Subtle changes in individual joints result in both positive and negative change scores in a patient: results from a clinical trial in patients with rheumatoid arthritis.

BACKGROUND: Radiographic progression in clinical trials is assessed by interpreting changes in total radiographic joint score, and the reliability of those scores depends on an evaluation of sum scores. It is not known how consistently changes in individual joints are identified by independent readers and in independent readings. PATIENTS AND METHODS: 7255 single joints from 178 patients who participated in the Trial of Etanercept and Methothrexate with Radiographic Patient Outcomes (TEMPO) trial were evaluated. Every image was independently scored twice according to the Sharp-van der Heijde method by two independent readers, so that four scores per joint were available. Absolute agreement and consistency of negative and positive erosion change scores across readers and readings were compared on a per-joint level, as well as on a per-patient level. RESULTS: The number of joints showing a change for erosion was very low in this trial: 691/7255 analysed joints had at least one non-zero change score out of four readings. Absolute agreement between readings was remarkably poor: only 12 joints showed a consistently positive or negative change in all four readings. Change scores in opposite directions in the same joint across independent readings were rare (25 joints). Frequency of opposite joint scores in the same patient (mixed change patterns) was reader dependent. CONCLUSION: Substantial intra and interreader disagreement in scoring change in individual joints is common. Opposite joint scores in the same patient, however, are rare and reader dependent. Notwithstanding these subtle inconsistencies on the individual joint level, the total Sharp score is a useful and discriminatory outcome measure.

Efficacy, safety and patient-reported outcomes of combination etanercept and sulfasalazine versus etanercept alone in patients with rheumatoid arthritis: a double-blind randomised 2-year study.

OBJECTIVE: To determine the efficacy and safety of etanercept and etanercept plus sulfasalazine versus sulfasalazine in patients with rheumatoid arthritis (RA) despite sulfasalazine therapy. METHODS: Patients were randomly assigned to etanercept (25 mg twice weekly; sulfasalazine was discontinued at baseline), etanercept plus sulfasalazine (unchanged regimen of 2-3 g/day) or sulfasalazine in a double-blind, randomised, 2-year study in adult patients with active RA despite sulfasalazine therapy. Efficacy was assessed using the American College of Rheumatology criteria, disease activity scores (DAS) and patient-reported outcomes (PRO). RESULTS: Demographic variables and baseline disease characteristics were comparable among treatment groups; mean DAS 5.1, 5.2 and 5.1 for etanercept (n = 103), etanercept plus sulfasalazine (n = 101) and sulfasalazine (n = 50), respectively. Withdrawal due to lack of efficacy was highest with sulfasalazine (26 (52%) vs 6 (6%) for either etanercept group, p<0.001). Patients receiving etanercept or etanercept plus sulfasalazine had a more rapid initial response, which was sustained at 2 years, than those receiving sulfasalazine: mean DAS 2.8, 2.5 versus 4.5, respectively (p<0.05); ACR 20 response was achieved by 67%, 77% versus 34% of patients, respectively (p<0.01) Overall, PRO followed a similar pattern; a clinically significant improvement in health assessment questionnaire was achieved by 76%, 78% versus 40% of patients, respectively (p<0.01). Commonly reported adverse events occurring in the etanercept groups were injection site reactions and pharyngitis/laryngitis (p<0.01). CONCLUSION: Etanercept and etanercept plus sulfasalazine are efficacious for the long-term management of patients with RA. The addition of etanercept or substitution with etanercept should be considered as treatment options for patients not adequately responding to sulfasalazine.

Level of radiographic damage and radiographic progression are determinants of physical function: a longitudinal analysis of the TEMPO trial.

