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ID PMID Title PublicationDate abstract
31379182 Neutrophil-lymphocyte and platelet-lymphocyte rate and their seasonal differences in ankyl 2019 OBJECTIVE: In recent years, neutrophil-lymphocyte rate (NLR) and platelet-lymphocyte rate (PLR) are reported to be increasing in plenty of rheumatological diseases and the latter rates to be disease activity indicators. In our study, we aimed to search for the difference in NLR and PLR before and after the treatment, their relationship with the disease activity and their seasonal differences in patients using anti-TNF medication for rheumatoid arthritis (RA) and ankylosing spondylitis (AS) while. METHOD: Sixty-eight RA and 203 AS patients using anti-TNF medication for at least 6 months were included in the study. Patients with acute infection, diabetes, hypertension, cancer, renal failure and liver failure were excluded from the study. NLR, PLR, seasonal differences and the disease activities of the patients were evaluated retrospectively. RESULTS: We determined that NLR and PLR are strongly correlated with disease activity, erythrocyte sedimentation rate (ESR) and c-reactive protein (CRP). In addition, we determined that disease activity, thrombocytes and PLR are increased in spring and winter, especially in patients with RA. CONCLUSION: NLR and PLR are simple, cheap, and easily accessible parameters which can be used to evaluate disease activity and treatment response before and after anti-TNF treatment. Further studies are needed to enlighten the effect of seasonal differences on disease activity (Tab. 2, Fig. 2, Ref. 43).
30718717 Understanding HLA associations from SNP summary association statistics. 2019 Feb 4 Strong genetic associations in the region containing human leukocyte antigen (HLA) genes have been well-documented in various human immune disorders. Imputation methods to infer HLA variants from single nucleotide polymorphism (SNP) genotypes are currently used to understand HLA associations with a trait of interest. However, it is challenging for some researchers to obtain individual-level SNP genotype data or reference haplotype data. In this study, we developed and evaluated a new method, DISH (direct imputing summary association statistics of HLA variants), for imputing summary association statistics of HLA variants from SNP summary association statistics based on linkage disequilibria in Asian and European populations. Disease association Z scores in DISH were highly correlated with those from imputed HLA genotypes in null model datasets (r = 0.934 in Asians; r = 0.960 in Europeans). We applied DISH to two previous GWAS datasets in Asian systemic lupus erythematosus and European rheumatoid arthritis populations. There was a high correlation between Z scores in the DISH and HLA genotype imputations, showing the same disease-susceptible and protective alleles. This study illustrated the usefulness of the DISH method in understanding and identifying disease-associated HLA variants in human diseases while maintaining individual-level data security.
31770498 Recent findings regarding the effects of microRNAs on fibroblast-like synovial cells in rh 2019 Dec Rheumatoid arthritis (RA) is a systemic autoimmune disease with severe joint inflammation and destruction characterized by marked hyperplasia of the lining layer of the synovium. Fibroblast-like synovial cells (FLS) is a key cellular component within the synovia; it plays pivotal roles in RA pathogenesis by unfavorable behaviors such as producing inflammatory cytokines and chemokines, and hyperproliferation. MicroRNAs are evolutionarily conserved small non-coding RNAs (length is 18-25 nucleotides) that regulate gene expression at the post-transcriptional level. There is increasing interest in the involvement of microRNAs in autoimmune diseases including RA. Recent studies revealed the regulation of the function of FLS by microRNAs. Here, we review the known functional microRNAs in RA and summarize the potential uses of these small molecules in the treatment of RA.
31596149 Aberrant dysregulated circular RNAs in the peripheral blood mononuclear cells of patients 2019 Dec Circular RNAs (circRNAs) represent a newly identified class of non-coding RNAs that have been shown to be involved in several diseases, including autoimmune diseases. Two studies have revealed the aberrant circRNA expression profiles in the peripheral blood mononuclear cells (PBMCs) of patients with rheumatoid arthritis (RA) by microarrays. However, due to the intrinsic defects of microarrays, such as their inability to detect unidentified circRNAs, we examined the circRNA expression profiles in the PBMCs from four RA patients and three healthy controls by RNA sequencing (RNA-seq) and further explored the value of circRNAs in diagnosing RA. The results showed 71 markedly dysregulated circRNAs, including 41 upregulated and 30 downregulated circRNAs; these data included several previously unidentified candidate circRNAs. Gene Ontology and pathway annotation revealed that the most altered pathways and genes were associated with inflammation and transcriptional activity, such as the TNF pathway. The selected dysregulated circRNAs were verified by qRT-PCR in the PBMCs of 32 RA patients and 20 healthy controls, and the results indicated that hsa_circ_0000396 and hsa_circ_0130438 were downregulated in the RA group versus the healthy group, consistent with the RNA-seq data. The area under the receiver operating characteristic curve indicated the diagnostic value of both circRNAs for RA. Our results identified aberrant dysregulated circRNAs in RA patients, including several identified circRNAs, and the diagnostic value of circRNAs for RA, suggesting the superiority of RNA-seq versus microarrays for screening differentially expressed circRNAs and further strengthening the potential diagnostic value of circRNAs for the diagnosis of RA.
