RESUMO
BACKGROUND: The effect of specific immunotherapy (SIT) on eczema in atopic dermatitis is not known. Therefore, a multi-centre, randomized dose-response trial, double-blind with respect to the efficacy of a biologically standardized depot house dust mite preparation was performed. METHODS: Eighty-nine adults with a chronic course of atopic dermatitis, SCORAD >or=40 and allergic sensitization to house dust mites [CAP-FEIA >or=3] were included, of whom 51 completed the study. Subcutaneous SIT with a house dust mite preparation (Dermatophagoides pteronyssinus/D. farinae) applying maintenance doses of 20, 2,000 and 20,000 SQ-U in weekly intervals for 1 year. The main outcome measures addressed the change of the SCORAD as average of the values after 9 and 12 months of SIT in comparison with the value at baseline. RESULTS: The SCORAD declined in the three dose groups in a dose-dependent manner (P = 0.0368, Jonckheere-Terpstra test) and was significantly lower in the two high-dose groups (2,000, 20,000 SQ-U) compared with the low-dose group of 20 SQ-U (P = 0.0379, U-test) after 1 year of SIT. The use of topical corticosteroids was significantly reduced with higher doses (P = 0.0007, Mantel-Haenszel chi-square test). CONCLUSIONS: Allergen-SIT for 1 year with a house dust mite preparation is able to improve the eczema in patients with atopic dermatitis who are sensitized to house dust mite allergens and reduces the need for topical corticosteroids. SIT may be valuable in the treatment of this chronic skin disease.
Assuntos
Alérgenos/imunologia , Antígenos de Dermatophagoides/imunologia , Dermatite Atópica/terapia , Dessensibilização Imunológica , Hipersensibilidade/prevenção & controle , Pyroglyphidae/imunologia , Adolescente , Adulto , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Ageing involves the whole organism, including the immune system. Age-dependent alterations of immune functions are located in both the adaptive and innate parts of the immune system. The most important cell type of the innate immune system are the dendritic cells, because their capacity to induce primary immune responses via professional antigen presentation is crucial for the initiation of the adaptive immune response. Evidence exists that dendritic cells of the systemic immune system, represented by lymph-node and blood-derived dendritic cells, as well as of local immunity, represented by Langerhans cells of the skin, participate in ageing processes. In animal models of older mice, dendritic cells of lymph nodes show degenerative characteristics with decreased adhesion molecule expression, less dendrite formation, and reduced antigen trapping capacity, which together imply disruption of functional activity. In contrast, dendritic cells generated from peripheral blood of elderly people were not impaired in their capacity to induce T-cell responses. Together, these findings indicate that in old individuals in vivo dendritic cells of the systemic immune system are reduced in their functional capacity to stimulate immune responses, whereas in vitro generated dendritic cells are fully functional, and therefore might be used in therapeutic approaches to treat age-associated malfunctions of the immune system. Thus far, only morphological descriptions about age-associated changes of dendritic cells (in particular the Langerhans cells) of the skin exist. In the skin, effects of naturally occurring ageing have to be differentiated from UV-radiation-induced ageing processes. The hallmark of Langerhans cell changes in natural as well as UV-induced skin ageing is their reduction in cell number within the epidermis. In addition, they show an atrophic morphology with less dendrites, and less Birbeck granules. It is assumed that these morphological changes are associated with loss of dendritic cell functions, and that this contributes to age-associated development of skin cancer. Therapeutic strategies against natural and UV-induced skin ageing should include a reduction of these changes of Langerhans cells in order to strengthen the immunological functions of the body's outer surface.
