Early Biomarkers for Severe Drug Hypersensitivity Reactions

Biomarkers of immediate drug hypersensitivity

Immediate drug hypersensitivity reactions (IDHRs) are a burden for patients and the health systems. This problem increases when taking into account that only a small proportion of patients initially labelled as allergic are finally confirmed after an allergological workup. The diverse nature of drugs involved will imply different interactions with the immunological system. Therefore, IDHRs can be produced by a wide array of mechanisms mediated by the drug interaction with specific antibodies or directly on effector target cells. These heterogeneous mechanisms imply an enhanced complexity for an accurate diagnosis and the identification of the phenotype and endotype at early stages of the reaction is of vital importance. Currently, several endophenotypic categories (type I IgE/non-IgE, cytokine release, Mast-related G-protein coupled receptor X2 (MRGPRX2) or Cyclooxygenase-1 (COX-1) inhibition and their associated biomarkers have been proposed. A precise knowledge of endotypes will permit to discriminate patients within the same phenotype, which is crucial in order to personalise diagnosis, future treatment and prevention to improve the patient's quality of life.

Antibiotic Allergy De-Labeling: A Pathway against Antibiotic Resistance

Antibiotics are one of the most frequently prescribed drugs. Unfortunately, they also are the most common cause for self-reported drug allergy, limiting the use of effective therapies. However, evidence shows that more than 90% of patients labeled as allergic to antibiotics are not allergic. Importantly, the label of antibiotic allergy, whether real or not, constitutes a major public health problem as it directly impacts antimicrobial stewardship: it has been associated with broad-spectrum antibiotic use, often resulting in the emergence of bacterial resistance. Therefore, an accurate diagnosis is crucial for de-labeling patients who claim to be allergic but are not really allergic. This review presents allergy methods for achieving successful antibiotic allergy de-labeling. Patient clinical history is often inaccurately reported, thus not being able to de-label most patients. In vitro testing offers a complementary approach but it shows limitations. Immunoassay for quantifying specific IgE is the most used one, although it gives low sensitivity and is limited to few betalactams. Basophil activation test is not validated and not available in all centers. Therefore, true de-labeling still relies on in vivo tests including drug provocation and/or skin tests, which are not risk-exempt and require specialized healthcare professionals for results interpretation and patient management. Moreover, differences on the pattern of antibiotic consumption cause differences in the diagnostic approach among different countries. A multidisciplinary approach is recommended to reduce the risks associated with the reported penicillin allergy label.

Advances and highlights in T and B cell responses to drug antigens

The immunological mechanisms involved in drug hypersensitivity reactions (DHRs) are complex, and despite important advances, multiple aspects remain poorly understood. These not fully known aspects are mainly related to the factors that drive towards either a tolerant or a hypersensitivity response and specifically regarding the role of B and T cells. In this review, we focus on recent findings on this knowledge area within the last 2 years. We highlight new evidences of covalent and non-covalent interactions of drug antigen with proteins, as well as the very first characterization of naturally processed flucloxacillin-haptenated human leukocyte antigen (HLA) ligands. Moreover, we have analysed new insights into the identification of risk factors associated with the development of DHRs, such as the role of oxidative metabolism of drugs in the activation of the immune system and the discovery of new associations between DHRs and HLA variants. Finally, evidence of IgG-mediated anaphylaxis in humans and the involvement of specific subpopulations of effector cells associated with different clinical entities are also topics explored in this review. All these recent findings are relevant for the underlying pathology mechanisms and advance the field towards a more precise diagnosis, management and treatment approach for DHRs.

Lab-Based Culprit Drug Identification Methods for Cutaneous Drug Eruptions: A Scoping Review

BACKGROUND

Identification of culprit drugs when managing cutaneous drug eruptions is essential. Causality assessment methods (CAMs) have been proposed, including lab-based techniques. However, no consensus guidelines exist.

OBJECTIVES

To identify and map the functionality and feasibility of lab-based CAMs.

METHODS

A scoping review was conducted to identify culprit drug identification methods. Publications on lab-based methods were analyzed. Medline, Embase, and Cochrane Central Register of Controlled Trials databases were searched.

