Biomarker Commons

[Role of microRNA in rheumatoid arthritis].

Nihon Rinsho Meneki Gakkai Kaishi. 2012;35(1):69-74

Authors: Mizoguchi F, Kohsaka H

Abstract
MicroRNAs (miRNAs) are endogenous non-coding small RNAs of approximately 22 nucleotides in length. miRNAs repress expression of target genes at the posttranscription level. Biological relevance of miRNAs have been investigated in physiological and pathological conditions, revealing their involvement in fine tuning of the biological events, such as cell proliferation, differentiation and cell death. In 2008, miR-146a and miR-155 were reported to be involved in the pathology of rheumatoid arthritis. Subsequently, expression and function of other miRNAs in rheumatoid arthritis have been reported. These reports suggest that miRNAs could be novel candidates for the therapeutic target or biomarker of rheumatoid arthritis. Further investigations are required to identify, characterize and modulate the key miRNA in the pathology of rheumatoid arthritis.

PMID: 22374446 [PubMed - indexed for MEDLINE]

Increased microRNA-146a/b, TRAF6 gene and decreased IRAK1 gene expressions in the peripheral mononuclear cells of patients with Sjögren's syndrome.

Immunol Lett. 2012 Jan 30;141(2):165-8

Authors: Zilahi E, Tarr T, Papp G, Griger Z, Sipka S, Zeher M

Abstract
MicroRNA-146a (miR-146a) is a microRNA supposed to regulate innate immune, inflammatory response and antiviral pathway negatively. Recently, its potential use as a biomarker for disease diagnosis, prevention and treatment has become widely investigated. In the current study, we measured the expression of miR-146a/b, and their target genes, IRAK1, IRAK4, TRAF6 in the peripheral mononuclear cells of patients with Sjögren's syndrome (n=21) and healthy controls (n=10) by quantitative reverse transcription polymerase chain reaction. We found that both miR-146a and miR-146b, furthermore, the gene of TRAF6 were significantly overexpressed in the Sjögren's patients, whereas the expression of IRAK1 gene was significantly decreased. The expression of IRAK4 did not differ significantly. These results suggest that in the peripheral mononuclear cells of Sjögren's patients, the transcriptional repression of IRAK1 is taking place, whereas the other NF-κB pathway regulating gene, TRAF6 is overexpressed. As IRAK1 has been regarded a crucial gene in the pathogenesis of systemic lupus erythematosus, TRAF6 can be a Sjögren's syndrome specific biomarker, confirming and partly explaining the existance of different pathogenic pathways in the two diseases. These observations, however, need still wider confirmations.

PMID: 22033216 [PubMed - indexed for MEDLINE]

Synovial infiltration with CD79a-positive B cells, but not other B cell lineage markers, correlates with joint destruction in rheumatoid arthritis.

J Rheumatol. 2011 Nov;38(11):2301-8

Authors: Mo YQ, Dai L, Zheng DH, Zhu LJ, Wei XN, Pessler F, Shen J, Zhang BY

Abstract
OBJECTIVE: The efficacy of B cell depletion in the treatment of patients with rheumatoid arthritis (RA) has revitalized interest in the pathogenic role(s) of B cells in RA. We evaluated the distribution of synovial B lineage cells and their correlation with histologic disease activity and joint destruction in RA.
METHODS: Synovial tissue samples were obtained by closed-needle biopsy from 69 Chinese patients with active RA, from 14 patients with osteoarthritis (OA), and from 15 with orthopedic arthropathies (OrthA) as disease controls. Serial tissue sections were stained immunohistochemically for CD79a (pro-B cell to plasma cell), CD20 (B cells), CD38 (plasma cells), CD21 (follicular dendritic cells), CD68 (macrophages), CD3 (T cells), and CD34 (endothelial cells). Densities of positive-staining cells were determined and correlated with histologic disease activity (Krenn 3-component synovitis score) and radiographic joint destruction (Sharp score).
RESULTS: Mean sublining CD79a-positive cell density was significantly higher in RA than in OA (p <0.001) or OrthA (p = 0.003). Receiver operating characteristic curve analysis showed that CD79a-positive cell density differentiated RA well from OA [area under the curve (AUC) = 0.79] or OrthA (AUC = 0.75). Spearman's rank order correlation showed significant correlations between sublining CD79a-positive cell density and the synovitis score (r = 0.714, p < 0.001), total Sharp score (r = 0.490, p < 0.001), and the erosion subscore (r = 0.545, p < 0.001), as well as the joint space narrowing subscore (r = 0.468, p = 0.001) in RA.
CONCLUSION: Synovial CD79a-positive B cells may be a helpful biomarker for histologic disease activity in RA and may be involved in the pathogenesis of joint destruction in RA.

PMID: 22002013 [PubMed - indexed for MEDLINE]

Rheumatoid arthritis synovial fibroblasts produce a soluble form of the interleukin-7 receptor in response to pro-inflammatory cytokines.

