Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: HUMANGGP:017444 (TNF)
 61,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytokines and growth factors are involved in all important biological processes. Hence it is anticipated that they will be of importance in autoimmune disease. The pathogenesis of autoimmune diseases involves a number of stages, initiation, perpetuation and tissue damage, each of which involves different cell and molecular interactions. In this review, we will discuss an outline of the cytokine involvement in the various stages of autoimmune development, prior to focusing on the analysis of cytokines in rheumatoid arthritis. Cytokines exert their effect via high affinity cell surface receptors. Thus an understanding of cytokines involves the analysis of receptor expression, and also of cytokine inhibitors. Currently there is only adequate knowledge of these aspects in rheumatoid arthritis (RA), and as such the emphasis of this review is on RA. One of the major reasons for being interested in the role of cytokines in autoimmunity is to define possible therapeutic targets. There is now considerable evidence that TNF alpha is such a target in RA, and the effect of anti TNF alpha monoclonal antibody therapy in RA is discussed.
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PMID:Evaluation of the role of cytokines in autoimmune disease: the importance of TNF alpha in rheumatoid arthritis. 130 91

Two types of tumor necrosis factor receptors have been characterized, both capable of transmitting the signal and exerting the biological functions of TNF and lymphotoxin. We measured the plasma concentrations of two types of TNF binding proteins (sTNFR-A and sTNFR-B) in patients with rheumatoid arthritis (RA) and spondylarthropathies (SpA) using an enzyme-linked binding assay. In normal controls (n = 43), mean plasma concentrations were 1030 +/- 55 and 1461 +/- 59 pg/ml for sTNFR types A and B, respectively. In 67 patients with moderate RA, mean levels were 1422 +/- 82 pg/ml (type A) and 2088 +/- 109 pg/ml (type B); in 34 patients with severe RA, 2588 +/- 279 pg/ml and 4494 +/- 550 pg/ml, respectively, were measured (P less than 0.0001 compared to normal controls). Concentrations of both type A and type B sTNFR were highly correlated in severe RA (R2 = 0.7) but not in SpA or normal controls. T lymphocytes in synovial fluid of patients with RA expressed predominantly type A TNF receptors on their surface; in some patients a weaker expression of type B receptors was also detectable. Soluble TNF binding proteins in patients with RA were able to neutralize TNF in a cytotoxicity assay, demonstrating their ability to act as "TNF-inhibiting factors". We conclude that both types of TNF receptors are parameters of disease activity in RA and may also act as TNF antagonists.
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PMID:Elevated TNF receptor plasma concentrations in patients with rheumatoid arthritis. 131 22

We previously proposed the hypothesis that the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) plays a pivotal role in the pathogenesis of rheumatoid arthritis (RA) based on our observations that it is the dominant inducer of interleukin-1 (IL-1) and granulocyte-macrophage colony-stimulating factor (GM-CSF) production in RA synovial joint mononuclear (MNC) cells in culture. Since TNF-alpha acts via two membrane receptors, we have extended those studies to investigate the distribution of the p55 and p75 TNF receptors (TNF-R) in RA tissue. Surface receptor expression was quantitated by flow cytometry using monoclonal antibodies specific to the p55 (HTR-9) and the p75 (UTR-1) TNF-R. Both receptors were significantly increased on MNC isolated from the synovial membrane of RA patients compared to normal or RA peripheral blood MNC. Interestingly, the p75 TNF-R was increased both on large monocytic/macrophage-type cells and CD3+ lymphocytes. Furthermore, there was a significant increase in the proportion of CD3+ cells in RA synovial fluid expressing the p75 TNF-R, compared to matched peripheral blood MNC. In contrast to RA synovial MNC, p75 or p55 TNF-R expression was not significantly increased in osteoarthritis synovial MNC. In addition, Northern blot analysis indicated abundant expression of both p55 and p75 mRNA in RA synovial joint MNC. This was in contrast to normal peripheral blood MNC cells which contained little or no constitutive TNF-R mRNA; following stimulation with phytohemagglutinin and IL-2, a rapid and transient expression of both receptor mRNA was induced. These results, therefore, indicate that in RA synovial joint tissue there is up-regulation of both p55 and p75 TNF-R mRNA and surface protein expression, and with the presence of TNF-alpha in RA tissues, these results provide support to our hypothesis that TNF-alpha is of critical importance in the pathogenesis of RA.
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PMID:Enhanced expression of tumor necrosis factor receptor mRNA and protein in mononuclear cells isolated from rheumatoid arthritis synovial joints. 132 May 71

