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Biomedical subjects

R Benner

Publications and source records attributed to R Benner.

At least 19 recordsLinked to original sources
PubMed1997

The IL-1 system in psoriatic skin: IL-1 antagonist sphere of influence in lesional psoriatic epidermis.

The epidermal expression of IL-1 in psoriasis is clearly altered, but data are still incomplete and poorly understood. To thoroughly study the IL-1 system in psoriasis, we semiquantitatively analyzed the expression of all currently characterized IL-1 isoforms and their receptors in parallel in both lesional (PP) and nonlesional psoriatic (PN) epidermis. Immunostaining of skin sections showed that IL-1alpha, located in the basal keratinocytes of normal control (NN) and PN epidermis, was significantly decreased to negligible levels in PP epidermis. IL-1 receptor antagonist (IL-1ra) and IL-1R type II (IL-1RII) were both significantly overexpressed in mutually exclusive compartments of PP epidermis, the suprabasal and basal compartment, respectively. A significant inverse correlation was found between the expressions of IL-1alpha and these two IL-1 antagonists, which may be inherent to the accelerated terminal differentiation of the psoriatic keratinocyte. In situ hybridization of IL-1(R) mRNAs confirmed the staining results. Levels of IL-1ra mRNA, however, were not increased in PP epidermis, suggesting that the overexpression of IL-1ra protein may be explained at the level of translation. The more sensitive PCR demonstrated a clearly increased expression of IL-1beta mRNA in PP epidermal cells (EC), which may be related to the inflammatory response in psoriasis. IL-1RI mRNA was clearly present in both PP and NN EC. The mRNA levels of the secreted IL-1ra isoform, but not intracellular IL-1raI and II, and IL-1RII were elevated in PP EC and paralleled those of IL-1beta. In summary, this study provides a defined phenotype of the complete epidermal IL-1 system in psoriasis; it shows that the expressions of IL-1(R) isoforms are coordinately altered, resulting in a predominance of IL-1 antagonists, which may represent a negative feedback response to IL-1 agonists, leading to a decreased IL-1 responsiveness.

Epidermis↗
PubMed1996

Expression of platelet-derived growth factor (PDGF) and PDGF receptors in human malignant mesothelioma in vitro and in vivo.

The expression of platelet-derived growth factor (PDGF) and PDGF receptors was studied in human normal and malignant mesothelial cells in vitro and in vivo. Staining with anti-cytokeratin and ME1 antibodies and ultrastructural analysis confirmed the mesothelial nature of the cell lines used to study PDGF and PDGF receptor expression in vitro. Using antibodies, mesothelioma cell lines were found to express PDGF and both the PDGF alpha- and the PDGF beta-receptor, whereas cultured normal mesothelial cells expressed PDGF and PDGF alpha-receptor. This PDGF and PDGF receptor staining pattern largely reflects the earlier described mRNA expression in these cell lines. The only exception was the immunocytochemical detection of PDGF alpha-receptors in the mesothelioma cell lines, which is different from the inability to detect alpha-receptor transcripts on Northern blots. Expression was also investigated in mesothelial cells in vivo. Expression of PDGF was observed in malignant mesothelioma cells on frozen tissue sections. In pleural effusions, a double immunofluorescence staining procedure for PDGF and epithelial membrane antigen (EMA) revealed PDGF expression by EMA-positive malignant mesothelioma cells. PDGF beta-receptors and occasionally PDGF alpha-receptors were detected in frozen tissue sections of malignant mesotheliomas, whereas mesothelioma cells in effusions showed faint expression of only the PDGF beta-receptor. In contrast, in effusions containing non-malignant mesothelial cells, only a very low level of PDGF alpha-receptor could be detected. Taken together, these results indicate that the pattern of PDGF and PDGF receptor expression in mesothelial cells in vivo largely corresponds to expression of PDGF and its receptors in vitro. Malignant mesothelioma cell lines thus constitute a good model system for studies on the role of PDGF in this malignancy. Furthermore, the data reported in this paper are consistent with the idea that an autocrine growth stimulatory effect of PDGF via PDGF receptors may play a role in the pathogenesis of malignant mesothelioma.

Cryopreservation↗
PubMed1996

Expression of cytokines and their receptors by psoriatic fibroblast. I. Altered IL-6 synthesis.

