Human mast cells produce IL-8

Recruitment of neutrophils is a common feature in diseases that are associated with mast cell activation. The mechanisms that mediate neutrophil activation are not well understood. IL-8 is a recently described potent chemotactic factor that might be pathogenetically involved in this process. We therefore studied the human mast cell line HMCI and human skin mast cells for their ability to produce IL-8 using various stimuli. IL-8-mRNA was expressed in a stimulus- and time-dependent fashion as detected by Northern blot analysis with an IL-8-specific cDNA probe. The molecular mass of HMCI-derived IL-8 was determined to be about 8 kDa by immunoblot analysis. Immunoreactive and biologically active IL-8 protein was measured in the cell culture supernatants of HMCI cells by an ELISA and a chemotaxis assay, respectively. On immunoelectron microscopy of stimulated skin mast cells, IL-8 was found along cytoplasmatic membranes and in intracellular granules. Our data indicate that mast cells may contribute to neutrophil recruitment by secretion of IL-8.

IL-8 produced by human malignant melanoma cells in vitro is an essential autocrine growth factor

Normal melanocytes require a number of exogenous growth factors in contrast to most metastatic malignant melanomas. This investigation demonstrates that endogenously produced human IL-8 can act as an important growth factor for human melanoma cells. In the present study, six out of eight human melanoma cell lines tested secrete IL-8 protein into the culture supernatant. In two of these IL-8-secreting melanoma cell lines, SK-MEL 13 and SK-MEL 23, we have determined the IL-8 requirement for their proliferative capacity. These melanoma cell lines produced significant amounts of bioactive IL-8 as measured by the ELISA technique. Secretion of human IL-8 was inducible by IL-1 and by PMA. Human IL-8-specific mRNA was already detected in unstimulated melanoma cells. In addition, human IL-8-R mRNA could be detected for the first time in human melanoma cells. Exposure of the two melanoma cell lines in vitro to antisense oligonucleotides targeted against two different sites of human IL-8 mRNA-inhibited cell proliferation, colony formation in soft agar, and secretion of IL-8 protein into culture supernatant in a dose dependent fashion. Effects were reversible either by removal of the oligomers or by addition of exogenous IL-8 protein. In contrast, exposure to IL-8 sense probes or oligonucleotides in sense or antisense orientation specific for IL-7, TGF-alpha, TGF-beta, and MGSA had no such effect. A monospecific immune serum and two IL-8-specific mAb were also capable of inhibiting melanoma cell proliferation in the same manner. These results provide strong evidence for an autocrine IL-8 synthesis and for an IL-8-dependent proliferation in a subgroup of human melanomas. Furthermore, they suggest that IL-8 may play a role not only in immunomodulation but also in melanoma progression and metastatic spread.

IL-8 produced by human malignant melanoma cells in vitro is an essential autocrine growth factor

Normal melanocytes require a number of exogenous growth factors in contrast to most metastatic malignant melanomas. This investigation demonstrates that endogenously produced human IL-8 can act as an important growth factor for human melanoma cells. In the present study, six out of eight human melanoma cell lines tested secrete IL-8 protein into the culture supernatant. In two of these IL-8-secreting melanoma cell lines, SK-MEL 13 and SK-MEL 23, we have determined the IL-8 requirement for their proliferative capacity. These melanoma cell lines produced significant amounts of bioactive IL-8 as measured by the ELISA technique. Secretion of human IL-8 was inducible by IL-1 and by PMA. Human IL-8-specific mRNA was already detected in unstimulated melanoma cells. In addition, human IL-8-R mRNA could be detected for the first time in human melanoma cells. Exposure of the two melanoma cell lines in vitro to antisense oligonucleotides targeted against two different sites of human IL-8 mRNA-inhibited cell proliferation, colony formation in soft agar, and secretion of IL-8 protein into culture supernatant in a dose dependent fashion. Effects were reversible either by removal of the oligomers or by addition of exogenous IL-8 protein. In contrast, exposure to IL-8 sense probes or oligonucleotides in sense or antisense orientation specific for IL-7, TGF-alpha, TGF-beta, and MGSA had no such effect. A monospecific immune serum and two IL-8-specific mAb were also capable of inhibiting melanoma cell proliferation in the same manner. These results provide strong evidence for an autocrine IL-8 synthesis and for an IL-8-dependent proliferation in a subgroup of human melanomas. Furthermore, they suggest that IL-8 may play a role not only in immunomodulation but also in melanoma progression and metastatic spread.

