In situ expression of the costimulatory molecules CD80 and CD86 on Langerhans cells and inflammatory dendritic epidermal cells (IDEC) in atopic dermatitis

Abstract The functional expression of costimulatory molecules on antigen-presenting cells may be a key event in the pathogenesis of atopic dermatitis (AD). Recently, the expression of CD86 (B7-2/B70) has been demonstrated on CD1a⁺ epidermal dendritic cells (DC) in AD lesions by immunohistological and functional analysis. Therefore, we sought to further characterize the in situ expression of costimulatory molecules on these cells, considering the two subpopulations of (1) CD1a⁺⁺⁺/CD11b^– Langerhans cells (LC) containing Birbeck granules and (2) CD1a⁺/CD11b⁺⁺⁺ inflammatory dendritic epidermal cells (IDEC), devoid of Birbeck granules, from AD and other inflammatory skin diseases. Flow cytometry, skin mixed lymphocyte reactions (SMLR) and immunohistological analysis were performed, and showed that IDEC and not LC are the relevant cells expressing the costimulatory molecules CD80 and CD86 in situ. This expression varied with the underlying diagnosis, with AD showing the highest expression of both CD80 and CD86 in situ. Furthermore, the expression of CD80, CD86 and CD36 were significantly correlated. With short-term culture, both CD80 and CD86 were further upregulated on LC and IDEC. Finally, anti-CD86 antibody reduced the stimulatory activity of epidermal DC. These results indicate that costimulatory molecules on LC and IDEC might play a role in the pathogenesis of AD. Received: 7 June 2000 / Accepted: 21 January 2001     

Expression and functional role of co-stimulatory molecules in CD40+IL-4-stimulated B cells from atopic and non-atopic donors

As immunological dysregulation is a possible key defect in atopic diseases, we have studied the expression and function of costimulatory molecules in atopic dermatitis (AD) patients compared with normal controls. Using flow cytometry, we showed that CD80 and CD86 are expressed at increased levels on human peripheral B cells in both groups after stimulation with anti-CD40 and interleukin 4 (IL-4), but to a significantly higher extent in the AD group. Furthermore, baseline expression of CD80 and CD86 on peripheral B cells was low in normal donors and increased in AD donors. To study the functional role of the costimulatory molecules in CD40+IL-4-stimulated peripheral mononuclear cells from normal and atopic donors, proliferation and IgE production were analysed in the presence of antibodies against the receptors of the costimulatory molecules. In the presence of either anti-CD28 or anti-CTLA-4, cell proliferation and IgE synthesis were significantly enhanced in the atopic group in anti-CD40+IL-4-stimulated peripheral mononuclear cells. These findings suggest that interaction of CD80 and CD86 with their receptors CD28 and CTLA-4 selectively promotes cell activation, including proliferation and IgE production in CD40+IL-4-stimulated peripheral blood mononuclear cells from atopic donors. It remains to be elucidated whether these changes are primary, based on the genetic background of atopics, or whether they are induced secondarily in the context of atopic pathology.     

Effects of CD40 ligation on human keratinocyte accessory function

Abstract CD40/CD40 ligand interactions are known to play a key role in the development of immune reactions, especially by enhancing the costimulatory function of professional antigen-presenting cells (APC). Little is known, however, about the role this receptor plays on occasional APC, i.e. cells that are induced to express MHC class II molecules following an inflammatory process. In this study, we used CD40 ligand-transfected cells to analyze the effect of CD40 ligation on the phenotype, as well as accessory function, of human keratinocytes. We found that CD40 ligation enhanced ICAM-1 expression and did not upregulate HLA-DR, CD80 or CD86 expression on IFN-γ-treated keratinocytes. CD40 triggering was not sufficient to generate primary allogeneic T-cell responses even in the presence of anti-CD28 monoclonal antibody (mAb). Moreover, CD40 ligation, in the presence or not of IFN-γ, did not alter the accessory function of keratinocytes in PHA- or superantigen-induced T-cell activation. The lack of effect on the T-cell response was confirmed in blocking experiments using anti-CD40 mAbs. Collectively, these results suggest that CD40-CD40 ligand interactions on nonprofessional APC may amplify the inflammatory reaction without providing a mitogenic signal to the T cells. Received: 10 November 1997     

