IFN-γ ELISpot in Severe Cutaneous Adverse Reactions to First-Line Antituberculosis Drugs in an HIV Endemic Setting

First-Line Antituberculosis Drug Challenge Reactions in Drug Reaction with Eosinophilia and Systemic Symptoms Syndrome in an HIV Endemic Setting

BACKGROUND

In high HIV prevalence settings, first-line antituberculosis drug (FLTD)-associated drug reaction with eosinophilia and systemic symptoms (DRESS) poses therapeutic challenges. A sequential and additive drug challenge (SADC) of FLTDs best identifies offending drug(s), avoids unnecessary exclusions, and optimizes reinitiation of nonoffending drugs. However, SADC-associated reaction complexities limit its utility.

OBJECTIVE

We aimed to describe the characteristics of patients with FLTD-associated DRESS, their treatment-limiting SADC reactions, and related outcomes.

METHODS

Patients hospitalized with FLTD-associated DRESS from 2013 to 2023 in a South African tertiary hospital and enrolled (retrospectively or prospectively) in an existing registry were eligible.

RESULTS

SADC was undertaken in 41 patients. Overall, 47 classifiable reactions occurred. 34/47 (72%) reactions in 29/41 (71%) patients were treatment-limiting and 12 of 41(29%) patients reinitiated FLTDs uneventfully. Fifteen single and 8 multiple drug reactors were identified. Rifampicin in 13 of 23(57%) reactors was the most common individual offender. Ethambutol was most frequently involved in multiple drug reactors. The median (interquartile range) time to a detectable reaction was 24(12-120) hours, 6 of 34(18%) being immediate (<6 hours). Itch (65%), eosinophilia (56%), fever (41%), atypical lymphocytosis (41%), rash (38%), transaminitis (32%), and facial edema (18%) singly or in combination were the most common features. Three reactions, 1 epidermal necrolysis and 2 liver derangements, were Common Terminology Criteria for Adverse Events grade 4 (life-threatening) events. No predictors of multiple drug reactivity were identified, but multiple reactors were hospitalized significantly longer, 125(100-134) days versus 60(45-80) days.

CONCLUSIONS

SADC optimizes FLTD reinitiation. However, timing, clinical presentation, and severity of SADC-associated reactions after FLTD-associated DRESS are markedly heterogeneous. Additionally, multiple drug reactors are a complex group that require longer hospitalization. There are no routine biomarkers available to distinguish true multiple drug hypersensitivity from nonspecific flare-ups and to guide long-term drug avoidance strategies.

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms. Part II diagnosis and management

Drug-induced hypersensitivity syndrome, also known as drug reaction with eosinophilia and systemic symptoms, is a severe cutaneous adverse reaction characterized by an exanthem, fever, and hematologic and visceral organ involvement. The differential diagnosis includes other cutaneous adverse reactions, infections, inflammatory and autoimmune diseases, and neoplastic disorders. Three sets of diagnostic criteria have been proposed; however, consensus is lacking. The cornerstone of management is immediate discontinuation of the suspected drug culprit. Systemic corticosteroids remain first-line therapy, but the literature on steroid-sparing agents is expanding. Longitudinal evaluation for sequelae is recommended. Adjunctive tests for risk stratification and drug culprit identification remain under investigation. Part II of this continuing medical education activity begins by exploring the differential diagnosis and diagnosis of drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms and concludes with an evidence-based overview of evaluation and treatment.

Skin infiltrating T-cell profile of drug reaction with eosinophilia and systemic symptoms (DRESS) reactions among HIV-infected patients

Introduction

Drug Reaction with Eosinophilia Systemic Symptoms (DRESS) is more common in persons living with HIV (PLHIV), and first-line anti-TB drugs (FLTDs) and cotrimoxazole are the commonest offending drugs. Limited data is available on the skin infiltrating T-cell profile among DRESS patients with systemic CD4 T-cell depletion associated with HIV.