Demonstration of the high-affinity IgE receptor on human Langerhans cells in normal and diseased skin

Epidermal dendritic cells of normal adult foreskin, and of lesional skin from patients with atopic eczema, stasis eczema and urticaria pigmentosa are shown to be highly reactive with two different monoclonal antibodies (29C6 and 6F7) specific for extracellular domains of the alpha-chain of the high-affinity IgE receptor. By their distribution pattern, the reactive cells are Langerhans cells. This is confirmed by immunoelectron microscopic demonstration of Birbeck granules in the labelled epidermal cells. Very weak staining is observed on the same cells with an antibody (Tü1) against the low-affinity IgE receptor. Pre-incubation of the sections with IgE partially blocks binding of 6F7 antibody. Langerhans cells, together with dermal mast cells, can therefore bind IgE with high efficiency, and may in this way participate in IgE-mediated cutaneous diseases.

Tumour progression and metastatic behaviour in vivo correlates with integrin expression on melanocytic tumours

In order to evaluate the significance of adhesion molecules expressed on melanocytic tumours for progression and prognosis in vivo, we studied integrin expression (VLA-1 to VLA-6, CD18, CD51, CD61) on 10 naevi, 40 primary malignant melanomas, and 11 metastases by immunohistology using the APAAP technique. Evaluation was done by grouping the percentage of positive tumour cells in six categories. Statistical analysis (Wilcoxon rank test, Scheffe test) revealed significant differences in the expression of VLA-1 (P < 0.0001), VLA-2 (P = 0.0001), VLA-5 (P = 0.0093), VLA-6 (P = 0.0232), and CD61 (P = 0.0002) between naevi and primary melanomas. Comparing primary melanomas with metastases, a statistically significant decrease in the expression of VLA-1, VLA-2, and VLA-6 was detectable, as well as a significant increase in VLA-4 and VLA-5. There was no correlation between integrin expression and tumour type (superficial spreading melanoma, nodular melanoma, lentigo maligna melanoma), regression and ulceration. Changes of VLA-1, VLA-4, and VLA-6 expression correlated with the tumour thickness of the primary melanoma, but only VLA-4 and VLA-6 expression on primary melanomas correlated significantly with the development of metastases (P = 0.024 and P = 0.001). These changes of integrin expression during tumour progression particularly, the data showing an increase of VLA-4, and a decrease of VLA-6 expression support the concept that integrins are a new additional set of prognostic markers which indicate predisposition to the development of metastases.

Determination of granulocyte/macrophage-colony-stimulating factor secretion by human melanoma cells and its effects on human melanoma cell proliferation

Recently, granulocyte/macrophage-colony-stimulating factor (GM-CSF) became available for overcoming chemotherapy-induced granulocytopenia. GM-CSF not only has a prominent role in the regulation of proliferation and differentiation of haematopoietic cells but it is also secreted by a variety of solid tumours and is capable of exerting growth-stimulatory effects. To evaluate the safety of GM-CSF administration in the treatment of malignant melanoma, we investigated GM-CSF secretion, GM-CSF receptor expression and the effect of GM-CSF on the proliferation of human melanoma cells in vitro. A panel of eight human melanoma cell lines and two fresh tumour specimen was studied. GM-CSF protein was not detectable in culture supernatants by ELISA without stimulation. Interleukin-1 and tumour necrosis factor alpha induced GM-CSF secretion in all four melanoma cell lines tested. When biotinylated GM-CSF was used, the corresponding receptor was not detectable by immunohistochemical or FACScan analysis. The proliferation of eight human melanoma cell lines and two fresh melanoma specimens was determined by the MTT test after 4-6 days of growth in the presence of different concentrations of GM-CSF (0.1-1000 U/ml). Neither proliferation nor growth inhibition was observed. Therefore the effect of GM-CSF on residual tumour cells in vivo may not present a problem during clinical use to stimulate marrow regeneration after or during chemotherapy of metastatic malignant melanoma.