31336227 Rheumatoid arthritis is associated with exacerbated body composition deterioration in Kaza 2019 Oct OBJECTIVE: The aim of this study was to assess the magnitude of changes in nutritional body composition components as a consequence of rheumatoid arthritis (RA) and the extent to which these components are associated with RA clinical characteristics, serologic markers, and osteoporosis-related phenotypes (OP-RPs). Early pathologic signs, if detected, could assist in future preventative techniques. METHODS: The study sample was comprised of 260 women with RA and 168 first-degree female relatives without RA who returned for body composition measurements using bioelectrical impedance analysis, from a previously established epidemiologic study conducted in Kazakhstan. RESULTS: In multivariate logistic regression, body composition components, the fat mass index (odds ratio [OR], 0.848; 95% confidence interval [CI], 0.786-0.913; P < 0.001) and the phase angle (PA; OR, 0.654; 95% CI, 0.467-0.826; P = 0.001), were independently and significantly negatively associated with RA after disease development. In multilinear regression analysis, PA was consistently associated with OP-RP, specifically concerning the spongial bone mineral density (BMDSPN) and cortical index, where ageing, reduced PA and increased disease duration explained 31.5% of BMDSPN and 37.3% of cortical index variation. CONCLUSION: Data on RA in women in Kazakhstan consistently show that fat mass index and PA act as independent major covariates associated with RA affection status. These findings suggest exacerbated body composition deterioration when compared with healthy controls, potentially indicating the early appearance of sarcopenia and likely cachexic-like properties. The data also suggest that PA could serve as a potential predictor of RA prognosis, and the concomitant development of osteoporosis.
31255405 Comparison of Expectations and Outcomes in Rheumatoid Arthritis Versus Osteoarthritis Pati 2019 Sep BACKGROUND: We hypothesized that patients undergoing primary total knee arthroplasty (TKA) for rheumatoid arthritis (RA) would have different preoperative expectations compared to osteoarthritis (OA) patients, and that postoperative satisfaction would correlate with specific postoperative pain and functional domains. METHODS: This is a retrospective cohort study of RA patients matched based on age, gender, American Society of Anesthesiologists score, and Charlson Comorbidity Index score 1:2 with OA patients (76 RA, 152 OA) who underwent primary TKA. The Hospital for Special Surgery Knee Replacement Expectations Survey, Visual Analogue Scale for Pain (VAS), Knee injury and Osteoarthritis Outcome Score (KOOS), and the Short Form-12 (SF-12) were compared at baseline and at 2 years postoperatively. Minimum clinically important differences (MCIDs) were calculated for KOOS and SF-12 subdomains. RESULTS: Preoperatively, RA patients had lower expectations, worse VAS Pain, and worse KOOS Pain, Symptoms, and Activities of Daily Living (P < .05). However, at 2 years, RA patients had significantly larger improvements in VAS (P = .01) and these 3 KOOS subdomains (P < .05), achieving comparable absolute scores to OA patients. Overall, 86.1% of RA and 87.1% of OA patients were either somewhat or very satisfied with their TKA. Patient satisfaction correlated with VAS Pain and KOOS outcome scores in both groups. RA and OA patients had high rates of achieving MCID in SF-12 physical component scores and all 5 KOOS subdomains. A higher proportion of RA patients achieved MCID in KOOS Symptoms (98.4% vs 77.2%, P < .001). CONCLUSION: RA patients had lower baseline expectations compared to OA patients. However, RA patients had greater improvements in KOOS and SF-12 subdomains, and there was no difference in satisfaction compared to OA patients after TKA.
