What have we learned about the allergenicity and adverse reactions associated with the severe acute respiratory syndrome coronavirus 2 vaccines: One year later.

OBJECTIVE: The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the most rapid response and scale-up in vaccine and therapeutic development in history. We highlight the history of these amazing achievements with a focus on the description of the classification and mechanisms of allergic reactions and adverse events relevant to the allergist and immunologist that have been associated with the SARS-CoV-2 vaccines. Finally, we offer a detailed management approach in the context of a possible allergic reaction. DATA SOURCES: Using defined search strategy, we identified peer-reviewed articles within PubMed that were published between January 1, 2019, and December 4, 2021. STUDY SELECTIONS: All recent articles on COVID-19 published in English were reviewed with focus on the immunogenicity and allergenicity of the current existing COVID-19 vaccines. RESULTS: Following a detailed literature review, we discuss the evolution and development of the new vaccines for SARS-CoV-2. Furthermore, we provide evidence regarding the significance and mechanisms of allergic reactions associated with the vaccines and offer a management approach for those with an increased risk of presenting an allergic or other relevant vaccine reaction. CONCLUSION: The international rollout of COVID-19 vaccination started with reports of immediate allergic reactions. Although we still need to understand the mechanisms of these reactions, we can be reassured that patients with underlying allergic disease will not need to avoid SARS-CoV-2 vaccination. In addition, the vast majority of those with a first-dose reaction will tolerate subsequent doses.

Worldwide Prevalence of Antibiotic-Associated Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: A Systematic Review and Meta-analysis.

Importance: Antibiotics are an important risk for Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN), which are the most severe types of drug hypersensitivity reaction with a mortality rate up to 50%. To our knowledge, no global systematic review has described antibiotic-associated SJS/TEN. Objective: To evaluate the prevalence of antibiotics associated with SJS/TEN worldwide. Data Sources: The MEDLINE and Embase databases were searched for experimental and observational studies that described SJS/TEN risks since database inception to February 22, 2022. Study Selection: Included studies adequately described SJS/TEN origins and specified the antibiotics associated with SJS/TEN. Data Extraction and Synthesis: Two reviewers (E.Y.L. and C.K.) independently selected the studies, extracted the data, and assessed the risk of bias. A meta-analysis using a random-effects model was performed in the studies that described patient-level associations. Subgroup analyses were performed to explore the heterogeneity. The risk of bias was assessed using the Joanna Briggs Institute checklist, and the certainty of evidence was rated using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. Main Outcomes and Measures: Prevalence of antibiotic-associated SJS/TEN was presented as pooled proportions with 95% CIs. Results: Among the 64 studies included in the systematic review, there were 38 studies that described patient-level associations; the meta-analysis included these 38 studies with 2917 patients to determine the prevalence of single antibiotics associated with SJS/TEN. The pooled proportion of antibiotics associated with SJS/TEN was 28% (95% CI, 24%-33%), with moderate certainty of evidence. Among antibiotic-associated SJS/TEN, the sulfonamide class was associated with 32% (95% CI, 22%-44%) of cases, followed by penicillins (22%; 95% CI, 17%-28%), cephalosporins (11%; 95% CI, 6%-17%), fluoroquinolones (4%; 95% CI, 1%-7%), and macrolides (2%; 95% CI, 1%-5%). There was a statistically significant heterogeneity in the meta-analysis, which could be partially explained in the subgroup analysis by continents. The overall risk of bias was low using the Joanna Briggs Institute checklist for case series. Conclusion and Relevance: In this systematic review and meta-analysis of all case series, antibiotics were associated with more than one-quarter of SJS/TEN cases described worldwide, and sulfonamide antibiotics remained the most important association. These findings highlight the importance of antibiotic stewardship, clinician education and awareness, and weighing the risk-benefit assessment of antibiotic choice and duration.

HIV-Associated Immune Dysregulation in the Skin: A Crucible for Exaggerated Inflammation and Hypersensitivity.

Skin diseases are hallmarks of progressive HIV-related immunosuppression, with severe noninfectious inflammatory and hypersensitivity conditions as common as opportunistic infections. Conditions such as papular pruritic eruption are AIDS defining, whereas delayed immune-mediated adverse reactions, mostly cutaneous, occur up to 100-fold more during HIV infection. The skin, constantly in contact with the external environment, has a complex immunity. A dense, tightly junctioned barrier with basal keratinocytes and epidermal Langerhans cells with antimicrobial, innate-activating, and antigen-presenting functions form the frontline. Resident dermal dendritic, mast, macrophage, and innate lymphoid cells play pivotal roles in directing and polarizing appropriate adaptive immune responses and directing effector immune cell trafficking. Sustained viral replication leads to progressive declines in CD4 T cells, whereas Langerhans and dermal dendritic cells serve as viral reservoirs and points of first viral contact in the mucosa. Cutaneous cytokine responses and diminished lymphoid populations create a crucible for exaggerated inflammation and hypersensitivity. However, beyond histopathological description, these manifestations are poorly characterized. This review details normal skin immunology, changes associated with progressive HIV-related immunosuppression, and the characteristic conditions of immune dysregulation increased with HIV. We highlight the main research gaps and several novel tissue-directed strategies to define mechanisms that will provide targeted approaches to prevention or treatment.

Identification of drug-specific public TCR driving severe cutaneous adverse reactions.

Drug hypersensitivity such as severe cutaneous adverse reactions (SCAR), including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), could be life-threatening. Here, we enroll SCAR patients to investigate the T cell receptor (TCR) repertoire by next-generation sequencing. A public αßTCR is identified from the cytotoxic T lymphocytes of patients with carbamazepine-SJS/TEN, with its expression showing drug/phenotype-specificity and an bias for HLA-B*15:02. This public αßTCR has binding affinity for carbamazepine and its structural analogs, thereby mediating the immune response. Adoptive transfer of T cell expressing this public αßTCR to HLA-B*15:02 transgenic mice receiving oral administration of carbamazepine induces multi-organ injuries and symptoms mimicking SCAR, including hair loss, erythema, increase of inflammatory lymphocytes in the skin and blood, and liver and kidney dysfunction. Our results not only demonstrate an essential role of TCR in the immune synapse mediating SCAR, but also implicate potential clinical applications and development of therapeutics.