Biomarkers For Rheumatoid Arthritis Research Articles

A method to identify trace sulfated IgG N-glycans as biomarkers for rheumatoid arthritis

N-linked glycans on immunoglobulin G (IgG) have been associated with pathogenesis of diseases and the therapeutic functions of antibody-based drugs; however, low-abundance species are difficult to detect. Here we show a glycomic approach to detect these species on human IgGs using a specialized microfluidic chip. We discover 20 sulfated and 4 acetylated N-glycans on IgGs. Using multiple reaction monitoring method, we precisely quantify these previously undetected low-abundance, trace and even ultra-trace N-glycans. From 277 patients with rheumatoid arthritis (RA) and 141 healthy individuals, we also identify N-glycan biomarkers for the classification of both rheumatoid factor (RF)-positive and negative RA patients, as well as anti-citrullinated protein antibodies (ACPA)-positive and negative RA patients. This approach may identify N-glycosylation-associated biomarkers for other autoimmune and infectious diseases and lead to the exploration of promising glycoforms for antibody therapeutics.

Cartilage oligomeric matrix protein (COMP) in rheumatoid arthritis and its correlation with sonographic knee cartilage thickness and disease activity.

The aim of the study is to investigate the correlation of serum cartilage oligomeric matrix protein (COMP) levels with articular cartilage damage based on sonographic knee cartilage thickness (KCT) and disease activity in rheumatoid arthritis (RA). A total of 61 RA patients and 27 healthy controls were recruited in this study. Serum samples were obtained from all subjects to determine the serum COMP levels. All subjects had bilateral ultrasound scan of their knees. The KCT was based on the mean of measurements at three sites: the medial condyle, lateral condyle and intercondylar notch. Besides, the RA patients were assessed for their disease activity based on 28-joint-based Disease Activity Score (DAS 28). Serum COMP concentrations were significantly elevated in the RA patients compared to the controls (p=0.001). The serum COMP levels had an inverse relationship with bilateral KCT in RA subjects and the healthy controls. COMP correlated significantly with disease activity based on DAS 28 (r=0.299, p=0.010), disease duration (r=0.439, p=<0.05) and mean left KCT (r=-0.285, p=0.014) in RA. The correlation between serum COMP and DAS 28 scores was comparable to the traditional markers of inflammation: erythrocyte sedimentation rate (ESR) (r=0.372, p=0.003) and C-reactive protein (CRP) (r=0.305, p=0.017). The serum COMP is a promising biomarker in RA which reflects disease activity and damage to the articular cartilage.

Isotypes of autoantibodies against differentially expressed novel malondialdehyde-modified peptide adducts in serum of Taiwanese women with rheumatoid arthritis

This study identified and validated four differentially expressed novel malondialdehyde (MDA)-modified peptide adducts and evaluated autoantibodies against native and MDA-modified peptides among Taiwanese women patients with rheumatoid arthritis (RA), osteoarthritis (OA) and healthy controls (HCs). Ig kappa chain C region76–99, alpha-1-antitrypsin284–298, alpha-2-macroglobulin824–841, and apolipoprotein B-1004022–4040 exhibiting 2-fold differences in relative modification ratios were identified by concanavalin A (Con A) affinity chromatography, 1D SDS-PAGE, in-gel digestion, nano-LC/MS/MS and nano-LC/MS using pooled serum-derived Con A-captured proteins from 9 RA and 9 age-matched HCs. Furthermore, the levels of proteins, serum MDA, and MDA-modified protein adducts were further validated against individual serum from 20 RA and 20 HCs, and autoantibodies against native and their MDA-modified peptides used 45 RA, 30 OA and 45 HCs. Levels of serum MDA and MDA-modified protein adducts were significantly higher in RA than HCs but protein levels were not significantly different. Serum Igs G and M against MDA-modified peptides showed better diagnostic performance in differentiating among patients with RA, OA and HCs, with an area under the receiver operating characteristic curve of 0.96–0.98, sensitivity of 88.9%–97.8%, and specificity of 88.9%–100%. Autoantibodies against MDA-modified epitopes become useful clinical biomarkers for RA. Biological significanceBy using a label-free relative quantitative proteomic analysis of concanavalin A (Con A)-bound serum samples, the current study discovered and validated malondialdehyde (MDA)-modified peptide adducts as novel biomarkers for differentiating between rheumatoid arthritis (RA) patients and healthy controls (HCs). In addition, the serum levels of MDA, proteins, and MDA-modified protein adducts as well as the MDA modification of proteins were determined. Isotypes of autoantibodies against MDA-modified peptide adducts can be used as serological biomarkers for further discriminating among RA patients, osteoarthritis patients and HCs. This strategy can become the basis for identifying potential diagnostic and pathological biomarkers for RA.

