郎格罕氏细胞在大鼠H-Y不相容性皮肤移植物排斥过程中的作用

本文报告了关于郎格罕氏细胞于免疫排斥过程中具有重要作用的动物实验证据.BN/Ss大鼠H-Y不相容性皮肤移植的排斥反应与移植物本身内的LC密度有关;密度越高越易被排斥.将BNH-Y不相容性皮肤移植物内的LC更替为雌性同种异基因LC后,存活期可明显延渭;但更替为雌性同基因LC后,存活期并不延长.     

口服芳香族维甲酸对鼠郎格罕细胞的作用

目前有关维甲酸对免疫系统的作用知道很少, 新近的研究已提示其有免疫增强作用.几项电子显微研究结果提示芳香族维甲酸可刺激郎格罕细胞(LC),而LC被认为在表皮的免疫反应中起着关键的作用.因而,弄清楚维甲酸对表皮LC的数量和(或)功能是否有影响是很有意义的.为此,作者通过Ia抗原染色法和T细胞增殖试验分别检测口服芳香族维甲酸后对鼠表皮Ia~+LC的密度及向同种异体Ia反应性克隆T细胞系呈递Ia抗原作用的影响,并观察了表皮LC的形态和位置的改变.结果发现无论用大剂量或小剂量芳香族维甲酸处理,在最初几天表皮的LC密度增加,用大剂量对这种变化更加明显.之后趋向降低,2周后LC密度的降     

皮肤癣菌病患者表皮LC观察

本文应用ATPase组化方法对30例皮肤癣菌病患者皮损表皮及70例对照者相应部位表皮作了LC观察,并对其中3例患者及1例对照者表皮LC作了TEM观察.结果发现患者LC形态改变,数量减少或消失及细胞超微结构受损.并发现上述改变程度与病程、病型有关.本文首次提出LC与皮肤癣菌病的免疫病理改变有密切关系,可能皮肤癣菌的入侵使LC受损,从而干扰了T淋巴细胞诱导的机体对病原体的清除功能.本文还讨论了两种方法的注意点.     

大鼠郎格罕氏细胞Ia抗原及ATP酶的研究

本文报告于大鼠LC表面也具有Ia抗原及ATP酶活性;用Ia抗原间接免疫荧光染色可清晰地显示成年大鼠表皮内的LC:ATP酶染色可用于新生大鼠表皮内LC的检查.本文详细叙述了用I成原间接免疫荧光染色、Ia抗厚间接免疫过氧化酶染色及ATP酶染色显示大鼠表皮内LC的步骤与注意事项.     

他克莫司对朗格汉斯细胞迁移能力的影响

目的：观察他克莫司对朗格汉斯细胞（LC）迁移能力的影响,为明确他克莫司在治疗疾病中的作用途径打下基础。方法：在不同时间段内将不同浓度的他克莫司腹腔注射C5UBL／6小鼠,再用异硫氰酸荧光素（FITC）刺激小鼠耳背部皮肤,12h后通过流式细胞仪检测小鼠耳背部淋巴结内摄取抗原的LC数量。通过免疫组化法检测抗原致敏处LC的数量。结果：他克莫司腹腔注射过的小鼠耳背皮肤受到FITC刺激后,其皮肤局部摄取抗原的LC迁移至局部淋巴结的数量明显减少,尤其在FITC刺激前12h注射他克莫司的小鼠皮肤局部LC的迁移能力受到显著抑制,在注射高剂量他克莫司组与低剂量且之间存在明显差异。而同时他克莫司腹腔注射过的小鼠,其耳背部受到FITC刺激后的皮肤局部LC的数量高于未注射组。结论：他克莫司作为一种免疫抑制剂,其发挥治疗作用途径有可能通过抑制LC的迁移能力,从而上或减弱了某些免疫反应。     

红斑性狼疮皮损中郎格罕氏细胞电镜观察

本文用电镜观察3例SLE、2例DLE,1例SCLE皮损中的LC.发现某些细胞呈活跃状态,一个细胞正穿过基底膜进入真皮,在表皮真皮内可见与LC接触、附着的激活的淋巴细胞.从而证实LC在LE病理性免疫应答中起作用.     