Comparative analysis of CD80 and CD86 on human Langerhans cells: expression and function

Abstract Although both CD80 (B7–1) and CD86 (B7–2/B70) have been recently identified in cultured human Langerhans cells (LC), little is known of the role and regulatory properties of CD80 and CD86 on human LC. We present here the results of a study comparing the expression and function of CD80 and CD86 in human LC using the T-helper type-1 cytokines IL-2 and interferon γ (IFN)-γ, and the T-helper type-2 cytokines IL-10, IL-4 and granulocyte/macrophage colony-stimulating factor (GM-CSF). Freshly isolated human LC expressed little CD80 and CD86 in vitro, but the expression of both molecules was rapidly induced during a 72-h incubation with cytokines and the expression of CD86 occurred much earlier and more strongly than that of CD80. The expression of both CD80 and CD86 was upregulated by GM-CSF and downregulated by IL-10, and the expression of CD86, but not that of CD80, was upregulated by both IL-4 and IFN-γ. Finally, pretreatment of LC with GM-CSF and IFN-γ, but not with IL-4, enhanced the alloreactive T-cell proliferation induced by the LC, and IL-10 pretreatment of LC decreased their capacity for alloreaction. These results indicate that the expression of both CD80 and CD86 on human LC may be regulated by these cytokines (IL-2, IL-4, GM-CSF, IFN-γ and IL-10) secreted from helper T cells infiltrating into the inflammatory microenvironment. Received: 4 December 1997     

Characterization of human skin-derived CD1a-positive lymph cells

Abstract The phenotype and function of CD1a⁺ lymph cells is of considerable interest. By means of microsurgical lymph cannulation human lymph derived from normal skin was sampled. Cells were isolated and processed for immunocytochemistry, electron microscopy, flow cytometry and functional assays. The majority of the cells, (62%), were T cells. The other cells comprised CD1a⁺ cells (7%), monocytes/macrophages (8%), and B cells (1%); the remainder were erythrocytes or uncharacterized cells. The CD1a⁺ cells reacted with antibodies against protein S-100, HLA-DR, the Lag antigen, CD4, CD11a, CD11b, CD18, CD25, CD40, CD54, CD80 and CD86. Interestingly, a small prolow portion the of CD1a⁺ cells (about 5%) reacted with an antibody to CD14. The CD1a⁺ cells did not react with an antibody against human follicular dendritic cells nor were they CD19-, CD23-, E-cadherin- or factor XIIIa-positive. Both allogenic and antigen-specific T cell proliferation stimulated by antigen-presenting lymph cells were strongly inhibited by adding anti-CD80 and anti-CD86 antibodies. By electron microscopy Birbeck granules were detected in only 22% of the CD1a⁺ lymph cells and these cells exhibited an extensive ruffling of the surface. These findings demonstrate that CD1a⁺ lymph cells, which do not express the dermal dendritic cell marker factor XIIIa, resemble dendritic cells formerly designated as ‘veiled’ as well as lymphoid dendritic cells, suggesting that after migration to the regional lymphoid organs, Langerhans cells form a more differentiated population of dendritic cells specialized in sensitizing T lymphocytes. Our results add further support to the view that resident Langerhans cells may be precursors of lymphoid dendritic cells acquiring the final phenotype in the microenvironment of the lymph node. Received: 30 July 1998 / Received after revision: 30 September 1998 / Accepted: 19 October 1998     

