CD4+ and CD8+ T cells mediated direct cytotoxic effect against Trichophyton rubrum and Trichophyton mentagrophytes

Background The cellular immune system is the most dominant factor in curing acute dermatophytosis. However, the exact immune mechanisms involved in generating this defense are complex and still obscure. The aim of this study was to investigate the fungicidal mechanism of T cells in the normal population versus patients with chronic fungal infections. Methods Thirty patients were included in the study: 15 patients with chronic dermatophytosis and 15 normal healthy patients with a history of acute dermatophytosis. The procedures were performed as follows. 1) Proliferation and cytotoxic activity of lymphocytes cultured with various dermatophytes homogenate such as, Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum gypseum. 2) CD4⁺ and CD8⁺ T cells were separated by magnetic beads before culture with fresh spores of either T. mentagrophytes or T. rubrum. 3) Routine histology and ultrastructural study were performed to illustrate the mode of activity of the T cells against the dermatophytes. Results The study showed that both CD4 and CD8 possess cytotoxic activity against dermatophytes. However, the results demonstrated a suppression of lymphocyte proliferation response and a significant lower cytotoxic effect in chronic patients. Ultra structure and histological evaluation of the culture of hyphae with CD4⁺ or CD8⁺ T cells showed more prominently destructive effects in the culture of cells that had been obtained from normal population than those of patients with long‐lasting fungal infections. Conclusion The study suggests a selective impairment of lymphocyte function against dermatophytes, in patients with chronic dermatophytoses.     

Decreased suppression of CD8+ and CD4+ T cells by peripheral regulatory T cells in generalized vitiligo due to reduced NFATC1 and FOXP3 proteins

Regulatory T cells (Tregs) are involved in the suppression of activated T cells in generalized vitiligo (GV). The study was aimed to investigate Tregs functional defects in Treg:CD8⁺ and Treg:CD4⁺ T cells' co-culture systems of 55 GV patients and 45 controls. CD8⁺ and CD4⁺ T-cell proliferation was assessed by BrdU assay; production of IL-10, TGF-β and IFN-γ cytokines was assessed by ELISA; and FOXP3, CD25, NFATC1 and CD44 proteins were measured by flow cytometry. Generalized vitiligo patients showed reduced suppression of CD8⁺ and CD4⁺ T cells (P = .0384, P = .0084), increased IFN-γ (P < .0001, P = .0019), decreased IL-10 and TGF-β (P < .0001) and decreased FOXP3, CD25 and NFATC1 proteins (P < .0001). Active vitiligo (AV) patients showed reduced suppression of CD8⁺ & CD4⁺ T cells (P = .006, P = .015), increased IFN-γ (P = .036, P = .045), decreased IL-10 (P = .009, P = .021), FOXP3 (P = .0244) and NFATC1 (P = .019). Severe GV (50%-75% VASI) patients showed reduced suppression of CD8⁺ and CD4⁺ T cells (P = .0003, P = .001), increased IFN-γ (P = .0029, P < .0001), decreased IL-10 (P = .0057, P = .0017), FOXP3 (P = .002) and NFATC1 (P = .0347). VASI score was positively correlated with the suppression of CD8⁺ and CD4⁺ T cells (P = .0006, P < .0001), IL-10 (P = .0096, P = .029), FOXP3 (P = .0008) and NFATC1 (P = .043), whereas it was negatively correlated with IFN-γ (P = .0029, P = .0017). Early age of onset patients' Tregs demonstrated decreased suppression of CD8⁺ and CD4⁺ T cells (P = .0156, P = .0074), decreased TGF-β (P = .0212, P = .0083) and NFATC1 (P = .0103). NFATC1 was positively correlated with FOXP3 in Tregs (P < .0001). Our results suggest impaired Tregs suppressive function in GV patients due to decreased NFATC1, FOXP3, CD25, IL-10 and TGF-β resulting into increased CD8⁺ and CD4⁺ T-cell proliferation and IFN-γ production. For the first time, decreased NFATC1 levels were correlated with decreased FOXP3, thereby altering Treg cell function in GV patients. Additionally, decreased Treg cell function also affected onset, activity and severity of GV.     