银屑病皮损中郎格罕氏细胞的初步观察

本文应用ATP酶法和抗T6单克隆抗体OKT6直接免痊荧光法,对6例寻常型银屑病皮损及其邻近正常皮中的LC进行了初步对比观察.结果两法在正常皮肤部位显示表皮内的LC带有树枝状突起,分布均匀,主要位于中层;且OKTs法尚可显示真皮内少最散在的LC.而皮损部位则表皮内LCJL平消失,偶见1~2七且其突起消失.呈小圆圈状;真皮内未见可辨认的LC.以上所见提示皮肤中的LC可能与银屑病的发病机理有关.     

实验性接触性变态反应中郎格罕氏细胞的动态观察

作者应用DNCB诱发琢鼠实验性接触性皮炎定时活检,制备表皮片,用改进的ATP酶细胞化学方法染色,连续观察表皮LC的动态变化.在变态反应性接触性皮炎,抗原激发后12小时内.LC密度显著下降,树枝状突减少:2~5天内,表皮LC几乎完全消失;以后LC开始重建.14天内密度恢复正常.而在原发刺激性接触性皮炎2小时内LC树技状突即减少,6小时LC密度即显著降低.LC恢复亦较迅速,作者认为这种差异主要是因为两种皮炎的发病机制不同.实验所见提示LC在接触性变态反应的早期、初期以及恢复期均起重要作用.此外,本文还就实验动物的选择、诱发试剂的浓度以及ATP酶细胞化学染色的特异性等问题进行了讨论.     

糖皮质激素对豚鼠表皮郎格罕细胞的影响及形态定量研究

运用ATP酶、电镜及体视学方法对局部及全身应用GCS豚鼠表皮LC变化进行系统研究。试图阐明GCS皮肤病学药效作用中可能存在的另一机理—LC途径。结果发现表面涂布DA及PA均可显著降低LC密度,下降幅度与药物效能及浓度有关。腹腔注射DAP也引起LC密度明显降低,同时其形态和着色程度也有改变。电镜观察显示LC与IC亚微结构有损伤征象,形态定量与光镜所见一致。     

花斑癣患者表皮郎格罕细胞的观察

作者采用ATP酶染色方法对10例花斑癣患者皮损表皮内郎格罕细胞(LC)进行了观察,并对4例患者与皮损相对应部位的正常皮肤进行了同样检查.与此同时,取4名正常人胸腹部正常皮肤作对照检查.结果表明:花斑癣皮损表皮内LC密度明显减少,与正常对照组相比,P<0.001,有灶性集聚现象,许多LC的树枝突缩短、减少或消失.4例花斑癣患者与皮损相对应部位的正常皮肤表皮内LC的变化与皮损表皮内LC的变化相类似.作者认为,LC在花斑癣的免疫病理中可能起着重要作用.     

Migration of Langerhans cells into the epidermis of human skin grafted into nude mice.

In a previous study, it was demonstrated that human Langerhans cells (LC) are preserved in human skin grafted onto a nude mouse. Moreover, although it was observed that mouse LC of the host invade skin grafts from allogeneic mouse or rat, they do not penetrate in human skin grafts. In most of the human skin equivalent systems produced in vitro, LC appear to be lost. The present study was designed to investigate whether the mouse LC will repopulate a human skin equivalent. For this purpose, two different systems of skin equivalent have been grafted into the nude mouse. They were composed of human keratinocytes deposited on dead human dermis, or on lattice composed of human fibroblasts embedded in type I collagen. At different times after grafting, the presence of LC in the transplants was assayed either by indirect immunofluorescence or by electron microscopy. Indirect immunofluorescence was performed on frozen sections or on epidermal sheets with anti-Ia, anti-HLA-DR, or OKT6 antibodies. It was observed that, at 2 months after grafting, Ia(+) HLA-DR(-) OKT6(-) cells are present in grafted human epidermis. Moreover, LC with typical Birbeck granules are also detected by electron microscopy. It could be concluded, from this study, that mouse LC can repopulate human epidermis devoid of human LC.     

