Signalling, inflammation and arthritis: NF-kappaB and its relevance to arthritis and inflammation

In the synovial cells of patients with RA, activation of thenuclear factor-B (NF-B) pathway results in the transactivationof a multitude of responsive genes that contribute to the inflammatoryphenotype, including TNF- from macrophages, matrix metalloproteinasesfrom synovial fibroblasts and chemokines that recruit immunecells to the inflamed pannus. This is largely a consequenceof activation of the ‘canonical’ NF-B pathway thatinvolves heterodimers of p50/p65. Whilst much information onthe role of NF-B in inflammation has been gleaned from geneticdeficiency of the respective genes in mice, important differencesexist in the signalling networks between human and murine immunecells and immortalized cell lines. Despite these differencesat the molecular level, the importance of NF-B in inflammationis undisputed and inhibition of the pathway is widely believedto have great potential as a therapeutic target in RA. Commercialeffort has gone into developing inhibitors of NF-B activation.However, inhibition of the NF-B activation can result in anexacerbation of inflammation if TNF- production by macrophagesis not controlled. It will be important that such inhibitorsare carefully monitored before their long-term use in chronicinflammatory conditions such as RA. KEY WORDS: NF-B, Signalling pathways, Review Submitted 13 July 2007; revised version accepted 4 October 2007.     

Suppression of tumour necrosis factor production from mononuclear cells by a novel synthetic compound, CLX-090717

Objectives. To evaluate the clinical efficacy of a novel syntheticperoxisome proliferator-activated receptor gamma (PPAR-) agonist,CLX-090717, in several in vitro cell culture systems and murineCIA, an experimental model of RA. Methods. Peripheral blood monocytes purified by elutriation,and rheumatoid synovial cells isolated from clinical tissuewere cultured with CLX-090717 and TNF- release was measured.Molecular mechanism of action was analysed by western blottingand electrophoretic mobility shift assay. Thioglycollate-elicitedmurine peritoneal macrophages were cultured with CLX-090717and lipopolysaccharide (LPS)-induced TNF- release was assayed.Therapeutic studies were done in mice with established arthritisby evaluating clinical parameters and histology. In addition,type II collagen response of lymphocytes from mice with CIAwas examined. Results. CLX-090717 significantly inhibited spontaneous TNF-release by RA synovial membrane cells, as well as LPS-inducedTNF- release from human and murine monocytic cells. Inhibitionof TNF- in monocytes was mediated partially through a nuclearfactor-B (NF-B)-dependent pathway, as judged by sustained levelsof IB in cytosolic extracts and a reduced level of LPS-inducedNF-B activity in nuclear extracts. CLX-090717 reduced clinicalsigns of arthritis and damage to joint architecture when administeredtherapeutically to arthritic mice. Mechanisms of action in CIAinvolved the reduction in proliferation of arthritic lymphocytesto antigen in vitro as well as reduced TNF- release. Conclusions. Our data suggest that the synthetic compound CLX-090717has potential as a small molecular weight anti-inflammatorytherapeutic for chronic inflammatory conditions. KEY WORDS: Arthritis, Collagen, Cytokines, Monocytes, Synovium, Inflammation     

T-CELL RECEPTOR GAMMA-DELTA POSITIVE LYMPHOCYTES IN SYNOVIAL MEMBRANE

The distribution of T-lymphocytes expressing CD3 and T-cellreceptor gamma-delta (T/) has been examined by immunocytochemistryin the synovial membrane of eight patients with inflammatoryarthritis (six rheumatoid arthritis, two spondyloarthritis)and eight with non-inflammatory arthritis (four osteoarthritis,four post-traumatic arthritis). T/ cells were present in eightout of eight inflammatory arthritis synovial membranes, butin only one out of eight noninflammatory membranes (P<0.005).The mean T/ percentage (of total T-cells) in inflammatory arthritiswas 14% (range 7–25%). T/ cells were found mainly in thetransitional area of the synovial membrane with a scattereddistribution as single cells or couplets. No relation was foundbetween the presence and percentage of T/ cells and diseaseduration or steroid treatment. KEY WORDS: Rheumatoid arthritis, Inflammatory arthritis, Degenerative joint disease, Synovium, Lymphocytes     

