γδ T cells augment rejection of skin grafts by enhancing cross-priming of CD8 T cells to skin-derived antigen

Gamma delta T cells (γδ T cells) possess innate-like properties and are proposed to bridge the gap between innate and adaptive immunity. In this study, we explored the role of γδ T cells in cutaneous immunity using a skin transplantation model. Following engraftment of skin expressing cell-associated model antigen (Ag) (ovalbumin) in epithelial keratinocytes, skin-resident γδ T cells enhanced graft rejection. Although the effector function of CD8 T cells was intact in the absence of γδ T cells, cross-priming of CD8 T cell to graft-derived Ag was impaired in the absence of γδ T cells. The reduced graft rejection and graft priming of γδ T-cell-deficient mice was evident in both acutely inflamed and well-healed grafting models. Furthermore, expression of the CD40 activation marker on migrating dendritic cells was lower in TCRδ(-/-) mice compared with wild-type mice, regardless of the presence or absence of inflammation associated with grafting. These results indicate that γδ T cells enhance graft priming and consequently the likelihood of a successful immune outcome in the context of skin graft rejection, suggesting that γδ T cells may be an important component of immunity to epithelial cancers or infection.     

Expression of IFNγ, coexpression of TNFα and matrix metalloproteinases and apoptosis of T lymphocytes and macrophages in granuloma annulare

Abstract Granuloma annulare, a prototype noninfectious granulomatous dermatitis, is morphologically characterized by a necrobiotic core surrounded by a cellular infiltrate. Because of many morphological similarities to tuberculosis, granuloma annulare has been suggested to represent a delayed-type hypersensitivity (Th1) reaction in the course of which inflammatory cells elicit matrix degradation. In the present study we (1) investigated the expression of interferon-á as the most important Th1-associated cytokine, (2) sought in situ evidence for the coexpression of the proinflammatory cytokine tumor necrosis factor-· and cytokine-regulated matrix metalloproteinases 2 (gelatinase A) and 9 (gelatinase B), and (3) sought to determine whether shrunken cells seen within necrobiotic areas of granuloma annulare are apoptotic cells. In situ hybridization combined with immunofluorescence showed that large numbers of infiltrating CD3⁺ lymphocytes express interferon-á. Application of catalyzed signal amplification in immunodetection revealed that the vast majority of CD3⁺ lymphocytes and CD68⁺ macrophages contained tumor necrosis factor-·. Immunohistochemistry demonstrated that macrophages producing tumor necrosis factor-· coexpress matrix metalloproteinases 2 and 9. In situ end-labeling combined with immunofluorescence detected few apoptotic T cells in perivascular regions and numerous apoptotic macrophages within necrobiotic areas. These results suggest that in granuloma annulare interferon-á⁺ Th-1 lymphocytes may cause a delayed-type hypersensitivity reaction whereby macrophages are differentiated to aggressive effector cells expressing tumor necrosis factor-α and matrix metalloproteinases. In parallel, activation-induced apoptosis in lymphocytes and macrophages may serve to restrict the destructive potential of the inflammatory cells. Received: 23 November 1999 / Received after revision: 28 March 2000 / Accepted: 14 April 2000     

Comparative Analysis of Human Epidermal and Peripheral Blood γδ T Cell Cytokine Profiles

Background

Human epidermal γδ T cells are known to play crucial roles in the defense and homeostasis of the skin. However, their precise mechanism of action in skin inflammation remains less clear.

Objective

In this study, we analyzed the cytokine expression profile of human epidermal γδ T cells and compared it to that of peripheral blood γδ T cells to investigate the specific activity of epidermal γδ T cells in modulating skin inflammation.

Methods

We isolated γδ T cells from epidermal tissue or peripheral blood obtained from healthy volunteers. Isolated γδ T cells were stimulated using immobilized anti-CD3 antibody and interleukin-2 plus phytohaemagglutinin, and were then analyzed using a cytokine array kit.

Results

Both epidermal and peripheral blood γδ T cells produced comparable levels of granulocyte-macrophage colony-stimulating factor, I-309, interferon-γ, macrophage migration inhibitory factor, macrophage inflammatory protein-1α, and chemokine (C-C) ligand 5. The epidermal γδ T cells produced significantly higher levels of interleukin-4, -8, -13, and macrophage inflammatory protein-1β than the peripheral blood γδ T cells did. Notably, the epidermal γδ T cells produced several hundred-fold higher levels of interleukin-13 than interleukin-4.