Relationship between serum calprotectin (S100A8/9) and clinical, laboratory and ultrasound parameters of disease activity in rheumatoid arthritis: A large cohort study.

BackgroundCalprotectin may be a sensitive biomarker of rheumatoid arthritis (RA) disease activity.ObjectivesIn the current study, we investigated whether calprotectin is a better biomarker than CRP for predicting clinical activity and ultrasound parameters in patients with RA.MethodsA total of 160 patients with RA underwent clinical (swollen joint count—SJC, tender joint count—TJC, Disease Activity Score—DAS28, Clinical Disease Activity Index—CDAI, and simplified Disease Activity Index—SDAI) and ultrasound (German US7) examination. Clinical and laboratory measures were correlated with ultrasound findings using Spearman´s correlation coefficient. Differences in serum calprotectin levels in patients with variable disease activity according to the DAS28-ESR and CDAI scores were assessed using ANOVA. Multivariate regression analysis was used to determine the predictive values of calprotectin, CRP and SJC for CDAI and PD US synovitis scores.ResultsSerum calprotectin was significantly associated with DAS28-ESR (r = 0.321, p<0.001), DAS28-CRP (r = 0.346, p<0.001), SDAI (r = 0.305, p<0.001), CDAI (r = 0.279, p<0.001) scores and CRP levels (r = 0.556, p<0.001). Moreover, calprotectin was significantly correlated with GS (r = 0.379, p<0.001) and PD synovitis scores (r = 0.419, p<0.001). The multivariate regression analysis showed that calprotectin is a better predictor of the CDAI score and PD US synovitis than CRP.ConclusionsThe results of this study support an additional role of calprotectin in assessing inflammatory activity in patients with RA.

Increased amount of phosphorylated proinflammatory osteopontin in rheumatoid arthritis synovia is associated to decreased tartrate-resistant acid phosphatase 5B/5A ratio.

BackgroundOsteopontin (OPN) is an immunoregulatory protein which production increases in both rheumatoid arthritis (RA) and osteoarthritis (OA). Phosphorylated osteopontin (Phospho-OPN) is known to increase macrophage and osteoclast activation, this process is controlled by extracellular tartrate-resistant acid phosphatase (TRAcP), also a biomarker for RA. Here, we evaluated the phosphorylation status of OPN in RA and OA synovia, as well as its correlation with TRAcP isoforms.MethodsSynovial tissue and fluid were obtained from 24 RA (14 seropositive and 10 seronegative) and 24 OA patients. Western blotting was used to analyze the extent of OPN phosphorylation. TRAcP isoforms were measured in synovial fluid using ELISA; immunohistochemistry assessed the distribution of OPN and TRAcP expressing cells in the synovial tissue, especially distinguishing between the TRAcP isoforms.ResultsFull-length OPN was more phosphorylated in RA than in OA (p<0.05). The thrombin cleaved C-terminal end of OPN was also more phosphorylated in RA (p<0.05). RA patients had a lower concentration of TRAcP 5B and higher concentration of less active 5A in their synovial fluid compared to OA patients. The TRAcP 5B/5A ratio was decreased in RA and correlated negatively with the amount of phospho-OPN (p<0.05). TRAcP positive cells for both isoforms were found all along the synovial lining; OPN antibody staining was localized in the extracellular matrix.ConclusionOur data suggests that in RA the synovial fluid contains insufficient amounts of TRAcP 5B which increase levels of the proinflammatory phospho-OPN. This may lead to increased macrophage and osteoclast activation, resulting in the increased local inflammation and bone resorption present in RA joints.

