Expressão de antígenos MHC classe I e de células CD4 e CD8 na polimiosite e dermatomiosite / MHC class I antigens, CD4 and CD8 expressions in polymyositis and dermatomyositis

Objetivo: Analisar as frequências de expressão dos antígenos de complexo principal de histocompatibilidade classe I (MHC-I) e células CD4 e CD8 no músculo esquelético na polimiosite (PM) e dermatomiosite (DM). Métodos: Estudo retrospectivo de 34 casos de PM, oito casos de DM e 29 controles com miopatias não inflamatórias. Resultados: Os antígenos MHC-I expressaram-se no sarcolema e/ou sarcoplasma em 79,4% dos casos de PM, 62,5% dos casos de DM e 27,6% dos controles (a expressão de CD4 foi observada em 76,5%, 75% e 13,8%, respectivamente). Quando os antígenos de MHC-I foram coexpressados com CD4, houve elevada suspeita de PM/DM (principalmente PM). Em 14,3% dos casos de PM/DM, observou-se a expressão isolada dos antígenos MHC-I, sem células inflamatórias. Conclusão: A expressão dos antígenos MHC-I e a positividade do CD4 podem aumentar a suspeita diagnóstica de PM/DM. Não foi observado infiltrado celular em 14,3% dos casos. .

Objective: To analyze the frequencies of the expression of major histocompatibility complex class I (MHC-I) antigens, and CD4 and CD8 cells in skeletal muscle in polymyositis (PM) and dermatomyositis (DM). Methods: This was a retrospective study of 34 PM cases, 8 DM cases, and 29 control patients with non-inflammatory myopathies. Results: MHC-I antigens were expressed in the sarcolemma and/or sarcoplasm in 79.4% of PM cases, 62.5% of DM cases, and 27.6% of controls (CD4 expression was observed in 76.5%, 75%, and 13.8%, respectively). There was a high suspicion of PM/DM (mainly PM) in participants in whom MHC-I antigens and CD4 were co-expressed. In 14.3% of PM/DM cases, we observed MHC-I antigens expression alone, without inflammatory cells. Conclusion: MHC-I antigens expression and CD4 positivity might add to strong diagnostic suspicion of PM/DM. No cellular infiltration was observed in approximately 14.3% of such cases. .

The human leukocyte antigen G molecule (HLA-G) expression in patients with nasal polyposis / A expressão do antígeno humano leucocitário G (HLA-G) em pacientes com polipose nasossinusal

INTRODUCTION: Sinonasal polyposis (NP) is a chronic inflammatory pathology of the nasal/paranasal cavities which affects from 1%-4% of the population. Although polyps seem to be a manifestation of chronic inflammation in both allergic and non-allergic subjects, the pathogenesis of nasal polyposis remains unknown. HLA-G molecules are a kind of no classic class I antigen with anti-inflammatory and tolerogenic properties. Little attention has been paid to the role of HLA-G chronic inflammatory disorders. OBJECTIVE: The aim of this study is to investigate the expression of HLA-G in the NP. MATERIALS AND METHODS: Prospective study involving samples of patients presenting with nasal polyposis that were subjected to the immunohistochemistry technique. After a skin prick test, all patients were divided into atopic and nonatopic groups and classified as asthmatic or non-asthmatic. RESULTS: Immunohistochemical staining demonstrated a higher expression of the HLA-G molecule in samples from nonatopic than in those from atopic patients, and was significantly lower in the non-asthmatic patients. CONCLUSION: These results indicate that HLA-G may play an important role in the pathology of nasal polyposis. Considering the anti-inflammatory properties of HLA-G, this study suggests that it could reduce susceptibility to atopy and asthma. .