BACKGROUND: Many studies have examined the relationship between long-term radiographic damage and physical function. However, it is not known if short-term radiographic progression is also associated with physical function. AIM: To investigate the longitudinal relationship between physical function and both the level of radiographic damage and the radiographic progression rate in patients with early or advanced active rheumatoid arthritis. METHODS: The database for the 2-year Trial of Etanercept and Methotrexate with Radiographic Patient Outcomes (TEMPO) was used for this study. Physical function was measured by the Health Assessment Questionnaire (HAQ) score at baseline, 6 months and 1 and 2 years. Radiographs of the hands and feet, taken at the same time points, were scored by the van der Heijde-modified Total Sharp Score (TSS). The HAQ score was modelled using generalised mixed linear modelling by TSS or progression in TSS (interval 0-1 year and 1-2 years) adjusted for age, sex, treatment and disease activity. RESULTS: After adjustment for age, sex and disease activity, both TSS and the change in TSS (progression rate) were significant determinants of the HAQ score. When radiographic progression was divided into four categories (negative, zero, minor and greater progression), results showed that HAQ scores tended to be higher with a higher rate of progression. Patients with negative progression scores had lower HAQ scores than patients with positive progression scores. CONCLUSIONS: Patients with greater radiographic damage, and those with recent radiographic progression, have a higher degree of disability.

Reliability and sensitivity to change of the Simple Erosion Narrowing Score compared with the Sharp-van der Heijde method for scoring radiographs in rheumatoid arthritis.

OBJECTIVE: To compare the performance of a simplified scoring method for structural damage on radiographs of patients with rheumatoid arthritis (the Simple Erosion Narrowing Score or SENS) with the Sharp-van der Heijde Score (SHS) as reference. METHOD: We used the radiographic data from the Trial of Etanercept and Methotrexate with Radiographic Patient Outcomes (TEMPO trial). The SENS was derived from the crude SHS data. Inter-observer reliability for status scores and change scores was determined by intraclass correlation coefficients and by the Smallest Detectable Change method. The ability to discriminate between treatment groups was assessed by the Mann-Whitney U test. Stratifying the sensitivity to change and discriminative ability for different levels of disease severity assessed a potential ceiling effect. RESULTS: Inter-observer reliability was similar for both methods. Intraclass correlation coefficients were higher for status scores than for change scores. The Smallest Detectable Change was 4.98 (1.1% of possible maximum score) for SHS and 2.28 (3.5%) for SENS. Sensitivity of SENS to detect progression above the Smallest Detectable Change, with reference SHS, ranged from 45.0 to 88.7%. Specificity ranged from 81.5 to 97.3%, and the kappa coefficient (between-method agreement) ranged from 0.58 to 0.66. Discriminative ability between treatment groups was good and similar for both methods. A ceiling effect could not be detected. CONCLUSIONS: With regard to most of the tested properties, the performance of SENS is as good as that of SHS. This confirms that SENS is a valuable method, which may be feasible in clinical practice.

Autoreactive T cells in murine lupus: origins and roles in autoantibody production.

The conventional paradigm to explain systemic lupus erythematosus (SLE) is that disease results from tissue deposition of pathogenic autoantibodies and immune complexes, secondary to activation of autoreactive B cells in the context of help from alphabeta T cells. Recent work in murine lupus has confirmed this notion and demonstrated that autoantigen-specific alphabeta T cells are absolutely required for full penetrance of disease, with such autoreactive alphabeta T cells, even in Fas-intact mice, likely arising from defects in peripheral tolerance. These studies have also revealed a network of regulation that also involves nonclassical pathogenic and downregulatory alphabeta and gammadelta T cells, suggesting that the lupus immune system involves more complex interactions than the conventional paradigm suggests.

Population-based pharmacokinetics of the soluble TNFr etanercept: a clinical study in 43 patients with ankylosing spondylitis compared with post hoc data from patients with rheumatoid arthritis.

