Yoshimi Yamazaki

Defective Regulatory T Cells In Patients with Severe Drug Eruptions: Timing of the Dysfunction Is Associated with the Pathological Phenotype and Outcome

Toxic epidermal necrolysis (TEN) and drug-induced hypersensitivity syndrome (DIHS) represent two ends of a spectrum of severe drug eruptions: DIHS is unique in that severe epidermal damage seen in TEN is absent, sequential reactivations of herpesviruses occur, and autoimmunity often ensues. To investigate whether changes in regulatory T (Treg) cell function would contribute to variability in the clinical manifestations, we examined the frequency, phenotype, and function of Treg cells both during the acute stage and again long after clinical resolution of both diseases. Dramatic expansions of functional Treg cells were found in the acute stage of DIHS. In contrast, Treg function was profoundly impaired in TEN, although present in normal frequency. Skin homing addressins were more preferentially expressed on Treg cells in DIHS than in TEN. Indeed, Treg cells were more abundantly present in the skin lesions of DIHS. Surprisingly, Treg cells contracted upon resolution of DIHS became functionally deficient, whereas their functional defects in TEN were restored upon recovery. These findings indicate that a transitory impairment in their function during the acute stage of TEN may be related to severe epidermal damage, while a gradual loss of their function after resolution of DIHS may increase the risk of subsequently developing autoimmune disease.

Direct Evidence for Interferon-γ Production by Effector-Memory-Type Intraepidermal T Cells Residing at an Effector Site of Immunopathology in Fixed Drug Eruption

Effector-memory T cells are strategically placed to epithelial tissues to provide frontline immune protection against pathogens. Their detrimental effects, however, have been rarely examined because of difficulty in sampling these T cells in pathological settings. Our previous studies suggested persistence of a similar subset of intraepidermal CD8(+) T cells at high frequencies in the lesions of fixed drug eruption, a localized variant of drug-induced dermatoses. In situ activation of this subset resulting in localized epidermal injury can be traced in the lesions after antigen challenge by paired immunohistochemical staining, reverse transcriptase-polymerase chain reaction in situ, and flow cytometry of dispersed cells. Here we show that effector-memory T cells were greatly enriched in these intraepidermal CD8(+) T cells, but not dermal and circulating counterparts, and that they constitutively express an early activation marker CD69 even before challenge. Surprisingly, a large proportion of these T cells expressed immediate effector function as evidenced by the rapid production of high levels of interferon-gamma in situ with much faster kinetics than their counterparts at the mRNA and protein levels after challenge. This was followed by localized epidermal injury. The intracellular cytokine assay ex vivo shows that the great majority of these dispersed T cells produce interferon-gamma. This study provides the first in situ description of the detrimental effects specifically mediated by effector-memory T cells residing at the effector site of immunopathology.

In vivo dynamics of intraepidermal CD8+ T cells and CD4+ T cells during the evolution of fixed drug eruption

Background  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.

In Vitro Differentiation from Naive to Mature E-Selectin Binding CD4 T Cells: Acquisition of Skin-Homing Properties Occurs Independently of Cutaneous Lymphocyte Antigen Expression

We previously showed that skin-homing CD4 T cells in peripheral blood can be subdivided into three populations on the basis of the expression pattern of the cutaneous lymphocyte Ag (CLA) and fucosyltransferase VII (FucT-VII): FucT-VII+CLA−, FucT-VII+CLA+, and FucT-VII−CLA+. In view of the known late appearance of CLA during T cell differentiation, T cells programmed to attain skin-homing properties may start to generate E-selectin-binding epitopes at early stages of differentiation before induction of CLA expression. To this end, the in vitro differentiation from naive to CLA+ memory T cells was followed after activation with anti-CD3 mAb. Here we demonstrate that naive skin-homing CD4 T cell precursors undergo a linear differentiation process from the FucT-VII+CLA− phenotype to the FucT-VII+CLA+ phenotype and eventually to the FucT-VII−CLA+ phenotype. The appearance of the FucT-VII+CLA− subset coincided with or could be immediately followed by the generation of E-selectin binding epitopes, and even after E-selectin-binding epitopes were no longer detectable, CLA remained expressed for prolonged periods of time, suggesting that induction of functional E-selectin ligands depends primarily on the expression of FucT-VII, but not CLA. Immunofluorescence and confocal microscopy studies of these T cells confirm that most E-selectin ligands were found independently of CLA expression.

Varicella-zoster virus antigen expression of eccrine gland and duct epithelium in herpes zoster lesions

Background  It is well known that varicella‐zoster virus (VZV) exhibits tropism for the epidermis and follicular epithelium, while little attention has been paid to eccrine gland and duct involvement by VZV. The presence of herpetic syringitis in immunocompromised hosts suggested the possibility of eccrine gland and duct involvement by VZV.