Adiponectin exerts a potent anti-arthritic effect and insulin resistance in collagen-induced arthritic rats.

Previous research has shown that adiponectin (AD) induces severe insulin resistance (IR) and exhibits pro-inflammatory effect, so it could serve as a useful risk biomarker in rheumatoid arthritis (RA). The present study aims to evaluate the effect of AD on IR and anti-arthritis in collagen-induced arthritic (CIA) rats. After immunization with bovine type II collagen (CII), Wistar rats were administered with AD (60μg/kg/day) or saline into the ankle joint cavity of the left hind leg for 15days. The severity of arthritis was clinically and histologically assessed. Arthritis score was recorded every other day for each paw. Paw volume was measured on alternate days to monitor the progression of the disease in the arthritic control group. Tumor necrosis factor (TNF)-α, interleukin (IL)-1, AD, insulin and fasting glucose were measured in sera. Histopathology of joint synovial tissues was also examined. Treatment with AD resulted in significantly delayed onset of arthritis as well as decreased clinical arthritis and histopathological severity scores. AD reduced both serum fasting glucose, TNF-α, IL-1 and IR. Histological analysis confirmed treatment with AD suppressed joint synovial inflammation and immunohistochemical expression of TNF-α compared to the CIA group. Surprisingly, adiponectin levels measured by enzyme-linked immunosorbent assay in serum were significantly increased in CIA rats compared to the normal group. Adiponectin might display anti-inflammatory effects. These results suggest that AD may be a potential immunosuppressant for the treatment of RA linked to metabolic disease.

Anti-carbamylated protein antibodies in systemic lupus erythematosus patients with articular involvement

Objective Several studies have evaluated the prevalence of rheumatoid factor (RF) and anti-citrullinated proteins antibodies (ACPA) in systemic lupus erythematosus (SLE) patients but no data are available on the anti-carbamylated proteins (anti-CarP), a new biomarker for rheumatoid arthritis (RA). We evaluated the anti-CarP prevalence in SLE patients with joint involvement and the associations with different phenotypes. Methods Seventy-eight SLE patients with joint involvement were enrolled (F/M 73/5; mean ± SD age 47.6 ± 11.2 years; mean ± SD disease duration 214.3 ± 115.6 months). As control groups, we evaluated SLE patients without joint manifestations ( N = 15), RA ( N = 78) and healthy individuals (HS, N = 98). Anti-CarP were assessed by home-made ELISA in all patients and controls, RF and ACPA in SLE patients with joint involvement (commercial ELISA kit). Results The prevalence of anti-CarP in SLE patients with joint involvement was similar to RA ( p = NS) and significantly higher compared with SLE without joint involvement and HS ( p < 0.0001, p < 0.0001, respectively). Four patients were positive for all three antibodies: seventy-five percent of these showed Jaccoud arthropathy. Fourty-five percent of ACPA-ve/RF-ve patients were anti-CarP + ve. Conclusions The evaluation of anti-CarP in SLE joint involvement demonstrated a prevalence of almost 50%, similar to RA and significantly higher than SLE without joint involvement and HS.

Evaluation of Toll-like-receptor gene family variants as prognostic biomarkers in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease whose main feature is persistent joint inflammation. Toll-like receptors (TLRs) play critical roles in the activation of innate and adaptive immune responses, and influence the activity of NFκB, a key player in chronic inflammation. We aimed at investigating the association of TLR allelic variants with susceptibility and severity of RA through a systematic, high-throughput, analysis of TLR genes. All coding exons and flanking regions of nine members of the TLR family (TLR1-9) were analyzed in 66 patients with RA and 30 healthy controls by next generation sequencing. We focussed on three single allelic variants, N248S in TLR1, Q11L in TLR7 and M1V in TLR8 based on the allelic frequencies in both patient and control populations, the predicted impact on protein function and the novelty in RA research. Analysis of these selected variants in a larger cohort of 402 patients with RA and in 208 controls revealed no association with susceptibility. However, the M1V allele was associated with a lower need for disease-modifying antirheumatic drugs (DMARDs) (p=0.008) and biologic treatments (p=0.021). Functional studies showed that the M1V variant leads to a reduced production of inflammatory cytokines, IL-1β, IL-6 and TNFα, in response to TLR8 agonists. Thus, the presence of this variant confers a significant protective effect on disease severity. These results show for the first time the association between the M1V variant of TLR8 and reduced disease severity in RA, which could have prognostic value for these patients.