J Cell Mol Med. 2011 Nov;15(11):2335-42

Authors: Badot V, Durez P, Van den Eynde BJ, Nzeusseu-Toukap A, Houssiau FA, Lauwerys BR

Abstract
We previously demonstrated that baseline synovial overexpression of the interleukin-7 receptor α-chain (IL-7R) is associated with poor response to tumour necrosis factor (TNF) blockade in rheumatoid arthritis (RA). We found that IL-7R gene expression is induced in fibroblast-like synovial cells (FLS) by the addition of TNF-α, IL-1β and combinations of TNF-α+ IL-1β or TNF-α+ IL-17, thereby suggesting that these cytokines play a role in the resistance to TNF blockade in RA. Because FLS and CD4 T cells also produce a soluble form of IL-7R (sIL-7R), resulting from an alternative splicing of the full-length transcript, we wondered whether expression of sIL-7R is similarly regulated by pro-inflammatory cytokines. We also investigated whether sIL-7R is detectable in the serum of RA patients and associated with response to TNF blockade. RA FLS were cultured in the presence of pro-inflammatory cytokines and sIL-7R concentrations were measured in culture supernatants. Similarly, sIL-7R titres were measured in sera obtained from healthy individuals, early untreated RA patients with active disease and disease-modifying anti-rheumatic drug (DMARD)-resistant RA patients prior to initiation of TNF-blockade. Baseline serum sIL-7R titres were correlated with validated clinical measurements of disease activity. We found that exposure of RA FLS to pro-inflammatory cytokines (TNF-α, IL-1β and combinations of TNF-α and IL-1β or TNF-α and IL-17) induces sIL-7R secretion. Activated CD4 T cells also produce sIL-7R. sIL-7R serum levels are higher in RA patients as compared to controls. In DMARD-resistant patients, high sIL-7R serum concentrations are strongly associated with poor response to TNF-blockade. In conclusion, sIL-7R is induced by pro-inflammatory cytokines in RA FLS. sIL-7R could qualify as a new biomarker of response to therapy in RA.

PMID: 21129157 [PubMed - indexed for MEDLINE]

CD23(+)/CD21(hi) B-cell translocation and ipsilateral lymph node collapse is associated with asymmetric arthritic flare in TNF-Tg mice.

Arthritis Res Ther. 2011;13(4):R138

Authors: Li J, Zhou Q, Wood RW, Kuzin I, Bottaro A, Ritchlin CT, Xing L, Schwarz EM

Abstract
INTRODUCTION: Rheumatoid arthritis (RA) is a chronic autoimmune disease with episodic flares in affected joints. However, how arthritic flare occurs only in select joints during a systemic autoimmune disease remains an enigma. To better understand these observations, we developed longitudinal imaging outcomes of synovitis and lymphatic flow in mouse models of RA, and identified that asymmetric knee flare is associated with ipsilateral popliteal lymph node (PLN) collapse and the translocation of CD23(+)/CD21(hi) B-cells (B-in) into the paracortical sinus space of the node. In order to understand the relationship between this B-in translocation and lymph drainage from flaring joints, we tested the hypothesis that asymmetric tumor necrosis factor (TNF)-induced knee arthritis is associated with ipsilateral PLN and iliac lymph node (ILN) collapse, B-in translocation, and decreased afferent lymphatic flow.
METHODS: TNF transgenic (Tg) mice with asymmetric knee arthritis were identified by contrast-enhanced (CE) magnetic resonance imaging (MRI), and PLN were phenotyped as "expanding" or "collapsed" using LNcap threshold = 30 (Arbitrary Unit (AU)). Inflammatory-erosive arthritis was confirmed by histology. Afferent lymphatic flow to PLN and ILN was quantified by near infrared imaging of injected indocyanine green (NIR-ICG). The B-in population in PLN and ILN was assessed by immunohistochemistry (IHC) and flow cytometry. Linear regression analyses of ipsilateral knee synovial volume and afferent lymphatic flow to PLN and ILN were performed.
RESULTS: Afferent lymph flow to collapsed nodes was significantly lower (P < 0.05) than flow to expanding nodes by NIR-ICG imaging, and this occurred ipsilaterally. While both collapsed and expanding PLN and ILN had a significant increase (P < 0.05) of B-in compared to wild type (WT) and pre-arthritic TNF-Tg nodes, B-in of expanding lymph nodes (LN) resided in follicular areas while B-in of collapsed LN were present within LYVE-1+ lymphatic vessels. A significant correlation (P < 0.002) was noted in afferent lymphatic flow between ipsilateral PLN and ILN during knee synovitis.
CONCLUSIONS: Asymmetric knee arthritis in TNF-Tg mice occurs simultaneously with ipsilateral PLN and ILN collapse. This is likely due to translocation of the expanded B-in population to the lumen of the lymphatic vessels, resulting in a dramatic decrease in afferent lymphatic flow. PLN collapse phenotype can serve as a new biomarker of knee flare.