In this study, positive correlations were found between tumor necrosis factor alpha (TNF alpha) levels in the sera of rheumatoid arthritis (RA) patients and the duration of morning stiffness, joint tenderness count, the Ritchie articular index and erythrocyte sedimentation rate. Further, higher mean grades of disease activity of RA were accompanied by correspondingly higher levels of serum and synovial TNF alpha. In the longitudinal study, when the disease activity of RA decreased after treatment, serum TNF alpha levels also decreased. This suggests that the levels of serum and synovial TNF alpha correlate positively with RA disease activity. The levels of TNF alpha in synovial fluid were significantly higher in RA and acute gouty arthritis (GA) patients than in osteoarthritis (OA) patients. This suggests that joint inflammation in inflammatory arthritis related to local production of TNF alpha in the joint cavities. Serum TNF alpha levels in RA patients were significantly higher than those in the OA patients; no statistical difference was found between acute GA and OA patients.
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PMID:Correlation of tumor necrosis factor alpha levels with disease activity of rheumatoid arthritis. 134 40

Human TNF alpha locus locates between HLA-B and DR region on the short arm of chromosome 6. The 5.5 kb and 10.5 kb of TNF alpha restriction fragment length polymorphic (RFLP) bands were identified by Southern hybridization using a restriction enzyme, NcoI. The frequencies of those bands were not different among patients with systemic lupus erythematosus (SLE), those with rheumatoid arthritis and normal controls. In the lupus patients, proteinuria was more frequent in the patients with the 5.5 kb RFLP band (19/39: 48.7%) than those without 5.5 kb band (7/35: 20%) (p less than 0.05). Furthermore, this band was strongly associated with the haplotype HLA B44-DRw13-DQw1. In order to investigate the association between this gene polymorphism and the production of TNF alpha, peripheral blood mononuclear cells from patients with SLE and normal controls were cultured for 24 hours with lipopolysaccharide and concanavalin A and the amount of TNF alpha in the supernatant was measured by enzyme linked immunosorbent assay. The TNF alpha production of lupus patients was not statistically different from that of normal controls. The production of TNF alpha was not related to 5.5 kb RFLP band, but in the patients with SLE, the mean value of TNF alpha in patients with the 5.5 kb RFLP band tended to be higher than those without the band. Lupus patients were divided into two groups by the production of TNF alpha i.e. low TNF alpha inducibility group and high TNF alpha inducibility group. Patients with proteinuria were more frequent in patients of the high TNF alpha inducibility group than those of low TNF alpha inducibility group (p less than 0.05). There were four patients with HLA B44-DRw13-DQw1 who had the 5.5 kb RFLP band and three of them belonged to the high TNF alpha inducibility group with nephrosis. These data suggest that TNF alpha and HLA are possibly associated with the severity of lupus nephritis.
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PMID:[Tumor necrosis factor alpha in systemic lupus erythematosus: evaluation by restriction fragment length polymorphism and production by peripheral blood mononuclear cells]. 135 65

Seventeen patients with steroid-refractory rheumatoid arthritis were treated with a monoclonal antibody: anti-T CD4/B-F5 (IgG1) for 10 days. The daily dose was 20 mg. No severe side effects were observed and clinical improvement was seen in 15 patients, accompanied by a steep decline in C reactive protein levels. This improvement persisted as long as 12 months in 3 patients. A decline in lymphocyte counts was observed 2 hours after infusion. CD3+, CD4+, CD8+ and B cells were affected. Monocyte levels also decreased, whereas NK cell levels remained unchanged. After 24 hours a subsequent recovery of lymphocyte cell numbers made it possible to return to pre-treatment levels. Residual CD4+ cells coated with CD4 antibody were sporadically found even if residual antibody could be detected in the serum. These results indicate insufficient mAb concentrations. No patients developed detectable anti-mouse Ig antibodies during the treatment period, but 5 patients developed antibodies 15 to 30 days after the end of the treatment. Proliferative responses (mainly the response to ConA) were reduced at the end of the treatment. One month later the proliferative response returned to pre-treatment levels. mAb treatment did not induce long lasting cell activation, as indicated by the low levels of CD25+ or DR+ cells. Soluble IL2 receptor levels were significantly higher before treatment, but did not change after treatment. Soluble CD8 and soluble CD4 molecules were also more numerous before treatment and this increase was correlated with clinical parameters. Of interest was the correlation between the variations in soluble CD8 and the Ritchie index during treatment. The increased levels of serum TNF alpha and IL6 were not modified by treatment. A randomized study now appears necessary to prove the efficacy of the treatment. Such a study would also provide biological data and thus help to define factors predictive of a response in this heterogeneous disease.
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PMID:Immunological follow-up of 17 patients with rheumatoid arthritis treated in vivo with an anti-T CD4+ monoclonal antibody (B-F5) 139 16

