RESUMO
BACKGROUND: Infections are one of the most common causes of morbidity and mortality in patients with systemic lupus erythematosus (SLE). SLE patients have a higher risk of tuberculosis (TB) infection due to impaired immune defence. OBJECTIVES: To investigate the demographics, clinical characteristics and outcomes of patients with SLE and concomitant TB. METHODS: Medical records of SLE patients with TB who were admitted to Peking Union Medical College (PUMC) Hospital in 1983-2019 were retrospectively reviewed. Age- and sex-matched SLE inpatients without TB were randomly selected as controls. Clinical and laboratory features and treatment were analysed and compared, and subjects were followed up to assess their outcome. RESULTS: Of the 10 469 SLE inpatients, 249 (2.4%) were diagnosed with TB. Compared with controls, SLE/TB + patients exhibited higher frequency of prior haematologic, mucocutaneous and musculoskeletal system involvement, and prior treatment with potent glucocorticoid/immunosuppressive agents (GC/ISA). Arthritis and alopecia, positive T-SPOT.TB test and lymphocytopenia were more common in SLE/TB + patients. SLE/TB + patients with lupus before TB (SLE â TB) had higher risk of miliary TB (22.8%) and intracranial TB (16.5%) than SLE/TB + patients with lupus after TB (TB â SLE). SLE/TB + patients exhibited shorter long-term survival than SLE/TB- patients; those with poorer in-hospital outcomes had more severe lymphocytopenia and had received less treatment with ISAs. CONCLUSION: Systemic lupus erythematosus patients treated vigorously with GC/ISA should be alerted of increased risk of TB infection, especially miliary and intracranial TB. Positive T-SPOT.TB and lymphocytopenia served as discriminatory variables between SLE/TB + and SLE/TB- patients. Lymphocytopenia was associated with poorer outcomes in SLE/TB + patients.
Assuntos
Hospedeiro Imunocomprometido , Lúpus Eritematoso Sistêmico/complicações , Lúpus Eritematoso Sistêmico/imunologia , Tuberculose/complicações , Estudos de Casos e Controles , Glucocorticoides/efeitos adversos , Humanos , Imunossupressores/efeitos adversos , Estudos Longitudinais , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Linfopenia/etiologia , Prognóstico , Estudos Retrospectivos , Fatores de RiscoRESUMO
BACKGROUND: We estimated the prevalence and incidence, clinical features, treatment, and prognosis of systemic lupus erythematosus (SLE) patients in the Thrace region of Turkey. METHODS: We retrospectively evaluated 331 patients (307 female, 24 male, mean age 38.5 years) diagnosed with SLE between 2003 and 2014. Clinical features, treatments, and response to various treatment modalities were recorded. Our hospital has been the only tertiary referral center for rheumatological diseases for a mixed rural and urban population of 620,477 people (306,036 females, 314,411 males) for more than 16 years. RESULTS: The mean annual incidence of SLE was 4.44/100,000 (females, 8.4/100,000; males, 0.6/100,000). The overall prevalence of SLE was 51.7/100,000 (females, 97.7/100,000; males, 7/100,000). Major organ involvement was present in the following percentages: neurologic involvement: 20.1%; renal involvement: 28.2%; autoimmune hemolytic anemia: 9.6%; thrombocytopenia: 14.7%. Seventeen SLE patients (13 females, four males) died at a median follow-up of 48 months. The five-year survival was 94.5%, and the ten-year survival was 89.9%. According to Kaplan-Meier survival analysis, poor prognostic factors were: male gender (p = 0.015); smoking (p = 0.02); pleural involvement (p = 0.011); thrombocytopenia (p = 0.021); myocarditis (p = 0.028); renal involvement (p = 0.037); treatment with cyclophosphamide (p = 0.011); and an initial high SLEDAI score (>4) (p = 0.02). Lymphopenia at the time of diagnosis appeared as a favorable prognostic factor (p = 0.008). Cox regression analysis revealed myocarditis (OR: 20.4, p = 0.018) and age at diagnosis (OR: 1.11, p = 0.035) to be poor, and lymphopenia at the time of diagnosis to be good prognostic factors (OR:0.13, p = 0.031). CONCLUSIONS: The annual incidence and prevalence of SLE in the Thrace region of Turkey is lower than those reported in North America, however they are similar to those reported for European countries. Clinical manifestations appear to be milder, whereas survival was similar to those recorded in Western countries.
