We investigated the influence of antibodies against infliximab and etanercept on the serum trough levels of these agents and the influence of these antibodies on the effectiveness of treatment in patients with rheumatoid arthritis treated with these agents. Forty patients treated with infliximab for 54 weeks and 40 patients treated with etanercept for 32 weeks were enrolled. They were divided into responder and non-responder groups. Serum trough levels of and antibodies against these agents were measured by enzyme-linked immunosorbent assay or radioimmunoassay. Of the 40 patients treated with infliximab, 14 (35%) had anti-infliximab antibodies. Serum trough levels were significantly lower in the non-responder group (14 patients) than in the responder group (26 patients) 6 weeks after initiation of infliximab (p < 0.05). Conversely, titers of anti-infliximab antibody were significantly higher in the non-responder group than in the responder group between 6 and 38 weeks after initiation of infliximab (p < 0.05). Anti-etanercept antibodies were not detected in any patients on etanercept. Serum trough levels of etanercept were not significantly different between the responder (31 patients) and non-responder groups (9 patients). It seems that the appearance of anti-infliximab antibodies might decrease infliximab serum concentrations and, thereby, reduce the agent's effectiveness. The clinical efficacy of etanercept does not appear to be affected by the serum concentrations if it is administered at standard doses.
Objectives Compared to conventional disease-modifying antirheumatic drugs (DMARDs), biological DMARDs demonstrate superior efficacy but come with higher costs and increased infection risks. The ability to stop and resume biological DMARD treatment while maintaining remission would significantly alleviate these barriers and anxieties. The objective of this study was to identify biomarkers that can predict an imminent relapse, hopefully enabling the timely resumption of biological DMARDs before relapse occurs. Methods Forty patients with rheumatoid arthritis who had been in remission for more than 12 months were included in the study. The patients discontinued their biological DMARD treatment and were monitored monthly for the next 24 months. Out of the 40 patients, 14 (35%) remained in remission at the end of the 24-month period, while 26 (65%) experienced relapses at different time points. Among the relapse cases, 13 patients experienced early relapse within 6 months, and another 13 patients had late relapse between 6 months and 24 months. Seventy-three cytokines in the sera collected longitudinally from the 13 patients with late relapse were measured by multiplex immunoassay. Using cytokines at two time points, immediately after withdrawal and just before relapse, volcano plot and area under the receiver operating characteristic curves (AUC) were drawn to select cytokines that distinguished imminent relapse. Univariate and multivariate logistic regression analyses were used for the imminent relapse prediction model. Results IL-6, IL-29, MMP-3, and thymic stromal lymphopoietin (TSLP) were selected as potential biomarkers for imminent relapse prediction. All four cytokines were upregulated at imminent relapse time point. Univariate and multivariate logistic regression showed that a combination model with IL-6, MMP-3, and TSLP yielded an AUC of 0.828 as top predictors of imminent relapse. Conclusions This methodology allows for the prediction of imminent relapse while patients are in remission, potentially enabling the implementation of on- and off-treatments while maintaining remission. It also helps alleviate patient anxiety regarding the high cost and infection risks associated with biological DMARDs, which are the main obstacles to benefiting from their superb efficacy.
Autoantibodies in the sera of patients with systemic lupus erythematosus were examined with respect to their specificity for proteolytic fragments of histone H1 that retain, or do not retain, DNA-binding domains. 16 of 31 sera contained IgG and IgM antibodies to histone H1. IgM antibodies to H1 in 8 sera (50%) were directed at 18 kD and 20 kD alpha-chymotrypic H1 fragments that bore binding sites for DNA, as identified by staining immunoblots containing the fragments with ssDNA plus 6/0, a mouse monoclonal antibody against ssDNA, IgM with this type of histone H1 specificity did not react with comparably-sized V8 protease fragments of H1. IgM antibodies to H1 in the other patients were directed against entirely different epitopes which were preserved in V8 protease digests of H1. In serial studies of three patients during different phase of their SLE, the level of antibodies against the 18 kD and 20 kD histone H1 fragments varied in parallel with the level of anti-ssDNA antibodies in one and varied inversely in the other two. The data suggest that a significant proportion of autoantibodies to histone H1 are directed at a limited number of epitopes localized to H1 fragments containing DNA-binding sites.