Assuntos
Células Dendríticas/fisiologia , Envelhecimento da Pele/fisiologia , Animais , Contagem de Células , Células Cultivadas , Senescência Celular/fisiologia , Citocinas/fisiologia , Células Dendríticas/citologia , Células Dendríticas/efeitos da radiação , Humanos , Sistema Imunitário/fisiologia , Sistema Imunitário/efeitos da radiação , Células de Langerhans/citologia , Células de Langerhans/fisiologia , Células de Langerhans/efeitos da radiação , Camundongos , Ratos , Raios Ultravioleta/efeitos adversosRESUMO
Micro flow modules with optical detection have been fabricated in a way which enables optical waveguiding inside and a defined interaction length along the fluid channel. Because of the usually lower refractive index of the solution compared with that of the substrate, so-called "leaky" optical wave-guiding must be employed. The combination of the fluid flow channel function with that of the optical waveguide has advantages for all miniaturized optical detection cells. It has been shown for hyper Rayleigh scattering (HRS) that improvement of the analytical principle is inherent in the miniaturization. The detection limit can be enhanced by at least a factor of 20. The applied HRS measurement procedure also enables simultaneous detection of two photon absorption (TPA) fluorescence. The severe boundary conditions of capillary electrophoresis were used as micro flow module design constraints to enable the transfer of the approach to other types of analysis.
RESUMO
The present study assessed the molecular mechanism underlying ultraviolet (UV) B radiation-induced inhibition of the expression of the adhesion molecule ICAM-1 in human antigen-presenting cells (APC). UVB radiation-induced inhibition of ICAM-I expression in human peripheral blood monocytes was associated with the generation of cyclobutane pyrimidine dimers (CPD). CPD were reduced by 60% after treatment with liposomal packed photolyase, an enzyme which removes CPD after absorption of photoreactivating light. Although incomplete, reduction of CPD was associated with complete restoration of ICAM-1 expression at the mRNA and protein level. Neither reduction of CPD level nor restoration of ICAM-1 expression were observed, if monocytes were treated with empty liposomes, or if they were irradiated with photoreactivating light prior to application of photolyase. DNA damage might also induce soluble mediators capable of autocrine inhibition of ICAM-1 expression. UVB irradiation of monocytes did not induce IL-10 production, but resulted in release of prostaglandin (PG) E2. Treatment of unirradiated monocytes with PGE2 completely inhibited ICAM-1 expression, thus mimicking the UVB effect. Inhibition of monocytic PGE2 production by indomethacin, however, did not restore ICAM-1 expression. These results suggest that formation of CPD is necessary and sufficient for UVB radiation-induced inhibition of ICAM-1 expression. In contrast, PGE2 might serve a paracrine role in UVB radiation-induced immunosuppression.
Assuntos
Células Apresentadoras de Antígenos/efeitos da radiação , Reparo do DNA , Desoxirribodipirimidina Fotoliase/metabolismo , Regulação da Expressão Gênica/fisiologia , Molécula 1 de Adesão Intercelular/genética , Dímeros de Pirimidina/metabolismo , Raios Ultravioleta , Células Apresentadoras de Antígenos/fisiologia , Células Cultivadas , Cianobactérias/enzimologia , Desoxirribodipirimidina Fotoliase/administração & dosagem , Dinoprostona/farmacologia , Portadores de Fármacos , Escherichia coli , Regulação da Expressão Gênica/efeitos da radiação , Humanos , Lipossomos , Monócitos/efeitos dos fármacos , Monócitos/fisiologia , Monócitos/efeitos da radiação , RNA Mensageiro/genética , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transcrição Gênica/efeitos da radiaçãoRESUMO
A 32-year-old patient developed an anaphylactic reaction minutes after oral intake of acetaminophen-containing tablets (Doregrippin)). Scratch testing of the whole preparation was positive in contrast with the negative results obtained with pure acetaminophen. Therefore, scratch tests with the remaining drug components were performed and showed polyvinylpyrrolidone (PVP) to be the aetiological agent. Furthermore, specific IgE antibodies against PVP were demonstrated using a dot blot technique, thus ruling out a pseudo-allergic reaction. This case underlines the necessity to consider not only the active ingredient, but also additives as the causative agent.
