Setsuya Aiba

Dermatofibrosarcoma protuberans is a unique fibrohistiocytic tumour expressing CD34

Summary Dermatofibrosarcoma protuberans (DFSP) is a slow growing, locally invasive tumour whose differentiation from other fibrohistiocytic tumours sometimes poses serious diagnostic problems. We investigated CD34 expression immunohistologically in various fibrohistiocytic tumours including dermatofibroma, DFSP, malignant fibrous histiocytoma (MFH), infantile myofibromatosis, fibrosarcoma, hypertrophic scar and keloid. Among these, DFSP was unique in that tumour cells themselves expressed CD34, whereas in other tumours, CD34 expression was observed only on vascular endothelial cells amongst the tumour cells. Until now, there have been no reports of useful immunohistological markers for DFSP. CD34 expression by the tumour cells can be an extremely useful marker in establishing a definitive diagnosis of DFSP.

A randomized double-blind trial of intravenous immunoglobulin for pemphigus

BACKGROUND Pemphigus is a rare life-threatening intractable autoimmune blistering disease caused by IgG autoantibodies to desmogleins. It has been difficult to conduct a double-blind clinical study for pemphigus partly because, in a placebo group, appropriate treatment often must be provided when the disease flares. OBJECTIVE A multicenter, randomized, placebo-controlled, double-blind trial was conducted to investigate the therapeutic effect of a single cycle of high-dose intravenous immunoglobulin (400, 200, or 0 mg/kg/d) administered over 5 consecutive days in patients relatively resistant to systemic steroids. METHODS We evaluated efficacy with time to escape from the protocol as a novel primary end point, and pemphigus activity score, antidesmoglein enzyme-linked immunosorbent assay scores, and safety as secondary end points. RESULTS We enrolled 61 patients with pemphigus vulgaris or pemphigus foliaceus who did not respond to prednisolone (> or =20 mg/d). Time to escape from the protocol was significantly prolonged in the 400-mg group compared with the placebo group (P < .001), and a dose-response relationship among the 3 treatment groups was observed (P < .001). Disease activity and enzyme-linked immunosorbent assay scores were significantly lower in the 400-mg group than in the other groups (P < .05 on day 43, P < .01 on day 85). There was no significant difference in the safety end point among the 3 treatment groups. LIMITATION Prednisolone at 20 mg/d or more may not be high enough to define steroid resistance. CONCLUSION Intravenous immunoglobulin (400 mg/kg/d for 5 d) in a single cycle is an effective and safe treatment for patients with pemphigus who are relatively resistant to systemic steroids. Time to escape from the protocol is a useful indicator for evaluation in randomized, placebo-controlled, double-blind studies of rare and serious diseases.

Targeting Apoptotic Tumor Cells to FcγR Provides Efficient and Versatile Vaccination Against Tumors by Dendritic Cells

Dendritic cells (DCs) loaded with tumor-associated Ags (TAAs) act as potent adjuvant that initiates antitumor immune responses in vivo. However, TAA-based DC vaccination requires prior identification of TAAs. Apoptotic tumor cells (ATCs) can be an excellent source for DC loading because their potential uncharacterized Ags would be efficiently presented to T cells without any prior characterization and isolation of these Ags. However, ATCs alone are considered to be inefficient for activating antitumor immunity, possibly because of their inability to induce DC maturation. In this study, the aim was to enhance antitumor immune response by taking advantage of ATCs that have been opsonized with IgG (ATC-immune complexes, ATC-ICs) so as to target them to FcR for IgG (FcγRs) on DCs. It was found that when compared with ATCs, ATC-ICs were efficiently internalized by DCs via FcγRs, and this process induced maturation of DCs, which was more efficient than that of ATCs. Importantly, ATC-IC loading was shown to be more efficient than ATCs alone in its capacity for inducing antitumor immunity in vivo, in terms of cytotoxic T cell induction and tumor rejection. These results show that using ATC-ICs may overcome the limitations and may enhance the immune response of current ATC-based DC vaccination therapy.

Simple chemicals can induce maturation and apoptosis of dendritic cells

As is well known in the case of Langerhans cells, dendritic cells (DCs) play a crucial role in the initiation of immunity to simple chemicals such as noted in the contact hypersensitivity. Because DCs are scattered in non‐lymphoid organs as immature cells, they must be activated to initiate primary antigen‐specific immune reactions. Therefore, we hypothesized that some simple chemicals must affect the function of DCs. In this paper, we first demonstrated that human monocyte‐derived DCs responded to such simple chemicals as 2,4‐dinitrochlorobenzene (DNCB), 2,4,6‐trinitrochlorobenzene (TNCB), 2,4‐dinitrofluorobenzene (DNFB), NiCl2, MnCl2, CoCl2, SnCl2, and CdSO4 by augmenting their expression of CD86 or human leucocyte antigen‐DR (HLA‐DR), down‐regulating c‐Fms expression or increasing their production of tumour necrosis factor‐α (TNF‐α). In addition, the DCs stimulated with the chemicals demonstrated increased allogeneic T‐cell stimulatory function. Next, we found that, among these chemicals, only NiCl2 and CoCl2 induced apoptosis in them. Finally, we examined the effects of these chemicals on CD86 expression by three different macrophage subsets and DCs induced from the cultures of human peripheral blood monocytes in the presence of macrophage colony‐stimulating factor (M‐CSF), M‐CSF + interleukin‐4 (IL‐4), granulocyte–macrophage colony‐stimulating factor (GM‐CSF), and GM‐CSF + IL‐4, respectively. Among them, only DCs dramatically augmented their expression of CD86. These observations have revealed unique characteristics of DCs, which convert chemical stimuli to augmentation of their antigen presenting function, although their responses to different chemicals were not necessarily uniform in the phenotypic changes, cytokine production or in the induction of apoptosis.