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. Objectives 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. Methods 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. Results 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). Conclusions 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.     

CD70-CD27 interaction augments CD8+ T-cell activation by human epidermal Langerhans cells

Human cutaneous dendritic cells (DCs) from epidermal and dermal compartments exhibit functional differences in their induction of CD4+ T-cell and humoral immune responses; however, differences in the regulation of memory CD8+ T-cell responses by human skin DCs remain poorly characterized. We tested the capacity of human Langerhans cells (LCs) and dermal dendritic cells (DDCs) to induce antigen-specific cytokine production and proliferation of memory CD8+ cells. Although tumor necrosis factor-α-matured human DCs from both epidermal and dermal compartments showed efficient potential to activate CD8+ cells, LCs were constitutively more efficient than DDCs in cross-presenting CD8+ epitopes, as well as direct presentation of viral antigen to Epstein-Barr virus-specific CD8+ T cells. LCs showed greater expression of CD70, and blockade of CD70-CD27 signaling demonstrated that superiority of CD8+ activation by epidermal LC is CD70 dependent. This CD70-related activation of CD8+ cells by LCs denotes a central role of LCs in CD8+ immunity in skin, and suggests that regulation of LC CD70 expression is important in enhancing immunity against cutaneous epithelial pathogens and cancer.     

Augmentation of monocyte interleukin-8 production by psoralen/UVA-treated CD4+ T cells

Treatment of cells with psoralen and ultraviolet A light (UVA) modulates their cytokine production. As extracorporeal photochemotherapy has been reported to induce cytokine production by monocytes, we quantified interleukin-8 (IL-8), a representative chemokine produced by monocytes, in culture supernatants from human peripheral blood mononuclear cells (PBMC) treated with 8-methoxypsoralen (8-MOP) and UVA. Lipopolysaccharide stimulated IL-8 production in 8-MOP-phototreated PBMC more efficiently than those untreated or treated with 8-MOP or UVA. More interestingly, when cultured with T-cell-stimulating anti-CD3 and anti-CD28 antibodies, 8-MOP/UVA-treated PBMC produced enhanced amounts of IL-8 with an increased level of IL-8 mRNA expression. Depletion of CD4 but not CD8 T cells from PBMC abrogated this augmented IL-8 elaboration, and CD4 T cells per se secreted no substantial amount of IL-8 even upon CD3/CD28 stimulation. Thus, 8-MOP/UVA-treated CD4 T cells stimulated monocytes to secrete IL-8. The IL-8 overproduction was induced by direct contact of monocytes with 8-MOP/UVA-treated CD4 T cells but not by cytokines from the treated CD4 T cells. These findings imply that in extracorporeal photochemotherapy, monocytes effectively produce IL-8 by cell-to-cell contact with 8-MOP/UVA-treated malignant CD4 T cells. The augmentation of monocyte cytokine/chemokine production by 8-MOP/UVA may be one of the mechanisms underlying the therapeutic efficacy of extracorporeal photochemotherapy.     

Correlation of psoriasis activity with abundance of CD25+CD8+ T cells: conditions for cloning T cells from psoriatic plaques

The role of T cells in the pathogenesis of psoriasis is widely acknowledged. However, key aspects of their precise function in the disease as well as the relative pathogenic contribution of T-cell subsets are still unknown. T-cell clones have been isolated from psoriatic plaques but a study of conditions affecting the isolation and expansion of T-cell clones from psoriatic skin has not been reported to date. Here, we observe a correlation of disease activity with the frequency of the CD3(+)CD8(+)CD25(+) subset. We show that prolonged in vitro culture changes the phenotypic subset distribution of T-cell lines derived from psoriatic skin and that T-cell clones can be isolated by sorting of CD25(+) cells emigrated from skin fragments after 7 days. We evaluate various conditions affecting expansion of psoriatic T-cell clones in vitro and show that blocking apoptosis can facilitate proliferation of activated T-cell clones in vitro. Our results indicate a prominent role of the CD8(+)CD25(+) T-cell subset in disease pathogenesis and should be useful in the design of experiments aiming at a systematic analysis of the specificity of clones present in psoriatic plaques.     

