity reactions. Much of the data on these reactions are from case reports and series or retrospective review studies. There are limited prospective observational studies dedicated to these adverse drug reactions. We review the more common and life-threatening neutrophilic drug reactions, their proposed mechanism of action, and their management.

ß-Lactam allergy and risk of multidrug-resistant bacteria in the intensive care unit: A cohort study.

Patients identified as allergic to ß-lactams are frequently exposed to treatment with broad-spectrum antibiotics. However, the risk of carriage of extended-spectrum ß-lactamase (ESBL)-producing isolates in this population has been poorly investigated. The aim of this study was to evaluate the characteristics and clinical outcomes of patients admitted to the intensive care unit (ICU) with and without declared ß-lactam allergy at admission. A retrospective monocentric study was performed including adult patients admitted to the ICU between 2007 and 2012. The presence of multidrug-resistant bacteria was documented in rectal and nasal swabs at admission and discharge. Patients labelled allergic to ß-lactams and unlabelled patients were compared. Patients labelled allergic had significantly higher rates of ESBL at admission (13.3% vs. 4.3%; P = 0.0220) and discharge (20.0% vs. 9.0%; P = 0.0460) compared with unlabelled patients, but no significant difference in rates of ESBL acquisition in the ICU was detected. No differences in mortality, duration of hospitalisation or typical risk factors for ESBL acquisition (intubation, central venous catheter and duration of hospitalisation) were reported. No differences in carriage of methicillin-resistant Staphylococcus aureus were detected. This study showed that patients with declared ß-lactam allergy had a higher risk of ESBL carriage at ICU admission and discharge.

Are apoptosis-determining techniques useful to establish an early diagnosis of acute graft-vs-host disease in pediatric patients under treatment with multiple drugs?

BACKGROUND: There are no pathognomonic histopathological features to distinguish acute graft-vs-host disease (aGVHD) from skin drug reactions (SDRs) in pediatric patients with multiple drug regimens that have received blood transfusions and/or transplants. We aimed to determine if the addition of apoptosis markers is helpful to distinguish aGVHD from SDRs in these patients. METHODS: Skin biopsy specimens from patients with a clinical diagnosis of aGVHD or SDRs were evaluated for the presence of apoptotic bodies, satellitosis, interface damage, vasculitis, and inflammatory infiltrate on H&E stain. Information was completed with apoptotic markers (transferase-mediated dUTP nick end-labeling [TUNEL], bcl-2, and caspase-3). RESULTS: The skin biopsy specimens of 32 patients with aGVHD and 11 with SDRs were included for study. Only the number of apoptotic keratinocytes per 10 high-power fields (hpf) showed a significant difference between both groups (P = 0.02); the presence of ≥4 apoptotic keratinocytes per 10 hpf was identified as the optimal cut-off point to discriminate aGVHD from SDRs. No SDRs cases had follicular apoptotic cells. TUNEL, bcl-2, and caspase-3 determination showed no difference between both groups. CONCLUSIONS: The presence of ≥4 apoptotic keratinocytes per 10 hpf (in aGVHD) and the absence of follicular apoptotic cells (in SDRs) might be a useful marker to distinguish between them.

Update on the Management of Nonsteroidal Anti-Inflammatory Drug Hypersensitivity.

The clinical phenotypes of nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity are heterogeneous with various presentations including time of symptom onset, organ involvements, and underlying pathophysiology. Having a correct diagnosis can be challenging. Understanding their respective mechanisms as well as developing a comprehensive classification and diagnostic algorithm are pivotal for appropriate management strategy. Treatment modalities are based on the subtypes and severity of hypersensitivity reactions. Insights into the phenotypes and endotypes of hypersensitivity reactions enable personalized management in patients with suboptimal control of disease. This review updated the recent evidence of pathophysiology, classification, diagnostic algorithm, and management of NSAID hypersensitivity reactions.

An autopsy case of sudden unexpected death with loxoprofen sodium-induced allergic eosinophilic coronary periarteritis.

Although the cause of eosinophilic coronary periarteritis (ECPA) remains unclear, an allergic background is present in fewer patients than expected. A 50-year-old man with no history of allergy or symptoms suggestive of cardiac or respiratory disorders suddenly died shortly after oral administration of loxoprofen sodium. Autopsy showed eosinophilic coronary periarteritis in three main branches of the coronary arteries, characterized by eosinophil-predominant inflammation without fibrinoid necrosis or granulomatous change in the adventitia and its surroundings of the three main branches of the coronary arteries, in addition to the localized sign of bronchial asthma in the lung. Immunohistochemical examination showed that many mast cells positive for human mast cell tryptase were evident in the perivascular tissue containing peripheral nerve trunks. Whereas the blood concentration of loxoprofen sodium was within the therapeutic range, significant elevation of the serum histamine and tryptase levels was found. The present case suggests that eosinophilic coronary periarteritis may be caused by a type I allergic reaction in some patients and that loxoprofen sodium can trigger a life-threatening type I allergic reaction, including eosinophilic coronary periarteritis, leading to sudden unexpected death.