In vitro treatment of human transforming growth factor‐β1‐treated monocyte‐derived dendritic cells with haptens can induce the phenotypic and functional changes similar to epidermal Langerhans cells in the initiation phase of allergic contact sensitivity reaction

Human monocyte‐derived dendritic cells (MoDCs) obtained from peripheral blood monocytes (PBMC) cultured with granulocyte–macrophage colony‐stimulating factor (GM‐CSF) and interleukin‐4 (IL‐4) can be activated in vitro by a variety of simple chemicals such as haptens and several metals. Recently, it has been demonstrated that transforming growth factor‐β1 (TGF‐β1) can induce further differentiation of MoDCs to the cells that share some characteristics with epidermal Langerhans cells, i.e. they contain Birbeck granules and express E‐cadherin. In this study, using such TGF‐β1‐treated dendritic cells (TGF‐β1+ DCs), we examined the in vitro effects of representative haptens, i.e. NiCl2 and dinitrochlorobenzene (DNCB), on their phenotypic and functional characteristics, comparing with those reported in vivo in epidermal Langerhans cells during the sensitization phase of a contact sensitivity reaction. Treatment of TGF‐β1+ DCs with NiCl2 increased their expression of the molecules related to antigen presentation such as CD86, major histocompatibility complex class I and class II, and CD83, although weakly, in addition to that of those essential for their migration to the regional lymph nodes, such as CD49e, CD44 and its variant 6, while it down‐regulated the expression of the molecules required for homing to the skin and staying in the epidermis, such as cutaneous leucocyte antigen (CLA) and E‐cadherin. It also increased the production of tumour necrosis factor‐α, but not that of IL‐1β or IL‐12. DNCB also increased their CD86 expression and down‐regulated E‐cadherin and CLA, but did not affect other phenotypic changes that were observed in TGF‐β1+ DCs treated with NiCl2. TGF‐β1+ DCs treated with either NiCl2 or DNCB increased their allogeneic T‐cell stimulatory function. In addition, reverse transcribed polymerase chain reaction revealed augmented expression of chemokine receptor 7 mRNA by TGF‐β1+ DCs when treated with either NiCl2 or DNCB. Moreover, consistent with this data, TGF‐β1+ DCs treated with these chemicals chemotactically responded to macrophage inflammatory protein‐3β. These data suggest the possibility that TGF‐β1+ DCs present a good in vitro model to study the biology of epidermal Langerhans cells.

A role of melatonin in neuroectodermal-mesodermal interactions: the hair follicle synthesizes melatonin and expresses functional melatonin receptors

Since mammalian skin expresses the enzymatic apparatus for melatonin synthesis, it may be an extrapineal site of melatonin synthesis. However, evidence is still lacking that this is really the case in situ. Here, we demonstrate melatonin‐like immunoreactivity (IR) in the outer root sheath (ORS) of mouse and human hair follicles (HFs), which corresponds to melatonin, as shown by radioimmunoassay and liquid chromatography/tandem mass spectrometry (LC/MS/MS). The melatonin concentration in organ‐cultured mouse skin, mouse vibrissae follicles, and human scalp HFs far exceeds the respective melatonin serum level and is significantly increased ex vivo by stimulation with norepinephrine (NE), the key stimulus for pineal melatonin synthesis. By real‐time PCR, transcripts for the melatonin membrane receptor MT2 and for the nuclear mediator of melatonin signaling, retinoid orphan receptor α (ROR)α, are detectable in murine back skin. Transcript levels for these receptors fluctuate in a hair cycle‐dependent manner, and are maximal during apoptosis‐driven HF regression (catagen). Melatonin may play a role in hair cycle regulation, since its receptors (MT2 and RORα) are expressed in murine skin in a hair cycle‐dependent manner, and because it inhibits keratinocyte apoptosis and down‐regulates ERα expression. Therefore, the HF is both, a prominent extrapineal melatonin source, and an important peripheral melatonin target tissue. Regulated intrafollicular melatonin synthesis and signaling may play a previously unrecognized role in the endogenous controls of hair growth, for example, by modulating keratinocyte apoptosis during catagen and by desensitizing the HF to estrogen signaling. As a prototypic neuroectodermal‐mesodermal interaction model, the HF can be exploited for dissecting the obscure role of melatonin in such interactions in peripheral tissues.

