Masato Mizuashi

Cellular Basis of the Role of Diesel Exhaust Particles in Inducing Th2-Dominant Response

There is growing evidence that diesel exhaust particles (DEP) can induce allergic diseases with increased IgE production and preferential activation of Th2 cells. To clarify the cellular basis of the role of DEP in the induction of Th2-dominant responses, we examined the effects of DEP on the cytokine production by T cells stimulated with anti-CD3/CD28 Ab and on that by monocyte-derived dendritic cells (MoDCs) stimulated with CD40L and/or IFN-γ. We examined IFN-γ, IL-4, IL-5, IL-8, and IL-10 produced by T cells and TNF-α, IL-1β, IL-10, and IL-12 produced by MoDCs using real-time PCR analysis or by ELISA. To highlight the effects of DEP, we compared the effects of DEP with those of dexamethasone (DEX) and cyclosporin A (CyA). DEP significantly suppressed IFN-γ mRNA expression and protein production, while it did not affect IL-4 or IL-5 mRNA expression or protein production. The suppressive effect on IFN-γ mRNA expression was more potent than that of DEX and comparable at 30 μg/ml with 10−7 M CyA. The suppressive effect on IFN-γ production was also more potent than that of either DEX or CyA. DEP suppressed IL-12p40 and IL-12p35 mRNA expression and IL-12p40 and IL-12p70 production by MoDCs, while it augmented IL-1β mRNA expression. Finally, by using a thiol antioxidant, N-acetyl cysteine, we found that the suppression of IFN-γ production by DEP-treated T cells was mediated by oxidative stress. These data revealed a unique characteristic of DEP, namely that they induce a Th2 cytokine milieu in both T cells and dendritic cells.

A Comparison of the Efficacy, Relapse Rate and Side Effects among Three Modalities of Systemic Corticosteroid Therapy for Alopecia Areata

Background: Systemic corticosteroids are one of the most commonly used therapeutic modalities for patients with extensive alopecia areata (AA), although they entail several drawbacks. Objective: To determine the best modality for systemic corticosteroid use in terms of their efficacy, relapse rate, and side effects. Methods: Fifty-one patients with single or multiple AA (AA/multiplex) and 38 patients with alopecia totalis or AA universalis (AA totalis/universalis) were enrolled in this open study. They were randomly divided into three groups depending on the time of their initial visit. They were administered (1) oral dexamethasone (Dex) 0.5 mg/day for 6 months (Dex group), (2) intramuscular triamcinolone acetonide (imTA) 40 mg once a month for 6 months followed by 40 mg once every 1.5 months for 1 year (imTA group), and (3) pulse therapy (PT) using oral predonine 80 mg for 3 consecutive days once every 3 months (PT group). After the treatment, each treatment modality was evaluated by the response rate, relapse rate, and side effect profile. Results: The response rate of AA/multiplex was significantly better in the imTA group than in the Dex group. The overall relapse rate and that of AA totalis/universalis were significantly better in the PT group than in the Dex group. Dysmenorrhea was the most common and problematic side effect. Impairment of the adrenocortical reserve was seen in 7% of the PT group and 23% of the imTA group, which was recov ered without any further medical treatment. Conclusion: imTA or pulse therapy is effective for AA and has an acceptable level of side effects. The development of a new strategy to reduce the relapse rate is needed.

TGF-β1 dampens the susceptibility of dendritic cells to environmental stimulation, leading to the requirement for danger signals for activation