尖锐湿疣患者外周血单一核细胞共刺激分子CD28,CD40的检测

目的探讨免疫共刺激分子CD28/CD152-CD80/CD86,CD40-CD40L在尖锐湿疣患者外周血单一核细胞(PBMC)中的表达情况。方法采用流式细胞仪(FCM)检测60例CA患者(初发组30例、复发组30例)和30例健康对照者外周血CD28,CD152,CD40L在CD4+,CD8+T细胞上CD80,CD86,CD40在CD19+B细胞上的表达水平。结果CA患者CD28,CD40L在CD4+,CD8+T细胞的表达,与对照组(42.36%,13.85%,5.08%,2.58%)相比,复发组(37.10,11.66%,2.57%,1.25%)较初发组(39.69%,12.76%,3.93%,1.96%)明显降低(P<0.01);CD80,CD86,CD40在CD19+B细胞上的表达与对照组(1.59%,3.83%,14.25%)相比,复发组(0.65%,3.05%,10.24%)较初发组(1.04%,3.45%,12.21%)显著降低(P<0.01),而CD152在CD4+,CD8+T细胞上的表达与对照组(1.71%,9.62%)相比,复发组(39.2%,12.15%)较初发组(2.64%,10.90%)显著增高(P<0.01)。结论尖锐湿疣患者外周血淋巴细胞CD28/CD152-CD80/CD86,CD40-CD40L共刺激分子的异常表达可能与其免疫功能紊乱及复发机制有一定关系。     

Functional CD86 (B7-2/B70) is predominantly expressed on Langerhans cells in atopic dermatitis

Recently, we reported the functional expression of CD86 on cultured human Langerhans cells derived from normal epidermis. In the present study, we investigated the expression and function of co-stimulatory molecules in the pathogenesis of atopic dermatitis. In immunohistochemical analysis, CD80 and/or CD86 were detected on dendritic-shaped cells not only in the epidermis but also in the dermis in the inflammatory lesions of atopic dermatitis (n = 12). CD80 was expressed in only five cases (42%), while CD86 was expressed in all cases (100%). These molecules were not detected in normal control subjects (n = 8). In non-lesional skin of atopic dermatitis (n = 4). CD86 but not CD80 was detected in one case. CD86 was preferentially induced on dendritic-shaped cells in positive patch test sites to Dermatophagoides pteronyssinus or house dust allergen in atopic dermatitis (n = 4). The CD80- or CD86-positive cells were confirmed as Langerhans cells by double immunostaining using anti-CD1a monoclonal antibody. Neither CD86 over that CD80 was detected n keratinocytes. Similar results of the stronger expression of CD86 over that of CD80 were obtained from psoriasis vulgaris (n = 11) and from contact dermatitis (n=7), although CD86 was expressed only in 57% of the contact dermatitis cases. The percentage of Langerhans cells positive for CD86 was higher than for CD80, i.e. 48% compared with 9%, respectively, in the epidermis of lesional skin of atopic dermatitis (n=8). The expression rate of these molecules on Langerhans cells increased in the dermis. To investigate the function of co-stimulatory molecules on Langerhans cells in atopic dermatitis, we conducted an inhibition test with antibodies. Anti-CD86 monoclonal antibody almost completely nhibited T-cell proliferation stimulated with crude extract of D. pteronyssinus in the presence of epidermal cells as antigen-presenting cells, whereas anti-CD80 monoclonal antibody produced less of an inhibitory effect. These data indicate that CD86 expressed on Langerhans cells may play an important part in the pathogenesis of atopic dermatitis.for Investigative Dermatology. Washington, DC (1–5 May 1996).     

Alteration in the production of IL-10 and IL-12 and aberrant expression of CD23, CD83 and CD86 by monocytes or monocyte-derived dendritic cells from atopic dermatitis patients