Antibody to HA4 of gingipain of Porphyromonas gingivalis is a possible biomarker for rheumatoid arthritis

Abstract Porphyromonas gingivalis (Pg) may play a role in the pathogenesis of rheumatoid arthritis (RA). Arg-gingipain A (RgpA), one of the virulence factors of Pg contains catalytic domain, hemagglutinin domain and sub-hemagglutinin domain including HA-1, HA-2 &amp;HA-3, and HA-4. We detected the antibody against hemaglutinin domain (anti-HA), catalytic domain, HA-1, HA-2 &amp;HA-3, and HA-4 in patients with autoimmune diseases and periodontitis by ELISA and Western blot Methods RgpA hemagglutinin domain and its subdomains were cloned respectively. ELISAs and Western blot using these recombinant proteins were developed and antibody reactivities examined in patients with RA, SLE, healthy normal controls, and individuals with PD. Results By ELISA, no serum from patients with RA, PD or normal controls was found to react with RgpA catalytic domain. In analysis of anti-RgpA hemagglutinin domain antibodies, 42 of 155 RA patients (27.1%), 16 of 48 PD patients (33.33%) were found to react with RgpA hemagglutinin domain. Anti-HA1 antibody, 39 of 155 RA patiens (25.16%), 6 of 48 PD patients (12.5%). Anti-HA2&amp;3 antibody, 43 of 155 RA patients (27.74%), 10 of 48 PD patients (20.83%). Anti-HA4 antibody, 51 of 155 RA patients (32.9%), 2 of 36 SLE patients (5.56%), 7 of 48 PD patients (14.58%). By Western Blot, serum from patients with both RA and PD reacted to HA (150kDa), HA1 (72kDa), and HA2/3 (45kDa), respectively. But only serum from patients with RA reacted to HA4(55kDa), not serum from patients with PD, SLE or healthy controls. Conclusion Only Serum from patients with RA recognize HA4. HA4 at the C-terminal domain of RgpA hemagglutinin of Pg is a target of RA. Anti-HA4 antibody is a candidate predictive biomarker for RA.

The feature selection approach for evaluation of potential rheumatoid arthritis markers using MALDI-TOF datasets

BackgroundThe selection of the most representative mass profiles, in rheumatoid arthritis (RA) serum samples was developed. This allows for selection and identification of potential biomarkers in RA serum samples. MethodsThe RA and controls samples were analyzed using MALDI-TOF. Two different protein elution procedures utilizing ZipTips (E1 and E2) were examined. The statistical evaluation of data was performed using different feature selection (FS) methods in combination with different classifiers, while identification of selected masses was performed using MALDI-TOF-TOF. ResultsUtilization of proposed statistical strategy allowed for the selection of different masses according to FS method and elution procedure. Obtained masses were further subjected for targeted identification. The panel of proteins were identified as potential markers. The role of these proteins was discussed in relation to pathomechanism of RA. ConclusionApplication of advanced biostatistical analysis of obtained MALDI-TOF datasets, resulted with targeted selection of potential RA biomarkers. Five proteins were identified due the E1 procedure, and six proteins were identified due the E2 procedure, respectively. The panel of identified proteins suggest that presented statistical methodology and proteomic strategy was correct and gave valid results. Obtained results may contribute to development of clinically useful multicomponent diagnostic tool.