In contrast to its favourable effects on Langerhans cell (LC) differentiation, transforming growth factor (TGF)‐β1 has been reported to prevent dendritic cells from maturing in response to tumour necrosis factor (TNF)‐α, interleukin (IL)‐1β, or lipopolysaccharide (LPS). We first characterized the effects of TGF‐β1 on dendritic cell function by testing the response of TGF‐β1‐treated monocyte‐derived dendritic cells (MoDCs) to maturation stimuli that LCs receive in the epidermis, namely, haptens, ATP and ultraviolet (UV). TGF‐β1 treatment, which augmented E‐cadherin and down‐regulated dendritic cell‐specific ICAM3‐grabbing non‐integrin on MoDCs, significantly suppressed their CD86 expression and hapten‐induced expression of IL‐1β and TNF‐α mRNA and protein. As TGF‐β1‐treated MoDCs lacked Langerin expression, we demonstrated the suppressive effects of TGF‐β1 on haematopoietic progenitor cell‐derived dendritic cells expressing both CD1a and Langerin. These suppressive effects of TGF‐β1 increased with the duration of treatment. Furthermore, TGF‐β1‐treated MoDCs became resistant to apoptosis/necrosis induced by high hapten, ATP or UV doses. This was mainly attributable to dampened activation of p38 mitogen‐activated protein kinase (MAPK) in TGF‐β1‐treated MoDCs. Notably, although ATP or hapten alone could only induce CD86 expression weakly and could not augment the allogeneic T‐cell stimulatory function of TGF‐β1‐treated MoDCs, ATP and hapten synergized to stimulate these phenotypic and functional changes. Similarly, 2,4‐dinitro, 1‐chlorobenzene (DNCB) augmented the maturation of TGF‐β1‐treated MoDCs upon co‐culture with a keratinocyte cell line, in which ATP released by the hapten‐stimulated keratinocytes synergized with the hapten to induce their maturation. These data may suggest that TGF‐β1 protects LCs from being overactivated by harmless environmental stimulation, while maintaining their ability to become activated in response to danger signals released by keratinocytes.

Oxidation of Cell Surface Thiol Groups by Contact Sensitizers Triggers the Maturation of Dendritic Cells

p38 mitogen-activated protein kinase (MAPK) has a crucial role in the maturation of dendritic cells (DCs) by sensitizers. Recently, it has been reported that the oxidation of cell surface thiols by an exogenous impermeant thiol oxidizer can phosphorylate p38 MAPK. In this study, we examined whether sensitizers oxidize cell surface thiols of monocyte-derived DCs (MoDCs). When cell surface thiols were quantified by flow cytometry using Alexa fluor maleimide, all the sensitizers that we examined decreased cell surface thiols on MoDCs. To examine the effects of decreased cell surface thiols by sensitizers on DC maturation, we analyzed the effects of an impermeant thiol oxidizer, o-phenanthroline copper complex (CuPhen). The treatment of MoDCs with CuPhen decreased cell surface thiols, phosphorylated p38 MAPK, and induced MoDC maturation, that is, the augmentation of CD83, CD86, HLA-DR, and IL-8 mRNA, as well as the downregulation of aquaporin-3 mRNA. The augmentation of CD86 was significantly suppressed when MoDCs were pretreated with N-acetyl-L-cystein or treated with SB203580. Finally, we showed that epicutaneous application of 2,4-dinitrochlorobenzene on mouse skin significantly decreased cell surface thiols of Langerhans cells in vivo. These data suggest that the oxidation of cell surface thiols has some role in triggering DC maturation by sensitizers.

Cadexomer as well as cadexomer iodine induces the production of proinflammatory cytokines and vascular endothelial growth factor by human macrophages

Abstract:  Although cadexomer iodine is widely used for the treatment of skin ulcers such as decubitus ulcers, the mechanism by which it enhances wound healing is not clear. Recently, it has been demonstrated that macrophages play an important role in wound healing by inducing inflammation and angiogenesis.

A randomized double-blind trial of intravenous immunoglobulin for bullous pemphigoid.