PLASMA LEVELS OF INTERLEUKIN-1-ALPHA IN RHEUMATOID ARTHRITIS

Interleukin-1-beta (IL-1ß has been implicated as aninflammatory mediator in rheumatoid arthritis (RA) but littleis known about the related cytokine, IL-1, in this disease.IL-1 has biological properties similar to IL-1ß but,unlike IL-1ß remains mostly cell-associated. In thisstudy plasma IL- was measured by radioimmunoassay in patientswith RA and in healthy controls. Plasma levels were comparedwith conventional measures of disease activity. The mean levelsin the two groups were not significantly different and, withinthe patient group (n = 53), the only significant cross-sectionalcorrelation was between plasma IL-1 and ESR. In longitudinalstudies, some individual patients had plasma IL-1 levels thatcorrelated with different measures of disease activity. We concludethat while IL- may be involved in the immunopathogenesis ofRA, its measurement in plasma seems to offer little of clinicalvalue. KEY WORDS: Interleukin-1-alpha, Plasma, Rheumatoid arthritis, Prospective longitudinal study     

IL-1 SECRETING CELL ASSAY AND ITS APPLICATION TO CELLS FROM PATIENTS WITH RHEUMATOID ARTHRITIS

The cells within a population that were secreting interleukin-1(IL-1) were enumerated and visualized by an ELISA-SPOT assay.Initial experiments designed to validate the assay revealedthat the number of IL-1ß spot forming cells was increasedby exposing normal blood monocytes to LPS and that spot formationwas prevented by incubating the cells with cycloheximide. Normalblood polymorphonuclear leucocytes (PMNs) produced IL-1 andIL-1ß in response to recombinant granulocyte monocytecolony stimulating factor (rhGMCSF) but not to cytochalasinB, calcium ionophore or LPS. Monocytes and PMN were isolatedfrom the synovial fluid (SF) and blood of patients with rheumatoidarthritis (RA) and the ability of these cells to secrete IL-1and IL-1ß compared. A higher proportion of SF derivedmonocytes were found to secrete IL-1 spontaneously comparedto the corresponding blood cells. IL-1 secreting monocytes werenot detected although high numbers of IL-1 secreting cells werefound among cells isolated from rheumatoid synovium. By contrastSF PMNs did not produce IL-1 or IL-1ß whereas bloodPMNs from some (3/8) RA patients produced IL-1 and/or IL-1ß.It is considered that the IL-1 ELISA-SPOT is a highly sensitivetechnique for detecting IL-1 secreting cells. KEY WORDS: Synovial cells, Interleukin-i1, Interleukin-1ß, Rheumatoid arthritis     

Combined tumour necrosis factor-alpha and tumour necrosis factor receptor genotypes could predict rheumatoid arthritis patients' response to anti-TNF-alpha therapy and explain controversies of studies based on a single polymorphism

SIR, Tumour necrosis factor- (TNF-) blocker therapies are widelyused in the treatment of chronic inflammatory diseases. However,patients show large heterogeneity in their response to anti-TNF-therapy. The genotypic background of TNF- and TNF receptor (TNFR)genes could account for patients’ resistance to TNF- blockers[1, 2]. HLA-DR haplotypes have been related with rheumatoidarthritis (RA) susceptibility, severity and course [3], butTNF and TNFR polymorphisms seem to have independent predictivevalue of patients’ response to anti-TNF- therapy [2, 4,5     

Visceral leishmaniasis infection in a rheumatoid arthritis patient treated with adalimumab

SIR, Anti-tumour necrosis factor- (TNF-)-based therapies representan important innovation in rheumatoid arthritis (RA) treatment,demonstrating efficacy in reducing disease activity and in retardingradiographic progression. Three different TNF- blockers havebeen approved for the treatment of these conditions: infliximab,adalimumab and etanercept. TNF- is essential for granuloma formationand maintenance, which are key components of host defences againstintracellular pathogens [1]. The clinical use of TNF- blockershas been associated with an increased risk of reactivation ofgranulomatous infectious diseases     

Is TNFalpha really a good therapeutic target in motoneuronal degeneration? A case of amyotrophic lateral sclerosis in a patient with RA receiving infliximab

SIR, Tumour necrosis factor- (TNF-) has been implicated in thepathogenesis of various inflammatory conditions such as rheumatoidarthritis (RA), Crohn's disease and psoriasis. In these diseases,TNF- blockade is a successful and safe treatment option [1].TNF- can be neurotoxic and has also been implicated in the pathogenesisof some central nervous system diseases where inflammation hasrecently emerged as a significant contributor to motor neurondamage [2]. TNF- acts as the main driver for neuroinflammationin amyotrophic lateral sclerosis (ALS). Animal studies [3–5]as well as phase II     