31572403 Functional Regulation of Macrophage Phenotypes by MicroRNAs in Inflammatory Arthritis. 2019 Inflammatory arthritis including rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) exhibit the shared feature of changes in activation and polarization of circulating monocytes and tissue macrophages. Numerous microRNAs (miRs) have been found to have key functions in regulating inflammation and macrophage polarization. Although there is increasing interest in the roles of miRs in both RA and JIA, less is known regarding how miRs relate to functional properties of immune cells, including monocytes and macrophages. Interestingly, miRs can function both to promote inflammatory phenotypes and pro-inflammatory polarization, as well as through negative-feedback loops to limit inflammation. Here, we review the functional roles of several miRs in macrophages in inflammatory arthritis, with a particular focus on vivo effects of miR alteration in experimental arthritis. We also consider how current efforts to target miRs clinically could modify functional monocyte and macrophage polarization in vivo, and serve as novel therapies for diseases such as RA and JIA.
32598682 [Endothelial damage and circadian blood pressure profile in rheumatoid arthritis]. 2019 May 15 AIM: To study the influence of the state of endothelium on the daily profile of arterial pressure (AP) in patients with rheumatoid arthritis (RA). MATERIALS AND METHODS: In 70 RA pts carried out C-reactive protein (CRP), vascular endothelial adhesion molecule type 1 (sVCAM-1), antigen von Willebrand Factor (AG WF), interleukin-8 (Il-8), rheumatoid factor (RF), IgG, endotheline-1 (ET-1), number of desquamated endotheliocytes cells (DE), VS, activity of renin by immunoenzyme analysis. The dysfunction of endothelium was evaluated by calculation of DE. The functional methods included the daily monitoring of arterial pressure (AP). RESULTS: Arterial hypertension (AH) occurred in 40 (57.1%) pts. RA pts are revealed the signs of endothelial dysfunction, about which significant differences among the indices of activation of endothelium in comparison with control group testify. ET-1, sVCAM-1, vWF AG, Il-8, CRP content was higher in RA pts. Reliably above there was a number of DE. Reliable differences according to these indices depending of RA activity were discovered. With conducting of correlation analysis it is revealed, that markers of the activation of endothelium: sVCAM-1, vWF AG positively correlated with increasing RF IgG and indices of the immune inflammation: CRP, and DE number. In patients suffering from RA, showed signs of endothelial dysfunction. The positive correlation between endothelial damage and daily profile of AP show the relationship of these processes. CONCLUSION: Positive correlations between the damage of endothelium and disturbance of AP daily profile testify about the interrelation of these processes.
31078317 Monitoring Drug Safety in Rheumatoid Arthritis Prevention Trials. 2019 Jul This commentary discusses issues particular to drug safety monitoring in prevention trials. Although the general approach to safety assessment applies across all clinical trials, prevention trials pose special challenges given that the patient population is currently asymptomatic or experiencing only mild symptoms of the targeted disease. This sways the risk-benefit analysis balance toward minimal acceptable risk. Definition of the predisease state with validated biomarkers or other assessment tools is essential. The timing and required length of exposure to the disease intervention to produce an effect requires special methodologic considerations. In addition, prevention trials generally have a longer duration with higher dropout rates. As a result, there is an enhanced focus on lessening patient burden in regard to data collection and finding ways to minimize the safety signal to noise ratio to enable product causality assessment. To meet these challenges, clinical safety monitoring in prevention trials involves 3 essential steps: safety planning, systematic data collection and evaluation, and transparent communication of safety information. We discuss some of these issues using historical experience with primary prevention cardiovascular trials and then focus on unique issues surrounding patient populations at risk for rheumatoid arthritis.
31064209 An image-based method to measure joint deformity in inflammatory arthritis: development an 2019 Aug Quantifying joint deformity in people with rheumatoid (RA) and psoriatic arthritis (PsA) remains challenging. Here, we demonstrate a new method to measure bone erosions and abnormal periosteal growths, based on the difference between a predicted healthy and actual diseased joint surface. We optimized the method by creating and measuring artificial bone erosions and growths. Then we measured 46 healthy and diseased patient surfaces. We found average sensitivity errors of ≤0.27 mm when measuring artificial erosions and growths. Patients had significantly more bone erosion than healthy subjects. Surface based outcomes are a novel way to interpret and quantify bone changes in PsA and RA.