Repeatability and response to therapy of dynamic contrast-enhanced magnetic resonance imaging biomarkers in rheumatoid arthritis in a large multicentre trial setting

ObjectivesTo determine the repeatability and response to therapy of dynamic contrast-enhanced (DCE) MRI biomarkers of synovitis in the hand and wrist of rheumatoid arthritis (RA) patients, and in particular the performance of the transfer constant Ktrans, in a multicentre trial setting.MethodsDCE-MRI and RA MRI scoring (RAMRIS) were performed with meticulous standardisation at baseline and 6 and 24 weeks in a substudy of fostamatinib monotherapy in reducing synovitis compared with placebo or adalimumab. Analysis employed statistical shape modelling to avoid biased regions-of-interest, kinetic modelling and heuristic analyses. Repeatability was also evaluated.ResultsAt early study termination, DCE-MRI data had been acquired from 58 patients in 19 imaging centres. Ktrans intra-subject coefficient of variation (N = 14) was 30%. Ktrans change demonstrated inferiority of fostamatinib (N = 11) relative to adalimumab (N = 10) after 6 weeks (treatment ratio = 1.92, p = 0.003), and failed to distinguish fostamatinib from placebo (N = 10, p = 0.79). RAMRIS showed superiority of fostamatinib relative to placebo at 6 weeks (p = 0.023), and did not distinguish fostamatinib from adalimumab at either 6 (p = 0.175) or 24 (p = 0.230) weeks.ConclusionThis demonstrated repeatability of Ktrans and its ability to distinguish treatment groups show that DCE-MRI biomarkers are suitable for use in multicentre RA trials.Key Points• DCE-MRI biomarkers are feasible in large multicentre studies of joint inflammation.• DCE-MRI Ktransshowed fostamatinib inferior to adalimumab after 6 weeks.• Ktransrepeatability coefficient of variation was 30% multicentre.

The acetyl code in rheumatoid arthritis and other rheumatic diseases.

Growing evidence supports the idea that aberrancies in epigenetic processes contribute to the onset and progression of human immune-mediated inflammatory diseases, such as rheumatoid arthritis (RA). Epigenetic regulators of histone tail modifications play a role in chromatin accessibility and transcriptional responses to inflammatory stimuli. Among these, histone deacetylases (HDACs) regulate the acetylation status of histones and nonhistone proteins, essential for immune responses. Broad-spectrum HDAC inhibitors are well-known anti-inflammatory agents and reduce disease severity in animal models of arthritis; however, selective HDAC inhibitors remain poorly studied. In this review, we describe emerging findings regarding the aberrant acetyl code in RA and other rheumatic disorders which may help identify not only novel diagnostic and prognostic clinical biomarkers for RA, but also new targets for epigenetic pharmacological applications.

Homo-Genius: Homocitrulline Can Be a Better Target than Citrulline as a Biomarker for Rheumatoid Arthritis?

Homo-Genius: Homocitrulline Can Be a Better Target than Citrulline as a Biomarker for Rheumatoid Arthritis?

Studying of B-cell differentiation and macrophage colony-stimulating factors as new players in the diagnosis of rheumatoid arthritis

Background/aim There is an imperative, yet unmet need for the development of a biomarker panel for progression of rheumatoid arthritis (RA). This study aimed to investigate the reliability of B-cell differentiation factor (BCDF) and macrophage colony-stimulating factor (MCSF) as diagnostic and prognostic biomarkers of RA. Patients and methods A total of 25 RA patients were enrolled and divided into three subgroups according to the disease activity score, remission/minimal, moderate, and severe, in addition to 20 healthy controls. Enzyme-linked immunosorbent assay was used to measure serum BCDF, MCSF, and interleukin (IL)-2, and the calorimetric method was used to measure immunoglobulin G (IgG). In addition, the erythrocyte sedimentation rate was measured at 1 h in the RA patients. Results BCDF, MCSF, and IgG were significantly higher in the RA patients compared with the controls. BCDF was significantly higher in the severe disease group compared with the remission/mild and the moderate disease groups, whereas IgG was significantly higher among the moderate disease group compared with the remission/mild disease group, and among the severe disease group compared with the remission/mild disease group, whereas the erythrocyte sedimentation rate did not show any significant difference between the three subgroups of the disease group. BCDF delineates RA from controls at a cut-off value of 102 pg/ml, whereas at a cut-off value of 37.5 ng/l MCSF delineates RA from controls. Conclusion Serum BCDF and MCSF can be used as RA diagnostic biomarkers, whereas BCDF can be used additionally as a prognostic biomarker.

