Cytokines, Vascular Endothelial Growth Factors, and PlGF in Autoimmunity:Insights From Rheumatoid Arthritis to Multiple Sclerosis

In this review, we will explore the intricate roles of cytokines and vascular endothelial growth factors in autoimmune diseases (ADs), with a particular focus on rheumatoid arthritis (RA) and multiple sclerosis (MS). AD is characterized by self-destructive immune responses due to auto-reactive T lymphocytes and Abs. Among various types of ADs, RA and MS possess inflammation as a central role but in different sites of the patients. Other common aspects among these two ADs are their chronicity and relapsing-remitting symptoms requiring continuous management. First factor inducing these ADs are cytokines, such as IL-6, TNF-α, and IL-17, which play significant roles in the pathogenesis by contributing to inflammation, immune cell activation, and tissue damage. Secondly, vascular endothelial growth factors, including VEGF and angiopoietins, are crucial in promoting angiogenesis and inflammation in these two ADs. Finally, placental growth factor (PlGF), an emerging factor with bi-directional roles in angiogenesis and T cell differentiation, as we introduce as an "angio-lymphokine" is another key factor in ADs. Thus, while angiogenesis recruits more inflammatory cells into the peripheral sites, cytokines secreted by effector cells play critical roles in the pathogenesis of ADs. Various therapeutic interventions targeting these soluble molecules have shown promise in managing autoimmune pathogenic conditions. However, delicate interplay between cytokines, angiogenic factors, and PlGF has more to be studied when considering their complementary role in actual pathogenic conditions. Understanding the complex interactions among these factors provides valuable insights for the development of innovative therapies for RA and MS, offering hope for improved patient outcomes.

Characteristics of patients with psoriatic arthritis in Korea: focusing on axial involvement

Background/Aims@#We aimed to clarify the clinical characteristics of psoriatic arthritis (PsA) in Korean patients focusing on PsA with axial involvement. @*Methods@#A retrospective medical chart review was performed to identify PsA patients at a single tertiary center. Cases of AS patients with psoriasis were recruited from a prospective AS registry of the same center. Demographics, laboratory findings, and radiologic characteristics were assessed. @*Results@#A total of 69 PsA patients were identified. In PsA patients, spondylitis (46.4%) was the most common form. Compared to AS patients with psoriasis, PsA patients with radiographic axial involvement were older (50.9 vs. 32.4 years; p < 0.001) and showed greater peripheral disease activity (peripheral arthritis 78.1 vs. 12.5%, p < 0.001; enthesitis 50.0 vs. 6.3%, p = 0.003). AS patients with psoriasis presented a higher rate of HLA-B*27 positivity (81.3 vs. 17.2%; p < 0.001) and a more frequent history of inflammatory back pain (100.0 vs. 75.0%; p = 0.039) than PsA patients with radiographic axial involvement. Significant proportions of PsA patients with radiographic axial involvement had cervical spine involvement (10/18, 55.6%) and spondylitis without sacroiliitis (10/23, 43.5%). @*Conclusions@#We demonstrate that axial involvement is common in Korean PsA patients, and its characteristics can be distinct from those of AS.

Predictors of renal relapse in Koreans with lupus nephritis after achieving complete response: a 35-years of experience at a single center

Background/Aims@#Renal relapse has known to be a poor prognostic factor in patients with lupus nephritis (LN), but there were few studies that identified the risk factors of renal relapse in real world. We conducted this study based on 35-years of experience at a single center to find out predictors of renal relapse in Korean patients with LN after achieving complete response (CR). @*Methods@#We retrospectively analyzed the clinical, laboratory, pathologic and therapeutic parameters in 296 patients of LN who reached CR. The cumulative risk and the independent risk factors for renal relapse were examined by Kaplan-Meier methods and Cox proportional hazards regression analyses, respectively. @*Results@#The median follow-up period from CR was 123 months. Renal relapse had occurred in 157 patients. Renal relapse occurred in 38.2%, 57.6% and 67.9% of patients within 5-, 10-, and 20-year, respectively. The age at diagnosis of SLE and LN were significantly younger, and the proportions of severe proteinuria and serum hypoalbuminemia were higher in patients with renal relapse. Interestingly, the proportion of receiving cytotoxic maintenance treatment was higher in patients with renal relapse. In Cox proportional hazards regression analyses, only young-age onset of LN (by 10 years, HR = 0.779, p = 0.007) was identified to independent predictor of renal relapse. @*Conclusions@#Young-age onset of LN was only independent predictor and the patients with severe proteinuria and serum hypoalbuminemia also tended to relapse more, despite of sufficient maintenance treatment. Studies on more effective maintenance treatment regimens and duration are needed to reduce renal relapse.