PMID: 21884592 [PubMed - indexed for MEDLINE]

Correspondence between salivary proteomic pattern and clinical course in primary Sjögren syndrome and non-Hodgkin's lymphoma: a case report.

J Transl Med. 2011;9:188

Authors: Baldini C, Giusti L, Ciregia F, Da Valle Y, Giacomelli C, Donadio E, Ferro F, Galimberti S, Donati V, Bazzichi L, Bombardieri S, Lucacchini A

Abstract
BACKGROUND: In the last years human proteomic has represented a promising tool to promote the communication between basic and clinical science.
METHODS: To explore the correspondence between salivary proteomic profile and clinical response, herein, we used a proteomic approach to analyse the whole saliva of a patient with primary Sjögren's Syndrome (pSS) and non-Hodgkin's-MALT type parotid lymphoma before, during and after a standard treatment with cyclophosphamide (CTX) and rituximab (RTX). To identify any discriminatory therapeutic salivary biomarker patient's whole saliva was collected at the baseline, after the fourth infusion of rituximab, and on remission and analysed combining two-dimensional electrophoresis (2DE) and MALDI-TOF/TOF mass spectrometry.
RESULTS: Proteomic results obtained from the comparison of salivary samples indicated several qualitative and quantitative modifications in the salivary expression of putative albumin, immunoglobulin J chain, Ig kappa chain C region, alpha-1-antitrypsin, haptoglobin and Ig alpha-1 chain C region.
CONCLUSION: This study suggests that clinical and functional changes of the salivary glands driven by autoimmune and lymphoproliferative processes might be reflected in patients' whole saliva proteins, shedding new light on the potential usefulness of salivary proteomic analysis in the identification of prognostic and therapeutic biomarkers for patients with pSS and non Hodgkin's lymphomas.

PMID: 22047044 [PubMed - indexed for MEDLINE]

Novel multiplex technology for diagnostic characterization of rheumatoid arthritis.

Arthritis Res Ther. 2011;13(3):R102

Authors: Chandra PE, Sokolove J, Hipp BG, Lindstrom TM, Elder JT, Reveille JD, Eberl H, Klause U, Robinson WH

Abstract
INTRODUCTION: The aim of this study was to develop a clinical-grade, automated, multiplex system for the differential diagnosis and molecular stratification of rheumatoid arthritis (RA).
METHODS: We profiled autoantibodies, cytokines, and bone-turnover products in sera from 120 patients with a diagnosis of RA of < 6 months' duration, as well as in sera from 27 patients with ankylosing spondylitis, 28 patients with psoriatic arthritis, and 25 healthy individuals. We used a commercial bead assay to measure cytokine levels and developed an array assay based on novel multiplex technology (Immunological Multi-Parameter Chip Technology) to evaluate autoantibody reactivities and bone-turnover markers. Data were analyzed by Significance Analysis of Microarrays and hierarchical clustering software.
RESULTS: We developed a highly reproducible, automated, multiplex biomarker assay that can reliably distinguish between RA patients and healthy individuals or patients with other inflammatory arthritides. Identification of distinct biomarker signatures enabled molecular stratification of early-stage RA into clinically relevant subtypes. In this initial study, multiplex measurement of a subset of the differentiating biomarkers provided high sensitivity and specificity in the diagnostic discrimination of RA: Use of 3 biomarkers yielded a sensitivity of 84.2% and a specificity of 93.8%, and use of 4 biomarkers a sensitivity of 59.2% and a specificity of 96.3%.
CONCLUSIONS: The multiplex biomarker assay described herein has the potential to diagnose RA with greater sensitivity and specificity than do current clinical tests. Its ability to stratify RA patients in an automated and reproducible manner paves the way for the development of assays that can guide RA therapy.

PMID: 21702928 [PubMed - indexed for MEDLINE]

The relation between cartilage biomarkers (C2C, C1,2C, CS846, and CPII) and the long-term outcome of rheumatoid arthritis patients within the CAMERA trial.

Arthritis Res Ther. 2011;13(3):R70

Authors: Bakker MF, Verstappen SM, Welsing PM, Jacobs JW, Jahangier ZN, van der Veen MJ, Bijlsma JW, Lafeber FP,