Assuntos
Anafilaxia/induzido quimicamente , Excipientes Farmacêuticos/efeitos adversos , Povidona/efeitos adversos , Acetaminofen , Adulto , Analgésicos não Narcóticos , Humanos , Imunoglobulina E/sangue , Masculino , Testes CutâneosRESUMO
Chronic inflammatory conditions of human skin, such as prurigo lesions of atopic dermatitis, are characterized clinically by intense pruritus and histologically by increased innervation. Regulation of skin innervation is thought to depend on neurotrophic factors. In this study, human skin cells were identified as a source of neurotrophins. Cultured keratinocytes expressed neurotrophin-4, whereas dermal fibroblasts expressed neurotrophin-3. In vitro stimulation with interferon-gamma, a marker cytokine for atopic eczema, induced keratinocyte neurotrophin-4 production, which was able to support growth of a neuroglioblastoma-derived cell line. In vivo, immunohistochemistry of human skin for neurotrophins showed neurotrophin-4 staining in the epidermal layer and neurotrophin-3 staining in the dermal compartment. Neurotrophin-4 but not neurotrophin-3 expression was markedly increased in interferon-gamma-injected skin. Prurigo lesions of atopic dermatitis skin were characterized by intense epidermal staining for neurotrophin-4, suggesting a pathophysiologic role for this neurotrophin in the increased innervation characteristic for these skin lesions. This study demonstrates differential expression and regulation of neurotrophins in human skin. It also identifies keratinocyte-derived neurotrophin-4 as a possible link between the immune and the nerve system of human skin.
Assuntos
Queratinócitos/citologia , Fatores de Crescimento Neural/genética , Anticorpos/análise , Western Blotting , Células Cultivadas , Dermatite Atópica/genética , Fibroblastos , Humanos , Recém-Nascido , Masculino , Fatores de Crescimento Neural/imunologia , Fármacos Neuroprotetores/metabolismo , RNA Mensageiro/metabolismoRESUMO
Ultraviolet-B (UVB) (290-320 nm) radiation-induced cyclobutane pyrimidine dimers within the DNA of epidermal cells are detrimental to human health by causing mutations and immunosuppressive effects that presumably contribute to photocarcinogenesis. Conventional photoprotection by sunscreens is exclusively prophylactic in nature and of no value once DNA damage has occurred. In this paper, we have therefore assessed whether it is possible to repair UVB radiation-induced DNA damage through topical application of the DNA-repair enzyme photolyase, derived from Anacystis nidulans, that specifically converts cyclobutane dimers into their original DNA structure after exposure to photoreactivating light. When a dose of UVB radiation sufficient to induce erythema was administered to the skin of healthy subjects, significant numbers of dimers were formed within epidermal cells. Topical application of photolyase-containing liposomes to UVB-irradiated skin and subsequent exposure to photoreactivating light decreased the number of UVB radiation-induced dimers by 40-45%. No reduction was observed if the liposomes were not filled with photolyase or if photoreactivating exposure preceded the application of filled liposomes. The UVB dose administered resulted in suppression of intercellular adhesion molecule-1 (ICAM-1), a molecule required for immunity and inflammatory events in the epidermis. In addition, in subjects hypersensitive to nickel sulfate, elicitation of the hypersensitivity reaction in irradiated skin areas was prevented. Photolyase-induced dimer repair completely prevented these UVB radiation-induced immunosuppressive effects as well as erythema and sunburn-cell formation. These studies demonstrate that topical application of photolyase is effective in dimer reversal and thereby leads to immunoprotection.
Assuntos
Dano ao DNA/efeitos da radiação , Reparo do DNA/genética , Pele/efeitos da radiação , Adulto , Cianobactérias/enzimologia , Desoxirribodipirimidina Fotoliase/metabolismo , Desoxirribodipirimidina Fotoliase/uso terapêutico , Dermatite de Contato/genética , Dermatite de Contato/imunologia , Imunofluorescência , Humanos , Imunossupressores/farmacologia , Molécula 1 de Adesão Intercelular/metabolismo , Interferon gama/farmacologia , Queratinócitos , Linfócitos/metabolismo , Masculino , Microscopia de Fluorescência , Níquel/farmacologia , Proteolipídeos/uso terapêutico , Dímeros de Pirimidina/genética , Pele/patologia , Raios UltravioletaRESUMO
The FRAP-p70s6K signaling pathway was found to be constitutively phosphorylated/active in MiaPaCa-2 and Panc-1 human pancreatic cancer cells and a pancreatic cancer tissue sample as judged by the retarded electrophoretic mobility of the two major FRAP downstream targets, p70s6K and 4E-BP1. Treatment of cells with rapamycin, a selective FRAP Inhibitor, inhibited basal p70s6K kinase activity and induced dephosphorylation of p70s6K and 4E-BP1. Moreover, rapamycin inhibited DNA synthesis as well as anchorage-dependent and -independent proliferation in MiaPaCa-2 and Panc-1 cells. Finally, rapamycin strikingly inhibited cyclin D1 expression in pancreatic cancer cells. Thus, inhibitors of the constitutively active FRAP-p70s6K pathway may provide a novel therapeutic approach for pancreatic cancer.