OBJECTIVE: The purpose of this study was to evaluate the pharmacokinetics of etanercept in patients with ankylosing spondylitis (AS) in a phase 3 study. METHODS: Serum etanercept concentrations were analyzed from samples obtained at weeks 4 and 12 from 43 patients with AS (median age: 45 years; median body weight: 75 kg; white/non-white: 40/3; male/female: 34/9) receiving 25 mg subcutaneously twice weekly for 12 weeks. A population pharmacokinetics analysis using NONMEM was conducted to estimate individual etanercept pharmacokinetic parameters. Initially, appropriate base and covariate population pharmacokinetic models were built based on data from 10 prior clinical studies of etanercept administered subcutaneously or intravenously to healthy subjects (n = 53) and to patients with rheumatoid arthritis (RA) (n = 212). The influence of demographic characteristics on the pharmacokinetics of etanercept was thoroughly evaluated. The stability of the final model was evaluated using both internal (bootstrapping) and external (data splitting) validation approaches. Finally, the selected final population covariate model was used to estimate the Bayesian pharmacokinetic parameters for the patients with AS. RESULTS: The data from the 10 prior clinical studies were optimally fitted to a 2-compartment linear population covariate model. Both age (< 17 years) and body weight (< 60 kg) were found to be important covariates on clearance. Both bootstrapping and data splitting validated the population model. The mean Bayesian-predicted etanercept clearance and steady-state trough concentration were 0.072 l/h and 2,004 ng/ml, respectively. The pharmacokinetic parameters of etanercept in the patients with AS were similar to those observed in the patients with RA. CONCLUSIONS: The pharmacokinetics of etanercept in patients with AS were similar to those in patients with RA. The AS disease state does not appear to alter the disposition of etanercept.

Disease remission and sustained halting of radiographic progression with combination etanercept and methotrexate in patients with rheumatoid arthritis.

OBJECTIVE: The Trial of Etanercept and Methotrexate with Radiographic Patient Outcomes (TEMPO) is a 3-year, double-blind, multicenter study evaluating the efficacy and safety of etanercept, methotrexate, and the combination of etanercept plus methotrexate in patients with active rheumatoid arthritis (RA). The results after 1 and 2 years of the study have been previously reported. Here we provide the 3-year clinical and radiographic outcomes and safety of etanercept, methotrexate, and the combination in patients with RA. METHODS: In this randomized, double-blind, multicenter TEMPO study, 682 patients received etanercept 25 mg twice weekly, methotrexate < or =20 mg weekly, or the combination. Key efficacy assessments included the Disease Activity Score (DAS) and the DAS in 28 joints. RESULTS: Combination therapy resulted in significantly greater improvement in the DAS and in more patients with disease in remission than either monotherapy. This finding was confirmed by longitudinal analysis; patients receiving combination therapy were more than twice as likely to have disease in remission than those receiving either monotherapy. Independent predictors of remission included male sex, lower disease activity, lower level of joint destruction, and/or better physical function. Combination and etanercept therapy both resulted in significantly less radiographic progression than did methotrexate (P < 0.05). Etanercept and combination treatment were well tolerated, with no new safety findings. CONCLUSION: Etanercept plus methotrexate showed sustained efficacy through 3 years and remained more effective than either monotherapy, even after adjustment for patient withdrawal. Combination therapy for 3 years led to disease remission and inhibition of radiographic progression, 2 key goals for treatment of patients with RA.

Patient reported outcomes in a trial of combination therapy with etanercept and methotrexate for rheumatoid arthritis: the TEMPO trial.

OBJECTIVE: To compare patient reported measures of function, health related quality of life (QoL), and satisfaction with medication among patients with rheumatoid arthritis (RA) treated with methotrexate (MTX), etanercept, or both for up to 1 year. METHODS: In a 52 week, double blind, clinical trial, patients with active RA were randomised to receive etanercept 25 mg twice weekly, methotrexate up to 20 mg weekly, or combination therapy. The Health Assessment Questionnaire (HAQ) disability index, EuroQoL health status visual analogue scale (EQ-5D VAS), patient global assessment, and patient general health VAS were administered at baseline and weeks 2, 4, 8, 12, 16, 20, 24, 32, 40, 48, and 52. Satisfaction with the medication was compared at 52 weeks. RESULTS: Of 682 enrolled patients, 522 completed 52 weeks of treatment. Mean improvement from baseline in HAQ score was 0.65, 0.70, and 1.0 for MTX, etanercept, and the combination, respectively. The mean percentage and absolute improvement in the HAQ was significantly higher (p<0.01) for combination therapy than for either of the monotherapies. Combination therapy produced significantly more rapid achievement of HAQ < or =0.5 sustained for 6 months than either of the monotherapies (p<0.01). Compared with patients receiving monotherapy, those receiving combination therapy achieved a significantly better (p<0.05) health state as measured by the EQ-5D VAS (mean (SD) 63.7 (3.2), 66.8 (3.2), 72.7 (3.1) for MTX, etanercept, and the combination, respectively). Results were similar for other assessments (p<0.01). Patients in combination and etanercept groups were significantly more likely (p<0.0001, p = 0.0009, respectively) to report satisfaction with the medication. CONCLUSIONS: Combination therapy with etanercept and methotrexate improved function, QoL, and satisfaction with the medication significantly more than monotherapy.