Atopic dermatitis (AD) is characterized by the presence of Th2-type cells in the skin infiltration as well as in the peripheral blood, although a predominant infiltration of interferon-gamma (IFN-gamma)-producing cells is also reported in the chronic skin lesions of AD. Recently it has become clear that the development of Th1 or Th2 is strongly influenced by factors produced by the antigen presenting cells (APCs). To clarify whether APCs from AD patients play a favorable role in the differentiation of Th2 cells, we compared the production of cytokines and the expression of co-stimulatory molecules by monocytes (MOs) and monocyte-derived DCs (MoDCs) after stimulations with various reagents between 13 AD patients and 13 age-matched healthy controls. We examined their production of IL-1 beta, IL-10, IL-12p40, and IL-12p70, and their expression of CD23, CD40, CD54, CD80, CD83, CD86 and HLA-DR. We stimulated them with superantigens, lipopolysaccharide (LPS), agonistic anti-CD40 antibody, phytohemagglutinins (PHA), IL-1beta/TNF-alpha, IL-4, or IFN-gamma. The following results were obtained (1): IL-10 production was significantly enhanced in AD MOs after LPS stimulation. In contrast, IL-12p40 production was significantly lower in AD MOs than in HC MOs after a variety of stimulations (2). IL-12p40 was also significantly lower in AD MoDCs after LPS stimulation (3). The induction of CD23 with IL-4 was significantly higher in AD MOs. and finally (4), AD MoDCs augmented the expression of CD83, CD86, and HLA-DR less significantly than HC MoDCs after anti-CD40 Ab stimulation. These data indicate that AD APCs show some responses different from those observed in HC APCs after several stimulations, such as LPS, IL-1 beta/TNF-alpha, IL-4, or anti-CD40 Ab, and that these responses might play a role in the polarizing process of helper T cells into Th2 cells as recognized in AD patients.     

系统性红斑狼疮患者外周血淋巴细胞CD80和CD86的表达

目的 探讨系统性红斑狼疮(SLE)患者外周血淋巴细胞(PBLC)CD80和CD86的表达及其意义。方法 采用流式细胞仪检测了30例SLE患者PBLC的CD80和CD86抗原,并以25例正常人作为对照。结果 SLE患者PBLC上CD86的表达显著低于正常对照组(P<0.05);CD80表达与正常对照组差异无显著性;SLE患者活动期和非活动期、有肾病组和无肾病组的CD80和CD86的表达差异均无显著性;CD80和CD86水平与SLE疾病活动指数(SLEDAI)、ANA滴度、IgG、和C3水平无相关关系。结论 SLE患者PBLC上CD86的表达降低,可能与SLE发病机制有关。     

复发性生殖器疱疹患者外周血单一核细胞CD40和CD40L的表达

目的 探讨复发性生殖器疱疹患者外周血单一核细胞CD40、CD40L的表达。方法 利用流式细胞仪对30例复发性生殖器疱疹患者和20例正常人对照者外周血单一核细胞(PBMC)CD40、CD40L的表达及T淋巴细胞亚群进行检测。结果 病例组PBMC中CD40阳性细胞百分数较对照组显著降低(P=0.0061);CD40L阳性细胞百分数较对照组明显降低(P=0.041);CD3⁺T细胞和CD4⁺T细胞百分数亦显著低于对照组(其P值分别为0.025和0.032)。结论 CD40-CD40L共刺激作用低下是生殖器疱疹复发的重要原因之一。     

Natural killer (NK) cell activity and NK-related cell surface markers in patients with atopic dermatitis

Natural killer (NK) cell activity and NK-related surface markers in peripheral blood mononuclear cells (PBMC) in thirty-three patients with adult type atopic dermatitis (AD) were investigated. NK cell activity, detectable by cytolysis of erythroleukemic cell line K562 cells, was reduced in patient PBMC as compared with healthy controls. Imbalances in the lymphocyte populations reactable with the monoclonal antibodies, anti-HNK-1, and anti-CD16 were found in the patient PBMC. Some positive correlations between these cell populations and the NK cell activities were recognized. In most cases, high levels of serum IgE were inversely correlated with NK cell activity. Depletion of the macrophages from patient PBMC had no effect on NK cell activities. These activities were enhanced by culture with β-interferon for 18 hours, as were the NK cell activities of healthy controls. These results suggest that reduced numbers or imbalances in the lymphocyte population with NK cell activity, are responsible for the pathogenesis and the prognosis of adult type atopic dermatitis.     