32598687 [Chronic kidney disease in rheumatoid arthritis patients: prevalence, risks factors, histo 2019 May 15 The present review is focused on risk factors of chronic kidney disease in rheumatoid arthritis (RA). According to recent data, the chronic kidney disease (CKD) in RA patients is more often than at patients without RA. It is closely associated with risk of cardiovascular disease and high mortality. Besides of general population risk factors of CKD, the activity of the disease is independent predictors of reduction in glomerular filtration rate less than 60 ml/min/1.73 m2. In the review, histopathological variants and mechanisms of CKD on basis of international experience are also considered. Suppression of inflammation by basic therapy of RA and biological therapy have changed outcomes RA, prevalence, and structure of kidney involvement in recent years.
31226103 Effects of Mediterranean diet on the treatment of rheumatoid arthritis. 2019 Jun 11 INTRODUCTION: It has been suggested that environmental and lifestyle factors might contribute to the severity and progression of inflammation in rheumatoid arthritis. An intervention generating high interest due to its supposed anti-inflammatory properties is the Mediterranean diet. METHODS: We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified seven systematic reviews including four primary studies, of which only one corresponded to a randomized trial. We concluded Mediterranean diet may make little or no difference in pain or disease activity and may slightly increase weight in rheumatoid arthritis patients, but the certainty of the evidence is low. On the other hand, it was not possible to clearly establish whether Mediterranean diet has any effect on functionality, morning stiffness or quality of life as the certainty of the existing evidence has been assessed as very low.
31410660 Association of rheumatoid arthritis-related autoantibodies with pulmonary function test ab 2019 Dec INTRODUCTION: We investigated whether rheumatoid arthritis (RA)-related autoantibodies were associated with abnormalities on pulmonary function tests (PFTs). METHODS: We studied RA serostatus and PFT abnormalities within a RA registry. RA serostatus was assessed by research assays for cyclic citrullinated peptide (CCP) and rheumatoid factor (RF). Outcomes were abnormalities on clinically indicated PFTs, including restriction, obstruction, and diffusion abnormality. Logistic regression was used to obtain ORs and 95% CIs for the PFT abnormalities by RA serologic phenotypes independent of lifestyle and RA characteristics. RESULTS: Among 1272 analyzed subjects, mean age was 56.3 years (SD 14.1), 82.2% were female, and 69.5% were seropositive. There were 100 subjects with abnormal PFTs. Compared with seronegativity, seropositivity was associated with increased odds of any PFT abnormality (multivariable OR 2.29, 95% CI 1.30-4.03). When analyzing type of PFT abnormality, seropositivity was also associated with restriction, obstruction, and diffusion abnormalities; multivariable ORs were 2.48 (95% CI 1.26-4.87), 3.12 (95% CI 1.28-7.61), and 2.30 (95% CI 1.09-4.83), respectively. When analyzing by CCP and RF status, the associations were stronger for RF+ than for CCP+ (any PFT abnormality OR 1.99, 95% CI 1.21-3.27 for RF+ vs. RF-; OR 1.67, 95% CI 1.03-2.69 for CCP+ vs. CCP-) with a dose effect of higher RF titer increasing odds for each PFT abnormality (p for trend < 0.05). CONCLUSIONS: Seropositive RA patients had two-fold increased risk for abnormalities on PFTs performed for clinical indications compared with seronegative RA. Patients with seropositive RA, particularly those with high-titer RF positivity, may be more likely to have obstructive and restrictive abnormalities, independent of smoking.Key points• Due to the known excess pulmonary morbidity/mortality in RA, we studied the relationship of rheumatoid arthritis (RA)-related autoantibodies with pulmonary function test (PFT) abnormalities using a large RA registry.• We evaluated whether presence and levels of cyclic citrullinated peptide (CCP) and rheumatoid factor (RF) were associated with restriction, obstruction, and diffusion abnormalities on PFTs among 1272 subjects with RA.• Seropositivity was associated with two-fold increased risk for any PFT abnormality, independent of confounders including smoking. Higher titers of RF conferred greatest risk for all PFT outcomes: obstruction, restriction, and diffusion abnormality.• These results provide evidence that patients with RA should be closely monitored for pulmonary involvement, particularly those with high-titer RF seropositivity.