Assuntos
Carcinoma/patologia , Proteínas de Ciclo Celular , Ciclina D1/biossíntese , Proteínas de Neoplasias/fisiologia , Neoplasias Pancreáticas/patologia , Fosfotransferases (Aceptor do Grupo Álcool)/fisiologia , Proteínas Quinases , Proteínas Quinases S6 Ribossômicas/fisiologia , Transdução de Sinais/fisiologia , Sirolimo/farmacologia , Proteínas Supressoras de Tumor , Proteínas Quinases Dependentes de Cálcio-Calmodulina/fisiologia , Carcinoma/enzimologia , Ciclo Celular/efeitos dos fármacos , Meios de Cultura Livres de Soro/farmacologia , Ciclina D1/genética , Ciclina E/metabolismo , Inibidor de Quinase Dependente de Ciclina p27 , Humanos , Proteínas Associadas aos Microtúbulos/metabolismo , Proteína Quinase 1 Ativada por Mitógeno , Proteínas de Neoplasias/antagonistas & inibidores , Neoplasias Pancreáticas/enzimologia , Fosforilação/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Serina-Treonina Quinases TOR , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismoRESUMO
BACKGROUND: Anecdotal reports suggest that patients with fungal infection of necrotizing pancreatitis (NP) have worse outcomes than those with bacterial infection. Our aim was to compare the clinical course and outcomes of patients with NP infected with fungal versus nonfungal organisms. STUDY DESIGN: Prospectively collected data on 57 patients with infected NP (1983-1995) were reviewed. RESULTS: Seven patients (12%) developed fungal infection, and 50 (88%) developed bacterial infection. Groups had similar mean ages (60 versus 63 years) and APACHE-II scores on admission (9 each). The cause of NP was ERCP-induced in 3 of 7 with fungal infection versus 3 of 50 with bacterial infection. Patients with fungal infection had been treated with a mean of 4 different antibiotics for a mean of 23 days, and 4 of 7 (57%) required mechanical ventilation preoperatively. In addition, postoperative ICU stays were longer (20 versus 10 days), as were total hospital stays (59 versus 41 days). Mortality was higher with fungal infection; 3 of 7 patients (43%) died versus 10 of 50 patients (20%). CONCLUSIONS: Although NP presents with similar initial severity, patients with fungal infection of NP tend to have a more complicated course and worse outcomes compared with those with bacterial infection. Low-dose antifungal prophylaxis should be added to early management of NP.
Assuntos
Infecções Bacterianas , Micoses , Pancreatite Necrosante Aguda/microbiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Infecções Bacterianas/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Micoses/terapia , Pancreatite Necrosante Aguda/terapia , Estudos Prospectivos , Fatores de RiscoRESUMO
Secretory synovial-type PLA2 (sPLA2-II) in peripheral blood is known to be associated with systemic complications in patients with severe diseases. Being the pacemaking enzyme in eicosanoid synthesis, sPLA2-II is a mediator of the inflammatory response and plays a role in host defense against bacterial infection. We evaluated the clinical role of systemic sPLA2-II in bacterial infection of pancreatic necroses in severe acute pancreatitis. In 58 patients with acute pancreatitis, pancreatic and sPLA2-I and sPLA2-II were measured daily for the first 14 days of hospital treatment by a time-resolved fluoroimmunoassay. All 36 patients with necrotizing pancreatitis underwent regular fine needle aspiration (FNA) to monitor bacterial infection. In 10 patients, infected necroses were found on FNA and postoperative examination. On admission and at most days throughout the observation period, systemic sPLA2-II was significantly higher in patients with infected necroses than in patients with sterile necroses or interstitial pancreatitis. This difference was not found for sPLA2-I, but values were higher in necrotizing pancreatitis than in interstitial pancreatitis at the first 2 days of hospital treatment. If sPLA2-II was >300 ng/ml on 2 successive days within the first 4 days, infected necroses could be predicted with a sensitivity of 89%, a specificity of 88%, and a negative predictive value of 95%. Systemic sPLA2-II has the potential to identify patients at risk of bacterial infection of pancreatic necroses and its routine measurement may therefore, in combination with FNA, offer a valuable tool in monitoring patients with acute necrotizing pancreatitis.