Further evidence for the self-reproducing capacity of Langerhans cells in human skin

The limited number of Langerhans cells (LC) in the epidermis is one of the main reasons for the technical difficulties in resolving the question of LC kinetics. In the present paper, we describe a method to evaluate the LC replication potential in epidermis. The procedure is based on the specific incorporation of bromodeoxyuridine (BrdU), a thymidine analogue, into the DNA during the S-phase of the cell cycle. Mice, bearing human skin grafts, were injected s.c. every 6 h for up to 17 days with BrdU. At different times, the incorporated BrdU as well as the human epidermal LC were revealed on skin sections using anti-BrdU and OKT-6 monoclonal antibodies, respectively. After 6 h, 4.9% of the LC were labeled with BrdU. Then, the number of OKT-6(+) BrdU(+) cells increased in a linear manner and achieved 34% at 120 h, 67% at 240 h, and 94% at 400 h during the course of continuous labeling procedures. Based on this result we calculated a total cell cycle time of 392 h (16.3 days) and 12 h for the S-phase for human epidermal LC. Applying this technique, we were able to show also that 48 h after local treatment with 12-O-tetradecanoylphorbol-13-acetate or after stripping, the number of BrdU-labeled LC was considerably increased. Furthermore, after i.p. injection of colchicine in the nude mouse, human epidermal LC undergoing mitosis were evidenced by electron microscopy in the graft. From these results we conclude that the LC are actively cycling--therewith a self-reproducing cell population in human epidermis.     

Biology of Langerhans cells: analysis by experiments to deplete Langerhans cells from human skin

In vivo studies have demonstrated that various treatments of skin, e.g., UV irradiation, topical corticosteroids, and tape-stripping, will temporarily deplete the epidermis of Langerhans cells (LC). Whether this loss represents simply a loss of cell surface markers unique to LC, or actual depletion of cells, is unknown. By design, normal human skin transplanted to the congenitally athymic (nude) mouse is a system devoid of circulating precursors for human LC. Because LC have been shown to be of bone marrow origin, any depletion of these cells in this system should be permanent. Treatments to deplete LC from human skin grafts on nude mice after grafting included: (a) large doses of UV radiation (400 mJ/cm2 every 48 h, X 3), (b) potent high-dose topical corticosteroids (2.5 mg betamethasone valerate/cm2 every day, X 5), (c) tape-stripping (X 20). Treatments before grafting included: (a) treating donor skin with 900 R of gamma irradiation, (b) complement fixing monoclonal antibody to Ia-like antigens of LC, followed by fresh complement, (c) monoclonal antibody conjugated to toxins. Quantitation of the number of LC was analyzed on control and treated epidermal sheets using immunodiagnostic reagents, anti-HLA-DR, and surface ectoenzymes , ATPase. Results show that both UV irradiation and topical corticosteroids reduce the number of LC by these analyses. However, within 3 weeks, recovery to pretreatment levels has occurred. X-irradiation and tape-stripping were without effect. Despite evidence that the monoclonal antibody, complement, and toxic systems were delivered to the LC within the epidermis, there is no evidence that these treatments resulted in a decrease in LC. It appears that LC are currently either long-lived or replaced locally from a proliferative pool and that certain cell membrane determinants of human LC are somewhat differentially sensitive to UV radiation and corticosteroids.     

Comparative epidermal Langerhans cell migration studies in epidermal and epidermal/dermal equivalent grafts.

Immigration of Langerhans cell precursors from the peripheral blood to the skin was studied in human grafts placed on severe combined immunodeficient (SCID) mice. Monocyte fractions of human blood were injected intraperitoneally to SCID bearing either reconstituted (Langerhans cell free) epidermal sheets (E) or living skin equivalents (E/D) consisting of both epidermis and dermis. A range of immunocytochemical and ultrastructural markers was employed to monitor the colonization of the grafts, i.e., CD1a/c, Birbeck granules. In situ hybridization with probes against Alu sequences of human DNA were employed together with immunostaining for MHC class I mouse and human antigens to document graft survival. Although unequivocal LC were detected within E grafts, including both human (CD1a positive) and murine (NLDC-145 positive), no migration was achieved in the E/D situations.     