Etanercept and sulfasalazine, alone and combined, in patients with active rheumatoid arthritis despite receiving sulfasalazine: a double-blind comparison.

OBJECTIVE: To compare the efficacy and safety of etanercept and sulfasalazine, alone and in combination, in patients with active rheumatoid arthritis despite sulfasalazine treatment. METHODS: A double-blind, randomised study in adult patients with active rheumatoid arthritis despite stable sulfasalazine (2-3 g/day) treatment. The primary end point was a 20% response by the American College of Rheumatology (ACR) criteria at 24 weeks. RESULTS: At baseline, the three treatment groups (sulfasalazine, n = 50; etanercept, n = 103; etanercept and sulfasalazine, n = 101) were comparable for demographic variables and disease activity. Lack of efficacy was the primary reason for discontinuation (sulfasalazine, n = 12; etanercept, n = 1; etanercept and sulfasalazine, n = 4; p<0.001). Significantly more patients receiving etanercept, alone or in combination (74% for each), achieved ACR 20 responses at 24 weeks than those receiving sulfasalazine (28%; p<0.01). Similarly, more patients in the etanercept groups achieved ACR 50 and ACR 70 responses than those in the sulfasalazine group (p<0.01). In the groups receiving etanercept, significant differences in the ACR core components were observed by week 2 compared with those receiving sulfasalazine alone (p<0.01). The incidences of several common adverse events (headache, nausea, asthenia) were lower with etanercept alone than with the combination (p<0.05), but infections and injection site reactions were higher with etanercept alone (p<0.05). The safety profiles of both etanercept treatment groups were comparable with previous experience of etanercept. CONCLUSIONS: For all efficacy variables assessed, etanercept alone or in combination with sulfasalazine resulted in substantial and similar improvement in disease activity from baseline to week 24 compared with sulfasalazine alone in patients with active rheumatoid arthritis despite their sulfasalazine treatment. All three treatments were generally well tolerated.

Etanercept 50 mg once weekly is as effective as 25 mg twice weekly in patients with ankylosing spondylitis.

OBJECTIVE: To compare the efficacy, pharmacokinetics and safety of etanercept 50 mg once weekly with 25 mg twice weekly and placebo in patients with ankylosing spondylitis. METHODS: A 12-week, double-blind, placebo-controlled study compared the effects of etanercept 50 mg once weekly, etanercept 25 mg twice weekly and placebo in 356 patients with active ankylosing spondylitis (3:3:1 randomisation, respectively). The primary end point was the proportion of patients achieving a response at week 12 based on the Assessment in Ankylosing Spondylitis Working Group criteria (ASAS 20). The pharmacokinetics of etanercept 50 mg once weekly and 25 mg twice weekly were analysed. RESULTS: Baseline characteristics and disease activity were similar among the three groups: etanercept 50 mg once weekly, etanercept 25 mg twice weekly and placebo. The percentage of patients discontinuing therapy was 9.0%, 9.3% and 13.7% for the three respective groups. ASAS 20 response at 12 weeks was achieved by 74.2% of patients with etanercept 50 mg once weekly and 71.3% of those with etanercept 25 mg twice weekly, both significantly higher than the percentage of patients taking placebo (37.3%, p<0.001). Percentages of patients with ASAS 5/6 response (70.3%, 72.0% and 27.5%, respectively; p<0.001) and those with ASAS 40 response (58.1%, 53.3% and 21.6%, respectively; p<0.001) followed a similar pattern. Significant improvement (p<0.05) was seen in measures of disease activity, back pain, morning stiffness and C reactive protein levels as early as 2 weeks. Serum etanercept exposure was similar between the etanercept groups. Incidence of treatment-emergent adverse events, including infections, was similar among all three groups, and no unexpected safety issues were identified. CONCLUSIONS: Patients with ankylosing spondylitis can expect a comparable significant improvement in clinical outcomes with similar safety when treated with etanercept 50 mg once weekly or with 25 mg twice weekly.