Immunohistochemical Detection of Skin-Homing T Cells Expressing Fucosyltransferase VII (Fuc-TVII) In Vitro and In Situ

Although expression of cutaneous lymphocyte-associated antigen (CLA) is thought to be a specific marker of skin “homing” T cells, it has become clear that CLA is a good marker for high levels of fucosyltransferase VII (Fuc-TVII) activity but does not necessarily represent the epitope required for binding to E-selectin (Wagers et al, 1996, 1997). Therefore, expression of Fuc-TVII is an attractive candidate for identifying skin “homing” T cells. However, analyses of Fuc-TVII expression in human T cells have been performed only at the mRNA level (Nakayama et al, 2000) because of the lack of mAb. In this study Fuc-TVII was for the first time visualized in individual cells by using a novel mAb that we developed. Double immunofluorescence and immunohistochemistry demonstrated the coexpression of Fuc-TVII and CLA in cell lines in which Fuc-TVII mRNA was shown to be expressed at high levels: whereas CLA expression was seen in the cell membrane, Fuc-TVII was identified in a supra- or perinuclear location. Cytoplasmic Fuc-TVII expression was also detectable in both CD4+ and CD8+ T cells purified from peripheral blood. Fuc-TVII was also expressed at high levels in many CLA+ T cells infiltrating the skin. In these peripheral T cells, unlike in cell lines, cytoplasmic expression of Fuc-TVII was not always associated with surface CLA expression. This mAb would serve as a valuable tool for selectively identifying a novel subset of skin “homing” T cells that are not detected by the conventional method because of the lack of CLA expression.

Localized hypohidrosis is an unrecognized sequela of herpes zoster.

The effectiveness of PRP is based on its high level of growth factors such as PDGF, TGF, and EGF. These growth factors are important in modulating mesenchymal cell proliferation, and extracellular matrix synthesis during healing. PRP has shown to be effective at propagating new healthy tissue growth in a wide range of medical conditions such as diabetic foot ulcers, venous stasis ulcers, and tendonopathy. The vast majority of published literature shows that autologous PRP has minimal risk of scar tissue formation or serious adverse events (SAEs). Previously, 1 study examined injections of a combination of PRP and fat-derived mesenchymal cells in 15 women with VLS. The authors reported that ‘‘all patients reported total disappearance of pain and symptoms.’’ However, a significant limitation of the study was that 2 concurrent interventions were performed, which limited the ability to determine which intervention was efficacious or necessary. In addition, no objective measures of efficacy were used. In contrast, our study used an objective endpoint (decrease in histopathologic inflammation) measured by masked evaluators. Limitations of this study are the small sample size, lack of placebo control, and short-term follow-up. However, the statistically significant results suggest that PRP decreased histopathologic inflammation in women with VLS without the potential side effects associated with topical or systemic immunomodulators.

IgA vasculitis with severe gastrointestinal symptoms may be an unusual manifestation of varicella-zoster virus reactivation

Immunoglobulin A vasculitis (IAV), formerly called Henoch-Schonlein purpura, is an acute leukocytoclastic vasculitis of unknown etiology that is manifested as palpable purpura or petechiae associated with arthralgia, abdominal pain, and nephritis.1, 2 This article is protected by copyright. All rights reserved.

Lichen amyloidosus as a sweat gland/duct-related disorder: Resolution associated with restoration of sweating disturbance

Although a number of pathological processes resulting in amyloid deposition have been described in lichen amyloidosus (LA), no attention has been paid to the involvement of sweat glands/ducts in the pathogenesis of LA. According to recent studies, follicular structures are usually spared in serial histological sections of LA, and deposits of amyloid are likely to be confined to areas that display xerosis, suggesting that decreases in skin wetness by sweating disturbance seem to initiate LA.

Pathological Role of Regulatory T Cells in the Initiation and Maintenance of Eczema Herpeticum Lesions

It remains unknown why the occurrence of eczema herpeticum (EH) caused by an extensive disseminated cutaneous infection with HSV-1 or HSV-2 is associated with the exacerbation of atopic dermatitis lesions after withdrawal of treatment. Although regulatory T cells (Tregs) limit the magnitude of HSV-specific T cell responses in mice, their role in the induction and resolution of EH has not been defined. We initially investigated the frequencies, phenotype, and function of Tregs in the peripheral blood of atopic dermatitis with EH (ADEH) patients at onset and after clinical resolution, atopic dermatitis patients without EH, and healthy controls. Tregs with the skin-homing phenotype and the activated/induced phenotype were expanded at onset and contracted upon resolution. Treg-suppressive capacity was retained in ADEH patients and, the expanded Tregs suppressed IFN-γ production from HSV-1–specific CD8+ and CD4+ T cells. The increased frequency of CD14dimCD16+ proinflammatory monocytes (pMOs) was also observed in the blood and EH skin lesions. Thus, pMOs detected in ADEH patients at onset were characterized by an increased ability to produce IL-10 and a decreased ability to produce proinflammatory cytokines, unlike their normal counterparts. Our coculture study using Tregs and pMOs showed that the pMOs can promote the expansion of inducible Tregs. Tregs were detected frequently in the vicinity of HSV-expressing and varicella zoster virus–expressing CD16+ monocytes in the EH lesions. Expansions of functional Tregs, together with pMOs, initially required for ameliorating excessive inflammation occurring after withdrawal of topical corticosteroids could, in turn, contribute to the initiation and progression of HSV reactivation, resulting in the onset of EH.