Interleukin(IL-)6 is overproduced in psoriatic lesions. We investigated the contribution of dermal fibroblasts to the local IL-6 production. Fibroblasts (passageno. 2 to 6) derived from lesional psoriatic (PP) and normal human (NN) skin were used to analyse the secretion of IL-6, and the related cytokines IL-1, IL-8 and TNF-alpha, and the expression of their corresponding mRNA by bioassay, ELISA and Northern hybridization, respectively. PP fibroblasts cultured under serum-free conditions produced increased amounts of bioactive IL-6 when compared to NN fibroblasts. Differences were partially restored in the presence of growth factors or serum. The serum-induced IL-6 production reached a maximum within 24 h after seeding and remained unchanged in PP fibroblasts, whereas comparable amounts of IL-6 were produced only 6 days later in NN fibroblasts. There was a clear expression of IL-6 mRNA in both types of fibroblasts under serum-free conditions. Unexpectedly, fetal calf serum, inactivated fetal calf serum as well as human serum completely inhibited the expression of IL-6 mRNA in all the PP fibroblast cultures investigated. NN fibroblasts were clearly less sensitive to this inhibiting effect of serum. Furthermore, medium supplemented with serum-free component or calcium also repressed IL-6 mRNA expression in PP fibroblasts in contrast to NN fibroblasts. Cycloheximide fully restored the repressing effect of serum indicating that serum induced a labile repressor protein. PP and NN fibroblasts produced negligible amounts of IL-1 and TNF-alpha, but the production of IL-8, however, was comparable to that of IL-6. Our results show a differently regulated IL-6 synthesis in PP fibroblasts in vitro, suggesting an active contribution of dermal fibroblasts to the local IL-6 production in psoriasis.

Blotting, Northern↗
PubMed1996

Expression of cytokines and their receptors by psoriatic fibroblasts. II. decreased TNF receptor expression.

Psoriatic fibroblasts produce enhanced amounts of IL-6 in vitro. This state of activation may reflect an altered expression of cytokine receptors, involved in auto/paracrine induction of IL-6. Cultures of dermal fibroblasts derived from lesional psoriatic (PP) and normal control (NN) skin were therefore analysed for their ability to bind biotinylated recombinant human cytokines using flow cytometry. PP and NN fibroblasts bound negligible amounts of IL-1 alpha and IL-1 beta, but clearly bound IL-4, IL-6 and TNF-alpha. Serum upregulated the number of NN fibroblasts which bound TNF-alpha, and to a lesser extent IL-6, but not the number of binding sites per cell. In contrast, this upregulation was significantly less in PP fibroblasts. This was not a result of differences in growth characteristics, receptor occupancy or an inability of stimulated PP fibroblasts to bind TNF-alpha. Immunocytochemistry of cells grown on slides showed that the TNF receptor type 1 (TNFR1, p55) was the predominant receptor in NN fibroblasts and was localized to the nucleus of cytoplasma. The expression of TNFR1 was clearly decreased in PP fibroblasts, which confirmed the binding studies. A slow and serum-induced shedding of TNFR1 was observed, but not of the TNFR2 (p75), in both types of fibroblasts. Confluent multi-passaged PP fibroblasts display both a decreased TNFR expression as well as an enhanced IL-6 production under serum conditions. These inherent abnormalities of PP fibroblasts imply the involvement of dermal fibroblasts in the maintenance of chronic inflammation in psoriasis.

Calcium↗
PubMed1996

Adhesion molecules and IL-1 costimulate T lymphocytes in the autologous MECLR in psoriasis.

Membrane molecules such as CD36 (OKM5), intercellular adhesion molecule-1 (ICAM-1, CD54), gamma interferon-induced protein 10 (gamma-IP10) and IL-1 are induced and/or upregulated in psoriatic epidermis. These molecules have important accessory, trafficking or signalling functions in the immune system and also play a role in the pathophysiology of psoriasis. The relevance of adhesion molecules, CD36 and epidermal IL-1 in psoriasis was studied in vitro in the autologous mixed epidermal cell - T lymphocyte reaction (MECLR). Their level of expression was quantitated in epidermal cell suspensions (ECS) from patients with psoriasis and their function was assessed by blocking with specific mAbs and antisera or by depleting CD36+ cells from the ECS prior to the MECLR. ECS from psoriatic lesions contained increased numbers of CD36+ (23 +/- 12%), ICAM-1(+) (31 +/- 14%) and IL-1(+) (57 +/- 21%) cells. The autologous MECLR was inhibited in samples from all patients by mAb to CD2 (LFA-2), CD11a (LFA-1alpha), CD18 (LFA-1beta), ICAM-1, CD58 (LFA-3) and an antiserum to IL-1beta. Thus, adhesion molecules facilitate inflammation in psoriasis not only via adhesion and recruitment of T lymphocyte in psoriatic lesions, but also via activation of T cells. Furthermore CD36 molecules on psoriatic epidermal cells do not costimulate autologous T lymphocytes in psoriasis. The observed costimulatory function of IL-1beta in the MECLR emphasizes its relevance in psoriasis.