Differential diagnosis of cutaneous infiltrates of B lymphocytes with follicular growth pattern

The differential diagnosis of cutaneous B-cell infiltrates with follicular pattern of growth is one of the most vexing problems in dermatopathology. In this study we focused on histopathologic, immunophenotypic, and molecular differential diagnostic criteria between Borrelia burgdorferi (Bb)-associated lymphocytoma cutis (LC), primary cutaneous follicle center cell lymphoma (FCCL), and primary cutaneous marginal zone lymphoma (MZL) with reactive germinal centers (GCs). A total of 47 patients were included in the study, including 12 cases of LC (M:F = 2:1; mean age: 38.0; median: 31; range: 9-75), 29 cases of FCCL (M:F = 1.2:1; mean age: 57.5; median: 57; range: 24-97), and 6 cases of MZL (M:F = 1:1; mean age: 63.8; median: 67.5; range: 38-86). In all cases complete phenotypic data were available. In addition, the IgH gene rearrangement and the t(14;18) were analyzed using the polymerase chain reaction technique (PCR) in 41 (FCCL = 27, LC = 10, MZL = 4) and 18 cases (FCCL = 15, LC = 2, MZL = 1), respectively. Histology revealed in all cases of FCCL one or more atypical feature of the follicles including the lack of or a reduced mantle zone, lack of polarization, tendency to confluence, and absence of tingible body macrophages. In most cases of Bb-associated LC, the GCs were devoid of mantle zone, lacked polarization, and revealed tendency to confluence as well, but all cases showed the presence of several tingible body macrophages. In MZL, follicles showed typical features of reactive GCs. Immunohistology revealed a reduced proliferative activity of neoplastic follicles as detected by MIB-1 antibody in 23 of 29 cases of FCCL (79.3%), but only in 1 case of LC (8.3%). Proliferation of the GCs was normal in all cases of MZL. Positivity for CD10 and/or Bcl-6 was found in small clusters outside the follicles in 19 cases of FCCL (65.5%), and in 3 cases of LC (25%), but in no case of MZL. The intensity of CD10 staining on follicular cells on average was stronger in cases of FCCL, but overlapping features could be observed. Finally, staining for Bcl-2 protein was consistently negative on GC cells in cases of LC and MZL, and was positive on a variable proportion of the cells in 8 cases of FCCL (28.6%). Molecular analyses showed no evidence of the t(14;18) in all cases tested. Analysis of the IgH gene rearrangement revealed a monoclonal pattern in 1 of 10 cases of LC (10%), 14 of 27 cases of FCCL (51.9%), and 2 of 4 cases of MZL (50%) tested. In summary, Bb-associated LC and FCCL show sometimes overlapping histopathologic, immunohistochemical, and molecular features, whereas follicles in MZL show clear-cut aspects of reactive GCs. Absence of tingible body macrophages within follicles, reduced proliferation of the follicles as detected by immunohistology, presence of positivity for Bcl-2 protein within follicular cells, and monoclonality by PCR are the main criteria suggestive of malignancy. Diagnosis of cutaneous infiltrates of B lymphocytes with follicular growth pattern should be achieved by integration of clinical data with histopathologic, immunohistochemical, and molecular features of the lesions.     

In situ evidence that the population of Langerhans cells in normal human epidermis may be heterogeneous

Epidermal Langerhans cells (LC) may occur in subsets with different phenotypic and functional characteristics. In this work we give further evidence that the CDla-positive LC population in the normal human epidermis may be heterogeneous. We found that one of our monoclonal antibodies (TE4B) to stratum corneum chymotryptic enzyme (SCCE) stained a population of dendritic cells in the normal epidermis, in addition to high suprabasal keratinocytes. The staining of the dendritic cells was seen only when the biopsies had been fixed with formaldehyde and when the sections had been pretreated, either with proteolytic enzymes or with Triton X-100. The blinding of the antibody was mediated through its antigen binding site, as it could be inhibited by adsorption with recombinant pro-SCCE. Experiments with double labelling showed that the TE4B-positive dendritic cells were also CDla-positive. On the other hand, not all CDla-positive cells were TE4B-positive. By means of confocal microscopy of double-labelled cells, the TE4B binding site could be localized intracellularly. SCCE-mRNA could be detected by in situ hybridization in high suprabasal keratinocytes only. A possible explanation may be that there is a subset of LC which have taken up SCCE secreted by high suprabasal keratinocytes. Alternatively. TE4B may bind to an epitope present in a subgroup of epidermal LC which cross-reacts immunologically with SCCE. It is suggested that the demonstrated heterogeneity of the population of LC in the normal epidermis should be taken into account in studies on the possible role of epidermal autoantigens in the development of immune-mediated skin diseases.     