Evaluation of CD86 expression and MHC class II molecule internalization in THP-1 human monocyte cells as predictive endpoints for contact sensitizers

The aim of this study was to explore the usefulness of a human monocyte cell line in the development of in vitro models for predictive testing of contact sensitizers. Several studies have shown that contact sensitizers induce CD86 expression and enhanced internalization of MHC class II molecules in dendritic cells (DCs). We used THP-1, a human monocyte cell line, as a replacement for DCs for evaluation of these phenotypical alterations as predictive endpoints for contact sensitizers. Known sensitizers and irritants were evaluated. After 24-h exposure to samples, the expression of CD86 on THP-1 cells was measured by flow cytometry. Sensitizers such as dinitrochlorobenzene (DNCB), 2-mercaptobenzothiazole (MBT), eugenol, p-phenylenediamine (PPDA) and ammonium tetrachloroplatinate (Pt) enhanced CD86 expression on THP-1 cells, while nickel sulfate, cobalt sulfate and irritants such as methylsalicylate (MS), sodium dodecyl sulfate (SDS) and dimethyl sulfoxide (DMSO) did not augment CD86 expression. A synergistic effect was observed when DNCB and IFN-alpha were added simultaneously to a culture of THP-1 cells. Furthermore, internalization of MHC class II molecules was observed when the cells were treated with some of sensitizers for 2 h. The inducing effects of chemicals on the two phenotypical alterations were the same. These results suggest that these test systems can be used to predict contact-sensitizing ability of chemicals as an in vitro sensitization assay.

Immunohistologic analysis of the phenomenon of spontaneous regression of numerous flat warts.

Among various tumors induced by human papilloma virus (HPV), flat warts are unique in that they show a systemic regression phenomenon after sudden occurrence of inflammation in all the tumors, leaving permanent immunity to flat warts in the host. When studied immunohistochemically, the presence of HPV antigen using papilloma virus genus‐specific antiserum in 31 cases of regressing flat warts was not found; whereas it was demonstrated in the nuclei of upper epidermal cells of ordinary flat warts in 12 of 19 cases (63%). T‐cell phenotype assessment in nine regressing flat warts using monoclonal antibodies showed that helper/inducer subsets constituted a major peritumoral dermal infiltrate with a moderate number of intermingling OKT6+ cells. In contrast, the tumoral epidermis was invaded by almost equal number of suppressor/cytotoxic T‐cells and helper/inducer T‐cells, where at least some keratinocytes also expressed HLA‐DR antigen in addition to Langerhans cells. Most T‐cells expressed HLA‐DR antigen, a marker of activation, but only a small number of them were Tac antigen+, i.e., bearing interleukin 2 receptors. Leu 7+ natural killer cells were seldom found in the infiltrate. These data provide evidence that T‐cell‐mediated immune attack against tumor cells and not against intranuclear HPV antigen, induces the systemic spontaneous regression of numerous flat warts in humans.

Enhanced Apoptosis by Disruption of the STAT3-IκB-ζ Signaling Pathway in Epithelial Cells Induces Sjögren’s Syndrome-like Autoimmune Disease

Sjögrens syndrome (SS) is an autoimmune disease characterized by exocrinopathy that leads to dry eye and mouth. Although lymphocyte infiltration into exocrine glands and the generation of autoantibodies have been reported in SS, its pathogenic mechanism remains elusive. Here, we show that mice lacking the transcriptional regulator IκB-ζ developed SS-like inflammation characterized by lymphocyte-infiltrated dacryoadenitis and SS-associated autoantibodies. In particular, epithelial cells, but not hematopoietic cells, lacking IκB-ζ were essential for the development of inflammation. IκB-ζ-deficient epithelial cells in the lacrimal glands exhibited enhanced apoptosis even in the absence of lymphocytes. Administration of caspase inhibitors ameliorated the inflammation, indicating the critical role of caspase-mediated apoptosis. Furthermore, epithelial cell-specific STAT3-deficient mice developed SS-like inflammation with impaired IκB-ζ expression in the lacrimal glands. Thus, this study reveals a pathogenic mechanism of SS in which dysfunction of epithelial cells caused by disruption of STAT3-mediated IκB-ζ induction elicits the activation of self-reactive lymphocytes.

HLA-DR antigen expression on the keratinocyte surface in dermatoses characterized by lymphocytic exocytosis (e.g. pityriasis rosea)

We have investigated the immunoperoxidase staining pattern of the epidermis in several dermatoses characterized by exocytosis of mononuclear cells into the epidermis. We found that HLA‐DR antigens showed an intercellular distribution in localized areas of the epidermis in nine of ten cases of pityriasis rosea, and in all four cases of spontaneously regressing flat warts, two cases of pityriasis lichenoides chronica, two of Schambergs disease, and one case of lichen striatus. Lichen planus and mycosis fungoides cases were used as positive controls. OKT6 antigen was recognized only on the dendritic cells of the epidermis in all these cases. Judging from the distribution of Langerhans cells, the epidermal intercellular HLA‐DR antigen seems to be expressed on the keratinocytes in such diseases, and this feature was confirmed by immunoelectron microscopy. These findings support the hypothesis that the expression of HLA‐DR antigen on keratinocytes in these dermatoses is linked to cellular immune reactions involving the epidermis.