Antibodies, Monoclonal↗
PubMed1996

Differential effectiveness of anti-CD8 treatment on ongoing graft-versus-host reactions in mice.

Analysis of T cell subsets in the spleen during graft-versus-host (GVH) reactions in a fully allogeneic mouse strain combination demonstrated that first CD4+ T cells become activated, and initiate the GVH reaction. Subsequently, CD8+ T cells become involved. Here we show that anti-CD8 treatment on day +3 resulted in a significant increase in survival, while early treatment (day -1 or day +1) did not. Acute GVH reactions were induced (day 0) in lethally irradiated (C57BL/6 x CBA/J)F1 (H-2b/k) mice by intravenous injection of BALB/c (H-2d) spleen and lymph node cells (3.6 x 10(7)) within 24 h after irradiation. Mice were treated intraperitoneally with a single optimally depleting dose of rat anti-CD8 (YTS 169.4) or untreated. Symptoms of GVHD became obvious 6 days after reconstitution, and mortality started at day 8. The mutual influence of CD4+ and CD8+ T cells in the development of GVHD becomes apparent from our data, and demonstrates that GVHD lethality can be caused by CD8+ T cells as well as by CD4+ T cells.

Animals↗
PubMed1996

Allergy to carbamazepine: parallel in vivo and in vitro detection.

PURPOSE: Five to 20% of patients discontinue antiepileptic drug (AED) therapy because of adverse reactions. Careful reintroduction, however, may be considered if true drug allergy can be ruled out. Definitive assessment of such immunologically mediated reactions requires demonstration of either specific antibodies or sensitized lymphocytes. METHODS: We investigated whether skin patch tests (PTs) and in vitro lymphocyte proliferation assays (LPAs) were suitable for detection of allergy to carbamazepine (CBZ) and the possibly cross-reactive oxcarbazepine (OCBZ). Data of 65 patients displaying a wide range of possibly allergic side effects to CBZ were available for analysis. Data of CBZ users without any side effects and healthy volunteers served as controls. Both PTs and LPAs were done with CBZ, OCBZ and three metabolites [CBZ-10,11-epoxide (CBZ-E), 10-monohydroxy-CBZ (MHD), and 10,11-dihydroxy-CBZ (DIOL)]. RESULTS: Positive PTs with CBZ were seen in 20% and with OCBZ in 14% of the patients. Positive LPA results with CBZ and OCBZ, respectively, were found in 40 and 19%. Both tests were positive in 14 and 7% of the patients. Cross-reactivity to OCBZ was seen in -40% of CBZ-reactive patients in both PTs and LPAs. CONCLUSION: These data illustrate the additional value of LPAs in the detection of CBZ allergy while showing that a major part of side effects to CBZ and OCBZ is not immunologically mediated, according to PTs and LPAs.

Adolescent↗
PubMed1996

Increased expression of interleukin-4 receptors on psoriatic epidermal cells.

Abnormal keratinocyte proliferation and differentiation, the main characteristics of psoriasis, may be induced and maintained by cytokines produced by activated resident and recruited inflammatory cells in lesional skin. As the epidermal cytokine profile is clearly altered in psoriasis and because increased expression of interleukin-4 receptor (IL-4R) has been reported in some epithelial proliferative diseases, we investigated the expression of IL-4R on psoriatic epidermal cells (ECs). The expression of IL-4R on freshly isolated ECs from healthy skin and untreated psoriatic lesions was studied by immunostaining using an IL-4R-specific antibody and by examining their capacity to bind biotinylated recombinant human IL-4 using flow cytometry. The number of IL-4R+ ECs and the number of binding sites per cell were significantly increased on psoriatic ECs as compared with healthy control ECs. Immunostaining confirmed these results, whereby staining was mainly observed in the lower epidermal layers. In addition, an increased IL-4R mRNA expression was also observed in psoriatic epidermis using a digoxigenin-labeled IL-4R RNA probe. In short-term in vitro cultures, lipopolysaccharide/phorbol-myristate-acetate-stimulated and unstimulated psoriatic ECs did not produce any immunoreactive IL-4. The results of this study together with the reported increased expression of IL-4R in epithelial neoplasias suggest an association between overexpression of IL-4R and abnormal keratinocyte activation and proliferation.