Assuntos
Lúpus Eritematoso Sistêmico/epidemiologia , Adolescente , Adulto , Idoso , Distribuição de Qui-Quadrado , Progressão da Doença , Intervalo Livre de Doença , Feminino , Humanos , Imunossupressores/uso terapêutico , Incidência , Estimativa de Kaplan-Meier , Lúpus Eritematoso Sistêmico/diagnóstico , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Lúpus Eritematoso Sistêmico/mortalidade , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Prevalência , Modelos de Riscos Proporcionais , Indução de Remissão , Estudos Retrospectivos , Fatores de Risco , Centros de Atenção Terciária , Fatores de Tempo , Resultado do Tratamento , Turquia/epidemiologia , Adulto JovemRESUMO
Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease characterized by a loss of tolerance to multiple endogenous antigens. SLE etiology remains largely unknown, despite recent insight into the immunopathogenesis of the disease. T cells are important in the development of the disease by amplifying the immune response and contributing to organ damage. Aberrant signaling, cytokine secretion, and tissue homing displayed by SLE T cells have been extensively studied and the underlying pathogenic molecular mechanisms are starting to be elucidated. T-cell-targeted treatments are being explored in SLE patients. This review is an update on the T-cell abnormalities and related therapeutic options in SLE.
Assuntos
Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/terapia , Linfócitos T/imunologia , Animais , Receptores Coestimuladores e Inibidores de Linfócitos T/imunologia , Epigênese Genética , Humanos , Tolerância Imunológica , Interleucina-2/imunologia , Transdução de Sinais/genética , Subpopulações de Linfócitos T/imunologiaRESUMO
UNLABELLED: The complement system plays an important role in tissue inflammation and damage in SLE patients. High levels of C3d were detected on the surface of erythrocytes and lymphocytes of SLE patients. The objective of this study was to assess the functional consequences of C3d fragments deposited on the surface membrane of SLE T cells. METHODS: 46 SLE patients, 43 patients with other autoimmune diseases (OAD) and 33 healthy individuals (N) were enrolled in this study. T cells were isolated from peripheral blood and flow cytometry studies were conducted to assess the levels of C3d fragments, Ca++ influx responses and cytokine production. Confocal microscopy was used to study co-localized molecules. Student's t-test was performed to determine statistical significance among study groups. RESULTS: A significant percentage of the SLE T cells were found to be positive for C3d (13.58 ± 3.92%) when compared with normal T cells (4.52 ± 2.92%) (p < 0.0000547) and T cells from patients with other autoimmune diseases (6.31 ± 4.57%) (p < 0.00513). Peak Ca++ influx responses were significantly higher in C3d- SLE T cells compared with C3d+ SLE T cells (p < 0.011). C3d+ T cells produced significantly more IL-2, IFN-gamma, IL-4 and IL-17. In contrast to the increased production of IL-2 by the C3d+ T cells, the overall SLE T cell population produced less IL-2 when compared with T cells from normal individuals or patients with other autoimmune disease. The C3d fragments were found to be localized within the lipid rafts. CONCLUSION: C3d fragments are localized in the lipid rafts of SLE T cells and contribute to abnormal T cell function by modulating Ca++ influx responses and increased cytokine production.
Assuntos
Complemento C3d/metabolismo , Lúpus Eritematoso Sistêmico/imunologia , Microdomínios da Membrana/metabolismo , Linfócitos T/imunologia , Adolescente , Adulto , Idoso , Doenças Autoimunes/imunologia , Doenças Autoimunes/metabolismo , Cálcio/metabolismo , Estudos de Casos e Controles , Criança , Estudos de Coortes , Estudos Transversais , Citocinas/biossíntese , Feminino , Citometria de Fluxo , Humanos , Lúpus Eritematoso Sistêmico/metabolismo , Masculino , Microscopia Confocal , Pessoa de Meia-Idade , Adulto JovemRESUMO
The IL-10 cytokine family has nine members, four of which are located in the IL10 cluster on chromosome 1q32. These cytokines are the immune regulatory cytokine IL-10 itself, and the IL-20 subfamily members IL-19, IL-20, and IL-24. IL-10 instructs innate and adaptive immune responses and limits pro-inflammatory responses in order to prevent tissue damage. The IL-20 subfamily members are involved in host defense mechanisms, particularly from epithelial cells and seem essential for tissue integrity. Dysregulation of IL-10 family cytokines results in inflammation and autoimmune disease. Here, we discuss cellular source, gene regulation, and receptor complexes of cytokines in the IL10 cluster and their contribution to autoimmune disease and tissue damage.