Background: Studies of Caucasian patients with rheumatoid arthritis (RA) to identify genetic biomarkers of anti-tumor necrosis factor (TNF) response have used response at a single time point as the phenotype with which single nucleotide polymorphism (SNP) associations have been tested.The findings have been inconsistent across studies.Among Japanese patients, only a few SNPs have been investigated.We report here the first genome-wide association study (GWAS) to identify genetic biomarkers of anti-TNF response among Japanese RA patients, using response at 2 time-points for a more reliable clinical phenotype over time.Methods: Disease Activity Scores based on 28 joint counts (DAS28) were assessed at baseline (before initial therapy), and after 3 and 6 months in 487 Japanese RA patients starting anti-TNF therapy for the first time or switching to a new anti-TNF agent.A genome-wide panel of SNPs was genotyped and additional SNPs were imputed.Using change in DAS28 scores from baseline at both 3 (ΔDAS-3) and 6 months (ΔDAS-6) as the response phenotype, a longitudinal genome-wide association analysis was conducted using generalized estimating equations (GEE) models, adjusting for baseline DAS28, treatment duration, type of anti-TNF agent and concomitant methotrexate.Cross-sectional analyses were performed using multivariate linear regression models, with response from a single time point (ΔDAS-3 or ΔDAS-6) as phenotype; all other variables were the same as in the GEE models.Results: In the GEE models, borderline significant association was observed at 3 chromosomal regions (6q15: rs284515, p = 6.6x10 -7 ; 6q27: rs75908454, p = 6.3x10 -7 and 10q25.3:rs1679568, p = 8.1x10 -7 ), extending to numerous SNPs in linkage disequilibrium (LD) across each region.Potential candidate genes in these regions include MAP3K7, BACH2 (6q15), GFRA1 (10q25.3),and WDR27 (6q27).The association at GFRA1 replicates a previous finding from a Caucasian dataset.In the cross-sectional analyses, ΔDAS-6 was significantly associated with the 6q15 locus (rs284511, p = 2.5x10 -8 ).No other significant or borderline significant associations were identified. Conclusion:Three genomic regions demonstrated significant or borderline significant associations with anti-TNF response in our dataset of Japanese RA patients, including a locus previously associated among Caucasians.Using repeated measures of response as phenotype enhanced the power to detect these associations.
A 28-year-old Japanese woman with ulcerative colitis presented to our department with multiple sites of peripheral arthritis and back pain.Magnetic resonance imaging (MRI) of contrast-enhanced T1-weighted fat saturated images showed enthesitis of the spinal ligaments (interspinal ligament and supraspinal ligament) and left Achilles tendon (Picture 1-3).There were no signs of spondylitis or sacroiliitis.We diagnosed the patient to have peripheral spondyloarthritis (SpA) associated with ulcerative colitis.Enthesitis refers to inflammation at the sites of attachment of ligaments and tendons and is included in the clinical criteria for SpA.Although enthesitis of the appendicular skeleton is a wellknown complication of SpA (1), only a few previous studies have reported enthesitis of the spinal ligaments (2).Therefore, clinicians should keep in mind the potential for enthesitis of the spinal ligaments in addition to spondylitis and sacroiliitis in SpA patients who present with the chief complaint of back pain.
To examine the presence of high proliferative potential colony-forming cells (HPP-CFCs) in the peripheral blood of rheumatoid arthritis (RA) patients with and without interstitial lung disease (ILD).Peripheral blood mononuclear cells from 35 RA patients with and without ILD, 12 patients with infectious pulmonary diseases, 10 patients with idiopathic pulmonary fibrosis (IPF), and 20 healthy volunteers, were assayed for in vitro colony formation.HPP-CFCs were detected significantly more frequently in the peripheral blood of patients with ILD (11/14: 78%, p<0.05) than in that of patients without ILD (4/21: 19%). HPP-CFCs were not detected in the peripheral blood of patients with infectious pulmonary diseases, those with IPF or healthy volunteers.HPP-CFCs were frequently found in the peripheral blood of RA patients with ILD compared with those without ILD, suggesting the mobilization of HPP-CFCs from the bone marrow into the peripheral blood in association with ILD in RA.
Abstract Neuropsychiatric disease in systemic lupus erythematosus (NPSLE) is a poorly understood, but potentially fatal, disease manifestation. A pathogenetic role for autoantibodies is suspected, but the mechanism is unclear. Since immune complexes in SLE can stimulate IFN-α and there is strong evidence in humans and in mice that IFN-α can cause neuropsychiatric manifestations, we asked whether NPSLE patient serum and/or cerebrospinal fluid (CSF) contain abnormally high IFN-α-inducing activity. In a bioassay containing plasmacytoid dendritic cells and a source of Ag, NPSLE CSF induced significantly higher IFN-α compared with CSF from patients with multiple sclerosis or other autoimmune disease controls. When normalized for IgG concentration, NPSLE CSF was 800-fold more potent at inducing IFN-α compared with paired serum due to inhibitors present in serum. Analysis of Ig-deficient patient serum, depletion of IgG from normal serum, as well as addition of purified IgG to NPSLE CSF and serum in the bioassays revealed that one inhibitor was contained within the IgG fraction itself. In addition to IFN-α, immune complexes formed by CSF autoantibodies produced significantly increased levels of IFN-γ-inducible protein 10 (IP-10/CXCL), IL-8, and MCP-1, all of which have been reported to be elevated in CSF from NPSLE patients. Taken together, these findings are consistent with a two-step model of NPSLE whereby CSF autoantibodies bind to Ags released by neurocytotoxic Abs or other brain cell injury, and the resulting immune complexes stimulate IFN-α and proinflammatory cytokines and chemokines.