Pneumocystis carinii pneumonia following a second infusion of infliximab

SIR, Anti-tumour necrosis factor (TNF-) blockade is increasinglyused for severe rheumatoid arthritis (RA). There is an increasedrisk of infection, including atypical infection [1] associatedwith TNF- blockade. We report the development of Pneumocystiscarinii pneumonia (PCP) in a man with RA shortly after commencingtherapy with the anti-TNF- agent infliximab (Remicade). Thisoccurred in the setting of concomitant therapy with low-doseweekly methotrexate and corticosteroids. A 49-yr-old man who had had seropositive RA for 9 yr     

Successful treatment of refractory lupus-associated haemophagocytic lymphohistiocytosis with infliximab

SIR, Tolerance of tumor necrosis factor- (TNF-) inhibitors isusually excellent, but a number of recent publications callattention to some potentially paradoxical reactions to TNF-inhibitor therapy, worsening or new-onset palmoplantar pustulosisor psoriasis [1], as well as lupus-like syndrome and inflammatorybowel disease. It is puzzling that medications used to treatone disease may induce the same disease, suggesting a complexrole of TNF- inhibitors. Recently, some case reports of haemophagocyticlymphohistiocytosis (HLH) after treatment with TNF- inhibitors     

Unstable diabetes in a patient receiving anti-TNF-alpha for rheumatoid arthritis

SIR, Tumour necrosis factor- (TNF-) is a cytokine well-recognizedas having a significant role in the inflammatory process. Recentadvances have led to the production of drugs that inhibit theaction of TNF-, producing significant improvement in the controlof rheumatic diseases [1]. TNF- may also play a role in otherphysiological     

Anti-TNF-alpha therapies: they are all the same (aren't they?)

The development of anti-tumour necrosis factor (TNF-) therapyhas been a milestone in the treatment of rheumatoid arthritis(RA) and is proving equally important in other inflammatory-mediatedconditions [1–3]. The three currently licensed biologicalanti-TNF- drugs, etanercept, infliximab and adalimumab, haveall been clearly shown to suppress disease activity in RA. Theyall target the same molecule—but are they really justmore of the same and, indeed, are all three needed? As uptakeof anti-TNF- therapy increases around the world, these questionsare becoming increasingly posed. However, it is also becomingclear that these drugs possess significant differences, bothin vitro and clinically. Understanding these differences isof course important for the clinic, but equally important isthe appreciation that these     

Tumour necrosis factor inhibitors: maximizing patient safety

SIR, The tumour necrosis factor (TNF-)-inhibiting drugs infliximaband etanercept have revolutionized the management of severerheumatoid arthritis and other inflammatory arthropathies. Byblocking TNF- they exert potent immunosuppressive effects ina group of patients already at increased risk     

OPTIMIZING THE ASSESSMENT OF DISEASE ACTIVITY DURING TREATMENT WITH ANTI-RHEUMATOID DRUGS

Clinical trials in RA usually involve the use of several laboratoryassessments of disease activity. Their use is not universaland the relative value of many novel assessments has not beendetermined in relation to existing clinical and laboratory methods.This study attempts to investigate the value of establishedand novel assessments of disease activity during treatment withaccepted DMARDs. Over a 48-week study period, changes in cytidine deaminase (CD),ß₂-microglobulin, ₁-acid glycoprotein (₁-AGP) serumantibodies to Clostridium perfringens -toxin, pre-albumin andcaeruloplasmin were compared to a group of established clinicaland laboratory assessments including plasma viscosity, CRP haemoglobinand platelet count during treatment with the established second-linedrugs, D-penicillamine (n=20), sulphasalazine (n=17), gold (n=12)and hydroxychloroquine (n=18). Overall, the assessments showing the greatest degree of changewere plasma viscosity, articular index, summated change score,platelet count, CD, white cell count, ₁AGP, CRP and pain score.The assessments showing the greatest degree of change were nothomologous between the treatment groups and no single assessmentwas outstanding for a particular drug treatment. KEY WORDS: Rheumatoid arthritis, Cytidine deaminase, ß₂-microglobulin, ₁-acide glycoprotein, Caeruloplasmin     