Imbalance of CD4+CD29+ and CD4+CD45RA+ T-helper cell subsets in peripheral blood of patients with severe atopic dermatitis

To determine the proportion of T-helper cell subsets in the peripheral blood we studied 16 patients with mild, moderate and severe atopic dermatitis. Lymphocytes were isolated from heparinized peripheral blood and analysed by two-colour flow cytometry. Patients with severe atopic dermatitis had a decreased CD4+CD29+CD4+CD45RA+ ratio (p<0.01). We found a decreased absolute number of CD4+CD29+ cells (p<0.05) and an increased absolute number of CD4+CD45RA+ cells (p<0.05) in the peripheral blood. No significant changes in the CD4+CD29+CD4+CD45RA+ ratio were found in the peripheral blood of patients with clinically mild or moderate atopic dermatitis.     

Recombinant adeno-associated virus (rAAV) vector-mediated cotransduction of CD70 and CD80 into human malignant melanoma cells results in an additive T-cell response

Genetic modification of malignant melanoma cells by transduction of cDNA encoding costimulatory molecules, cytokines or tumor-associated antigens has been shown to induce antitumor immunity. An important step in this scenario is the activation of T cells. CD80 is a pivotal costimulatory molecule for T-cell activation. Another molecule with costimulatory activity is CD70. The purpose of this study was to evaluate the capacity of a combined expression of CD70 and CD80 on melanoma cells to amplify an antitumor response in vitro. Therefore, the CD70- and CD80-negative human malignant melanoma cell line Colo679 was transduced with adeno-associated virus vectors carrying either CD70 or CD80. The resulting cell strains Colo679-CD70, -CD80 and -CD70/CD80 showed strong expression of CD70, CD80 or both, respectively. As expected, the T-cell response to CD70-positive malignant melanoma cells was substantially weaker than to the CD80-positive cells. However, the combined expression of CD70 and CD80 resulted in a T-cell response clearly superior to the single expression of CD80 or CD70 alone. These results provide evidence that CD70 plays an additional role in T-cell activation and should be considered as a molecule of interest in the design of immune gene therapy strategies for the treatment of malignant melanoma.     

CD40 signalling induces IL-10-producing, tolerogenic dendritic cells

Abstract:  Dendritic cells (DC) are potent antigen-presenting cells capable to induce efficient antigen-specific T cell responses in vitro and in vivo . Herein, the maturation process is of great significance, as immature DC (iDC) are known to induce rather regulatory than effector T cell differentiation. This study was designed to characterize the role of the CD40-CD40L pathway for differentiation and function of human DC. Therefore, iDC were stimulated through CD40-CD40L interaction by transduction of DC with adenoviral vectors encoding for CD40L (Ad-CD40L). Resulting DC (CD40L-DC) were analysed concerning their phenotype, cytokine profile and T cell stimulatory capacity. Transduction induced a DC phenotype comparable to stimulation with proinflammatory cytokines as revealed by upregulation of CD83 and the costimulatory molecules CD80 and CD86. Additionally, Ad-CD40L-induced strong production of IL-12p70 not observed in cytokine-matured DC. Surprisingly, the T cell stimulatory capacity was markedly reduced in CD40L-DC. Furthermore, stimulation of CD8⁺ T cells by peptide-loaded CD40L-DC resulted in a substantial reduction of antigen-specific IFN-γ production. This phenomenon is due to an enhanced IL-10 production of CD40L-DC in DC-T cell coculture as well as a stabilization of the IL-10 receptor expression on activated T cells. These data demonstrate that DC stimulated through CD40-CD40L interaction differentiate into tolerogenic DC with immunomodulatory function.     

Expression of CD30 on T helper cells in the inflammatory infiltrate of acute atopic dermatitis but not of allergic contact dermatitis