Anticitrullinated protein antibodies: origin and role in the pathogenesis of rheumatoid arthritis.

This article reviews recent literature on the origin and pathogenic role of anticitrullinated protein antibodies (ACPAs) in rheumatoid arthritis (RA). ACPAs and ACPA-immune complexes interact with immune cells to facilitate articular inflammation. Findings from recent in vitro and in vivo studies are congruent with epidemiologic observations in RA supporting a pathogenic role of ACPAs. ACPAs target proteins/peptides with citrullinated epitopes and serve as informative RA biomarkers. ACPAs are generated within synovium and possibly at extra-articular sites prior to disease onset. Proximate to RA onset, critical qualitative and quantitative changes to ACPAs occur that drive proinflammatory responses. Unable to induce arthritis alone, the administration of ACPAs enhances the development and severity of inflammation in mice when a mild synovitis is already present. In vitro studies have elucidated several possible mechanisms linking ACPA to disease progression including: first, activation of inflammatory cells by ACPA-immune complexes; second, ACPA-mediated neutrophil cell death producing neutrophil extracellular traps, which drives inflammation and autoimmunity by releasing citrullinated autoantigen; and finally, direct binding of ACPAs to osteoclasts and resulting osteoclastogenesis. Together, these recent investigations have begun to elucidate the different mechanisms by which ACPAs may be directly pathogenic in RA.

Survivin controls biogenesis of microRNA in smokers: A link to pathogenesis of rheumatoid arthritis

MicroRNAs (miRs) represent a part of epigenetic control of autoimmunity gaining increasing attention in rheumatoid arthritis (RA). Since cigarette smoking plays important role in RA pathogenesis and reprograms transcriptional profile of miRNAs, we ask if the onco-protein survivin, a novel biomarker of RA, may provide a link between smoking and miRNA. Studying survivin expression in leukocytes of 144 female RA patients we observed that smoking patients had higher survivin transcription and a remarkable spreading of survivin isoforms. This was associated with restricted pattern and low production of miRs. Additionally, miRNA processing enzymes Dicer and DGRC8 were decreased in the patients with survivin isoform spreading. The direct contribution of survivin in miRs biogenesis was confirmed by a massive increase of miRs production following inhibition of survivin in leukocyte cultures. Dicer is shown to mediate these effects of survivin. Chromatin immunoprecipitation analysis demonstrated binding of survivin to the Dicer promoter region. Dicer expression increased 5-folds following survivin inhibition. Taken together, this study presents experimental evidence of a novel cellular function of survivin, control of miRs biogenesis. Up-regulation of survivin in smokers suggests its role as effector of the adverse epigenetic control in RA.

Integrative analysis for identification of shared markers from various functional cells/tissues for rheumatoid arthritis.

Rheumatoid arthritis (RA) is a systemic autoimmune disease. So far, it is unclear whether there exist common RA-related genes shared in different tissues/cells. In this study, we conducted an integrative analysis on multiple datasets to identify potential shared genes that are significant in multiple tissues/cells for RA. Seven microarray gene expression datasets representing various RA-related tissues/cells were downloaded from the Gene Expression Omnibus (GEO). Statistical analyses, testing both marginal and joint effects, were conducted to identify significant genes shared in various samples. Followed-up analyses were conducted on functional annotation clustering analysis, protein-protein interaction (PPI) analysis, gene-based association analysis, and ELISA validation analysis in in-house samples. We identified 18 shared significant genes, which were mainly involved in the immune response and chemokine signaling pathway. Among the 18 genes, eight genes (PPBP, PF4, HLA-F, S100A8, RNASEH2A, P2RY6, JAG2, and PCBP1) interact with known RA genes. Two genes (HLA-F and PCBP1) are significant in gene-based association analysis (P=1.03E-31, P=1.30E-2, respectively). Additionally, PCBP1 also showed differential protein expression levels in in-house case-control plasma samples (P=2.60E-2). This study represented the first effort to identify shared RA markers from different functional cells or tissues. The results suggested that one of the shared genes, i.e., PCBP1, is a promising biomarker for RA.