Adult↗
PubMed1996

Soluble tumour necrosis factor receptor release after anti-CD3 monoclonal antibody treatment in mice is independent of tumour necrosis factor-alpha release.

The involvement of TNF-alpha in the release of soluble TNF receptors was assessed in mice, treated with anti-CD3 monoclonal antibodies. After treatment with three different anti-CD3 mAb, we simultaneously studied serum levels of TNF-alpha, soluble TNF receptor P55 and P75. All three anti-CD3 mAb triggered the release of both of the soluble TNF receptors, whereas only one of the anti-CD3 mAb triggered TNF-alpha release. These data demonstrate that in our model soluble TNF receptor release is independent of TNF-alpha release.

Animals↗
PubMed1995

Fc receptor binding of anti-CD3 monoclonal antibodies is not essential for immunosuppression, but triggers cytokine-related side effects.

A major drawback to the use of OKT3, a mouse anti-CD3 monoclonal antibody (mAb), as an immunosuppressive agent is the associated cytokine release syndrome. We used a mouse model to elucidate the properties of anti-CD3 mAb responsible for these cytokine-related side effects. We have previously demonstrated that the hamster anti-CD3 mAb 145-2C11 induced strong cytokine release and morbidity in vivo, whereas two rat anti-CD3 mAb 17A2 and KT3 did not. In the current study, we show that the mitogenic capacity of soluble anti-CD3 mAb in vitro correlates with their induction of side effects in vivo. Mitogenesis in vitro and tumor necrosis factor-alpha (TNF-alpha) release in vivo induced by anti-CD3 mAb could be inhibited by the anti-Fc gamma R mAb 2.4G2, indicating that Fc gamma R binding of anti-CD3 mAb is responsible for their mitogenic properties and for their induction of side effects. Importantly, the two non-mitogenic rat anti-CD3 mAb were equally capable of suppressing skin allograft rejection as the mitogenic hamster anti-CD3 mAb, suggesting Fc gamma R binding of anti-CD3 mAb is not essential for their immunosuppressive properties. This suggestion is reinforced by our demonstration that administration of 2.4G2 in vivo did not interfere with immunosuppression of skin allograft rejection by 145-2C11. These findings suggest that clinical use of non-mitogenic anti-CD3 mAb will result in effective immunosuppression without cytokine-related side effects.

Animals↗
PubMed1995

Enhanced production of biologically active interleukin-1 alpha and interleukin-1 beta by psoriatic epidermal cells ex vivo: evidence of increased cytosolic interleukin-1 beta levels and facilitated interleukin-1 release.

The expression of interleukin (IL)-1 is altered in psoriatic lesions. However, little is known about the actual production of IL-1 alpha and IL-1 beta by psoriatic epidermal cells (EC). We monitored IL-1 in the extracellular, the membrane and the intracellular compartment of freshly isolated EC from untreated lesional psoriatic (PP) and normal healthy (NN) skin during non-stimulated short-term cultures, representing a psoriasis model ex vivo. Cytokines were measured using bioassays combined with neutralizing antibodies and enzyme-linked immunosorbent assay in parallel. PP EC released significantly increased amounts of biologically active IL-1 alpha and IL-1 beta in a ratio of 3:1, whereas NN EC only released IL-1 alpha. Also, the release of IL-6, but not of TNF-alpha, by PP EC was significantly increased. Membrane-associated IL-1 activity, analyzed using glutaraldehyde-fixed EC, was low and not unique to PP EC. The cytosol of PP EC contained significantly increased levels of immunoreactive IL-1 beta. Furthermore, PP EC displayed loss of membrane integrity, as determined by trypan blue exclusion and release of cytosolic lactate dehydrogenase. This facilitated release of intracellular IL-1. Depletion of CD45+ cells showed that intraepidermal leukocytes did not contribute to the production of IL-1. Our observations show that resident PP EC express enhanced IL-1 production ex vivo, which is due to an increased cytosolic IL-1 beta content and facilitated IL-1 release. This study provides the first evidence that PP EC can produce bioactive IL-1 beta.