Changes in the cholesterol profile of patients with rheumatoid arthritis treated with biologics or Janus kinase inhibitors

Objective@#To assess the effects of biological and targeted synthetic disease-modifying antirheumatic drugs (DMARDs) on lipid profiles in patients with moderate-to-severe rheumatoid arthritis (RA). @*Methods@#This retrospective single-center observational study included patients with RA taking a tumor necrosis factor-α inhibitor (TNFi), abatacept, tocilizumab, or a Janus kinase inhibitor (JAKi) for at least 6 months. Changes in lipid profile were assessed at 6 months after the start of treatment, and associations between changes in lipid profiles and clinical efficacy, concomitant medications, and comorbidities were evaluated. @*Results@#This study included 114 patients treated with TNFi, 81 with abatacept, 103 with tocilizumab, and 89 with JAKi. The mean percentage change (from baseline to 6 months) in total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and non-HDL-C levels was higher in those taking tocilizumab and JAKi than in those taking TNFi and abatacept. A significant change in non-HDL-C was associated with JAKi (versus TNFi: odds ratio [OR], 3.228; 95% confidence interval [CI], 1.536~6.785), tocilizumab (versus TNFi: OR, 2.203; 95% CI, 1.035~4.689), and statins (OR, 0.487; 95% CI, 0.231~1.024). However, changes in disease activity in 28 joints were not associated with a significant change in non-HDL-C. @*Conclusion@#Tocilizumab- and JAKi-associated increases in serum non-HDL-C levels were observed regardless of changes in disease activity. Statins are recommended for RA patients showing a significant increase in cholesterol levels after initiating biological and targeted synthetic DMARDs.

Time-integrated Cumulative Parameters Predictive of Radiographic Progression of Rheumatoid Arthritis: Real-world Data From a Prospective Single-center Cohort

Objective@#With many chronic inflammatory diseases, outcomes are determined by assessing both disease activity at presentation and cumulative activity over time. Here, we investigated whether cumulative activity better reflects the radiographic progression (RP) of rheumatoid arthritis (RA) than measurement of activity at a single time point. @*Methods@#From a prospective cohort of RA patients, most of whom were treated with anti-rheumatic drugs, we selected 117 subjects for whom laboratory, clinical, and radiographic parameters potentially influencing RP were monitored serially for more than 1 year. X-ray images of both hands and both feet were scored using the van der Heijde modified total Sharp score (mTSS). In addition to cross-sectional values at baseline, longitudinal and cumulative values for each parameter were calculated in a timeintegrated and averaged manner. @*Results@#Among the values measured at baseline, mTSS, but not the baseline erythrocyte sedimentation rate (ESR) or C-reactive protein level, was associated with RP. By contrast, multivariate analyses identified cumulative values such as the cumulative ESR, cumulative tender joint count, cumulative swollen joint count (SJC), and cumulative Disease Activity Score 28-ESR as major determinants of RP. In particular, the cumulative SJC showed the best predictive performance for RP. @*Conclusion@#This study highlights the importance of cumulative indices for predicting progression of RA. Specifically, dynamic and cumulative values of RA activity-related factors, particularly the cumulative SJC, may be the major determinants of RP in the current practice.

Clinical outcomes and pathological characteristics of immunoglobulin G4-related ophthalmic disease versus orbital inflammatory pseudotumor