Abstract
INTRODUCTION: The aim of this study was to investigate whether serum biomarker levels of C2C, C1,2C, CS846, and CPII can predict the long-term course of disease activity and radiographic progression early in the disease course of rheumatoid arthritis (RA).
METHODS: In patients in the CAMERA trial, levels of biomarkers were evaluated at baseline and after 1 year of treatment. Relations of (changes in) biomarker values with the mean yearly radiographic progression rate and mean disease activity over a 5-year period were evaluated by using regression analysis. The added predictive value of biomarkers over established predictors for long-term outcome was analyzed by multiple linear regression analysis.
RESULTS: Of 133 patients, serum samples were available at baseline and after 1 year of treatment. In the regression analysis C1,2C at baseline, the change in C2C, C1,2C, and the sum of the standardized changes in C2C + C1,2C scores were statistically significantly associated with the mean yearly radiographic progression rate; the change in CPII was associated with the mean disease activity over 5 years of treatment. In the multiple linear regression analysis, only the change in C1,2C was of added predictive value (P = 0.004) for radiographic progression. Explained variances of models for radiographic progression and disease activity were low (0.28 and 0.34, respectively), and the biomarkers only marginally improved the explained variance.
CONCLUSIONS: The change in C1,2C in the first year after onset of RA has a small added predictive value for disease severity over a 5-year period, but the predictive value of this biomarker combined with current predictive factors is too small to be of use for individual patients.

PMID: 21539729 [PubMed - indexed for MEDLINE]

Human tear protein analysis enabled by an alkaline microfluidic homogeneous immunoassay.

Anal Chem. 2011 Nov 1;83(21):8115-22

Authors: Karns K, Herr AE

Abstract
The ability to probe the protein content of human tear fluid has enormous potential for deepening our understanding of ocular and systemic disease pathology and enabling novel noninvasive tear-based diagnostic technologies. To overcome current challenges in tear proteomic measurements, we report on the first microfluidic homogeneous immunoassay capable of making rapid, quantitative, and specific measurements of endogenous tear protein biomarkers in human tear fluid. Lactoferrin (Lf) is a tear-specific biomarker for Sjögren's syndrome (SS), a serious systemic autoimmune disease currently diagnosed through rudimentary volumetric and surface chemistry measurements and an invasive lip biopsy. We detail optimization of a homogeneous electrophoretic immunoassay for Lf in <1 μL of tear fluid at clinically relevant concentrations. In particular, we present assay development details and a final assay that enables quantification of Lf in <5 s in a clinically relevant range for SS diagnostics. Characterization suggests the on-chip assay is accurate to within 15% of ELISA, specific (<15% nonspecific signal), and with a lower limit of detection of 3 ± 2 nM Lf in human tear matrix. Additionally, we develop and characterize a protocol for eluting proteins from nitrocellulose Schirmer strips, the clinical de facto standard for tear collection and storage. We relate on-chip measured Lf concentrations back to ocular surface concentrations for the first time to our knowledge. Taken in sum, this work details important steps toward (1) expanding the set of proteins quantified by electrophoretic immunoassays to encompass a wider range of isoelectric points than has been reported, (2) creating a first-in-kind translatable assay with clinical relevance to SS diagnostics, and (3) expanding the analytical toolkit available for rapid tear protein measurements, as is relevant to the advancement of basic research and clinical medicine.

PMID: 21910436 [PubMed - indexed for MEDLINE]

Soluble interleukin-18 receptor complex is a novel biomarker in rheumatoid arthritis.

Arthritis Res Ther. 2011;13(2):R52

Authors: Takei S, Hoshino T, Matsunaga K, Sakazaki Y, Sawada M, Oda H, Takenaka S, Imaoka H, Kinoshita T, Honda S, Ida H, Fukuda TA, Aizawa H

Abstract
INTRODUCTION: There has been no report in the literature of a soluble form of interleukin (IL)-18 receptor α (IL-18Rα). In this study, we evaluated the levels and characteristics of soluble IL-18Rα (sIL-18Rα) in the sera of patients with rheumatoid arthritis (RA) and compared these results to control populations.
METHODS: The sIL-18Rα complex was isolated from pooled human blood serum using an anti-IL-18Rα monoclonal antibody affinity column. The purified sIL-18Rα was then examined using Western blot analysis and used in experiments to evaluate the effects on an IL-18-responsive natural killer (NK) human cell line, NK0. An enzyme-linked immunosorbent assay was developed, and sera from 145 patients with RA, 6 patients with adult-onset Still's disease, 31 patients with osteoarthritis (OA), 39 patients with systemic lupus erythematosus (SLE) and 67 controls were tested, along with levels of immunoglobulin M, rheumatoid factor, anticyclic citrullinated peptide antibody, IL-18, IL-13 and interferon (IFN)-γ. Area under the receiver operating characteristic curve (ROC-AUC) analysis was used to evaluate the diagnostic utility of the sIL-18Rα complex.
RESULTS: The isolated sIL-18Rα complex can be associated with IL-18 and the soluble form of the IL-18Rβ chain. The sIL-18Rα complex bound to the surface to the NK0 cell line, antagonized the stimulatory effects of IL-18 and IL-2 on the NK0 cell line and inhibited IFN-γ production by the cells. The serum levels of sIL-18Rα complex in RA (186.0 ± 33.5 ng/mL, n = 145) and adult-onset Still's disease (98.2 ± 8.9 ng/mL, n = 6) were significantly (P < 0.001) higher than those in the healthy controls (52.3 ± 8.5 ng/mL, n = 67), OA (38.6 ± 5.4 ng/mL, n = 31), SLE (44.6 ± 3.2 ng/mL, n = 39). The serum level of sIL-18Rα complex was not significantly different between RA and adult-onset Still's disease patients. The serum levels of IL-18, IL-13 and IFN-γ in the RA patients were significantly (P < 0.01) higher than in OA and SLE patients as well as healthy controls. ROC-AUC analysis of the serum concentration of sIL-18Rα indicated that it was significantly diagnostic of RA. Moreover, a tumor necrosis factor inhibitor, etanercept, significantly (P < 0.0001) decreased levels of sIL-18Rα in the sera of 29 RA patients 6 months after treatment.
CONCLUSIONS: The sIL-18Rα complex could be a potentially useful biomarker for the diagnosis of RA.