Comparison of different definitions to classify remission and sustained remission: 1 year TEMPO results.

OBJECTIVE: To assess methods to calculate achieving and sustaining remission in a double blind randomised trial in patients with RA who received etanercept, methotrexate, or an etanercept/methotrexate combination. METHODS: Remission was defined as DAS <1.6, DAS28 <2.6, and ACR70 response. Sustaining remission was analysed in three ways: (a) analysis of sustained DAS remission, DAS28 remission, or ACR70 response continuously for 6 months; (b) analysis of sustained remission appraised through a continuity rewarded scoring system, which is the weighted sum of all intervals in the study in which patients are in DAS or DAS28 remission; or (c) longitudinal modelling of remission odds using generalised estimating equations. RESULTS: Significantly more patients treated with the etanercept/methotrexate combination reached DAS remission (37%) than those treated with either methotrexate (14%) or etanercept (18%) alone (p<0.01). Results for DAS28 and for the ACR70 response were similar. Agreement between DAS remission and DAS28 remission was good, but agreement between either of these and the ACR70 response was less. Patients in DAS or DAS28 remission had a lower level of disease activity (fewer active joints, lower ESR) than those achieving ACR70 response; the converse was seen using pain VAS. The three methods were comparable for sustainability of remission and showed significant advantage for combination therapy, which increased the number and durability of remission periods. CONCLUSIONS: DAS and DAS28 remission results were similar for assessing achieving and sustaining remission in RA, frequently differing from patients classified as ACR70 responders. The three methods of examining duration of remission produced comparable results.

Induction of nonpathologic, humoral autoimmunity in lupus-prone mice by a class II-restricted, transgenic alpha beta T cell. Separation of autoantigen-specific and -nonspecific help.

Murine lupus predominantly requires alpha beta T cells, which provide pathogenic help for autoantibody production and immune complex-associated end-organ disease. Autoantigen-specific, pathogenic alpha beta T cells have been isolated from some lupus-prone mice, but a requirement for such T cells in disease has not been clearly demonstrated. To address alpha beta T cell specificity in murine lupus, lupus-prone mice were generated that contained only a single population of alpha beta T cells of foreign specificity by generating anti-pigeon cytochrome c (AND) TCR transgenic TCRalpha -/- TCRbeta -/- MRL/Mp-lpr/lpr (MRL/lpr) mice, which lacked the ability to express endogenous TCRalpha or -beta genes. These AND alpha beta T cells induced hypergammaglobulinemia and autoantibody production, as seen in serum Ig, anti-DNA, anti-small nuclear ribonucleoprotein (snRNP) and rheumatoid factor titers, but failed to promote the development of lymphadenopathy or pathogenic immune-complex disease, as assayed by cutaneous, renal, and salivary gland lesions. Thus, antigen-nonspecific alpha beta T cell help can promote generalized autoimmunity, but autoantigen-specific alpha beta T cells are required to cause overt disease.

B cells process and present lupus autoantigens that initiate autoimmune T cell responses.