RESULTS

Twenty-five publications met inclusion criteria. Nine lab-based CAMs were studied, including lymphocyte transformation test, cytokine measurement (ELISpot, ELISA, beads array assay), modified IFN-ɣ ELISpot, CellScan, histamine release, granzyme B-ELISpot, intracellular granulysin, lymphocyte toxicity assay, and HLA allele genotyping. Diagnostic accuracy was reported for 8/9 methods. Clinical assessment and operational algorithms were commonly used as validation benchmarks. Lab-based methods were assessed at different phases of a drug eruption including in the acute (18.1%), recovery (27.3%), acute and recovery (27.3%), or an unspecified phase (27.3%). Lymphocyte transformation test (specificity 30% to 100%, sensitivity 27% to 73%) and cytokine measurement (specificity 76% to 100%, sensitivity 20% to 84%) were the most common methods studied.

CONCLUSIONS

Lab-based CAMs can be low-risk, effective, and complementary of clinical methods. High-quality studies are needed to adequately develop and validate these tools for clinical practice.

Application of HER2 peptide vaccines in patients with breast cancer: a systematic review and meta-analysis

Background

The E75 and GP2 vaccines are the few therapeutic vaccines targeting HER2 currently under clinical research for patients with breast cancer.

Methods

Databases, including the Cochrane Library, PubMed, Medline, Embase, and Web of Science, were used to retrieve clinical studies on E75 and GP2 vaccines. Retrieval time was from the beginning of database construction until May 31st, 2021.

Results

A total of 24 clinical studies were included in this analysis, including 1704 patients in the vaccinated group and 1248 patients in the control group. For the E75 vaccine, there were significant differences between the vaccinated group and the control group in the delayed-type hypersensitivity reaction (SMD = 0.685 95% CI 0.52–0.85, P_{Heterogeneity} = 0.186, P_DTH < 0.05) and the change in CD8⁺ T-cell numbers (SMD = − 0.864, 95% CI − 1.02 to − 0.709, P_{Heterogeneity} = 0.085, P_{CD8+ T cell} < 0.05) before and after injection. For the GP2 vaccine, there was a significant difference between the vaccinated group and the control group in the change in CD8⁺ T-cell numbers (SMD = − 0.584, 95% CI − 0.803 to − 0.294, P_{Heterogeneity} = 0.397, P_{CD8+ T cell} < 0.05) before and after injection. In addition, the clinical outcomes, including recurrence rate (RR = 0.568, 95% CI 0.444–0.727, P_{Heterogeneity} = 0.955, P_Recurrence < 0.05) and disease-free survival rate (RR = 1.149, 95% CI 1.050–1.256, P_{Heterogeneity} = 0.003, P_DFS < 0.05), of the E75-vaccinated group were different from those of the control group. However, we found that the overall survival rate with the E75 vaccine (RR = 1.032, 95% CI 0.998–1.067, P_{Heterogeneity} = 0.476, P_OS > 0.05) was not different between the two groups. Local and systemic toxicity assessments of the two vaccines showed minimal side effects.

Conclusions

The E75 vaccine was effective and safe in patients with breast cancer. The GP2 vaccine could elicit a strong immune response, but more trials are needed to confirm its clinical efficacy.

Advances and novel developments in drug hypersensitivity diagnosis

A correct diagnosis of drug hypersensitivity reactions (DHRs) is very important for both the patient and health system. However, DHRs diagnosis is complex, time consuming, requires trained personnel, is not standardized for many drugs, involves procedures not exempt of risk, and in most cases lacks standardized in vivo and in vitro tests. Thus, there is an urgent need for improving the different approaches to diagnose patients with suspected DHRs. In this review, we have analyzed the advances performed in immediate and nonimmediate DHRs diagnosis during the last two years and obtained several conclusions: the significant heterogeneity in current practice among centers illustrates the need to re-evaluate, update, and standardize in vivo tests and protocols for the diagnosis and management of patients with suspected drug allergy. Regarding in vitro tests, the latest studies have focused on increasing their sensitivity or on establishing the sensitivity and specificity for the tests performed with new drugs. There seems to be a consensus about combining in vivo and in vitro tests as the best way to increase the diagnostic accuracy.