BACKGROUND/AIMS: This study investigated the clinical and pathological features of immunoglobulin G4 (IgG4)-related ophthalmic disease. To clarify the features, we compared IgG4-related ophthalmic disease and orbital inflammatory pseudotumor. METHODS: We retrospectively reviewed the medical records of 103 patients who were initially diagnosed with orbital inflammatory pseudotumor, and identified 16 cases in which the diagnosis was based on surgical biopsy and for which data in medical records were sufficient for analysis. Immunohistochemical staining of pathological specimens for IgG and IgG4 was performed. Finally, six of IgG4-related ophthalmic disease patient and 10 of orbital inf lammatory pseudotumor patient were analyzed. RESULTS: The IgG4-related ophthalmic disease group had more IgG4-positive plasma cells and a higher IgG4/IgG plasma cell ratio than the orbital inflammatory pseudotumor group. Collagenous fibrosis and lacrimal gland involvement were significantly more frequent in the IgG4-related ophthalmic disease group. Dense lymphocyte infiltration, obliterative phlebitis, and bilateral lesions were more frequent in IgG4-related ophthalmic disease, but the differences were not significant. The recurrence-free period was shorter in the IgG4-related ophthalmic disease group (p = 0.035). CONCLUSIONS: The location of the lesion (lacrimal gland), count and ratio of IgG4-positive plasma cells, and collagenous fibrosis aid the diagnosis of IgG4-related ophthalmic disease in patients with idiopathic orbital mass-like lesions. In addition, maintenance therapy should be considered in patients with IgG4-related ophthalmic disease to prevent recurrence.

Erratum: Effects of Individual Education Using a Treating-to-target Strategy in Patients with Rheumatoid Arthritis

The original version of this article contained an error of the ORCID identifier of corresponding author (Ji Hyeon Ju).

Distinct Urinary Metabolic Profile in Rheumatoid Arthritis Patients: A Possible Link between Diet and Arthritis Phenotype

OBJECTIVE: We undertook this study to investigate the discriminant metabolites in urine from patients with established rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and from healthy individuals. METHODS: Urine samples were collected from 148 RA patients, 41 SLE patients and 104 healthy participants. The urinary metabolomic profiles were assessed using 1H nuclear magnetic resonance spectroscopy. The relationships between discriminant metabolites and clinical variables were assessed. Collagen-induced arthritis was induced in mice to determine if a choline-rich diet reduces arthritis progression. RESULTS: The urinary metabolic fingerprint of patients with established RA differs from that of healthy controls and SLE patients. Markers of altered gut microbiota (trimethylamine-N-oxide, TMAO), and oxidative stress (dimethylamine) were upregulated in patients with RA. In contrast, markers of mitochondrial dysfunction (citrate and succinate) and metabolic waste products (p-cresol sulfate, p-CS) were downregulated in patients with RA. TMAO and dimethylamine were negatively associated with serum inflammatory markers in RA patients. In particular, patients with lower p-CS levels exhibited a more rapid radiographic progression over two years than did those with higher p-CS levels. The in vivo functional study demonstrated that mice fed with 1% choline, a source of TMAO experienced a less severe form of collagen-induced arthritis than did those fed a control diet. CONCLUSION: Patients with RA showed a distinct urinary metabolomics pattern. Urinary metabolites can reflect a pattern indicative of inflammation and accelerated radiographic progression of RA. A choline-rich diet reduces experimentally-induced arthritis. This finding suggests that the interaction between diet and the intestinal microbiota contributes to the RA phenotype.

Rheumatoid arthritis is associated with early tooth loss: results from Korea National Health and Nutrition Examination Survey V to VI

BACKGROUND/AIMS@#To examine the association between rheumatoid arthritis (RA) and periodontitis or tooth loss.@*METHODS@#The study used data from the fifth and sixth Korea National Health and Nutrition Examination Surveys conducted from 2010 to 2015. RA was defined as participant-reported physician-diagnosed RA that was being treated. Periodontitis and the number of natural teeth were determined by dental examination. Periodontitis was defined according to the community periodontal index (periodontal probing depth ≥ 4 mm). The association between RA and periodontitis or tooth loss was examined after controlling for confounding variables (e.g., age, smoking status, socioeconomic status, dental caries, frequency of toothbrushing, body mass index, alcohol consumption, and diabetes) in men and women. Subgroup analyses stratified by age were also performed.@*RESULTS@#The study enrolled 20,297 participants aged ≥ 19 years (157 RA patients and 20,140 non-RA controls). There was no association between RA and periodontitis or tooth loss in men and women. Subgroup analyses in those aged < 60 years revealed a non-significant association between RA and periodontitis (adjusted odds ratio, 1.53; p = 0.162), but they revealed a significant association between RA and tooth loss (adjusted β, 0.20; p = 0.042).@*CONCLUSIONS@#RA was not associated with periodontitis, but was associated with tooth loss in younger adults. Younger RA patients are more likely to suffer tooth loss than general younger population; thus dental management is required.