We analyzed expression of HLA-DR and CD14 molecules on myelomonocytic cells and its regulation by various inflammatory cytokines in 6 patients with rheumatoid arthritis (RA) and 4 healthy individuals who had undergone bone marrow aspiration. At start of the bone marrow culture there was a significantly higher number of HLA-DR and CD14 positive bone marrow mononuclear cells in patients with RA than in normals. In addition, RA bone marrow mononuclear cells expressed an up to 10-fold higher mean density of both molecules than normal bone marrow mononuclear cells during the whole culture period of up to 14 days. The effect of the cytokines interferon-gamma (IFN-gamma), tumor necrosis factor alpha (TNF alpha), granulocyte monocyte colony stimulating factor (GM-CSF) and interleukin 1 (IL-1) on the expression of CD14 or HLA-DR was different: IFN-gamma strongly upregulated HLA-DR expression and down-regulated CD14 expression while TNF alpha, GM-CSF and IL-1 mainly stimulated CD14 expression on bone marrow mononuclear cells. Our data suggest that RA bone marrow mononuclear cells exhibit an activated phenotype and that TNF-alpha GM-CSF and IL-1 mainly stimulate the differentiation of bone marrow macrophages whereas IFN-gamma activates them.
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PMID:Activation and differentiation of myelomonocytic cells in rheumatoid arthritis and healthy individuals--evidence for antagonistic in vitro regulation by interferon-gamma and tumor necrosis factor alpha, granulocyte monocyte colony stimulating factor and interleukin 1. 138 Sep 87

There is considerable evidence implicating tumor necrosis factor alpha (TNF-alpha) in the pathogenesis of rheumatoid arthritis. This evidence is based not only on the universal presence of TNF-alpha in arthritic joints accompanied by the upregulation of TNF-alpha receptors but also on the effects of neutralizing TNF-alpha in joint cell cultures. Thus, neutralization of TNF-alpha in vitro results in inhibition of the production of interleukin 1, which like TNF-alpha, is believed to contribute to joint inflammation and erosion. To determine the validity of this concept in vivo, the effect of administering TNF-neutralizing antibodies to mice with collagen-induced arthritis has been studied. This disease model was chosen because of its many immunological and pathological similarities to human rheumatoid arthritis. TN3-19.12, a hamster IgG1 monoclonal antibody to murine TNF-alpha/beta, was injected i.p. into mice either before the onset of arthritis or after the establishment of clinical disease. Anti-TNF administered prior to disease onset significantly reduced paw swelling and histological severity of arthritis without reducing the incidence of arthritis or the level of circulating anti-type II collagen IgG. More relevant to human disease was the capacity of the antibody to reduce the clinical score, paw swelling, and the histological severity of disease even when injected after the onset of clinical arthritis. These results have implications for possible modes of therapy of human arthritis.
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PMID:Anti-tumor necrosis factor ameliorates joint disease in murine collagen-induced arthritis. 140 99

Joint swelling and tenderness in rheumatoid arthritis (RA) probably result from IgG aggregates activating complement with the consequent attraction of polymorphonuclear leucocytes (PMNs) and the liberation of their granule enzymes such as kininogenases. By contrast IL-1 and TNF are the major stimulants of cartilage and bone loss although other agents contribute. The fundamental drive for the production of these mediators is unknown but a role for heat shock proteins is suggested from work on pristane induced arthritis.
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PMID:Mediators of joint swelling and damage in rheumatoid arthritis and pristane induced arthritis. 147 43

Rheumatoid arthritis (RA) is associated with T- and B-cell dysfunction. Immunoglobulin (Ig) production is under the control of T cells and their derived cytokines such as interleukin 2 (IL-2) and IL-4. Herein we studied the regulation of the production of immunoglobulins and cytokines by peripheral blood mononuclear cells from RA patients and controls. In the controls, IL-4 inhibited Ig production in response to Staphylococcus aureus and pokeweed mitogen stimulation. IL-2 induced maximal Ig production in association with Staphylococcus aureus, whereas it inhibited pokeweed mitogen-induced production. In patients, levels of Ig production in response to mitogens and cytokines were reduced, particularly for the response to IL 2. The inhibitory effect of IL-4 on mitogen-induced Ig production was observed in RA patients as in the controls. Spontaneous production of IL-6 was increased in RA patients. These levels were correlated with indicators of active disease such as sedimentation rate and Ritchie index. IL-4 inhibited the production of IL-6, IL-1 beta, and tumor necrosis factor alpha (TNF alpha) by both controls and rheumatoid patients. Thus as first described for the T-cell response, mononuclear cells from RA patients display a reduced response to mitogens and cytokines which induce their B-cell differentiation into Ig-screening cells. However, IL-4 was able to inhibit Ig and cytokine production, properties suggesting a potential antiinflammatory role for this cytokine.
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PMID:Interleukin 4 inhibits polyclonal immunoglobulin secretion and cytokine production by peripheral blood mononuclear cells from rheumatoid arthritis patients. 155 40


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