Abstract  The CD30 molecule has been proposed as a marker for a subset of CD4⁺CD45RO⁺ (memory) T cells with potent B cell helper activity producing IL-5 and IFN-γ and as a specific marker for Th2 cells. Recently, an association has been demonstrated between elevated serum levels of soluble CD30, which is shed by CD30⁺ cells in vitro and in vivo, and atopic dermatitis but not respiratory atopic disorders or allergic contact dermatitis. We studied the expression of CD30 in the inflammatory infiltrate of atopic dermatitis compared with that of allergic contact dermatitis, with special regard to skin disease activity (acute vs subacute/ chronic). Biopsies were obtained from 16 patients suffering from atopic dermatitis (acute n = 6, subacute/ chronic n = 10), from 7 patients with acute allergic contact dermatitis and from 5 positive patch-test reactions. Paraffin-embedded as well as snap-frozen material was stained with anti-CD30 and anti-CD45RO mAbs according to standard procedures. Double-staining procedures for CD30CD3, CD30CD4, CD30CD45RO and CD30CD68 were also performed. Abundant CD45RO⁺ cells were detected both in atopic dermatitis and in allergic contact dermatitis lesions. We found scattered CD30⁺ cells in only one of six formalin-fixed paraffin-embedded acute atopic dermatitis biopsies, but in all of the respective snap-frozen specimens, possibly because CD30 expression on atopic dermatitis infiltrating cells is weak and sensitive to formalin fixation and paraffin embedding. CD30CD3 and CD30CD4 double staining identified CD30⁺ cells to be helper T lymphocytes. No significant CD30 expression (either in paraffin-embedded or in frozen material) could be found in subacute/chronic atopic dermatitis lesions or in any of the specimens of allergic contact dermatitis. The results suggest a specific regulatory function of CD30⁺ T cells in acute atopic dermatitis. With respect to the view that CD30 is a marker for Th2 cells, our observations confirm previous findings that Th2 cells predominate in the infiltrate particularly of acute atopic dermatitis. CD30 expression in acute atopic dermatitis but not in acute allergic contact dermatitis might be helpful in the histological differentiation of these disorders and in the further characterization of atopy patch testing. Received: 1 April 1998 / Received after revision: 28 May 1998 / Accepted: 3 July 1998     

Interferon-gamma differentially regulates CD80 (B7-1) and CD86 (B7-2/B70) expression on human Langerhans cells

CD80 (B7-1) and CD86 (B7-2/B70) have recently been identified in cultured human Langerhans cells (LCs), although their role and regulatory properties remain unclear. We present our comparison of the expression of the molecules, mRNAs and the function between CD80 and CD86 in human LCs treated by interferon γ (IFN_-γ). We examined the regulatory properties of CD80 and CD86 expression in human LCs pretreated with IFN_-γ. Flow cytometric analysis indicated that the mean fluorescence intensity of CD86 but not CD80 was enhanced. However, the percentage modulation of both CD80 and CD86 positive cells were significantly up-regulated in a dose-dependent manner, after 48-h culturing with IFN_-γ. The regulatory properties of CD80 and CD86 mRNA expressions in human LC were studied using polymerase chain reaction methods. We found that both CD80 and CD86 mRNA of enriched LCs following IFN_-γ pretreatment for 12 h were higher than those without pretreatment. We have demonstrated that the primary allogeneic mixed epidermal cell-lymphocyte reaction induced by human LCs treated by IFN_-γ increased in a dose-dependent manner. There was a 61.5% inhibition by anti-CD86 monoclonal antibody and a 32.5% inhibition by anti-CD80 monoclonal antibody. These data indicate that the CD80 and CD86 expression of human LCs may be differently regulated by IFN_-γ.     

CD80CD86 deficiency disrupts regulatory CD4+FoxP3+T cell homoeostasis and induces autoimmune‐like alopecia