PMID: 21435242 [PubMed - indexed for MEDLINE]

The role of synovial fluid markers of catabolism and anabolism in osteoarthritis, rheumatoid arthritis and asymptomatic organ donors.

Arthritis Res Ther. 2011;13(2):R50

Authors: Kokebie R, Aggarwal R, Lidder S, Hakimiyan AA, Rueger DC, Block JA, Chubinskaya S

Abstract
INTRODUCTION: The purpose of this study was to correlate the level of anabolic and catabolic biomarkers in synovial fluid (SF) from patients with rheumatoid arthritis (RA), patients with osteoarthritis (OA) and asymptomatic organ donors.
METHODS: SF was collected from the knees of 45 OA, 22 RA patients and 20 asymptomatic organ donors. Eight biomarkers were selected and analyzed by using an enzyme-linked immunosorbent assay: interleukin (IL)-1, IL-6, IL-8 and IL-11; leukemia-inhibitory factor (LIF); cartilage oligomeric protein (COMP); osteocalcin; and osteogenic protein 1 (OP-1). Data are expressed as medians (interquartile ranges). The effects of sex and disease activity were assessed on the basis of the Western Ontario and McMaster Universities index score for patients with OA and on the basis of white blood cell count, erythrocyte sedimentation rate and C-reactive protein level for patients with RA.
RESULTS: The mean ages (± SD) of the patients were as follows: 53 ± 9 years for patients with OA, 54 ± 11 years for patients with RA and 52 ± 7 years for asymptomatic organ donors. No effect of participants' sex was identified. In the SF of patients with RA, four of five cytokines were higher than those in the SF of patients with OA and those of asymptomatic organ donors. The most significant differences were found for IL-6 and IL-8, where IL-6 concentration in SF of patients with RA was almost threefold higher than that in patients with OA and fourfold higher than that in asymptomatic donor controls: 354.7 pg/ml (1,851.6) vs. 119.4 pg/ml (193.2) vs. 86.97 pg/ml (82.0) (P < 0.05 and P < 0.05, respectively). IL-8 concentrations were higher in SF of patients with RA than that in patients with OA as well as that in asymptomatic donor controls: 583.6 pg/ml (1,086.4) vs. 429 pg/ml (87.3) vs. 451 pg/ml (170.1) (P < 0.05 and P < 0.05, respectively). No differences were found for IL-11 in the SF of patients with RA and that of patients with OA, while a 1.4-fold difference was detected in the SF of patients with OA and that of asymptomatic donor controls: 296.2 pg/ml (257.2) vs. 211.6 pg/ml (40.8) (P < 0.05). IL-1 concentrations were the highest in the SF of RA patients (9.26 pg/ml (11.1)); in the SF of asymptomatic donors, it was significantly higher than that in patients with OA (9.083 pg/ml (1.6) vs. 7.76 pg/ml (2.6); P < 0.05). Conversely, asymptomatic donor control samples had the highest LIF concentrations: 228.5 pg/ml (131.6) vs. 128.4 pg/ml (222.7) in the SF of patients with RA vs. 107.5 pg/ml (136.9) in the SF of patients with OA (P < 0.05). OP-1 concentrations were twofold higher in the SF of patients with RA than those in patients with OA and threefold higher than those in asymptomatic donor control samples (167.1 ng/ml (194.8) vs. 81.79 ng/ml (116.0) vs. 54.49 ng/ml (29.3), respectively; P < 0.05). The differences in COMP and osteocalcin were indistinguishable between the groups, as were the differences between active and inactive OA and RA.
CONCLUSIONS: Activation of selected biomarkers corresponds to the mechanisms that drive each disease. IL-11, LIF and OP-1 may be viewed as a cluster of biomarkers significant for OA; while profiling of IL-1, IL-6, IL-8, LIF and OP-1 may be more significant in RA. Larger, better-defined patient cohorts are necessary to develop a biomarker algorithm for prognostic use.