CD8+ T cells are effector cells of contact dermatitis to common skin allergens in mice

Allergic contact dermatitis (ACD) to strong experimental haptens is mediated by specific CD8+ T cells. Here, we show that similar mechanisms occur for weak haptens, which comprise the vast majority of chemicals responsible for human ACD. We used a model of ACD, that is, the contact hypersensitivity reaction, to test for the allergenicity of three weak haptens involved in fragrance allergy. ACD to weak haptens could not be induced in normal mice. In contrast, mice acutely depleted in CD4+ T cells developed a typical ACD reaction to the three weak fragrance allergens that peaked 24 hours after challenge. Priming of CD8+ T cells was observed in draining lymph nodes 5 days after sensitization and development of ACD was associated with the infiltration of activated CD8+ T cells in the challenged skin. CD8+ T cells were effectors of the ACD reaction as in vivo treatment with depleting anti-CD8 mAbs abrogated the ACD responses and as purified CD8+ T cells could adoptively transfer ACD to naive recipients. In conclusion, our data demonstrate a dominant role of CD8+ T cells as initiators of ACD to weak haptens, and suggest that CD8+ T cells may represent potential targets for preventing or treating ACD.     

Expansion of IL-10-producing CD4+ and CD8+ T cells in fixed drug eruption

BACKGROUND: A severe form of fixed drug eruption (FDE) clinically and histologically mimics toxic epidermal necrolysis (TEN) but, unlike TEN, resolves spontaneously upon withdrawal of the causative drug. OBJECTIVE AND METHODS: We reported a case of a severe FDE caused by mefenamic acid that spontaneously resolved without use of systemic corticosteroids. To clarify the phenotype of the T cells responsible for clinical resolution of FDE, we kinetically examined gamma-interferon (IFN-gamma), interleukin (IL)-2, IL-4 and IL-10 production by peripheral blood T cells of the patient before and after oral challenge with the causative drug using flow cytometry. RESULTS: We found that the proportions of CD4+ and CD8+ T cells capable of producing IFN-gamma and IL-4 remained unchanged after challenge, while those of CD4+ and CD8+ T cells capable of producing IL-10 dramatically increased after challenge. The frequency of CD8+ T cells capable of producing IL-2 decreased after challenge. CONCLUSION: These results suggest that expansion of IL-10-producing CD4+ and CD8+ T cells may be responsible for spontaneous resolution of a severe form of FDE.     

寻常型银屑病患者外周血CD4~+CD25~+及CD8~+CD25~+细胞的检测

目的研究进展期寻常型银屑病患者外周血CD4+CD25+和CD8+CD25+调节性T细胞的数量变化及其在银屑病免疫病理学发病机制中的作用。方法应用流式细胞术对进展期寻常型银屑病患者外周血CD4+CD25+和CD8+CD25+调节性T细胞进行检测。结果进展期寻常型银屑病外周血CD4+CD25+细胞及CD8+CD25+调节性T细胞数量与正常对照组相比,均显著降低(P<0.05,P<0.005),而CD4+CD25+/CD8+CD25+比值无显著性差异(P>0.05)。结论寻常型银屑病的发病与CD4+CD25+和CD8+CD25+调节性T细胞的同步降低有关,与二者的比值无关。     

Molecular and functional bases of self-antigen recognition in long-term persistent melanocyte-specific CD8+ T cells in one vitiligo patient