Assuntos
Citocinas/imunologia , Animais , Doenças Autoimunes/imunologia , Citocinas/genética , Humanos , Ferimentos e Lesões/imunologiaRESUMO
T helper (Th)17 cells constitute a distinct subset of CD4(+) helper T cells that is mainly characterized by abundant interleukin (IL)-17 production and is involved in the host defence against bacteria and fungi as well as in the pathogenesis of autoimmune diseases. The retinoic orphan receptor (ROR)γt directs the transcriptional activation of the IL17 gene. Here, we report the presence of a novel RORγt isoform, RORγt-Δ(5-8), which lacks the hinge-encoding exons 5-8 and represses potently IL17 and IL21 gene transcription. It thereby reduces the expression of multiple Th17-assigned cytokines. We propose that RORγt-Δ(5-8) acts as a dominant-negative regulator of RORγt-mediated gene regulation and the balance between the full-length RORγt and the novel repressor isoform may arbitrate IL-17 production in human T cells.
Assuntos
Regulação da Expressão Gênica , Interleucina-17/imunologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/imunologia , Proteínas Repressoras/imunologia , Linfócitos T/imunologia , Células HEK293 , Humanos , Interferon gama/imunologia , Interleucina-17/genética , Interleucinas/genética , Interleucinas/imunologia , Ativação Linfocitária , Plasmídeos/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/imunologia , Proteínas Repressoras/genética , Linfócitos T/citologia , Transcrição Gênica , Transfecção/métodosRESUMO
Significant evidence implicates interleukin-17 (IL-17) in the pathogenesis of systemic lupus erythematosus (SLE), particularly in the development of tissue damage. IL-17 production and IL-17-producing CD4+ and CD3 + CD4-CD8- cells are increased in patients with SLE. IL-17-producing cells are present in the inflamed kidney tissues from patients with lupus nephritis. In lupus-prone mice, IL-17 production appears to be involved in the expression of disease pathology and pharmacologic or genetic manipulation of its production results in suppression of the disease. It becomes obvious that the use of biologics including humanized anti-IL-17 antibodies or decoy IL-17 receptors deserve clinical consideration. Similarly, the development of drugs that suppress the production of IL-17 is in order.
Assuntos
Interleucina-17/imunologia , Nefrite Lúpica/imunologia , Linfócitos T/imunologia , Animais , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/patologia , Quinases Associadas a rho/metabolismoRESUMO
Systemic lupus erythematosus (SLE) is a clinically heterogeneous disease diagnosed on the presence of a constellation of clinical and laboratory findings. At the pathogenetic level, multiple factors using diverse biochemical and molecular pathways have been recognized. Succinct recognition and classification of clinical disease subsets, as well as the availability of disease biomarkers, remains largely unsolved. Based on information produced by the present authors' and other laboratories, a lupus gene expression array consisting of 30 genes, previously claimed to contribute to aberrant function of T cells, was developed. An additional eight genes were included as controls. Peripheral blood was obtained from 10 patients (19 samples) with SLE and six patients with rheumatoid arthritis (RA) as well as 19 healthy controls. T cell mRNA was subjected to reverse transcription and PCR, and the gene expression levels were measured. Conventional statistical analysis was performed along with principal component analysis (PCA) to capture the contribution of all genes to disease diagnosis and clinical parameters. The lupus gene expression array faithfully informed on the expression levels of genes. The recorded changes in expression reflect those reported in the literature by using a relatively small (5 ml) amount of peripheral blood. PCA of gene expression levels placed SLE samples apart from normal and RA samples regardless of disease activity. Individual principal components tended to define specific disease manifestations such as arthritis and proteinuria. Thus, a lupus gene expression array based on genes previously claimed to contribute to immune pathogenesis of SLE may define the disease, and principal components of the expression of 30 genes may define patients with specific disease manifestations.