PMID: 21435227 [PubMed - indexed for MEDLINE]

Chemokine saliva levels in patients with primary Sjögren's syndrome, associated Sjögren's syndrome, pre-clinical Sjögren's syndrome and systemic autoimmune diseases.

Rheumatology (Oxford). 2011 Jul;50(7):1288-92

Authors: Hernández-Molina G, Michel-Peregrina M, Hernández-Ramírez DF, Sánchez-Guerrero J, Llorente L

Abstract
OBJECTIVE: To assess the saliva levels of CXCL13, CXCL10, CCL2, CCL3, CXCL12 and CCL5 in patients with primary SS (pSS), patients with associated SS (aSS), patients with systemic autoimmune disease (SAD) without SS, pre-clinical SS and healthy controls.
METHODS: We included 44 patients with pSS (Group A), 30 with aSS (Group B), 49 with SAD without SS (Group C), 14 patients with SAD and focal lip infiltrates, but who do not fulfil SS criteria (Group D, pre-clinical SS) and 32 healthy controls (Group E). Saliva samples were collected and analysed for chemokine levels by luminometry. We used descriptive statistics and the Mann-Whitney U-test and Kruskall-Wallis test.
RESULTS: All the studied chemokines were found at low concentration in controls with the exception of CCL2. Patients with pSS had higher levels CXCL10 and CCL2 than controls (P = 0.05). However, they had similar levels of CXCL13, CCL5, CXCL12, CCL2 and CXCL10 than patients with aSS and SAD without SS. Patients with pre-clinical SS had higher levels of CXCL10 than patients with pSS (P = 0.03), aSS (P = 0.04) and controls (P = 0.001). CCL2 levels were higher in all patients with an autoimmune background when compared with controls (P < 0.05 for each comparison).
CONCLUSION: We found no difference in salivary chemokines between patients neither with pSS or aSS nor in patients with SAD. CCL2 and CXCL10 were increased in all patients with an autoimmune background. CXCL10 was notably increased in pre-clinical SS, suggesting it could be an early inflammatory salivary biomarker.

PMID: 21330342 [PubMed - indexed for MEDLINE]

Macrophage positron emission tomography imaging as a biomarker for preclinical rheumatoid arthritis: findings of a prospective pilot study.

Arthritis Rheum. 2012 Jan;64(1):62-6

Authors: Gent YY, Voskuyl AE, Kloet RW, van Schaardenburg D, Hoekstra OS, Dijkmans BA, Lammertsma AA, van der Laken CJ

Abstract
OBJECTIVE: To conduct a prospective pilot study to determine whether macrophage targeting by 11C-(R)-PK11195 positron emission tomography (PET) can visualize subclinical synovitis in arthralgia patients who have anti-citrullinated protein antibodies (ACPAs).
METHODS: Twenty-nine arthralgia patients who were positive for ACPAs but did not have clinical arthritis were studied. High (spatial)-resolution 11C-(R)-PK11195 PET scans of the hands and wrists were performed. For all metacarpophalangeal, proximal interphalangeal, and wrist joints (i.e., 22 joints per patient), tracer uptake was scored semiquantitatively (0-3 scale) by 2 observers who were blinded with regard to the clinical data. Patients were followed up prospectively for 24 months to investigate the development of clinical arthritis.
RESULTS: Overall agreement and kappa values for the readings of the 2 observers were, respectively, 97% and 0.91 (95% confidence interval [95% CI] 0.74-1) at the patient level and 99% and 0.81 (95% CI 0.65-0.96) at the joint level. In 4 patients, at least 1 and as many as 5 PET-positive joints (score≥1) were found at baseline. Within 2 years of followup, 9 patients had developed clinical arthritis. This included all 4 patients with positive findings on the 11C-(R)-PK11195 scan, who developed clinical arthritis in the hand/wrist region, as identified on PET scans. Of the 5 remaining arthritis patients with negative findings on PET scans, 2 developed arthritis in the hand joints and 3 developed arthritis at locations outside the field of view of the PET scanner.
CONCLUSION: Subclinical arthritis in ACPA-positive arthralgia patients could be visualized by 11C-(R)-PK11195 PET scanning and was associated with development of arthritis within 2 years of followup. This indicates that 11C-(R)-PK11195 PET may be useful in determining arthritis activity in the preclinical phase of RA.

PMID: 21898356 [PubMed - indexed for MEDLINE]

CXCL13: a novel biomarker of B-cell return following rituximab treatment and synovitis in patients with rheumatoid arthritis.