Assuntos
Infecções Bacterianas/diagnóstico , Ensaios Enzimáticos Clínicos , Pancreatite Necrosante Aguda/diagnóstico , Pancreatite Necrosante Aguda/microbiologia , Pancreatite/diagnóstico , Fosfolipases A/sangue , Doença Aguda , Adulto , Idoso , Idoso de 80 Anos ou mais , Infecções Bacterianas/microbiologia , Biópsia por Agulha , Fosfolipases A2 do Grupo II , Humanos , Pessoa de Meia-Idade , Fosfolipases A2 , Valor Preditivo dos Testes , Estudos Prospectivos , Curva ROC , Sensibilidade e EspecificidadeRESUMO
The sunburn reaction is the most common consequence of human exposure to ultraviolet radiation (UVR), and is mediated at least in part by interleukin-6 (IL-6). The aim of this study was to determine if DNA is a major chromophore involved in the induction of IL-6 following UV irradiation of a human epidermoid carcinoma cell line (KB), and of normal human epidermal keratinocytes. We first confirmed that IL-6 release was associated with enhanced levels of IL-6 mRNA transcripts. The wavelength dependence for IL-6 release was then investigated by irradiating the cells at defined wavelengths (254, 302, 313, 334, and 365 nm) with a monochromator. The maximum effect on IL-6 release was observed at 254 nm with only low levels of induction observed at wavelengths above 313 nm. The wavelength dependence for UV-induced IL-6 release was similar to that for DNA absorption or for the induction of cyclobutane pyrimidine dimers (CPD). To determine whether UV-induced DNA damage mediated IL-6 secretion, the role of CPD was investigated by treating keratinocytes with photosomes (photolyase encapsulated in liposomes) followed by photoreactivating light. This photoreversal procedure led to a reduction in the levels of the UVC-induced secretion of IL-6, which in normal human keratinocytes was unambiguously associated with repair of CPD. We conclude that the release of IL-6 from human keratinocytes following short-wave UVC and UVB irradiation is mediated by DNA damage and that CPD play an important role in this process.
Assuntos
Dano ao DNA , Interleucina-6/biossíntese , Queratinócitos/efeitos da radiação , Raios Ultravioleta , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Linhagem Celular , Humanos , Queratinócitos/metabolismo , Dímeros de Pirimidina/biossíntese , Valores de ReferênciaRESUMO
The present study assessed the capacity of eosinophils (EOS) to synthesize the cytokine IL-12. Blood-derived, highly purified human EOS from six atopic patients and two nonatopic individuals were treated in culture with IL-4, IL-5, granulocyte-macrophage CSF, IFN-gamma, TNF-alpha, IL-1alpha, RANTES, and complement 5a, respectively. The expression of both IL-12 protein and mRNAs for the p35 and p40 IL-12 subunits was strongly induced in all donors by the Th2-like cytokines IL-4 and granulocyte-macrophage CSF and was also moderately induced by TNF-alpha and IL-1alpha. IL-5 treatment resulted in IL-12 synthesis in four atopic donors and one nonatopic donor, whereas IFN-gamma induced IL-12 synthesis in only two atopic donors. In contrast, RANTES exclusively induced mRNA for the p40 subunit without detectable protein release, and complement 5a had no effect on IL-12 mRNA or protein expression. EOS-derived IL-12 was biologically active, because supernatants derived from IL-4-treated EOS superinduced the Con A-induced expression of IFN-gamma by a human Th1-like T cell line. This activity was neutralized by anti-IL-12 Abs. In conclusion, EOS secrete biologically active IL-12 after treatment with selected cytokines, which mainly represent the Th2-like type. Consequently, EOS may promote a switch from Th2-like to Th1-like immune responses in atopic and parasitic diseases.