Assuntos
Perfilação da Expressão Gênica/métodos , Lúpus Eritematoso Sistêmico/classificação , Lúpus Eritematoso Sistêmico/diagnóstico , Lúpus Eritematoso Sistêmico/genética , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Adulto , Idoso , Artrite Reumatoide/genética , Feminino , Expressão Gênica , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
The emerging role of interleukin (IL)-17 as a hallmark proinflammatory cytokine of the adaptive immune system, produced primarily by a new T helper cell subset termed 'Th17', has received considerable attention. Differentiation of Th17 cells is driven by the simultaneous presence of transforming growth factor-beta and certain inflammatory cytokines (e.g. IL-6, IL-21), and recent studies have shown that inflammation instigated by IL-17-producing cells is central to the development and pathogenesis of several human autoimmune diseases and animal models of autoimmunity. In this review, we focus on the information regarding IL-17 and systemic lupus erythematosus (SLE), a chronic autoimmune disease. The work that has explored the development and behaviour of IL-17-producing cells in SLE is discussed, and different mechanisms by which IL-17 could potentially augment inflammation and autoantibody production in the context of SLE are proposed.
Assuntos
Autoanticorpos/imunologia , Interleucina-17/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Animais , Humanos , Camundongos , Camundongos Mutantes , Modelos Animais , Linfócitos T Auxiliares-Indutores/imunologia , Fator de Crescimento Transformador beta/imunologiaRESUMO
Lupus is an antibody-mediated autoimmune disease. The production of pathogenic, class switched and affinity maturated autoantibodies in lupus is dependent on T cell help. A potential mechanism of disease pathogenesis is a lack of control of pathogenic T helper cells by regulatory T cells in lupus. It has been repeatedly shown that the naturally occurring CD4+CD25+ regulatory T cells in lupus prone mice and patients with SLE are defective both in frequency and function. Thus, the generation of inducible regulatory T cells that can control T cell help for autoantibody production is a potential avenue for the treatment of SLE. We have found that oral administration of anti-CD3 monoclonal antibody attenuated lupus development and arrested on-going disease in lupus prone SNF1 mice. Oral anti-CD3 induces a CD4+CD25-LAP+ regulatory T cell that secrets high levels of TGF-beta and suppresses in vitro in TFG-beta-dependent fashion. Animals treated with oral anti-CD3 had less glomerulonephritis and diminished levels of anti-dsDNA autoantibodies. Oral anti-CD3 led to a downregulation of IL-17+CD4+ICOS-CXCR5+ follicular helper T cells, CD138+ plasma cells and CD73+ mature memory B cells. Our results show that oral anti-CD3 induces CD4+CD25-LAP+ regulatory T cells that suppress lupus in mice and is associated with downregulation of T cell help for autoantibody production.
Assuntos
Anticorpos/uso terapêutico , Complexo CD3/imunologia , Interleucina-17/metabolismo , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Lúpus Eritematoso Sistêmico/patologia , Linfócitos T Auxiliares-Indutores/patologia , Linfócitos T Reguladores/patologia , Administração Oral , Animais , Anticorpos/administração & dosagem , Anticorpos/farmacologia , Autoanticorpos/metabolismo , Linfócitos B/imunologia , Linfócitos B/patologia , Proliferação de Células , DNA/imunologia , Modelos Animais de Doenças , Feminino , Glomerulonefrite/prevenção & controle , Rim/patologia , Lúpus Eritematoso Sistêmico/imunologia , Masculino , Camundongos , Camundongos Endogâmicos NZB , Baço/patologia , Linfócitos T Auxiliares-Indutores/efeitos dos fármacos , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologiaRESUMO
T cells from patients with systemic lupus erythematosus display numerous signalling abnormalities. The T cell receptor complex is rewired with the common FcRgamma chain replacing the CD3 zeta chain while the T cell surface membrane lipid rafts are aggregated. These two aberrations result in enhanced early signalling events and altered downstream signalling events. These are in turn responsible for an altered expression of cytokines such as interleukin-6 (IL-6), IL-10, IL-2, IFNy and CD40 ligand. While some of these abnormalities explain the enhanced ability of T cells to help B cells to produce autoantibodies, decreased IL-2 production results in enhanced susceptibility to infections, reduced activation-induced cell death and prolonged survival of autoreactive T cells, which promote help to autoreactive B cells.
