In vivo dynamics of intraepidermal CD8+ T cells and CD4+ T cells during the evolution of fixed drug eruption
ABSTRACT Although a severe form of fixed drug eruption (FDE) clinically and histologically mimics toxic epidermal necrolysis (TEN), subsequent evolution of the two conditions is quite different. It remains unknown, however, which factors determine whether these lesions resolve spontaneously or subsequently progress to TEN.
Because epidermal injury in TEN can be locally reproduced in the evolving FDE lesions, we sought to investigate how epidermal damage can be induced in the evolving FDE lesions and how disease progression to TEN can be prevented, by analysing the FDE lesions induced by clinical challenge with the causative drug.
We immunohistochemically investigated in vivo dynamics of T-cell trafficking and activation that occur in the evolving FDE lesions using sequential biopsy specimens obtained at multiple time points from the FDE lesions.
Intraepidermal CD8+ T cells, which are resident in the lesional epidermis as a stable homogeneous population of memory T cells, transiently acquire a natural killer-like phenotype and express cytotoxic granules upon activation. The influx into the epidermis of CD4+ T cells including Foxp3+ regulatory T cells (Tregs) during the evolution serves to ameliorate epidermal damage induced by activation of the intraepidermal CD8+ T cells. Interleukin-15 derived from the lesional epidermis could maintain the survival of the intraepidermal CD8+ T cells even in the absence of antigenic stimulus over a prolonged period of time (> 4 years).
Whether Tregs could migrate to the lesions upon activation of intraepidermal CD8+ T cells would determine whether the inflammation becomes resolved spontaneously or progresses to TEN.
Article: [Cutaneous adverse drug reactions.][Show abstract] [Hide abstract]
ABSTRACT: Cutaneous adverse drug reactions (CADR) represent a heterogeneous field including various clinical patterns without specific features suggesting drug causality. Exanthematous eruptions, urticaria and vasculitis are the most common forms of CADR. Fixed eruption is uncommon in western countries. Serious reactions (fatal outcome, sequelae) represent 2% of CADR: bullous reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis), DRESS (drug reaction with eosinophilia and systemic symptoms or drug-induced hypersensitivity syndrome) and acute generalized exanthematous pustulosis (AGEP). These forms must be quickly diagnosed to guide their management. The main risk factors are immunosuppression, autoimmunity and some HLA alleles in bullous reactions and DRESS. Most systemic drugs may induce cutaneous adverse reactions, especially antibiotics, anticonvulsivants, antineoplastic drugs, non-steroidal anti-inflammatory drugs, allopurinol and contrast media. Pathogenesis includes immediate or delayed immunologic mechanism, usually not related to dose, and pharmacologic/toxic mechanism, commonly dose-dependent or time-dependent. In case of immunologic mechanism, allergologic exploration is possible to clarify drug causality, with a variable sensitivity according to the drug and to the CADR type. It includes epicutaneous patch testing, prick test and intradermal test. However, no in vivo or in vitro test can confirm the drug causality. To determine the cause of the eruption, a logical approach based on clinical characteristics, chronologic factors and elimination of differential diagnosis is required, completed with a literature search. A reporting to pharmacovigilance network is essential in case of a serious CADR whatever the suspected drug and in any case if the involved drug is a newly marketed one or unusually related to cutaneous reactions. Copyright © 2014 Société nationale française de médecine interne (SNFMI). Published by Elsevier SAS. All rights reserved.
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ABSTRACT: Non-immediate drug reactions (NIR) are induced by specific immunological mechanisms and involve the recognition of hapten molecules by the immune system, with the participation of dendritic cells and other antigen-presenting cells. This process is followed by an effector response that can induce several clinical entities, ranging from mild to severe. The type of immunological recognition can be used as the basis for the diagnostic approach. Both in vivo and in vitro tests are available for the diagnosis of NIR. In vivo tests consist of the reproduction of a diminished immune response with the culprit drug and in vitro tests are based on the stimulation of memory cells in culture. If both tests give negative results, a drug provocation test can be used.Expert Review of Clinical Immunology 10/2014; 10(11):1-12. DOI:10.1586/1744666X.2014.966691 · 3.34 Impact Factor
Article: FRT – Fondation Rene TouraineExperimental Dermatology 10/2014; 23(10). DOI:10.1111/exd.12534 · 4.12 Impact Factor