Assuntos
Eosinófilos/metabolismo , Interleucina-12/biossíntese , Ativação Linfocitária , Células Th1/imunologia , Linhagem Celular , Sistema Livre de Células/metabolismo , Ensaio de Imunoadsorção Enzimática , Eosinófilos/imunologia , Humanos , Interferon gama/biossíntese , Interferon gama/genética , Interleucina-12/isolamento & purificação , Interleucina-12/fisiologia , Ativação Linfocitária/efeitos dos fármacos , RNA Mensageiro/biossíntese , Células Th1/metabolismoRESUMO
BACKGROUND: Patients with chronic atopic dermatitis can become unresponsive to standard immunosuppressive therapy and thus pose a serious therapeutic problem. OBJECTIVE: Our purpose was to evaluate the therapeutic effectiveness of photopheresis in the management of patients with severe and intractable atopic dermatitis. METHODS: Photopheresis was used as monotherapy in patients (n = 3) who previously did not respond to treatment with glucocorticosteroids, cyclosporine, phototherapy, or photochemotherapy. Patients were treated at 2-week intervals (total number of treatments = 10). RESULTS: In all patients, photopheresis induced clinical improvement and reduction of elevated serum levels of eosinophil cationic protein and total IgE. Prolongation of the intervals between treatments from 2 to 4 weeks caused worsening in one patient, whereas shortening of treatment-free intervals improved both clinical and laboratory findings. CONCLUSION: These studies indicate that photopheresis may be used as monotherapy for the treatment of patients with severe atopic dermatitis that has become intractable to standard therapeutic modalities.
Assuntos
Dermatite Atópica/tratamento farmacológico , Fotoferese , Adulto , Esquema de Medicação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Resultado do TratamentoRESUMO
BACKGROUND: The results of an open, single-center study suggested that phototherapy with high doses of UVA1 radiation (UVA1R; 340-400 nm) is effective for acute, severe exacerbations of atopic dermatitis (AD). OBJECTIVE: The purpose of this study was to assess the effectiveness of high-dose UVA1 phototherapy for acute, severe AD in a randomized multicenter trial in direct comparison with topical glucocorticoid therapy. METHODS: Patients were treated with high-dose UVA1R (10 days, 130 J/cm2/day; n = 20), topically with fluocortolone (10 days, 1 x daily; n = 17), or with UVA-UVB therapy (10 days, 1 x daily, minimal erythema dose-dependent; n = 16). RESULTS: With a clinical scoring system, significant differences in favor of high-dose UVA1R and fluocortolone therapy were observed (p < 0.0001), as compared with UVA-UVB therapy. At day 10, high-dose UVA1R was superior to fluocortolone (p < 0.002) therapy. Serum levels of eosinophil cationic protein and the blood eosinophil count were significantly reduced after high-dose UVA1 or fluocortolone, but not UVA-UVB therapy. CONCLUSION: This study confirms the therapeutic effectiveness of high-dose UVA1 monotherapy for treatment of severe exacerbations of AD.