Assuntos
Lúpus Eritematoso Sistêmico/imunologia , Subpopulações de Linfócitos T/imunologia , Cálcio/metabolismo , Proteína Quinase Tipo 4 Dependente de Cálcio-Calmodulina/metabolismo , Humanos , Interleucina-2/biossíntese , Lúpus Eritematoso Sistêmico/terapia , Receptores de Antígenos de Linfócitos T/metabolismo , Transdução de Sinais/imunologia , Transcrição GênicaRESUMO
T cells from patients with systemic lupus erythematosus (SLE) have high levels of cAMP response element modulator (CREM)-alpha which bind to the interleukin (IL-2) promoter and limit IL-2 production. In this case-controlled study, we show that CREM-alpha mRNA levels were higher in T cells from patients with SLE than controls while CREB mRNA levels did not differ between the two groups. CREM-alpha mRNA levels did not correlate with clinical characteristics, disease activity or treatment. Nevertheless, there was a trend for patients on high doses of corticosteroids to have low levels of CREM-alpha mRNA. The discovery of specific non-toxic medications that block the expression of CREM-alpha may prove useful in reversing the aberrant T cell function in SLE.
Assuntos
Modulador de Elemento de Resposta do AMP Cíclico/genética , Lúpus Eritematoso Sistêmico/fisiopatologia , Corticosteroides/uso terapêutico , Adulto , AMP Cíclico/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Feminino , Expressão Gênica/imunologia , Humanos , Interleucina-2/metabolismo , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Lúpus Eritematoso Sistêmico/imunologia , Pessoa de Meia-Idade , RNA Mensageiro/metabolismo , Linfócitos T/fisiologiaRESUMO
Despite the fact that the etiopathogenesis of systemic lupus erythematosus is largely unknown, key steps in the pathophysiology of the disease have been recognized and targeted using gene therapy techniques. In animal models of lupus, gene transfer has been used to block the action of pro-inflammatory cytokines and co-stimulatory molecules leading to clinical improvement. In humans, ex vivo experiments have shown the feasibility of gene transfer in live T cells and its potential for restoring normal phenotype in T cells from patients with lupus. Still in experimental phase, gene therapy in lupus promises to correct the aberrant immunological response without the numerous side-effects of the currently used immunosuppressant medications.
Assuntos
Terapia Genética , Lúpus Eritematoso Sistêmico/terapia , Animais , Quimiocinas/imunologia , Quimiocinas/metabolismo , Engenharia Genética/métodos , Predisposição Genética para Doença , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Modelos Animais , Linfócitos T/citologia , Linfócitos T/metabolismoRESUMO
Preclinical studies have provided proof of concept for the feasibility and efficacy of gene therapy in human systemic lupus erythematosus (SLE). Successful efforts include gene constructs that alter the expression of cytokines or limit the cognate interaction of immune cells. Other efforts may include gene modified cell transfer such as autologous B cells transfected with tolerogenic constructs or T cells in which specific molecular aberrations have been corrected.
Assuntos
Terapia Genética , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/terapia , Mapeamento Cromossômico , Citocinas/antagonistas & inibidores , Citocinas/uso terapêutico , Humanos , Escore LodAssuntos
Dermatite Fotoalérgica/imunologia , Hipersensibilidade a Drogas/imunologia , Lúpus Eritematoso Cutâneo/imunologia , Linfócitos T/imunologia , Animais , Antineoplásicos/efeitos adversos , Apoptose , Autoanticorpos/imunologia , Fluoruracila/efeitos adversos , Humanos , Modelos Animais , Luz Solar/efeitos adversosRESUMO
T cells from patients with systemic lupus erythematosus (SLE) display antigen receptor-mediated signaling aberrations associated with defective T cell receptor (TCR) zeta chain expression. We determined the prevalence of TCR zeta chain deficiency in SLE from a large cohort of unselected racially diverse patients with different levels of clinical disease activity as determined by SLE Disease Activity Index (SLEDAI). Our data show that the occurrence of TCR zeta chain deficiency is 78% in SLE patients. There was no relationship between the deficiency of TCR zeta chain and the SLEDAI scores or theapy. TCR zeta chain deficiency was also not associated with age, race or gender and persisted over a 3 year follow-up period. Thus, there is a high prevalence of TCR zeta chain deficiency in SLE patients that is independent of disease activity, and persists over time indicating an important role for TCR zeta chain deficiency in SLE pathogenesis.