Conclusion

These results suggest that the epidermal γδ T cells have a stronger potential to participate in the Th2-type response than the peripheral blood γδ T cells do. Furthermore, epidermal γδ T cells might play an important role in the pathogenesis of Th2-dominant skin diseases because of their active production of interleukin-13.     

Hydroa vacciniforme is associated with increased numbers of Epstein-Barr virus-infected γδT cells

Hydroa vacciniforme (HV) is a rare photosensitivity disorder of childhood associated with Epstein-Barr virus (EBV)(+) T-cell infiltration. We have summarized clinical manifestations of HV, and analyzed EBV(+) T-cell subsets as well as EBV DNA load in lymphocyte fractions, in comparison with hypersensitivity to mosquito bites (HMB), an EBV-associated T/natural killer (NK) lymphoproliferative disorder. We found that 31 of 33 (93.9%) HV lesions were composed of EBV(+) T cells and reactive EBV(-) cytotoxic T cells, without significant CD56(+) cell infiltration, whereas many CD56(+) cells were present in 8 of 9 (88.9%) HMB lesions. Of 13 (20.6%) HMB patients with or without HV, 12 (92.3%) showed increased percentages (>32%) of NK cells in the peripheral blood, whereas in the 16 patients with HV alone, 14 (87.5%) showed no increase. Of the 11 HV patients, 10 (90.9%) had increased percentages (>5%) of circulating γδT cells, with a mean value of 15.7 ± 2.9%, and the γδT-cell fractions contained larger amounts of EBV DNA than non-γδT-cell fractions. A triple-labeling method revealed that all three HV patients examined had increased percentages of EBER(+), T-cell receptor (TCR)γδ(+), and TCRαβ(-) cells. Our observations indicate that HV is associated with increased numbers of EBV(+) γδT cells, whereas HMB is associated with EBV(+) NK cells.     

IL-21 enhances antitumor responses without stimulating proliferation of malignant T cells of patients with Sézary syndrome

IL-21, a common gamma-chain cytokine secreted by activated CD4+ T cells, influences both humoral and cell-mediated immune responses through the regulation of T, B, dendritic, and natural killer (NK) cells. Sézary syndrome is an advanced form of cutaneous T-cell lymphoma, a clonally derived malignancy of CD4+ T cells that is characterized by profound defects in host cellular immune function. As a modulator of both innate and adaptive immune responses, IL-21 could play an important role in augmenting cell-mediated immunity in these patients. Normal donor and Sézary syndrome patient peripheral blood mononuclear cells were cultured with IL-21 and tested for CD8+ T- and NK-cell activation, NK-cell cytotoxicity, and tumor cell proliferation and apoptosis. IL-21 resulted in a modest increase in CD8+ T- and NK-cell activation, associated with a marked increase in cytolytic activity against both K562 and malignant CD4+ T-cell targets. Although IL-21 failed to demonstrate pro-apoptotic effects on the malignant CD4+ T cells, it is noteworthy that it had no demonstrable proliferative effects on these cells. Thus, IL-21 may play an important role in enhancing the host immune response of Sézary syndrome patients through the increased cytolytic activity of T and NK cells.     

Variable CD7 expression on T cells in the leukemic phase of cutaneous T cell lymphoma (Sézary syndrome)

CD7, a molecule normally expressed on 90% of normal CD4+ T cells, is often deficient on the malignant T cells of cutaneous T cell lymphoma. To investigate the clinical and biologic implications of CD7 expression, blood lymphocytes from 42 patients with the leukemic phase of cutaneous T cell lymphoma (CD4/CD8 ratio of 10 or more with evidence of a T cell clone in the blood) were analyzed for level of expression of CD7 by flow cytometry. CD7 expression by cells did not clearly segregate into two distinct subgroups that are either CD7 positive or CD7 negative as generally thought; however, nine of 17 patients with a predominantly CD4+CD7+ tumor population on early studies became CD4+CD7- over time whereas the converse situation was not observed. In addition, of three patients with evidence of large tumor cells in the blood coexisting with smaller cells, discordant CD7 expression was observed in one instance. In lymph node specimens, the percentage of cells expressing CD7 and other T cell markers did not correlate with histologic evidence of involvement. CD7 expression on blood lymphocytes also did not correlate with patients' survival nor to serum IgE levels or blood eosinophil counts, a finding suggesting that this marker does not identify functional cell subsets that produce serum interleukin-4 or -5, respectively. We speculate that the level of CD7 expression on malignant T cells may be the effect of sustained antigen stimulation in vivo analogous to what has been proposed to occur with normal T cells during aging.     