BACKGROUND Patients with steroid-resistant bullous pemphigoid (BP) require an appropriate treatment option. OBJECTIVE A multicenter, randomized, placebo-controlled, double-blind trial was conducted to investigate the therapeutic effect of high-dose intravenous immunoglobulin (IVIG; 400mg/kg/day for 5days) in BP patients who showed no symptomatic improvement with prednisolone (≥0.4mg/kg/day) administered. METHODS We evaluated the efficacy using the disease activity score on day15 (DAS15) as a primary endpoint, and changes in the DAS over time, the anti-BP180 antibody titer, and safety for a period of 57days as secondary endpoints. RESULTS We enrolled 56 patients in this study. The DAS15 was 12.5 points lower in the IVIG group than in the placebo group (p=0.089). The mean DAS of the IVIG group was constantly lower than that of the placebo group throughout the course of observation, and a post hoc analysis of covariance revealed a significant difference (p=0.041). Furthermore, when analyzed only in severe cases (DAS≥40), the DAS15 differed significantly (p=0.046). The anti-BP180 antibody titers showed no difference between the two groups. CONCLUSION IVIG provides a beneficial therapeutic outcome for patients with BP who are resistant to steroid therapy.

Molecular Events in Human T Cells Treated with Diesel Exhaust Particles or Formaldehyde that Underlie Their Diminished Interferon-γ and Interleukin-10 Production

Background: A series of epidemiological and experimental studies have suggested that diesel exhaust particles (DEP) and formaldehyde (FA) may help trigger T helper type 2 (Th2)-mediated allergic responses. Methods: To identify the molecular events by which DEP and FA induce a Th2-skewed immune response, we stimulated T cells from healthy subjects with anti-CD3/anti-CD28 monoclonal antibodies and examined the effect of pretreatment with DEP or FA on mitogen-activated protein kinases (MAPKs) and nuclear factor (NF)-κB by Western blotting and colorimetric NF-κB assays. We also examined the mRNA expression profiles of the T cells by microarray and real-time PCR analyses. Results:FA selectively suppressed interferon (IFN)-γ and interleukin-10 mRNA expression and protein production in stimulated T cells, as we previously reported with DEP. In the present study, we found that both DEP and FA suppressed NF-κB signaling and activated MAPKs. Both also significantly suppressed the mRNA expression of T-bet, Txk and c-Maf. Microarrays revealed significant augmentation of the expression of 2 FoxO3a-dependent genes, namely glucocorticoid-induced leucine zipper and growth arrest and DNA damage-inducible gene 45α (Gadd45a), which are known to modulate T cell immune responses. Treatment with N-acetylcysteine reversed the augmented Gadd45a mRNA response and caused the suppressed IFN-γ mRNA response to recover. Conclusions:DEP and FA have similar transcriptional and nontranscriptional effects on T cell signaling that together promote a Th2-skewed immune response.

Comparison of Interleukin-17- Producing Cells in Different Clinical Types of Alopecia Areata

T helper 17 cells, characterized by interleukin-17 (IL-17) production, play a critical role in the pathogenesis of autoimmune disease, including alopecia areata (AA). In this report, we employed immunohistochemical staining for IL-17-producing cells, as well as interferon-γ-producing cells, granulysin-bearing cells and Foxp3+ regulatory T cells, and performed a quantitative analysis of IL-17-producing cells in the lesional skin of several clinical forms of AA by TissueFAXS analysis. Among them, interestingly, the ratio of IL-17-producing cells in acute, diffuse and total alopecia was significantly lower than those of multiple types of AA. Our study sheds light on one of the possible immunological mechanisms of AA.

Pseudolymphomatous angiokeratoma: report of three cases and an immunohistological study

Background.  Pseudolymphomatous angiokeratoma (PA), originally termed ‘acral pseudolymphomatous angiokeratoma of children’, is a disorder characterized clinically by development of red nodules on the extremities and histologically by a subepidermal dense lymphocyte infiltrate.

Successful treatment of syringotropic CD8+ mycosis fungoides accompanied by hypohidrosis with vorinostat and retinoids.

We describe a 34‐year‐old Japanese man with syringotropic CD8+ mycosis fungoides (MF) accompanied by hypohidrosis who was treated with vorinostat and retinoids. Interestingly, immunohistochemical staining for dermcidin revealed a decrease of sweat in the eccrine glands, and a sweat test by the iodine starch method proved hypohidrosis in the MF‐affected areas. Six months after treatment with this combination therapy, the patients advanced MF was under control.