Assuntos
Dermatite Atópica/radioterapia , Terapia Ultravioleta/métodos , Administração Tópica , Adulto , Anti-Inflamatórios/uso terapêutico , Dermatite Atópica/tratamento farmacológico , Feminino , Fluocortolona/uso terapêutico , Glucocorticoides , Humanos , Masculino , Dosagem RadioterapêuticaRESUMO
Interleukin-15 (IL-15) is a potent T-cell stimulating factor, which has recently been used for pre-clinical in vivo immunotherapy. Here, the IL-15 effect on CD3-stimulated peripheral human T cells was investigated. IL-15 induced a significant T-cell proliferation and upregulated CD25 expression. IL-15 significantly enhanced T-cell production of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and IL-10. Between 10- and 100-fold greater concentrations of IL-15 were necessary to reach a biological effect equivalent to that of IL-2. Blockade of IL-2 binding to the high-affinity IL-2 receptor did not affect the IL-15 effects, suggesting that IL-15 did not act by inducing endogenous IL-2. Exogenously administered IL-10 significantly reduced the IL-15 and IL-2-mediated IFN-gamma and TNF-alpha production, whereas T-cell proliferation and CD25 expression were not affected. The inhibitory effects of exogenously administered IL-10 on T-cell cytokine production appeared indirect, and are likely secondary to decreased IL-12 production by accessory cells. Inhibition of endogenous IL-10 binding to the IL-10 receptor significantly increased IFN-gamma and TNF-alpha release from T cells. These data suggest that endogenous IL-10 can regulate activated T-cell production of IFN-gamma and TNF-alpha via a paracrine negative feedback loop. The observations of this study could be of relevance for the therapeutic use of IL-15 in vivo.
Assuntos
Interleucina-10/farmacologia , Interleucina-15/farmacologia , Linfócitos T/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Separação Celular , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Humanos , Interleucina-10/metabolismo , Interleucina-15/metabolismo , Cinética , Proteínas Recombinantes/farmacologia , Linfócitos T/metabolismoRESUMO
Ultraviolet A (UVA) irradiation is effectively used to treat patients with atopic dermatitis and other T cell mediated, inflammatory skin diseases. In the present study, successful phototherapy of atopic dermatitis was found to result from UVA radiation-induced apoptosis in skin-infiltrating T helper cells, leading to T cell depletion from eczematous skin. In vitro, UVA radiation-induced human T helper cell apoptosis was mediated through the FAS/FAS-ligand system, which was activated in irradiated T cells as a consequence of singlet oxygen generation. These studies demonstrate that singlet oxygen is a potent trigger for the induction of human T cell apoptosis. They also identify singlet oxygen generation as a fundamental mechanism of action operative in phototherapy.
Assuntos
Apoptose/imunologia , Apoptose/efeitos da radiação , Oxigênio/farmacologia , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/efeitos da radiação , Terapia Ultravioleta , Anticorpos Bloqueadores/farmacologia , Apoptose/efeitos dos fármacos , Dermatite Atópica/imunologia , Dermatite Atópica/radioterapia , Deutério/farmacologia , Proteína Ligante Fas , Humanos , Ligantes , Glicoproteínas de Membrana/biossíntese , Glicoproteínas de Membrana/efeitos da radiação , Naftóis/farmacologia , Oxigênio Singlete , Azida Sódica/farmacologia , Linfócitos T Auxiliares-Indutores/efeitos dos fármacos , Receptor fas/imunologia , Receptor fas/metabolismoRESUMO
Normal ageing processes are associated with an accumulation of mutations within the mitochondrial (mt) DNA. The most frequent mutation is a 4977 base pair (bp) deletion known as common deletion. In order to test the hypothesis that chronically sun-exposed skin is characterized by an increased mutation frequency of mtDNA, the mutation frequency of the common deletion between skin and another replicating tissue (the hematopoietic system) and chronically sun-exposed versus sun-protected skin was compared in the same individuals. This was done by comparing the amount of mutated mtDNA molecules with the whole mitochondrial genome in the same specimen with a semiquantitative polymerase chain reaction method, thus allowing direct comparison of different tissues. In all skin specimens the common deletion could be observed. In contrast only 3 of 10 blood samples revealed detectable amounts of the common deletion. Comparison of sun-exposed versus sun-protected skin exhibited a higher content of the common deletion in sun-exposed skin in 7 of 10 individuals. Additionally, a hitherto undescribed mtDNA mutation was detected exclusively in human skin. These studies indicate that exposure of human skin to solar radiation leads to an accumulation of mtDNA mutations, possibly via oxidative damage, which may play an important role in photoageing.