Vitiligo patients possess high frequencies of circulating CD8+ T lymphocytes specific for the melanocyte differentiation antigen Melan-A/MART-1. These self-specific T cells exhibit intact functional properties and their T cell receptors are selected for a narrow range of high affinities of antigen recognition, suggesting their important role in the pathogenesis of vitiligo. In order to understand the molecular base for this unexpected, optimal T cell receptor recognition of a self-antigen, a tetramer-guided ex vivo analysis of the T cell receptor repertoire specific for the Melan-A antigen in a patient affected by vitiligo is reported. All T cell receptors sequenced corresponded to different clonotypes, excluding extensive clonal expansions and revealing a large repertoire of circulating Melan-A-specific T lymphocytes. A certain degree of T cell receptor structural conservation was noticed, however, as a single AV segment contributed to the alpha chain rearrangement in 100% of clones and a conserved amino acid sequence was found in the beta chain complementarity determining region 3 of various high affinity cells. We suggest that the conserved alpha chain confers self-antigen recognition, necessary for intrathymic selection and peripheral homeostasis, to many synonymous T cell receptors, whereas the beta chain fine tunes the T cell receptor affinity of the specific cells. In addition, we demonstrate that many high avidity T cell clones from this patient were capable of specifically lysing normal, HLA-matched melanocytes. These autoreactive clones persisted for more than 3 y in the patient's peripheral blood. These data, together with the skin-homing potential of the clones, directly point to the in vivo pathogenic role of melanocyte-specific cytotoxic T lymphocytes in vitiligo.     

T cell receptor-gamma gene analysis of CD30+ large atypical individual cells in CD30+ large primary cutaneous T cell lymphomas

The hallmark of primary cutaneous CD30+ large T cell lymphoma are large lymphoid tumor cells, at least 75% of which, by definition, must be positive for CD30. The relatively benign clinical course of this lymphoma type has been explained with CD30-induced apoptosis, on the assumption that expression of CD30 defines the tumor clone; however, this hypothesis has not been tested on the molecular level to date. In this study we analyzed CD30+ cells in four patients with primary cutaneous CD30+ large T cell lymphoma by single cell polymerase chain reaction of T cell receptor-gamma genes followed by sequencing. Here, we demonstrate that most of the large CD30+ atypical cells possessed identical T cell receptor-gamma gene rearrangements, indicative of clonal proliferation. Nevertheless, polyclonally rearranged T cells were present in all CD30+ samples studied. In addition, one patient showed a second clone in a separate biopsy and three of four patients showed chromosomal imbalances as revealed by comparative genomic hybridization. Taken together, our data suggest that the CD30+ population in primary cutaneous CD30+ large T cell lymphoma indeed contains the tumor clone, thus providing molecular support for a link between clinical course and CD30-related signaling. Importantly, however, CD30 expression does not define the tumor clone as bystander T cells, as well as occasional additional clones, are also present in this population.     

The role of CD4+ and CD8+ T cells in contact hypersensitivity and allergic contact dermatitis

Allergic contact dermatitis (ACD) and contact hypersensitivity (CHS) are delayed-type hypersensitivity reactions which are mediated by hapten specific T cells. During the sensitisation phases, both CD4+ and CD8+ T cell precursors are activated in the draining lymph nodes by presentation of haptenated peptides by skin dendritic cells. Subsequent hapten skin painting induces the recruitment of T cells at the site of challenge which induces inflammatory signals and apoptosis of epidermal cells, leading to the development of a skin inflammatory infiltrate and of clinical symptoms. There have been major controversies on the respective roles of CD4+ and CD8+ T cells in the development of the CHS inflammatory reaction. Experimental studies from the last 10 years have demonstrated that, in normal CHS responses to strong haptens, CD8+ type 1 T cells are effector cells of CHS while CD4+ T cells are endowed with down-regulatory functions. The latter may correspond to the recently described CD4+ CD25+ regulatory T cell population. However, in some instances, especially those where there is a deficient CD8 T cell pool, CD4+ T cells can be effector cells of CHS. Ongoing studies will have to confirm that the pathophysiology of human ACD is similar to the mouse CHS and that the CHS response to weak haptens, the most frequently involved in human ACD, is similar to that reported for strong haptens.     