Materials and methods

HIV cases with validated DRESS phenotypes (possible, probable, or definite) and confirmed reactions to either one or multiple FLTDs and/or cotrimoxazole were chosen (n = 14). These cases were matched against controls of HIV-negative patients who developed DRESS (n = 5). Immunohistochemistry assays were carried out with the following antibodies: CD3, CD4, CD8, CD45RO and FoxP3. Positive cells were normalized to the number of CD3+ cells present.

Results

Skin infiltrating T-cells were mainly found in the dermis. Dermal and epidermal CD4+ T-cells (and CD4+/CD8+ ratios) were lower in HIV-positive vs. negative DRESS; p < 0.001 and p = 0.004, respectively; without correlation to whole blood CD4 cell counts. In contrast, no difference in dermal CD4+FoxP3+ T-cells was found in HIV-positive vs. negative DRESS, median (IQR) CD4+FoxP3+ T-cells: [10 (0-30) cells/mm² vs. 4 (3-8) cells/mm², p = 0.325]. HIV-positive DRESS patients reacting to more than one drug had no difference in CD8+ T-cell infiltrates, but higher epidermal and dermal CD4+FoxP3+ T-cell infiltrates compared to single drug reactors.

Conclusion

DRESS, irrespective of HIV status, was associated with an increased skin infiltration of CD8+ T-cells, while CD4+ T-cells were lower in HIV-positive DRESS compared to HIV-negative DRESS skin. While inter-individual variation was high, the frequency of dermal CD4+FoxP3+ T-cells was higher in HIV-positive DRESS cases reacting to more than one drug. Further research is warranted to understand the clinical impact of these changes.

Updates on the immunopathology and genomics of severe cutaneous adverse drug reactions

Severe cutaneous adverse reactions (SCARs) such as Stevens-Johnson syndrome, toxic epidermal necrolysis (SJS/TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS)/drug-induced hypersensitivity syndrome (DIHS) cause significant morbidity and mortality and impede new drug development. HLA class I associations with SJS/TEN and drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome have aided preventive efforts and provided insights into immunopathogenesis. In SJS/TEN, HLA class I-restricted oligoclonal CD8+ T-cell responses occur at the tissue level. However, specific HLA risk allele(s) and antigens driving this response have not been identified for most drugs. HLA risk alleles also have incomplete positive and negative predictive values, making truly comprehensive screening currently challenging. Although, there have been key paradigm shifts in knowledge regarding drug hypersensitivity, there are still many open and unanswered questions about SCAR immunopathogenesis, as well as genetic and environmental risk. In addition to understanding the cellular and molecular basis of SCAR at the single-cell level, identification of the MHC-restricted drug-reactive self- or viral peptides driving the hypersensitivity reaction will also be critical to advancing premarketing strategies to predict risk at an individual and drug level. This will also enable identification of biologic markers for earlier diagnosis and accurate prognosis, as well as drug causality and targeted therapeutics.

Tools to improve the diagnosis and management of T-cell mediated adverse drug reactions

Delayed drug T-cell immune-mediated hypersensitivity reactions have a large clinical heterogeneity varying from mild maculopapular exanthema (MPE) to severe cutaneous adverse reactions (SCARs) such as acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS) and severe skin necrosis and blistering as seen in Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Given the knowledge gaps related to the immunopathogenesis of these conditions, the absence of validated diagnostic tools and the significant associated morbidity and mortality, patients with SCARs often have limited drug choices. We performed a comprehensive review aiming to evaluate in vivo diagnostic tools such as delayed intradermal skin and patch testing and ex vivo/in vitro research assays such as the lymphocyte transformation test (LTT) and the enzyme-linked ImmunoSpot (ELISpot) assay. We searched through PubMed using the terms “drug allergy,” “in vivo” and “ex vivo” for original papers in the last 10 years. A detailed meticulous approach adapted to the various clinical phenotypes is recommended for the diagnostic and management of delayed drug hypersensitivity reactions. This review highlights the current diagnostic tools for the delayed drug hypersensitivity phenotypes.