Cells, Cultured↗
PubMed1995

Effects of cyclosporine on cytokines and cytokine receptors in psoriasis.

BACKGROUND: Oral cyclosporine is effective in the treatment of recalcitrant psoriasis. However, the precise mechanism(s) are not fully understood. A possible mode of action may be via down-modulation of proinflammatory cytokines that are increased in psoriatic lesions. OBJECTIVE: This study was designed to monitor the effects of cyclosporine treatment on the expression of cytokines, cytokine receptors, and other markers of inflammation in psoriatic skin. METHODS: Ten patients with recalcitrant psoriasis were treated with cyclosporine. The in vivo effects of cyclosporine on cytokines and their receptors were studied by the use of cryostat-cut sections and a panel of antibodies. The in vitro effects were studied with flow cytometry of epidermal cell suspensions prepared from psoriatic lesions and control skin. RESULTS: Clinical improvement was noted in all patients after 2 weeks of cyclosporine treatment. The expression of interleukin-1 beta, interleukin-8, CD25(IL-2R), CD36 and E-selectin were significantly decreased, whereas the number of tumor necrosis factor-receptor-positive epidermal cells was significantly increased in psoriatic lesions. CONCLUSION: Clinical improvement of psoriasis with cyclosporine treatment is accompanied by down modulation of proinflammatory epidermal cytokines and decreased dermal inflammation. Thus besides suppressing cytokine production by the inflammatory infiltrate, the beneficial effect of cyclosporine in psoriasis also depends on the inhibition of the epidermal cytokine network.

Administration, Oral↗
PubMed1995

Hyposensitization in nickel allergic contact dermatitis: clinical and immunologic monitoring.

BACKGROUND: In allergic contact dermatitis (ACD) previously sensitized T cells cause skin damage. If an ubiquitous allergen such as nickel is involved, no effective treatment is available. Down-regulation of this allergic response has been described after antigen presentation in the absence of adequate costimulatory signals. UV exposure can enhance such hyposensitization. OBJECTIVE: The aim of this study was to establish the capability of a hyposensitization procedure to induce antigen-specific tolerance. METHODS: Twenty-one patients with nickel ACD were randomly assigned to either a hyposensitized or control group. A schedule consisting of UVB treatment and subcutaneous nickel sulfate administration (hyposensitization) or UVB only (control) was applied. During the ensuing 2 years, several clinical and immunologic features were monitored. RESULTS: During UVB treatment we observed a significant clinical improvement in both groups that persisted in the hyposensitized group. Except for increased slope variances of specific lymphocyte proliferation in time, no clear changes were seen in the immunologic findings. CONCLUSION: Despite significant clinical improvement induced by UVB, hyposensitization did not induce significant changes in the immunologic findings in patients with nickel ACD.

Adult↗
PubMed1994

Prevention of lethal graft-versus-host disease in mice by monoclonal antibodies directed to T cells or their subsets. II. Differential effectiveness of IgG2a and IgG2b isotypes of anti-CD3 and anti-CD4 moAb.

The effects of rat anti-CD3 and anti-CD4 moAb, of the IgG2a as well as of the IgG2b subclass, on the development of lethal graft-versus-host disease (GVHD) in a fully allogeneic mouse strain combination were compared in vivo. After treatment with these moAb, mice recovered from an initial loss of body weight. Moreover, their survival significantly improved. A single dose of 200 micrograms moAb resulted in a complete and long-term survival, which was not the case after treatment with anti-CD4 IgG2a moAb. A dose of at least 1 mg anti-CD4 IgG2a was necessary to induce a tolerant state. Mice effectively treated were fully repopulated with donor-type cells. Flow cytometric analysis of the recipient spleen cells demonstrated that the moAb caused depletion, modulation or coating of T cells or a combination of these. The moAb with the highest depleting capacity appeared to be anti-CD4 IgG2b moAb. Anti-CD3 IgG2a as well as IgG2b treatment resulted in a strong modulation of CD3 surface proteins, which was found on all days examined. Modulation of CD4 surface antigens did not occur in the case of anti-CD4 IgG2a moAb treatment. Anti-CD4 IgG2b moAb treatment, on the other hand, not only caused some CD4 modulation, but also, quite unexpectedly, a significant modulation of the CD3 molecule. Coating was only observed after treatment with anti-CD4 IgG2a moAb and lasted at least 1 week.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