MicroRNAs as potential biomarkers for rheumatoid arthritis

MicroRNAs play crucial roles in the pathogenesis of rheumatoid arthritis as negative regulators of the expression of target genes by repressing translation or through direct cleavage of mRNAs. More evidences suggest microRNAs may be a novel class of biomarkers for the diagnosis and predicting response to treatment of rheumatoid arthritis, rather than potential therapeutic targets. This review aims to summarize the current advances of microRNAs as potential biomarkers for rheumatoid arthritis. Key words: MicroRNAs/ME; Arthritis, rheumatoid/ME; Review

Anti-Drug Antibodies, Drug Levels, Interleukin-6 and Soluble TNF Receptors in Rheumatoid Arthritis Patients during the First 6 Months of Treatment with Adalimumab or Infliximab: A Descriptive Cohort Study.

ObjectivesWith the present study we wanted to explore the impact of treatment with a tumor necrosis factor-α -inhibitor (TNFi) on levels of soluble biomarkers in rheumatoid arthritis (RA) patients and to identify predictors of impaired drug levels and development of anti-TNFi antibodies (anti-TNFi Abs).MethodsBlood samples from 26 patients with established RA were taken at baseline and following 6 months of treatment with adalimumab or infliximab. Samples were analyzed for levels of TNFi, interleukin (IL)-6, and soluble TNF-receptors 1 and -2 (sTNF-R1 and -2) and for presence of anti-TNFi Abs. Clinical and demographic data were recorded as well.ResultsDuring the initial 6 months treatment, DAS28(CRP) (Disease activity score in 28 joints using C-reactive protein) and levels of IL-6 and sTNF-R2 decreased significantly in patients without anti-TNFi Abs and in patients retaining detectable drug levels. The levels of other tested cytokines (TNF-α, TNF-β, IL-1ra, IL-1b, IL-8, IL-10, IL-12(p70), IL-13, IL-17A, IL-17F, and IL-33) were generally below detection limits. Higher baseline levels of IL-6 associated with undetectable levels of TNFi at follow-up. Anti-TNFi Abs were associated with decreased drug levels, but no predictors for anti-TNFi Ab development could be found.ConclusionThe effect of treatment with TNFi on RA disease activity depends on levels of active drug, and by presence of anti-TNFi Abs. In patients who retain detectable drug levels, and in the absence of anti-TNFi Abs, clinical outcome is improved during treatment, and circulating levels of IL-6 and sTNF-R2 decrease. Baseline levels of IL-6 may predict depletion of TNFi and may identify patients at risk of treatment failure.

Leucine-rich Alpha-2 Glycoprotein is a Serum Biomarker of Mucosal Healing in Ulcerative Colitis.

Background and Aims:Although several noninvasive and easily accessible biomarkers for inflammatory bowel disease [IBD] are available, their sensitivity and specificity are not adequate to be used as single markers and do not overrule the need for endoscopic evaluation. We previously reported that serum leucine-rich alpha-2 glycoprotein [LRG] was a novel biomarker for rheumatoid arthritis and IBD. We herein investigated whether LRG could indicate endoscopic activity in patients with ulcerative colitis [UC].Methods:Serum LRG concentrations were determined by enzyme-linked immunosorbent assay [ELISA] in consecutive 129 patients with UC in two tertiary care hospitals, and associations of LRG with clinical and endoscopic activities were evaluated. Clinical activity index [CAI] < 6 was defined as clinical remission, and mucosal healing [MH] and complete mucosal healing were defined as Matts’ endoscopic grades of 1 or 2 and grade of 1, respectively.Results:Serum LRG levels were significantly increased and correlated with clinical and endoscopic activities in patients with UC. LRG levels were associated with both clinical and endoscopic activities even in patients with normal serum C-reactive protein [CRP] levels. Furthermore, LRG levels were significantly lower in patients with complete MH and deep remission. Serial measurements of LRG levels in a subset of patients demonstrated that LRG was significantly elevated during the endoscopically active stage compared with that during the MH stage.Conclusions:Serum LRG is a novel biomarker for detecting MH during disease course in patients with UC and a surrogate marker of endoscopic inflammation in patients with normal CRP levels.