糖皮质激素对SLE患者CD4＋、CD8＋T细胞Caspase-3及TRAIL受体基因表达的影响

目的探讨糖皮质激素对系统性红斑狼疮（SLE）患者CD4^＋．CD8^＋T淋巴细胞Caspase-3及肿瘤坏死因子相关凋亡诱导配体（TRAIL）受体基因表达的影响。方法免疫磁珠法分离20例糖皮质激素治疗前后SLE患者及10例正常人对照的外周血CD4^＋,CD8^＋T淋巴细胞，半定量逆转录聚合酶链反应（RT-PCR）分析其Caspase-3及TRAIL受体mRNA的表达。结果SLE患者治疗后CD4^＋T淋巴细胞TRAIL-R1表达显著降低（P〈0．05）；SLE患者治疗前后CD8^＋T细胞Caspase-3的表达显著高于正常人对照（P值分别〈0．01和〈0．05）；SLE患者治疗前CD8^＋T细胞TRAIL-R2的表达显著高于正常人对照（P〈0．05）。结论通过调节SLE患者T细胞TRAIL受体表达以抑制其凋亡可能是糖皮质激素治疗SLE的机制之一。     

Peripheral CD8+ T cell tolerance against melanocytic self-antigens in the skin is regulated in two steps by CD4+ T cells and local inflammation: implications for the pathophysiology of vitiligo

Experimental evidence has suggested a role for CD8+ cytotoxic T lymphocytes (CTL) in the pathophysiology of vitiligo, a pigmentation disorder with focal loss of melanocytes in the skin. The discovery of tyrosinase-related protein 2 (TRP2) as a model melanocytic self-antigen recognized by CD8+ CTL in C57BL/6 mice allowed us to analyze the requirements for CD8+ T cell-mediated autoimmune destruction of melanocytes in an experimental model. Using two different genetic methods for the induction of cellular immunity in vivo, gene gun bombardment of the skin and injection of recombinant adenovirus, we show that peripheral tolerance of CD8+ T cells recognizing a single TRP2-derived H2-Kb-binding peptide is regulated in two steps. In the induction phase, stimulation and expansion of TRP2-specific CD8+ T cells in vivo depend on CD4+ T cell help. In the effector phase, autoimmune destruction of melanocytes in the skin depends on local inflammation. Our results suggest that accidental stimulation of CD8+ CTL recognizing major histocompatibility complex class I-binding peptides derived from melanocytic proteins in the context of an inflammatory skin disease may play an important role in the pathophysiology of vitiligo.     

CD8~+T细胞对白癜风患者黑素细胞的杀伤机制

目的:明确CD8~+T细胞对白癜风患者黑素细胞的杀伤机制。方法:分选白癜风患者及正常人外周血CD8~+T细胞,分别与原代黑素细胞及永生化正常黑素细胞系PIG1及永生化白癜风黑素细胞系PIG3V建立共孵育杀伤模型,采用流式细胞术检测靶细胞被杀伤情况,酶联免疫吸附法(ELISA)检测杀伤环境中IFN-γ、TNF-α、颗粒酶B及穿孔素的分泌水平。结果:白癜风患者外周血CD8~+T细胞杀伤原代黑素细胞及PIG3V能力,分泌IFN-γ、颗粒酶B及穿孔素水平均高于健康对照,而杀伤PIG1能力和TNF-α水平并无显著差异;白癜风患者CD8~+T细胞IFN-γ分泌水平与细胞杀伤率呈明显正相关。结论:白癜风患者CD8~+T细胞杀伤黑素细胞是白癜风发病的重要机制,且该杀伤作用可能依赖IFN-γ、颗粒酶B及穿孔素分泌水平的上调。     