Demonstration of the high-affinity IgE receptor (Fc epsilon RI) on Langerhans cells of oral mucosa

Langerhans cells in the skin have recently been shown to bind IgE molecules via a high-affinity IgE receptor. Using two specific antibodies, 29C6 and 6F7, against the alpha-chain of the high-affinity IgE receptor, we here demonstrate that Langerhans cells express this receptor in oral mucosa. A specific antibody, Tü1, against the low-affinity IgE receptor showed only low expression of this receptor. High-affinity binding for IgE may be important for induction and support of Langerhans cell-dependent transepithelial IgE-mediated allergic reactions and inflammation.

[Recurrent paroxysmal neck swellings as the primary manifestation of a pheochromocytoma]

A 45-year-old female had been suffering for about 6 months almost daily from paroxysmal neck swellings with occasional difficulties in swallowing and from non-specific abdominal complaints. Hormone analyses, performed because of the marked blood pressure increase up to 210/120 mm Hg during such an attack, revealed an increase in vanillyl mandelic acid and epinephrine concentrations in the 24-hour urine. CT demonstrated a tumour of 4 x 5 x 5 cm size in the region of the right adrenal. The paroxysmal neck swellings and blood pressure increase could be reproduced by means of pressure applied over the tumour range with the ultrasound transducer. The tumour was extirpated and histology revealed a phaeochromocytoma. For more than one year now the patient has been free from complaints. To date, recurrent neck swellings have not been reported in association with a phaeochromocytoma. Possible causes may be an enhanced congestion of the deep neck vessels during paroxysmal blood pressure increase or an enhanced response by the adrenoreceptors of these vessels to the released catecholamines.

Acute monoblastic leukemia with skin nodules in an adult

An 18-year-old man had a 3-week history of malaise, a 1-week history of a papular eruption, and increasingly severe multisystem neurologic symptoms. A diagnosis of acute monoblastic leukemia was made. Immunophenotypic characterization of peripheral blood, bone marrow, and cutaneous infiltrates revealed a predominant myelomonocytic phenotype with the coexpression of intercellular adhesion molecule type 1, IgE receptor, terminal deoxynucleotidyl transferase, and some T-cell markers. These findings may have important clinical and pathogenetic implications regarding the biologic and pathologic behavior of the myelomonocytic leukemic cells. They also explain in part the impressive presentation of the disease in the skin.

Brain metastases of metastatic malignant melanoma: response to DTIC and interferon-gamma

The prognosis of patients with malignant melanoma and brain metastases is poor. Therapy of brain metastases is difficult and mostly unsuccessful, with brain metastases being the predominant factor which determines overall survival. We report here on a patient whose brain metastases responded to DTIC + INF-gamma. We present a short summary on the different effects on INF-alpha and INF-gamma and reach the conclusion that clinical trials which combine DTIC and INF-gamma should be performed. Based on this observation, combinations including INF-alpha are not necessarily comparable to modalities which include INF-gamma.

Primary leiomyosarcoma of the skin. A histological and immunohistochemical analysis

We report a rare case of a cutaneous leiomyosarcoma on the extensor surface of the proximal part of the left arm of an 84-year-old man. The tumour exhibited a number of histological and immunohistochemical features which are characteristic of a leiomyosarcoma. Leiomyosarcomas are frequently misdiagnosed on clinical grounds. Therefore, clinical features, differential diagnosis, histological and immunohistochemical criteria, therapy and prognosis of this rare malignant tumour are summarized on the basis of the present case and previously published reports.

[Treatment of vitiligo with phenylalanine and UV-A]

Seven patients with generalized vitiligo were treated with 100 mg/kg body weight phenylalanine in combination with UV-A. A 20% repigmentation of the vitiligenous area was achieved in only one patient. Three patients each showed either a sparse follicular repigmentation or no effect at all. Because of the disappointing therapeutic results and possible side effects, we cannot recommend a therapy with phenylalanine and UV-A for vitiligo.