31140226 ADORA2A Polymorphisms Influence Methotrexate Adverse Events in Rheumatoid Arthritis. 2019 May BACKGROUND: Methotrexate is the most frequently administered first-line treatment for rheumatoid arthritis (RA). The disease-modifying effects of methotrexate are mainly associated with enhanced release of free adenosine. The downstream anti-inflammatory effects of adenosine are mediated via its binding to adenosine receptor 2A (ADORA2A) and 3 (ADORA3). Many clinically important single nucleotide polymorphisms (SNPs) were reported in ADORA2A and ADORA3 genes. OBJECTIVES: To investigate whether tagging ADORA2A and ADORA3 polymorphisms influences methotrexate treatment in RA. METHODS: In total, 212 RA patients treated with methotrexate were genotyped for tagging ADORA2A (rs2298383, rs8141793, rs2236624, rs5751876, rs35320474, and rs17004921) and ADORA3 SNPs (rs2298191, rs1544223, rs78594984, rs35511654, rs2229155, rs3393, and rs3394). RESULTS: RA patients who carried ADORA3 rs35511654 G allele showed a tendency toward better response to methotrexate treatment (P = 0.054). Carriers of ADORA2A polymorphic allele rs2298383 (P = 0.011), rs2236624 (P = 0.027), rs5751876 (P = 0.018), and rs35320474 (P = 0.026) were less likely to experience methotrexate induced adverse events. All associations remained significant after adjustment for clinical factors. The effects of these polymorphisms were also significant in haplotype analyses. CONCLUSIONS: Polymorphisms in the ADORA2A gene may influence methotrexate treatment response and may be considered as a potential biomarker for methotrexate treatment in rheumatoid arthritis.
30644346 HLAs in Autoimmune Diseases: Dependable Diagnostic Biomarkers? 2019 BACKGROUND: The process of antigen presentation to immune cells is an undeniable contributor to the pathogenesis of autoimmune diseases. Different studies have indicated several factors that are related to autoimmunity. Human Leukocyte Antigens (HLAs) are among such factors, which have a key role in autoimmunity because of their involvement in antigen presentation process. METHODS: Relevant English language literature was searched and retrieved from Google Scholar search engine and PubMed database (1996-2018). The following keywords were used: "Human leukocyte antigen", "Behcet's syndrome", "Rheumatoid arthritis", "Systemic lupus erythematosus", "Type 1 diabetes", "Celiac Disease" and "Autoimmunity". RESULTS: There is a strong association between HLA alleles and autoimmune diseases. For instance, HLA-B alleles and Behcet's syndrome are strongly correlated, and systemic lupus erythematosus and Type 1 diabetes are related to HLA-DQA1 and HLA-DQB1, respectively. CONCLUSION: Association between numerous HLA alleles and autoimmune diseases may justify and rationalize their use as biomarkers as well as possible diagnostic laboratory parameters.
31843461 Auxiliary in vitro and in vivo biological evaluation of hydrogen peroxide sensitive prodru 2020 Jan 15 Rheumatoid arthritis (RA) is a chronic inflammatory disease that causes severe joints damage and other extra-articular alterations. Despite the efficacy of low-dose methotrexate (LD-MTX) in RA treatment, adverse effects are the predominant reasons for discontinuation of therapy. As a therapeutic targeting strategy, the presence of increased concentrations of reactive oxygen species (ROS) in the inflammatory environment can serve as the stimulus for prodrug activation in site-selective drug delivery systems. Our group has previously reported novel ROS sensitive prodrugs (1-3) of MTX and aminopterin (AMT) for site-selective delivery to inflammatory tissue associated with RA, with the aim of reducing side effects in RA therapy. Herein, we investigate the effect and toxicity of the same prodrugs in a rat CIA (collagen-induced arthritis) model of RA. We find that prodrug 1, an arylboronic acid ROS-sensitive MTX-prodrug, displays similar in vivo efficacy as MTX at an equimolar dose, while avoiding adverse effects known to restrict MTX treatment. To further characterize prodrug 1 and its ROS mediated activation, we synthesized compound 4, a negative control lacking the boronic acid moiety. We then investigated the effect of molecules on cell proliferation and cytotoxicity in the presence of the ROS scavenger pyruvate, as well as their stability in buffer and cell media, demonstrating a direct correlation between ROS concentration and the prodrug activity. Moreover, the in vitro ADME properties were investigated, including permeability, rat plasma and microsomal stability.