系统性红斑狼疮患者CCR7+CD8+CD45RO+T细胞诱导CD4＋T细胞向Th2分化

目的探讨系统性红斑狼疮(SLE)患者外周血CCR7 CD8 CD45RO 记忆性T细胞对CD4 T细胞的诱导分化作用及其与SLE发病的关系。方法流式细胞仪、实时定量RT-PCR和RNA印迹检测同系CCR7 CD8 CD45RO T细胞和树突细胞协同刺激CD4 T细胞分泌细胞因子。结果活动期SLE患者CCR7 CD8 CD45RO 记忆性T细胞诱导CD4 T细胞表达Th2类细胞因子:白介素4的表达效率显著高于正常人对照组和非活动期SLE患者组(P<0.01),1型调节性T细胞(Tr1)源性细胞因子:白介素10和转化生长因子β的表达效率均低于正常对照组和非活动期SLE患者组(P<0.01);而活动期和非活动期SLE患者干扰素γ的表达效率显著低于正常人对照组(P<0.01)。结论活动期SLE患者外周血CCR7 中央型记忆性T细胞可与树突细胞相互作用,诱导同系CD4 T细胞向Th2分化,发挥CCR7-CD45RO 效应性记忆性T细胞的功能。     

Mediation of alopecia areata by cooperation between CD4+ and CD8+ T lymphocytes: transfer to human scalp explants on Prkdc(scid) mice

OBJECTIVE: To determine the role of CD4+ and CD8+ T lymphocytes in the pathogenesis of alopecia areata. DESIGN: Relapse of alopecia areata was induced in autologous human scalp grafts on Prkdc(scid) mice by injection of activated T lymphocytes derived from lesional skin. CD4+ and CD8+ T cells were separated by magnetic beads before injection. SETTING: University-based dermatology practice. PARTICIPANTS: Eleven patients with either alopecia totalis or severe alopecia areata. MAIN OUTCOME MEASURES: Hair regrowth, hair loss, and immunohistochemical findings of scalp explants. INTERVENTION: Transfer of scalp T cells to autologous lesional scalp explants on Prkdc(scid) mice. RESULTS: Injection of unseparated T cells and mixed CD4+ plus CD8+ T cells resulted in significant hair loss (P<.01) in 5 of 5 experiments. However, injection of purified CD4+ or CD8+ T cells alone did not result in reproducible hair loss. CD4+ and CD8+ T cells induced follicular expression of intercellular adhesion molecule 1 (CD54), HLA-DR, and HLA-A, HLA-B, and HLA-C after injection into scalp grafts. CONCLUSIONS: CD4+ and CD8+ T cells have a role in the pathogenesis of alopecia areata. It is hypothesized that CD8+ T cells act as the effector cells, with CD4+ T cell help. It is now necessary to look for HLA-A, HLA-B, and HLA-C associations with alopecia areata. Therapeutic manipulations that interfere with CD8+ activity should be examined.     

梅毒患者外周血CD4~+、CD8~+调节性T细胞表达的临床意义

目的:监测梅毒患者外周血CD4~+、CD8~+调节性T细胞的表达水平,考察其在临床的参考价值。方法:将2014年12月至2015年9月,我院收治并确诊的32例梅毒患者作为研究对象。其中,Ⅰ期、Ⅱ期、潜伏期梅毒患者分别有11例、15例和6例。采用细胞免疫芯片检测(淋巴细胞CD4~+、CD8~+绝对数检测)技术检测并计算患者外周血中的调节性T细胞CD4~+、CD8~+表达水平及CD4~+、CD8~+的比值。并与同期就诊我科的30例非梅毒患者的相应指标数据进行比较。结果:与非梅毒患者比较,梅毒患者外周血中CD4~+、CD8~+细胞绝对值计数均显著下降(P0.05);CD4~+、CD8~+比值显著低于非梅毒患者组(P0.05)。在Ⅰ期、Ⅱ期、潜伏期梅毒患者间CD4~+、CD8~+绝对值计数均值水平的差异有统计学意义(P0.05)。结论:在梅毒患者外周血中CD4~+、CD8~+表达水平及CD4~+、CD8~+比值均显著降低,而在梅毒感染的不同疾病发展时期CD4~+、CD8~+表达水平也有着显著的差异。