Rheumatology (Oxford). 2011 Mar;50(3):603-10

Authors: Rosengren S, Wei N, Kalunian KC, Kavanaugh A, Boyle DL

Abstract
OBJECTIVES: The B-cell chemokine, CXCL13, is a proposed serum biomarker of synovitis in RA. Its behaviour in the context of B-cell depletion therapy and reconstitution was studied during treatment of RA with rituximab.
METHODS: Serum samples from 20 RA patients were analysed for CXCL13, RF-IgM and anti-CCP by ELISA before and 2 and 6 months following rituximab treatment. B cells were monitored by flow cytometry. Gene expression in blood and synovial biopsies was determined by qPCR.
RESULTS: Patients with detectable B cells at 6 months had significantly higher levels of CXCL13 and RF-IgM and slightly higher levels of anti-CCP throughout the study, including at baseline, compared with patients with undetectable B cells at 6 months. Conversely, 10 of 12 patients with high baseline CXCL13 had detectable circulating B cells at 6 months, whereas no B cells could be detected at 6 months in patients with low baseline CXCL13. Synovial CXCL13 expression at baseline correlated significantly with serum CXCL13 levels, and the synovium of patients with high serum CXCL13 expressed elevated levels of IL-1β, IL-8, MMP1 and MMP3. In addition, synovial CXCL13 expression correlated significantly with several synovial inflammatory markers.
CONCLUSIONS: Serum CXCL13 is predictive of the rate of B-cell repopulation following a course of rituximab in RA. Serum CXCL13 correlates with synovial CXCL13 measured at a single joint, suggesting synovitis as an important source of circulating CXCL13. Within the synovium, CXCL13 expression is highly correlated with markers of synovitis.
TRIAL REGISTRATION: ClinicalTrials.gov, http://clinicaltrials.gov/, NCT00147966.

PMID: 21098574 [PubMed - indexed for MEDLINE]

Expression of K2P5.1 potassium channels on CD4+ T lymphocytes correlates with disease activity in rheumatoid arthritis patients.

Arthritis Res Ther. 2011;13(1):R21

Authors: Bittner S, Bobak N, Feuchtenberger M, Herrmann AM, Göbel K, Kinne RW, Hansen AJ, Budde T, Kleinschnitz C, Frey O, Tony HP, Wiendl H, Meuth SG

Abstract
INTRODUCTION: CD4+ T cells express K(2P)5.1 (TWIK-related acid-sensitive potassium channel 2 (TASK2); KCNK5), a member of the two-pore domain potassium channel family, which has been shown to influence T cell effector functions. Recently, it was shown that K(2P)5.1 is upregulated upon (autoimmune) T cell stimulation. The aim of this study was to correlate expression levels of K(2P)5.1 on T cells from patients with rheumatoid arthritis (RA) to disease activity in these patients.
METHODS: Expression levels of K(2P)5.1 were measured by RT-PCR in the peripheral blood of 58 patients with RA and correlated with disease activity parameters (C-reactive protein levels, erythrocyte sedimentation rates, disease activity score (DAS28) scores). Twenty patients undergoing therapy change were followed-up for six months. Additionally, synovial fluid and synovial biopsies were investigated for T lymphocytes expressing K(2P)5.1.
RESULTS: K(2P)5.1 expression levels in CD4+ T cells show a strong correlation to DAS28 scores in RA patients. Similar correlations were found for serological inflammatory parameters (erythrocyte sedimentation rate, C-reactive protein). In addition, K(2P)5.1 expression levels of synovial fluid-derived T cells are higher compared to peripheral blood T cells. Prospective data in individual patients show a parallel behaviour of K(2P)5.1 expression to disease activity parameters during a longitudinal follow-up for six months.
CONCLUSIONS: Disease activity in RA patients correlates strongly with K(2P)5.1 expression levels in CD4+ T lymphocytes in the peripheral blood in cross-sectional as well as in longitudinal observations. Further studies are needed to investigate the exact pathophysiological mechanisms and to evaluate the possible use of K(2P)5.1 as a potential biomarker for disease activity and differential diagnosis.

PMID: 21314928 [PubMed - indexed for MEDLINE]

Elevated production of galectin-3 is correlated with juvenile idiopathic arthritis disease activity, severity, and progression.

Int J Rheum Dis. 2011 Oct;14(4):345-52

Authors: Ezzat MH, El-Gammasy TM, Shaheen KY, Osman AO

Abstract
OBJECTIVES: Galectin-3 is a carbohydrate-binding protein that plays many important regulatory roles in inflammation, immunity and cancers. Recent studies indicate that galectin-3 plays a role in rheumatoid arthritis (RA) pathogenesis and progression. Therefore, we sought to characterize the expression pattern and role of galectin-3 in juvenile idiopathic arthritis (JIA) and to explore whether galectin-3 investigated in serum and synovial fluid was associated with clinical, laboratory and radiological variables of JIA disease activity and severity.
METHODS: Levels of galectin-3 in serum and synovial fluid from patients with JIA and controls were determined by enzyme-linked immunosorbent assay.
RESULTS: Median (interquartile range) serum galectin-3 concentrations (ng/mL) were increasingly higher across the following groups: healthy controls (8.1 [4.9-16.7]), total JIA children with inactive disease (18.6 [9.7-28.8], P = 0.00039 vs. controls) and active disease (35.8 [15.8-60.8], P = 0.000012 vs. controls) (inactive vs. active, P = 0.00016). Highest serum expression was found in polyarthritic children. Galectin-3 concentrations in paired sera and synovial fluid samples could be related to each other. Serum and synovial concentrations of galectin-3 were positively correlated with total number of joints with active arthritis and with overall articular severity score. Patients with Larsen index and total radiographic score ≥ 1 had significant higher serum galectin-3 levels than patients with indices and scores < 1.
CONCLUSIONS: These results suggest that serum levels of galectin-3 are increased in active JIA children and galectin-3 can be a new biomarker indicating JIA disease activity, severity and progression, although its increment is not disease-specific.