Biologic therapy in clinical practice: enthusiasm must be tempered by caution

Rheumatoid arthritis (RA) is a major cause of disability andis associated with significant mortality in its own right [1–5].The effects of therapy with traditional disease-modifying drugson outcomes have previously left much to be desired. This isnot surprising, given the poor understanding of pathologicalmechanisms underlying this disease at the molecular and cellularlevels. A few years ago, however, seminal basic science workidentified the importance of the proinflammatory cytokines tumournecrosis factor (TNF-) and interleukin 1ß (IL-1ß)in RA. These observations rapidly led to the development ofagents that inhibited these cytokines and suppressed diseasein RA. Drugs current1y licensed for use in RA that inhibit theseinflammatory molecules—etanercept, infliximab (TNF-) andanakinra (IL-1ß)—have been shown clearly tobe effective in reducing disease activity. Indeed, their successin clinical trials is the     

THE RELATIONSHIP BETWEEN THE COMPLEX OF IMMUNOGLOBULIN A AND ALPHA-1-ANTITRYPSIN, ITS CONSTITUENT COMPONENTS AND THE ACUTE-PHASE RESPONSE AS MEASURED BY C-REACTIVE PROTEIN IN RHEUMATOID ARTHRITIS TREATED WITH GOLD OR D-PENICILLAMINE

Serum levels of immunoglobulin A (IgA), ₁ (AT), their complex(IgA-₁AT) and C-reactive protein (CRP) were measured prior totreatment and at 6 months, in 45 rheumatoid arthritis (RA) patients.Twenty-five patients were treated with D-penicillamine (DPA)and 20 patients with gold (sodium aurothiomalate). The levelof circulating complex was reduced by both treatments (p<0.001).There was a significant correlation between the circulatinglevels of IgA-₁AT complex and serum IgA (p<0.05). No relationshipwas observed between the level of circulating complex and CRP. These findings suggest that formation of IgA-₁AT complex inRA is dependent on the level of IgA. The complex is reducedby gold and DPA but it does not reflect an acute phase responseas measured by CRP. KEY WORDS: C-reactive protein, Immunoglobulin A, Alpha-1-antitrypsin, Rheumatoid arthritis, Immune complex     

Polymorphism of the tumour necrosis factor-alpha gene at position -308 and renal manifestations of primary Sjögren's syndrome

SIR, Tumour necrosis factor- (TNF-) is a pro-inflammatory cytokinewhich plays an important role in the pathogenesis of many inflammatoryand infectious diseases, including primary Sjögren's syndrome(pSS). TNF- is expressed in minor salivary gland duct cellsin patients with pSS [1]. It promotes the influx of mononuclearcells not only into the salivary glands but also, for example,to the renal epithelia [2], and has been shown to be involvedin the pathogenesis of experimental tubulointerstitial nephritis.The roles of TNF- in the     

Onset of systemic lupus erythematosus after conversion of infliximab to adalimumab treatment in rheumatoid arthritis with a pre-existing anti-dsDNA antibody level

SIR, Drug-induced systemic lupus erythematosus (SLE) has beendescribed for rheumatoid arthritis (RA) patients treated withthe tumour necrosis factor- (TNF-)-blocking agents, infliximaband etanercept [1, 2]. This complication of clinically manifestSLE seems to be induced considerably less often, if not at all,in patients treated with the fully human anti-TNF- antibody,termed adalimumab [3]. The present case report describes a patientwho develops SLE upon conversion of infliximab to adalimumaband provides data that indicate the involvement of a Th1-driveninflammatory response in this patient. A 56-yr-old Asiatic woman with     

ROLE OF TNF{alpha}, IN RELATION TO IL-1 AND IL-6 IN THE PROTEOGLYCAN TURNOVER OF HUMAN ARTICULAR CARTILAGE

In both young and old human articular cartilage explants, TNFinduced a concentration-dependent, reversible suppression ofthe proteoglycan (PG) synthesis. Young cartilage was more sensitiveto TNF than old cartilage: 50% suppression of PG synthesis wasreached at a TNF concentration of 5 U/ml for young and 30 U/mlfor old cartilage, whereas at 10³ U/ml the PG synthesis of youngcartilage was blocked and that of old cartilage suppressed by80%. These inhibition levels of PG synthesis resulted in 25%PG depletion of the explants after 8 days of culture. The releaseof cartilage PG not enhanced. TNF induced no detectable amountsof IL-1 (<0.01 U) in young or old cartilage but did induceIL-6 production. The induced amounts of IL-6 were higher inyoung than in old cartilage but no dose-dependency was evident.Antibodies to neither IL-1 nor IL-6 had any influence on theTNF-induced suppression of PG synthesis. The combination ofTNF and IL-1 led to an additive inhibition of PG synthesis whichhad no relationship to induced IL-6. TNF was about 100-foldless active than IL-1. KEY WORDS: Explant culture, Cytokines, Bioassay