30806731 Power-Doppler perfusion phenotype in RA patients is dependent on anti-citrullinated peptid 2019 Jun It is not known whether there are any consistent non-serological differences between seropositive and seronegative rheumatoid arthritis, and if any, whether they depend upon rheumatoid factor (RF), anti-citrullinated peptide antibodies (ACPA), or both. In a pilot study, we showed that the two forms could be differentiated using power-Doppler sonography (PDS), and that the difference is ACPA dependent. This extended study explored whether the previous findings could be confirmed. 103 patients 51 ACPA positive (ACPA +), 52 ACPA negative (ACPA -) with active wrist arthritis were examined using PDS. By means of a temporal image series, pulsatility was evaluated over a 3-5-s period, maximum and minimum perfusion signal were determined using a computer program counting the number of coloured pixels for each frame. Maxima (P(max)) and minima (P(min)) were determined, and the standardized peak-to-peak amplitude sA was calculated (sA = (P(max) - P(min))/P(max)). This parameter was then compared for ACPA + and ACPA- patients. In addition, a multivariate regression was performed, to determine which factors influence sA. sA differed significantly between ACPA + and ACPA- patients [20% (13-26) vs. 41% (32-57), p < 0. 0001]. In the multivariate analysis, age (t = 2.5, p = 0.02) and ACPA status (t = - 4.8, p < 0.0001) were independent predictors of sA. PDS perfusion patterns are different in seropositive and seronegative RA. The difference appears to be ACPA, not RF dependent. This suggests that the underlying pathophysiological process is different in ACPA-positive and ACPA-negative RA.
30710386 Identification of rheumatoid arthritis causal genes using functional genomics. 2019 May Over the past decade, genome-wide association studies have contributed a wealth of knowledge to our understanding of polygenic disorders such as rheumatoid arthritis. As the size of sample cohorts has improved so too have the computational and experimental methods used to robustly define variants associated with disease susceptibility. The challenge now remains to translate these findings into improved understanding of disease aetiology and patient care. Whilst much of the focus of translating the findings of genome-wide association studies has been on global analysis of all variants identified, careful functional study of individual disease susceptibility loci will be required in order to refine our understanding of how individual variants contribute to disease risk. Here, we present the argument behind such an approach and describe some of the novel tools being used to investigate risk loci. This includes the use of chromosomal conformation capture techniques and modifications of the CRISPR-Cas9 system, with several examples of their implementation being described.
31107887 Not all moderate disease is the same - Identification of disability trajectories among pat 2019 BACKGROUND: United Kingdom guidelines for the use of biologic disease modifying anti-rheumatic drugs (bDMARDS) for rheumatoid arthritis (RA) require patients to have active disease (Disease Activity Score [DAS28] >5.1) and have failed ≥2 previous conventional synthetic DMARDs (csDMARD). Patients with moderate disease activity (MDA) do not meet these criteria, yet often have poor outcomes. This study aimed to identify trajectory groups of disability scores over three years in RA patients with MDA. METHODS: The study included biologic-naïve patients receiving csDMARDs only with MDA (3.2
30834598 Analysis of differentially expressed genes in rheumatoid arthritis and osteoarthritis by i 2019 Aug BACKGROUND: Rheumatoid arthritis (RA) and osteoarthritis (OA) were two major types of joint diseases. This study aimed to explore the mechanism underlying OA and RA and analyze their difference by integrated analysis of multiple gene expression data sets. METHODS: Gene expression data sets of RA and OA were downloaded from The Gene Expression Omnibus. Shared and specific differentially expressed genes (DEGs) in RA and OA were identified by integrated analysis of multiple gene expression data sets. Functional annotation and protein-protein interaction (PPI) network construction of OA- and RA-specific DEGs were performed to further explore the molecular mechanisms underlying RA and OA and analyze the mechanism differences between them. RESULTS: Compared with normal controls, 3757 and 2598 DEGs were identified in RA and OA, respectively. Among them, 2176 DEGs were RA-specific DEGs and 1017 DEGs were OA-specific DEGs. Moreover, the expression of 17 DEGs played opposite pattern in RA and OA compared with normal controls. Chemokine signaling pathway and oxidative phosphorylation were significantly enriched pathways for RA- and OA-specific DEGs, respectively. BIRC2 and CSNK1E were respective hub genes of RA- and OA-specific PPI network. CONCLUSION: Our findings provided clues for the specific mechanism and developing specific biomarkers for RA and OA.