Antibodies against U small nuclear ribonucleoprotein (snRNP) particles are a common finding in the sera of humans with SLE and in certain strains of mice with murine lupus. It is likely that Th cells are important in amplifying this autoantibody response. The focus of this work was to investigate events that might initiate autoimmune B and T cell response in non-autoimmune mice to native snRNP particles. Mice that were immunized and boosted with native mouse snRNPs failed to produce any detectable specific anti-snRNP antibody or T cell responses, suggesting that these autoreactive cells were deleted from the repertoire or were anergic to stimulation with this self Ag. In contrast, immunization with native foreign (human) snRNPs elicited both T cells and cross-reactive anti-snRNP antibodies; the latter predominantly were directed toward the A protein of the U1 snRNP. When mice were immunized with human and mouse snRNPs together in adjuvant, T cells specific for mouse snRNPs could be elicited. The results of these experiments suggested that the mechanism of breaking T cell tolerance to self snRNPs was dependent on the ability of cross-reactive B cells to process and present these autoantigens. To address this hypothesis, B cells purified from mice immunized with recombinant human A protein were transferred into naive mice. Upon boosting with native mouse snRNPs, autoreactive CD4+ T cells specific for mouse Ags, and not cross-reactive with human snRNPs, were observed. These studies support a model of molecular mimicry whereby autoantigen-presenting B cells are generated by foreign cross-reactive determinants that can, in turn, elicit an autoimmune T cell response.

Central T cell tolerance in lupus-prone mice: influence of autoimmune background and the lpr mutation.

Lupus-prone mice develop a systemic autoimmune disease that is dependent upon the B cell help provided by autoreactive alphabeta CD4+ T cells. Since autoreactive T cells with high affinity for self peptides are normally deleted in the thymus, their presence in these mice suggests the possibility that intrathymic negative selection may be defective. Here, we directly compared central T cell tolerance in response to a conventional peptide Ag in lupus-prone MRL/MpJ mice with a nonautoimmune strain using an MHC class II-restricted TCR transgene. Our results did not demonstrate any defects after Ag exposure in the induction of intrathymic deletion of immature CD4+ CD8+ thymocytes, in TCR down-regulation, or in the number of apoptotic thymocytes in MRL/MpJ compared with nonautoimmune mice. Furthermore, we found that the lpr mutation had no influence upon the Ag-induced thymic deletion of immature thymocytes. These data support the notion that T cell autoreactivity in MRL/MpJ mice is caused by defects in peripheral control mechanisms.

Pattern of anti-small nuclear ribonucleoprotein antibodies in MRL/Mp-lpr/lpr mice suggests that the intact U1 snRNP particle is their autoimmunogenic target.

MRL/Mp-lpr/lpr (MRL/lpr) mice develop anti-Sm Abs that bind the B and D proteins of the U1 and other U small nuclear ribonucleoproteins (snRNPs). Humans with SLE also develop anti-Sm, but in contrast to MRL/lpr mice, anti-Sm Abs in humans are virtually always accompanied by anti-snRNP Abs that bind the A and 70 kDa proteins of the U1 snRNP. In this study, we identified anti-U1 snRNP Abs in 60% of MRL/lpr mice (40 of 66 animals), with the earliest and most frequent response directed against the A protein. This response was either accompanied or closely followed by Abs to other snRNP proteins, including the 70-kDa protein of the U1 particle and the B and D proteins that represent the anti-Sm response. Other U snRNPs were rarely bound by these sera, analogous to previous observations in human SLE. Using in vitro translated 5' and 3' deletion mutants, we found that these early Abs principally bound an epitope on the COOH-terminal of the murine A protein. As shown previously, human sera with anti-U1 snRNP reactivity bind a similar epitope. In summary, we have shown that anti-snRNP Abs in MRL/lpr mice are composed of a linked group of specificities against proteins of the U1 snRNP particle, similar to human SLE. These observations, in conjunction with our previous findings that intact snRNPs are necessary for diversification of Abs in normal mice immunized with snRNPs, strongly suggests that intact U1 particles may be targets of the immune response in this disease.

Role of intermolecular/intrastructural B- and T-cell determinants in the diversification of autoantibodies to ribonucleoprotein particles.

