Slow desensitization of imatinib-induced nonimmediate reactions and dynamic changes of drug-specific CD4+CD25+CD134+ lymphocytes

T-cell activation-induced marker assays in health and disease

Activation-induced marker (AIM) assays have proven to be an accessible and rapid means of antigen-specific T-cell detection. The method typically involves short-term incubation of whole blood or peripheral blood mononuclear cells with antigens of interest, where autologous antigen-presenting cells process and present peptides in complex with major histocompatibility complex (MHC) molecules. Recognition of peptide-MHC complexes by T-cell receptors then induces upregulation of activation markers on the T cells that can be detected by flow cytometry. In this review, we highlight the most widely used activation markers for assays in the literature while identifying nuances and potential downfalls associated with the technique. We provide a summary of how AIM assays have been used in both discovery science and clinical studies, including studies of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunity. This review primarily focuses on AIM assays using human blood or peripheral blood mononuclear cell samples, with some considerations noted for tissue-derived T cells and nonhuman samples. AIM assays are a powerful tool that enables detailed analysis of antigen-specific T-cell frequency, phenotype and function without needing to know the precise antigenic peptides and their MHC restriction elements, enabling a wider analysis of immunity generated following infection and/or vaccination.

Future perspectives on in-vitro diagnosis of drug allergy by the lymphocyte transformation test

This article aims to envisage future perspectives of the lymphocyte transformation test (LTT). We describe the select innovative techniques, which can be integrated at different stages of the LTT to potentially improve the sensitivity, specificity, or practicability of the LTT. We first focus upon the cell sorting techniques comprising immunomagnetic cell separation and flow cytometry, which can be implemented prior and after the LTT culturing step to concentrate and quantify specific immune cell types. Further, we elaborate upon three important omics techniques such as transcriptomics, proteomics, and metabolomics, which can be integrated downstream of the LTT to analyze molecular changes in specific immune cells following drug induced activation and proliferation. We also develop visions, how state of the art techniques used in other scientific fields, can be transferred and applied in the context of in-vitro detection of drug allergy.

The Roles of Immunoregulatory Networks in Severe Drug Hypersensitivity

The immunomodulatory effects of regulatory T cells (Tregs) and co-signaling receptors have gained much attention, as they help balance immunogenic and immunotolerant responses that may be disrupted in autoimmune and infectious diseases. Drug hypersensitivity has a myriad of manifestations, which ranges from the mild maculopapular exanthema to the severe Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome (DRESS/DIHS). While studies have identified high-risk human leukocyte antigen (HLA) allotypes, the presence of the HLA allotype at risk is not sufficient to elicit drug hypersensitivity. Recent studies have suggested that insufficient regulation by Tregs may play a role in severe hypersensitivity reactions. Furthermore, immune checkpoint inhibitors, such as anti-CTLA-4 or anti-PD-1, in cancer treatment also induce hypersensitivity reactions including SJS/TEN and DRESS/DIHS. Taken together, mechanisms involving both Tregs as well as coinhibitory and costimulatory receptors may be crucial in the pathogenesis of drug hypersensitivity. In this review, we summarize the currently implicated roles of co-signaling receptors and Tregs in delayed-type drug hypersensitivity in the hope of identifying potential pharmacologic targets.

Long induction of tolerance to imatinib

Imatinib is used to treat several haematological and solid malignancies. Cutaneous side effects could often limit the use of this medication. We present a case of a 62-year-old woman with a history of a gastrointestinal stromal tumour that developed a delayed cutaneous adverse reaction 10 days after starting imatinib 400 mg daily. She developed the same symptoms with reintroduction at a dose of 100 mg and with an alternative tyrosine kinase inhibitor, nilotinib 50 mg/day. Given that imatinib was considered her best treatment, she underwent a long induction of drug tolerance (IDT) protocol to imatinib. Patient tolerated the medication without further reactions for 6 months and had improvement of her cancer per last imaging studies. IDT should be considered in delayed hypersensitivity reactions to imatinib after a failed reintroduction of the drug or when no other equally effective agents are available.

Therapeutic drug monitoring-based dose optimization for imatinib-associated serious cutaneous reactions in a patient with gastrointestinal stromal tumours: A case report

WHAT IS KNOWN AND OBJECTIVE

Imatinib mesylate (IM) is the first-line therapy for unresectable or metastatic gastrointestinal stromal tumours (GISTs). Here, we report a case of successful progressive dose optimization by therapeutic drug monitoring (TDM) for a patient with GISTs who developed IM-associated serious cutaneous reactions.

CASE DESCRIPTION

A 72-year-old female patient received IM at a dose of 400 mg/day for GISTs. The patient developed serious eczematoid drug eruptions and desquamation, following which IM was discontinued. One year later, the GISTs recurred with metastasis, and IM was re-administered at a dose of 100 mg/day, and the dose was gradually increased on the basis of TDM. The final dose of IM was 200 mg/day, and the trough concentration (C_trough ) of IM was 1457.76 ng/mL. The images obtained from follow-up computed tomography (CT) showed a marked anti-tumour response. IM was well tolerated and the patient developed tolerable IM-associated cutaneous reactions.

WHAT IS NEW AND CONCLUSION

The strategy of TDM-guided dose optimization makes it possible to achieve optimal clinical efficacy for patients with GISTs who develop IM-associated serious cutaneous reactions.