Assuntos
DNA Mitocondrial/efeitos da radiação , Mutagênese , Pele/efeitos da radiação , Raios Ultravioleta , Adulto , Idoso , Idoso de 80 Anos ou mais , Células-Tronco Hematopoéticas/efeitos da radiação , Humanos , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Envelhecimento da Pele/efeitos da radiaçãoRESUMO
Cells from patients with xeroderma pigmentosum complementation group D (XP-D) and most patients with trichothiodystrophy (TTD) are deficient in excision repair of ultraviolet (UV) radiation-induced DNA damage. Although in both syndromes this defect is based on mutations in the same gene, XPD, only XP-D, not TTD, individuals have an increased risk of skin cancer. Since the reduction in DNA repair capacity is similar in XP-D and TTD patients, it cannot account for the difference in skin cancer risk. The features of XP-D and TTD might therefore be attributable to differences in the immune response following UV-irradiation, a factor which is presumed to be important for photocarcinogenesis. We have measured the capacity of UVB radiation to inhibit expression of the immunological key molecule intercellular adhesion molecule 1 (ICAM-1) in cells from three healthy individuals in comparison to cells from three XP-D and three TTD patients. Cells from XP-D patients, but not from TTD patients, exhibited an increased susceptibility to UVB radiation-induced inhibition of ICAM-1 expression. Transfection of XP-D cells with the wild-type XPD cDNA, but not with XPC cDNA, corrected this abnormal phenotype. Thus, the skin cancer risk in DNA repair-defective individuals correlated with the susceptibility of their cells to UVB radiation-induced inhibition of ICAM-1 expression, rather than with their defect in DNA repair. The XPD protein has dual roles: in DNA repair and transcription. The transcriptional role might be important for the control of expression of immunologically relevant genes and thereby contribute to the skin cancer risk of a DNA-repair-deficient individual.
Assuntos
Reparo do DNA/genética , Cabelo/anormalidades , Molécula 1 de Adesão Intercelular/biossíntese , Pele/patologia , Xeroderma Pigmentoso/genética , Células Cultivadas , Fibroblastos/metabolismo , Fibroblastos/patologia , Fibroblastos/efeitos da radiação , Transtornos do Crescimento/genética , Transtornos do Crescimento/patologia , Humanos , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , Molécula 1 de Adesão Intercelular/genética , Pele/efeitos da radiação , Síndrome , Raios Ultravioleta , Xeroderma Pigmentoso/patologiaRESUMO
BACKGROUND: Fibrotic skin lesions in patients with localized scleroderma can cause muscle atrophy, disfigurement, and flexion contractures. There is no effective therapy for this disease. Skin fibrosis is thought to be caused by decreased collagenase activity. Collagenase activity can be induced in dermal fibroblasts by UVA1 irradiation. OBJECTIVE: Our purpose was to assess whether UVA1 radiation therapy is effective for patients with localized scleroderma. METHODS: Patients with localized scleroderma (n = 17) were exposed 30 times to 130 J/cm2 UVA1 (high-dose UVA1 therapy; n = 10) or 20 J/cm2 UVA1 (low-dose UVA1 therapy; n = 7). Therapeutic effectiveness was assessed by evaluation of (1) clinical features, (2) thickness of sclerotic plaques, and (3) cutaneous elastometry. Sequential biopsy specimens from treated lesions were analyzed for collagenase I messenger RNA (mRNA) expression by semiquantitative reverse transcriptase-polymerase chain reaction. RESULTS: In all patients, high-dose UVA1 therapy softened sclerotic plaques, and complete clearance was observed in four of 10 patients. High-dose UVA1 therapy significantly reduced thickness and increased elasticity of plaques. These changes could not be detected in unirradiated control plaques and were still present in 9 of 10 patients 3 months after cessation of therapy. For all factors assessed, high-dose UVA1 was superior to low-dose UVA1 therapy (p = 0.001). High-dose UVA1 therapy increased collagenase I mRNA expression about 20-fold in treated plaques. CONCLUSION: High-dose UVA1 therapy is effective in the treatment of localized scleroderma. Effectiveness is UVA1 dose dependent and is associated with induction of collagenase I expression.