Human Langerhans cells in epidermal cell culture,in vitro skin explants and skin grafts onto “nude” mice

Summary In order to find a model system which best preserves human Langerhans cells (LC) outside of the human body, three possibilities were examined: epidermal cell culture, skin explants, and skin grafts onto nude mice. Using OKT-6 and anti-HLA-DR monoclonal antibodies, we quantified LC in epidermal sheets or epidermal cell cultures. All observations were carried out over a period of 4 weeks. We found that under epidermal cell culture conditions, LC rapidly disappeared, to the extent that after 10 days only rare HLA-DR-positive cells could be observed. In contrast, in the presence of intact dermis (explants and grafts), 60%–80% of the original number of LC, morphologically unchanged, dendritic and OKT-6 and HLA-DR-positive, were seen. These findings suggest that human LC are either a long-lived cell population or else can proliferate locally. The systems studied may be a useful tool for future investigation of LC function.     

Direct effects of glucocorticosteroids on epidermal Langerhans cells

To determine the direct effects of glucocorticosteroids on epidermal Langerhans cells (LC), we treated isolated LC with dexamethasone (DEX) in vitro, and investigated Ia expression by LC using immunofluorescence microscopy and FACS analysis. We found that DEX directly decreased the number of Ia+ LC in a dose- and time-dependent manner. Pulse incubation with DEX also inhibited the immunostimulatory function of LC in vitro. FACS analysis demonstrated that LC detected in DEX-treated culture expressed a similar amount of Ia antigen and Fc receptor on the cell surface as LC cultured with the solvent control, suggesting that LC may be composed of a heterogeneous population in terms of sensitivity to DEX, and DEX may completely abolish the expression of surface molecules on a subpopulation of LC or may be cytolytic to this sensitive population.     

Epidermal Langerhans cells--a target for HTLV-III/LAV infection

Langerhans cells (LC) are bone marrow-derived, Ia+, CD1+, CD4+, ATPase+ dendritic antigen-presenting cells within the human epidermis. Since the CD4 molecule has been implicated as a receptor structure for HTLV-III/LAV (human T-cell leukemia virus/lymphadenopathy-associated virus), we asked whether LC from HTLV-III/LAV-seropositive individuals display signs of HTLV-III/LAV infection. In skin biopsies from 7/40 HTLV-III/LAV-infected persons (1 asymptomatic carrier, 2 patients with acquired immunodeficiency syndrome (AIDS)-related complex and 4 patients with AIDS), LC were the only epidermal cells to react with a monoclonal antibody specific for the HTLV-III core protein p17. A varying percentage of p17+ LC were morphologically altered with blunt dendrites and poorly demarcated cellular contours. In one of these biopsies, the presence of LC-associated viral particles characteristic of HTLV-III/LAV as well as cytopathic changes in approximately one-third of the LC population were demonstrated by electron microscopy. These results strongly suggest that LC may harbor HTLV-III/LAV. The infection of LC with this retrovirus may have deleterious consequences for the immunologic functions of this cell system and may thus contribute to both the acquisition of immunodeficiency and the infectious and neoplastic complications of AIDS.     

Burow''s grafts in the facial region

BACKGROUND: Full-thickness skin grafts are an important tissue source for reconstructive surgery. Burow's grafts are full-thickness skin grafts that use adjacent lax skin as the donor site. This technique has also been referred to as island grafts, dog-ear grafts or adjacent-tissue skin grafts. OBJECTIVE: The objective was to describe the technique of Burow's grafts for reconstruction of facial defects taking account of its benefits and limitations. METHODS: The operative technique is simple: after a circular excision of the cutaneous lesion, we enlarged the excision line (towards one or both sides of the defect) following the relaxed tension lines. We created a secondary triangular defect by excising skin that is then used for the graft (as donor site). After adequate undermining, we proceeded to direct linear closure of this secondary defect. Finally, the graft was placed and sutured in the remaining defect. RESULTS: The proximity of the donor site provides an excellent tissue match because colour, hair density, texture, sebaceous features and thickness are similar to the recipient site. A good cosmetic result is therefore ensured. CONCLUSION: Burow's grafts can be a good choice for reconstruction of extensive facial surgical defects because of aesthetic results. In addition, it is a simple technique that can be performed in one sole surgical act, with local anaesthesia and without changing the operative site.