Assuntos
Lúpus Eritematoso Sistêmico/epidemiologia , Lúpus Eritematoso Sistêmico/imunologia , Proteínas de Membrana/deficiência , Receptores de Antígenos de Linfócitos T/deficiência , Adulto , Idoso , Feminino , Humanos , Lúpus Eritematoso Sistêmico/terapia , Masculino , Pessoa de Meia-Idade , Prevalência , Índice de Gravidade de Doença , Transdução de Sinais/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismoRESUMO
Systemic lupus erythematosus (SLE), the prototypic autoimmune disease, is characterized by defective expression of TCR zeta-chain. Elf-1 (E-74-like factor) is a member of the Ets (E-26-specific) family and is crucial for the basal transcription of TCR zeta-chain in Jurkat cells. We previously demonstrated that Elf-1 exists in the cytoplasm mainly as 80-kDa form and after phosphorylation and O-glycosylation it moves to the nucleus as a 98-kDa which binds DNA. We now demonstrate that Elf-1 is crucial for the transactivation of TCR zeta-chain promoter in normal and SLE T cells. Defective expression of TCR zeta-chain in SLE T cells is associated with two distinct molecular defects in the generation of the 98-kDa DNA binding Elf-1 form. In the first, the levels of the 98-kDa form were either decreased or absent. In the second, the apparent levels of the nuclear Elf-1 form were normal but included only two of the three bands into which the nuclear Elf-1 form separated in isoelectric focusing gels. Because both the transcription and the translation processes of Elf-1 gene are normal in SLE T cells, our data demonstrate that abnormal posttranslational mechanisms of the Elf-1 protein result in defective expression of functional Elf-1, and consequently, the transcriptional defect of TCR zeta-chain in patients of SLE.
Assuntos
Regulação para Baixo/imunologia , Efrina-A2/biossíntese , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/metabolismo , Proteínas de Membrana/biossíntese , Receptores de Antígenos de Linfócitos T/biossíntese , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/metabolismo , Regulação para Baixo/genética , Efrina-A2/deficiência , Efrina-A2/metabolismo , Efrina-A2/fisiologia , Feminino , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/imunologia , Humanos , Ponto Isoelétrico , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/patologia , Masculino , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Peso Molecular , Proteínas Nucleares/biossíntese , Proteínas Nucleares/deficiência , Proteínas Nucleares/metabolismo , Regiões Promotoras Genéticas/imunologia , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/deficiência , Proteínas Proto-Oncogênicas/fisiologia , Proteínas Proto-Oncogênicas c-ets , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/biossíntese , Receptores de Antígenos de Linfócitos T/antagonistas & inibidores , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Subpopulações de Linfócitos T/patologia , Fatores de Transcrição/biossíntese , Fatores de Transcrição/deficiência , Fatores de Transcrição/fisiologiaRESUMO
B cells from patients with systemic lupus erythematosus (SLE) display increased responses following cross-linking of the surface antigen receptor. We explored the possibility that the increased responses are at least partially due to simultaneous cross-linking of the complement receptor 2 (CR2). To this end, we stimulated fresh B cells from SLE patients with an anti-IgD antibody conjugated to the Epstein-Barr virus gp350 protein, which binds to CR2, and recorded the free intracytoplasmic calcium response during the first 10 min. Despite the fact that SLE B cells were found to express half as many surface CR2 as normal B cells, both peak responses and the percentage of responding cells were significantly increased in the former. These observations suggest that regulatory molecules such as CR2 are involved in the increased B cell responses in SLE patients. We propose that certain immune complexes that circulate in the sera of SLE patients that have anti-surface immunoglobulin specificities and are decorated with natural ligands of CR2, such as C3d, elicit and promote B cell overactivity.