Responsiveness to interferon treatment of human melanoma cells correlates to immunophenotype

Clinical trials with interferon (INF) treatment in patients with advanced metastatic melanoma have met with limited success, suggesting that only a small subgroup of patients with melanoma is sensitive to INF therapy. For therapeutic strategies, it would be of great value to discriminate and define markers related to the anti-proliferative effects of INF. In the present study, we report on the in vitro growth inhibitory effects of INF in six human melanoma cell lines; this is associated with a modulation of cell surface markers. The responsiveness of human melanoma cell lines in vitro to INF-alpha shows a good correlation with a specific immunophenotype (TA99-/EGF-R+ or HLA-DR+). No marker correlated with sensitivity or resistance to INF-beta or INF-gamma. This is the first report identifying cell surface markers of human melanoma cells which might have a predictive value for the clinical response to INF-alpha.

Patterns of cell death: the significance of apoptosis for dermatology

Development, function, remodelling, and senescence of multicellular organisms depend on the coordinated occurrence of physiological, actively induced cell death in two major patterns: terminal differentiation and programmed cell death (apoptosis). Apoptosis is a highly selective form of "cell suicide" with characteristic morphological and biochemical features: chromatin condensation, formation of apoptotic bodies, and DNA fragmentation by activation of endonucleases. Here, we outline the current understanding of apoptosis and its subtypes, discuss their biological functions, and delineate why apoptosis is relevant to the skin and its diseases. We distinguish apoptosis from necrosis, and discuss the regulation of apoptosis by selected genes, hormones, growth factors and cytokines. The epidermis and the regressing hair follicle offer interesting models for studying the as yet ill-understood biology of epithelial cell apoptosis. The selective manipulation of cell death programs may become part of the therapeutic arsenal of clinical dermatology.

Interferon-alpha therapy in atopic dermatitis

Thirteen patients with a severe adult form of atopic dermatitis (AD) received 3.0 x 10(6) IU of recombinant interferon-alpha 2a (rIFN-alpha 2a) 3 times a week. A satisfactory response was obtained in 5 of them. Serum IgE levels in all 13 patients remained unchanged throughout the study. Flu-like symptoms were common, but clinical or laboratory adverse effects were otherwise slight. The moderately beneficial therapeutic effects observed in this study support a possible role for IFN-alpha in controlling immunologic deficiencies in atopic dermatitis.

Long-term adjuvant immunotherapy in stage I high risk malignant melanoma, comparing two BCG preparations versus non-treatment in a randomised multicentre study (EORTC Protocol 18781)

The present study reports the results of a multicentre adjuvant trial with BCG (Bacillus Calmette-Guérin) in high risk patients (Breslow thickness > or = 1.5 mm, Clark level > or = III) with malignant melanoma, after surgical removal of their primary tumour. The trial was specifically designed in order to resolve the controversy and to provide some definite answers regarding the value of adjuvant BCG treatment in stage I malignant melanoma. Patients were randomised to either BCG RIV (108 patients) or BCG Pasteur (109 patients) for 3 years or to follow-up only (110 patients). The two vaccines used had greatly divergent properties regarding their mode of preparation, their composition and their immunomodulating activities. Of the 353 randomised patients, 23 were ineligible, 3 refused participation after randomisation and 327 were evaluable for final analysis. Median follow-up time was 6 years (range 0-10 years). The log-rank test comparison showed no statistical difference between the three arms regarding time to progression (P = 0.55) and duration of survival (P = 0.82). Treatment was generally well tolerated, with no major adverse events in either treatment arm. These findings confirm data with different BCG preparations and with stage II melanoma which also demonstrated no benefit regarding patient survival and time to relapse.

Is alopecia areata an autoimmune-response against melanogenesis-related proteins, exposed by abnormal MHC class I expression in the anagen hair bulb?