INTRODUÇÃO: Polipose nasossinusal (PNS) é uma patologia inflamatória crônica das cavidades nasais/paranasais que afeta 1%-4% da população. Embora os pólipos pareçam ser uma manifestação de inflamação crônica em ambos os indivíduos alérgicos e não alérgicos, a patogênese da polipose nasal permanece desconhecida. Moléculas HLA-G são antígenos não clássicos da classe I com propriedades anti-inflamatórias e tolerogênicas. Pouca atenção tem sido dada ao papel do HLA-G em doenças inflamatórias crônicas. OBJETIVO: Investigar a expressão de HLA-G na PNS. MATERIAIS E MÉTODOS: Estudo prospectivo de pacientes com polipose nasal que foram submetidas à técnica de imuno-histoquímica. Após realizarem teste cutâneo, os pacientes foram divididos em grupos atópicos e não atópicos e classificados como asmáticos ou não asmáticos. RESULTADO: A coloração imuno-histoquímica mostrou uma maior expressão da molécula HLA-G em pacientes não atópicos do que naqueles atópicos e foi significativamente inferior nos pacientes não asmáticos. CONCLUSÃO: Os resultados indicam que o HLA-G pode ter um papel importante na patologia da polipose nasal. Considerando as propriedades anti-inflamatórias do HLA-G, este estudo sugere que ele poderia reduzir a susceptibilidade a atopia e asma. .

Production of monoclonal antibodies to a tumor--associated antigen by spontaneous cell fusion.

Spontaneous cell fusion induced by the bacterium Haemophilus paragallinarum has been recently reported as an alternative technique to generate hybridomas producing monoclonal antibody (mAb). In order to investigate the advantages of this technique to produce anti-tumor monoclonal antibodies we performed comparative experiments between H. paragallinarum induced spontaneous cell fusion and polyethylene glycol (PEG) mediated fusion. Hybridomas producing monoclonal antibodies to an experimental murine lymphoma antigen, the Dalton's lymphoma associated antigen (DLAA) were generated and their sensitivity and specificity were ascertained. The spontaneous fusion yielded more number of stable and specific hybridomas than PEG mediated fusion. The results suggest the advantage of H. paragalinarum induced cell fusion for the simplified production of specific antitumor monoclonal antibodies.

Monophosphoryl lipid A (MPL) upregulates major histocompatibility complex (MHC) class I expression by increasing interferon-gamma (IFN-gamma)

Tumor immunity is primarily mediated by cells as CD8+ cytotoxic T lymphocytes (CTL) recognize tumor antigen by MHC class I molecules. But most tumors are associated with a decreased expression of MHC class I to escape the antitumor immunity of the host. Our previous data have demonstrated that MPL has an antitumor effect on metastatic lung cancer of B16 melanoma with enhancing cytotoxicity due to increase of IFN-gamma and IL-2, and decrease of IL-4, which indicates the stimulation of type 1 helper T cells (Th1). To determine the effects of MPL, IFN-gamma, TNF-alpha, and IL-1 alpha on MHC class I expression of B16 melanoma cells, we evaluated the expression of MHC class I molecules with treatments of MPL, IFN-gamma, TNF-alpha, and IL-1 alpha by flow cytometry. The supernatant of MPL-treated spleen cells in vitro upregulated the expression of MHC class I molecules of B16 melanoma cells compared to the control supernatant of spleen cells. The MHC class I expression of B16 melanoma cells treated with IFN-gamma, but not TNF-alpha or IL-1 alpha, increased in a time-dependent manner. In conclusion, MPL upregulated MHC class I expression of B16 melanoma cells by activating spleen cells via IFN-gamma. These data suggest that increased IFN-gamma by MPL is responsible for the upregulation of MHC class I expression to augment cytotoxicity. Therefore, we suggest that MPL could play an important role in immunotherapy.

Cytokine regulation of expression of class I MHC antigens

No abstract available.

Expression of major histocompatibility complex antigen in Lewis rat cornea

Fresh rat corneas as well as corneas preserved in several different corneal preservation media were stained with Avidin-Biotin-peroxidase Complex method in order to evaluate major histocompatibility complex (MHC) antigen expression. In fresh corneas, class I antigen was identified in corneal epithelium, stroma and endothelium. Class II antigen was identified only in stroma. In corneas preserved in the media which contained chondroitin and dextran for 7 days, class I antigen was somewhat decreased but class II antigen was increased. In corneas preserved in the medium which contained insulin or epidermal growth factor for 7 days, class II antigens seemed to be increased compaired to the fresh cornea. Expression of MHC antigens of corneas in the medium with fetal bovine serum were similar to those of fresh corneas.