The U1 small nuclear ribonucleoprotein (sn-RNP) particle, which consists of the U1 small RNA and multiple polypeptides, is a central target of the autoimmune response in systemic lupus erythematosus. Autoantibodies to the individual proteins of the U1 snRNP typically co-occur in patients with systemic lupus erythematosus, an observation reconciled by postulating that the intact RNA-protein complex serves as the autoimmunogen and that snRNP-specific autoreactive T cells are necessary for autoantibody production. In this study, we demonstrated that normal mice did not develop antibody responses following immunization with purified self (murine) snRNPs. However, when such mice were coimmunized with self snRNPs in conjunction with the human (foreign) U1 snRNP A protein, they developed autoantibodies directed against individual proteins of the U1 snRNP, in addition to anti-A antibodies; we have previously shown that such mice develop snRNP-specific, autoreactive T cells. Intact snRNPs as a co-immunogen were a prerequisite for antibody expansion, since this response was abrogated by disruption of snRNP particles with pancreatic RNase prior to immunization. These findings indicate that autoreactive helper T cells can drive autoantibody production to the individual proteins of snRNP particles and that such autoantibody responses may require the presence of intact snRNP particles that possess intrastructural B-cell and helper-T-cell determinants. These results also suggest that induction of an immune response to one component of an autoantigenic snRNP complex, possibly through priming with molecular mimics, can induce the diversification of autoantibodies that is characteristic of that found in patients with systemic lupus erythematosus.

Influence of antigen organization on the development of lupus autoantibodies.

OBJECTIVE: To investigate the reason for grouping of antibodies against small nuclear RNP (snRNP) particles, which are major autoantigens in systemic lupus erythematosus (SLE). METHODS: Mice were immunized with biochemically purified native snRNP particles or recombinant proteins, followed by assessment of antibody and T cell responses. Since mouse (self) snRNPs are not immunogenic in mice, a eukaryotic expression vector was constructed to induce high-level expression of the human U1 snRNP-associated A protein in murine cells. Native chimeric (mouse/human) snRNP particles were used to immunize normal mice of both H-2k and H-2b backgrounds. We also disrupted the native snRNPs by digestion with ribonuclease and used this mixture of proteins to immunize mice. RESULTS: Immunization with native chimeric snRNPs resulted in the development of antibodies against a set of snRNP-associated proteins, a response which was accompanied by breakdown in T cell tolerance to mouse snRNPs in mice immunized with chimeric snRNPs. We also demonstrated that the ordered production of these antibodies was due to the fact that snRNP-associated proteins are grouped together in snRNP particles, since disruption of the particles resulted in development of antibodies in a random order, distinct from antibodies seen with intact particles. CONCLUSION: Our findings directly demonstrate that the pattern of development of antibodies to native snRNPs is similar to that which is commonly observed in SLE, and that disruption of the particles results in disappearance of this ordered pattern. These results suggest that the autoimmune response to snRNPs, and possibly to other autoantigens, in lupus is a specific reaction similar to that seen in a typical immune response to foreign immunogens.

Outcomes of a multicentre randomised clinical trial of etanercept to treat ankylosing spondylitis.

OBJECTIVE: A double blind, randomised, placebo controlled study to evaluate the safety and efficacy of etanercept to treat adult patients with ankylosing spondylitis (AS). METHODS: Adult patients with AS at 14 European sites were randomly assigned to 25 mg injections of etanercept or placebo twice weekly for 12 weeks. The primary efficacy end point was an improvement of at least 20% in patient reported symptoms, based on the multicomponent Assessments in Ankylosing Spondylitis (ASAS) response criteria (ASAS 20). Secondary end points included ASAS 50 and ASAS 70 responses and improved scores on individual components of ASAS, the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), acute phase reactants, and spinal mobility tests. Safety was evaluated during scheduled visits. RESULTS: Of 84 patients enrolled, 45 received etanercept and 39 received placebo. Significantly more etanercept patients than placebo patients responded at the ASAS 20 level as early as week 2, and sustained differences were evident up to week 12. Significantly more etanercept patients reported ASAS 50 responses at all times and ASAS 70 responses at weeks 2, 4, and 8; reported lower composite and fatigue BASDAI scores; had lower acute phase reactant levels; and had improved spinal flexion. Etanercept was well tolerated. Most adverse events were mild to moderate; the only between-group difference was injection site reactions, which occurred significantly more often in etanercept patients. CONCLUSIONS: Etanercept is a well tolerated and effective treatment for reducing clinical symptoms and signs of AS.