Alopecia areata (AA) is an autoimmune disease that results in spot baldness in humans. Adequate animal models for AA are currently lacking. The objective of this study was to elucidate the mechanism of autoimmune-like alopecia (ALA) in C57BL/6.CD80CD86-deficient (B6.CD80CD86^−/−) mice. Incidence and severity of alopecia were analysed in 58 B6.CD80CD86^−/− mice using histological examination, flow cytometry, multiplex enzyme-linked immunosorbent assay, quantitative RT-PCR and CD25 inhibition test. Both male and female B6.CD80CD86^−/− mice showed almost 100% incidence of hair loss at 40 weeks of age. Moreover, CD4+FoxP3+Treg (Treg) cell population in B6.CD80CD86^−/− mice was significantly lower than in B6 mice, which presumably underlined autoimmune reaction. Histologically, B6.CD80CD86^−/− mice showed CD4+ and CD8+ T-cell infiltration around terminal follicle region and exhibited hair follicle destruction in the anagen or catagen stage. Negative correlation between the number of CD4+FoxP3+ Tregs and ALA was confirmed by the CD25 depletion test in B6 mice, as follicle destruction was similar to that observed in B6.CD80CD86^−/− animals. CD80CD86 deficiency disrupted CD4+FoxP3+ Treg homoeostasis and prompted the development of ALA. We demonstrated that B6.CD80CD86^−/− mice might have several advantages as an ALA model, because they exhibited high incidence of disease phenotype and epipathogenesis similar to that observed in human AA.     

复发性生殖器疱疹患者外周血淋巴细胞CD80和CD86的检测

目的探讨复发性生殖器疱疹患者外周血淋巴细胞(PBLC)CD80和CD86的水平及其意义。方法利用流式细胞仪对25例复发性生殖器疱疹患者和20例正常人对照者外周血淋巴细胞CD80和CD86的水平进行检测。结果病例组PBLC上CD80和CD68的水平均显著低于正常对照组(P均<0.01)。结论CD80和CD86的水平降低可能是生殖器疱疹复发的重要原因之一。     

Expression of CD80 (B7/BB-1) and CD28 in human white blood cells treated with urocanic acid

Urocanic acid (UCA) is formed in the epidermis where it accumulates to be converted fromtrans-tocis-UCA by ultraviolet (UV) radiation. The two isomers modulate immune functions in several experimental systems. In particular,cis-UCA has been shown to induce antigen-specific immune tolerance, but the molecular mechanism of this effect is unknown. The present investigation was instituted to disclose any effect of UCA isomers on the cellular expression of the costimulatory antigens CD80 (B7/BB-1) and CD28. CD80 expression was efficiently induced in monocytic (CD14⁺) cells by human interferon-γ, while CD28 levels on lymphocytes remained unchanged, as detected by flow cytometry. Neither UCA isomer showed any effect on the expression patterns of these costimulatory molecules. The results obtained suggest that the mode of action for epidermal UCA-induced tolerogenesis may not involve modulation of CD80 (B7/BB-1) or CD28 expression.     

OX40 ligand and OX40 are increased in atopic dermatitis lesions but do not correlate with clinical severity

Background The interaction between the OX40 ligand (OX40L) and OX40 has been suggested to have pathogenetic significance in atopic dermatitis (AD). Objective The purpose of this study was to investigate the expression and relevance of OX40L and OX40 in AD skin. Methods OX40L and OX40 were stained immunohistochemically on the cryosections of the lesional and non‐lesional skin of 17 subjects with moderate‐to‐severe AD and of 10 patients with psoriasis vulgaris. Phorbol myristate acetate (PMA) stimulated keratinocytes and cell membrane preparations from PMA‐stimulated keratinocytes or LAD‐2 mast cells were incubated with peripheral blood mononuclear cells (PBMC) in the presence or absence of blocking monoclonal antibodies to OX40L, CD30L or ICAM‐1. Results We show for the first time that the staining intensity of OX40L and the number of OX40⁺ cells are significantly greater in the lesional dermis than in the healthy‐looking dermis in AD (P < 0.001 in both comparisons) and also in psoriasis (P = 0.01 and P < 0.001 respectively), but neither molecule correlate significantly with the clinical severity of AD. Living keratinocytes and cell membranes from LAD‐2 mast cells and keratinocytes increased the PBMC proliferation response. Anti‐OX40L antibody inhibited, in a similar fashion as anti‐ICAM‐1 and anti‐CD30L, PBMC proliferation induced by LAD‐2 membranes, but stimulated that induced by keratinocytes. Conclusion Our findings provide evidence for the involvement of OX40 and OX40L in the pathogenesis of AD though they are not specific to AD and in vitro results suggest complex interaction.