Efficacy of excimer light therapy (308 nm) for palmoplantar pustulosis with the induction of circulating regulatory T cells

Abstract: In this open‐label study, we investigated the efficacy of excimer light (308 nm) with a filter to cut off wavelengths below 297 nm for the treatment of palmoplantar pustulosis (PPP). Twenty patients with PPP were recruited and treated once a week for a total of 30 sessions. Patient response was assessed every 10 sessions based on the Palmoplantar Pustulosis Area and Severity Index (PPPASI) score. Levels of Th17 cells and regulatory T cells (Treg) in the peripheral blood in patients with PPP were also evaluated. Mean PPPASI score was 19.5 at baseline, 13.2 at 10 treatments, 10.9 at 20 treatments and 9.5 at 30 treatments. Th17 levels after excimer therapy were not significantly different from those at baseline. In contrast, Treg levels after excimer therapy were significantly higher than those at baseline.     

Narrowband–UVB irradiation decreases the production of pro-inflammatory cytokines by stimulated T cells

Narrow-band ultraviolet B (UVB) phototherapy is an effective treatment for psoriasis. Owing to its limited penetration, the direct effects of UVB are mostly restricted to cells residing in the epidermis and papillary dermis, and are associated with epidermal depletion of Langerhans’ cells (LC) and T cells. It has been argued that the depletion of the skin-resident T-cell population may be due to a combination of UVB-induced apoptosis and decreased recruitment from the blood due to lower expression of the required adhesion and homing molecules. We have previously demonstrated that UVB treatment can alter the expression of adhesion molecules by blood lymphocytes, and as these can be influenced by cytokines, the aim of this study was to investigate whether UVB irradiation can also influence the cytokine production of circulating T cells. Four patients with active chronic plaque psoriasis were treated daily with narrow-band 312 nm UVB irradiation and blood samples obtained before treatment and weekly thereafter for 2 weeks. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured with a streptococcal superantigen or a conventional streptococcal antigen preparation, and cell culture supernatants were assayed for various cytokines. When stimulated with the superantigen, PBMCs from UVB-treated psoriasis patients secreted greater amounts of the anti-inflammatory cytokine IL-10, and showed markedly decreased production of IL-1β, IL-2, IL-5 and IL-6 compared to the pre-treatment values; the production of IFN-γ, IL-8 and IL-12p70 were also decreased but did not reach statistical significance. Thus, the combination of UVB-induced apoptosis, increased secretion of anti-inflammatory cytokines and decreased trafficking to the skin may help to explain the beneficial effects of UVB treatment on psoriasis and why disease remission can sometimes be sustained for a prolonged period.     

Dysfunctional γδ T cells contribute to impaired keratinocyte homeostasis in mouse models of obesity

Skin complications and chronic non-healing wounds are common in obesity, metabolic disease, and type 2 diabetes. Epidermal γδ T cells normally produce keratinocyte growth factors, participate in wound repair, and are necessary for keratinocyte homeostasis. We have determined that in γδ T cell-deficient mice, there are reduced numbers of keratinocytes and the epidermis exhibits a flattened, thinner structure with fewer basal keratinocytes. This is important in obesity, where skin-resident γδ T cells are reduced and rendered dysfunctional. Similar to γδ T cell-deficient mice, keratinocytes are reduced and the epidermal structure is altered in two obese mouse models. Even in regions where γδ T cells are present, there are fewer keratinocytes in obese mice, indicating that dysfunctional γδ T cells are unable to regulate keratinocyte homeostasis. The impact of absent or impaired γδ T cells on epidermal structure is exacerbated in obesity as E-cadherin localization and expression are additionally altered. These studies reveal that γδ T cells are unable to regulate keratinocyte homeostasis in obesity and that the obese environment further impairs skin structure by altering cell-cell adhesion. Together, impaired keratinocyte homeostasis and epidermal barrier function through direct and indirect mechanisms result in susceptibility to skin complications, chronic wounds, and infection.     

Immunohistochemical Analysis of Interleukin-17 Producing T Helper Cells and Regulatory T Cells Infiltration in Annular Erythema Associated with Sj?gren's Syndrome

Background

Peculiar erythema known as annular erythema associated with Sjögren''s syndrome (AESS) can be differentiated from autoimmune annular erythema and subacute cutaneous lupus erythematosus, both clinically and histologically. However, there are no detailed investigations on immune competent cells infiltration.

Objective

Preferential infiltration of interleukin-17-producing T helper (Th17) cells and regulatory T (Treg) cells into the labial salivary gland is reported to play a role in maintaining mucoepithelitis in patients with Sjögren''s syndrome. In this study, we evaluated Th17 and Treg cell infiltration into the lesional skin of AESS.