PMID: 22004231 [PubMed - indexed for MEDLINE]

A plasmablast biomarker for nonresponse to antibody therapy to CD20 in rheumatoid arthritis.

Sci Transl Med. 2011 Sep 21;3(101):101ra92

Authors: Owczarczyk K, Lal P, Abbas AR, Wolslegel K, Holweg CT, Dummer W, Kelman A, Brunetta P, Lewin-Koh N, Sorani M, Leong D, Fielder P, Yocum D, Ho C, Ortmann W, Townsend MJ, Behrens TW

Abstract
An important goal for personalized health care is the identification of biomarkers that predict the likelihood of treatment responses. Here, we tested the hypothesis that quantitative mRNA assays for B lineage cells in blood could serve as baseline predictors of therapeutic response to B cell depletion therapy in subjects with rheumatoid arthritis (RA). In samples from the REFLEX trial of rituximab in inadequate responders to antibodies to tumor necrosis factor-α, a 25% subgroup of treated subjects with elevated baseline mRNA levels of IgJ, a marker for antibody-secreting plasmablasts, showed reduced clinical response rates. There were no significant efficacy differences in the placebo arm subjects stratified by this marker. Prospective testing of the IgJ biomarker in the DANCER and SERENE rituximab clinical trial cohorts and the SCRIPT ocrelizumab cohort confirmed the utility of this marker to predict nonresponse to anti-CD20 therapy. A combination mRNA biomarker, IgJhiFCRL5lo, showed improved test performance over IgJhi alone. This study demonstrates that baseline blood levels of molecular markers for late-stage B lineage plasmablasts identify a ~20% subgroup of active RA subjects who are unlikely to gain substantial clinical benefit from anti-CD20 B cell depletion therapy.

PMID: 21937757 [PubMed - indexed for MEDLINE]

Inflammation and autoantibody markers identify rheumatoid arthritis patients with enhanced clinical benefit following rituximab treatment.

Arthritis Rheum. 2011 Dec;63(12):3681-91

Authors: Lal P, Su Z, Holweg CT, Silverman GJ, Schwartzman S, Kelman A, Read S, Spaniolo G, Monroe JG, Behrens TW, Townsend MJ

Abstract
OBJECTIVE: Rituximab significantly improves the signs and symptoms of rheumatoid arthritis (RA) and slows the progression of joint damage. The aim of this study was to identify clinical characteristics and biomarkers that identify patients with RA in whom the clinical benefit of rituximab may be enhanced.
METHODS: The study group comprised 1,008 RA patients from 2 independent randomized placebo-controlled phase III clinical trials (REFLEX [Randomized Evaluation of Long-Term Efficacy of Rituximab in Rheumatoid Arthritis] and SERENE [Study Evaluating Rituximab's Efficacy in Methotrexate Inadequate Responders]). A novel threshold selection method was used to identify baseline candidate biomarkers present in at least 20% of patients that enriched for placebo-corrected American College of Rheumatology 50% improvement (ACR50 response; a high clinical efficacy bar) at week 24 after the first course of rituximab.
RESULTS: The presence of IgM rheumatoid factor (IgM-RF), IgG-RF, IgA-RF, and IgG anti-cyclic citrullinated peptide (anti-CCP) antibodies together with an elevated C-reactive protein (CRP) level were associated with enhanced placebo-corrected ACR50 response rates in the REFLEX patients with RA who had an inadequate response to anti-tumor necrosis factor therapies. These findings were independently replicated using samples from patients in SERENE who had an inadequate response to disease-modifying antirheumatic drug treatment. The combination of an elevated baseline CRP level together with an elevated level of any RF isotype and/or IgG anti-CCP antibodies was further associated with an enhanced benefit to rituximab.
CONCLUSION: The presence of any RF isotype and/or IgG anti-CCP autoantibodies together with an elevated CRP level identifies a subgroup of patients with RA in whom the benefit of rituximab treatment may be enhanced. Although the clinical benefit of rituximab was greater in the biomarker-positive population compared with the biomarker-negative population, the clinical benefit of rituximab compared with placebo was also clinically meaningful in the biomarker-negative population.

PMID: 22127691 [PubMed - indexed for MEDLINE]