The etiology of alopecia areata (AA), a putative autoimmune disease characterized by sudden hair loss, has remained obscure. It is not understood, how the characteristic inflammatory infiltrate that selectively attacks anagen hair follicles in AA is generated. We hypothesize that this reflects an unexplored form of autoimmunity, a cytotoxic T cell attack on rhythmically synthesized autoantigens normally sequestered by a lack or very low level of MHC class I (MHC I)-expression, and suggest the following mechanism of AA pathogenesis: Microtrauma, neurogenic inflammation, or microbial antigens cause a localized breakdown of MHC I-"negativity" in the proximal anagen hair bulb via proinflammatory cytokines. This exposes autoantigens derived from melanogenesis-related proteins (MRP-DP), which are only generated during anagen, and triggers two successive waves of autoimmune responses: CD8+ cytotoxic T cells initiate AA after recognizing MRP-DP abnormally presented by MHC I molecules on hair matrix melanocytes and/or keratinocytes; a secondary attack, carried by CD4+ T cells and antigen presenting cells, is then mounted against MHC class II--presented additional autoantigens exposed by damaged melanocytes and keratinocytes. The latter causes most of the follicular damage, and extrafollicular disease, and depends greatly on the immunogenetic background of affected individuals. This unifying hypothesis explains the clinical heterogeneity and all salient features of AA, and argues that only the unlikely coincidence of multiple predisposing events triggers AA. The suppression of MHC I--expression and synthesis of MRP in the hair bulb, and the "tolerization" of MRP-DP autoreactive CD8+ T cells may be promising strategies for treating AA.

Skin prick tests to common allergens in adult atopic eczema and rhinitis patients: reproducibility on duplicate and repeated testing

Skin prick test reactivity to a battery of common allergens was examined in 26 adults with atopic eczema, in 9 patients with allergic rhinitis and in 10 nonatopic controls. In both patient groups, reactivity was most frequent for grass pollen, followed by rye, house dust mite, tree and herb, with no reactions to food allergens. Repeated tests at weekly intervals were less reproducible in weak reactions and in severely affected eczema patients compared to those lightly affected. Skin prick tests are therefore reliable and reproducible in atopics and provide means to counsel patients on avoidance of eliciting agents of their disease.

Topical tiacrilast, a potent mast cell degranulation inhibitor, does not improve adult atopic eczema

Tiacrilast is a potent mast cell degranulation inhibitor in vitro and in animal studies. Since mast cells and their mediators are possibly involved in atopic eczema, we have studied a topically applied 3% hydrogel formulation of tiacrilast against vehicle in a multicenter, double-blind, placebo-controlled trial. Drug or vehicle were applied on involved skin for 28 days. Efficacy was assessed weekly using a 4-point scale for erythema, scaling, induration, exudation and pruritus. An overall assessment of the sites for efficacy and site preference was performed at the end of treatment. In the 32 patients evaluable for efficacy, > 33% improvement was noted on 78% of the drug- and 75% of the vehicle-treated sites, with no statistically significant differences for any of the parameters tested. Treatment was generally well tolerated by all patients. These data suggest that mast cells may not play a major role in the maintenance of atopic eczema lesions.

[Ammonium bituminosulfonate (Ichthyol). Anti-inflammatory effect and inhibition of the 5-lipoxygenase enzyme]

Ammonium bituminosulphonate (Ichthyol) inhibits 5-lipoxygenase activity in human polymorphonuclear neutrophils. The inhibition is dose-dependent and occurs at non-cytotoxic concentrations of the drug. This results in a decreased release of Leukotriene B4 from polymorphonuclear neutrophils. Furthermore, when applied to the ear skin of AB/Bln mice pretreated with croton oil, Ichthyol reduces the inflammatory reaction.

Expression of the high affinity IgE-receptor on human Langerhans' cells. Elucidating the role of epidermal IgE in atopic eczema

Epidermal Langerhans' cells have previously been shown to bear IgE molecules, particularly in atopic dermatitis skin. Using two highly specific antibodies against the antibody-binding chain of the high affinity IgE-receptor, 29C6 and 6F7, we here provide evidence that Langerhans' cells express this receptor in both normal skin (foreskin) and in lesional skin of patients with atopic and stasis eczema. A specific antibody against the low affinity IgE-receptor, Tü1, showed only a low expression of this receptor. This finding has important potential functional implications for the role of Langerhans' cells in transepidermal, IgE-mediated allergy.