Methods

We analyzed the numbers and infiltration patterns of Th17 and FoxP3 (+) Treg cells in seven cases of AESS using immunohistochemistry. Seven patients with systemic lupus erythematosus (SLE), atopic dermatitis (AD) and psoriasis vulgaris (PV), which are representatives of Th17 cell-involved skin disorders, were enrolled as disease controls.

Results

Periappendageal and epidermal changes, such as follicular plugging and liquefaction, were evident in the annular erythema of SLE, not AESS, tissue samples. In AESS tissue samples, dense perivascular and periappendageal infiltration of lymph cells was observed in the middle-to-deep dermis, as previously described, in contrast to the superficial infiltration pattern observed in both AD and PV samples. While the total number of infiltrated lymphocytes was similar between AESS and SLE tissue samples, Th17 cells were found to be preferentially infiltrated in the middle-to-deep dermis in AESS samples.

Conclusion

These results suggest that an increased number and distribution of infiltration of Th17 cells is a preferential feature of AESS, rather than a characteristic feature of annular erythema of SLE.     

细胞毒T细胞识别皮肤T细胞淋巴瘤的T细胞受体个体基型肽抗原

目的 确定细胞毒Ｔ细胞是否能识别由第三互补决定区特异基因编码的肽。方法 选择两例皮肤Ｔ细胞淋巴瘤（ＣＴＣＬ）患者（ＳＳ和ＡＲ）和ＣＤ４＾＋、Ｖβ８＾＋恶性Ｔ细胞作为测定肽序列的细胞，ＣＤ８＾＋非恶性Ｔ细胞作为杀伤或反应性细胞，和转化的淋巴母细胞样细胞作为主要组织相容性复合体（ＭＨＣ）抗原提呈的细胞。结果 患者ＳＳ的恶性Ｔ细胞受体（ＴＣＲ）β链的个体基因型肽可刺激ＣＤ８＾＋Ｔ细胞产生肿瘤坏死因子（Ｔ     

细胞毒T细胞识别皮肤T细胞淋巴瘤的T细胞受体个体基因型肽抗原

目的确定细胞毒T细胞是否能识别由第三互补决定区特异基因编码的肽。方法选择两例皮肤T细胞淋巴瘤(CTCL)患者(SS和AR)的CD4 、Vβ8 恶性T细胞作为测定肽序列的细胞 ,CD8 非恶性T细胞作为杀伤或反应性细胞 ,和转化的淋巴母细胞样细胞作为主要组织相容性复合体(MHC)抗原提呈的细胞。结果患者SS的恶性T细胞的T细胞受体(TCR)β 链的个体基因型肽可刺激CD8 T细胞产生肿瘤坏死因子(TNF) α ,但患者AR的MTC的TCR蛋白的个体基因型区的对照肽则不刺激产生TNF α。反之 ,患者AR的CD8 T细胞藉分泌TNF α而对自身肽应答 ,但对来源于对照患者SS和人类免疫缺陷病毒感染患者的其他肽不应答。结论细胞毒T细胞对CTCL的淋巴细胞个体恶性克隆独特的特殊的MHCⅠ类相关肽的识别和应答具有特异性 ,确定CTCL的肿瘤特异性定位 ,可进一步为能够激发对肿瘤细胞的CD8 T细胞参与的免疫应答的疫苗研制和治疗提供新线索     

辅助性T细胞17和调节性T细胞与皮肤病

辅助性T细胞17和调节性T细胞是近年发现的CD4+T细胞亚群,辅助性T细胞17主要通过其分泌的白介素-17等细胞因子促进中性粒细胞的活化及募集,介导促炎症反应.调节性T细胞主要通过直接接触和分泌抑制性细胞因子等效应机制发挥免疫抑制作用,维持机体自身耐受.两者均参与自身免疫性疾病、感染性疾病及肿瘤等疾病的发生发展.有研究表明,辅助性T细胞17/调节性T细胞平衡异常引起全身或局部免疫应答异常是导致这些疾病的发生发展的重要机制之一.     

T细胞受体基因重排检测皮肤T细胞淋巴瘤

为了研究基因诊断在皮肤Ｔ细胞淋巴瘤的临床应用，采用聚合酶链反应技术，对６０例皮肤淋巴细胞浸润疾患进行了Ｔ细胞受体基因重排的检测。结果显示，检出ＴＣＲ－β和ＴＣＲ－γ基因克隆重排的有：３６／４０例ＣＴＣＬ，４／６例可疑蕈样肉芽肿／Ｓｅｚａｒｙ综合征和１／１例淋巴瘤样丘疹病。