Effects of Individual Education Using a Treating-to-target Strategy in Patients with Rheumatoid Arthritis

OBJECTIVE: To examine effects of an individual education program using the treating rheumatoid arthritis to target (RA T2T) strategy in patients with moderate-severe rheumatoid arthritis. METHODS: Patients were assigned randomly to an educational intervention (n=33) or conventional care group (n=33). The intervention was a nurse-delivered 9-month educational program consisting of 3 monthly sessions and monthly telephone counseling. The assessments occurred at the baseline and every 3 months in both groups, but only the intervention group completed the 9-month education follow-up. The outcome variables included the disease activity (DAS28), functional disability (KHAQ), fatigue (FACIT-Fatigue), and quality of life (SF-36). Repeated measures ANOVA and a Bonferroni multiple comparison were used to evaluate the outcome variables comparing the groups and follow-up times. RESULTS: Significant interactions were observed between the groups and follow-up times in the disease activity (p=0.041), fatigue (p=0.042), and physical (p=0.006) and mental (p=0.031) health-related quality of life, but there was no significant interaction in the functional disability (p=0.110). Significant differences were noted between the groups at the 9-month period (p=0.048) in disease activity and fatigue, and at the 6-month (p=0.023) and 9-month periods (p=0.027) in the physical health-related quality of life. CONCLUSION: This education program using the RA T2T strategy had significant benefits on the disease activity, fatigue, and quality of life in patients with moderate to severe rheumatoid arthritis, and the results suggested that this contributed to positive clinical outcomes as a good practical nursing intervention.

Microbiota in T-cell homeostasis and inflammatory diseases

The etiology of disease pathogenesis can be largely explained by genetic variations and several types of environmental factors. In genetically disease-susceptible individuals, subsequent environmental triggers may induce disease development. The human body is colonized by complex commensal microbes that have co-evolved with the host immune system. With the adaptation to modern lifestyles, its composition has changed depending on host genetics, changes in diet, overuse of antibiotics against infection and elimination of natural enemies through the strengthening of sanitation. In particular, commensal microbiota is necessary in the development, induction and function of T cells to maintain host immune homeostasis. Alterations in the compositional diversity and abundance levels of microbiota, known as dysbiosis, can trigger several types of autoimmune and inflammatory diseases through the imbalance of T-cell subpopulations, such as Th1, Th2, Th17 and Treg cells. Recently, emerging evidence has identified that dysbiosis is involved in the progression of rheumatoid arthritis, type 1 and 2 diabetic mellitus, and asthma, together with dysregulated T-cell subpopulations. In this review, we will focus on understanding the complicated microbiota-T-cell axis between homeostatic and pathogenic conditions and elucidate important insights for the development of novel targets for disease therapy.

Dysregulation of gut microbiota and chronic inflammatory disease: from epithelial defense to host immunity

No abstract available.

MicroRNA-143 and -145 modulate the phenotype of synovial fibroblasts in rheumatoid arthritis

Fibroblast-like synoviocytes (FLSs) constitute a major cell subset of rheumatoid arthritis (RA) synovia. Dysregulation of microRNAs (miRNAs) has been implicated in activation and proliferation of RA-FLSs. However, the functional association of various miRNAs with their targets that are characteristic of the RA-FLS phenotype has not been globally elucidated. In this study, we performed microarray analyses of miRNAs and mRNAs in RA-FLSs and osteoarthritis FLSs (OA-FLSs), simultaneously, to validate how dysregulated miRNAs may be associated with the RA-FLS phenotype. Global miRNA profiling revealed that miR-143 and miR-145 were differentially upregulated in RA-FLSs compared to OA-FLSs. miR-143 and miR-145 were highly expressed in independent RA-FLSs. The miRNA-target prediction and network model of the predicted targets identified insulin-like growth factor binding protein 5 (IGFBP5) and semaphorin 3A (SEMA3A) as potential target genes downregulated by miR-143 and miR-145, respectively. IGFBP5 level was inversely correlated with miR-143 expression, and its deficiency rendered RA-FLSs more sensitive to TNFα stimulation, promoting IL-6 production and NF-κB activity. Moreover, SEMA3A was a direct target of miR-145, as determined by a luciferase reporter assay, antagonizing VEGF165-induced increases in the survival, migration and invasion of RA-FLSs. Taken together, our data suggest that enhanced expression of miR-143 and miR-145 renders RA-FLSs susceptible to TNFα and VEGF165 stimuli by downregulating IGFBP5 and SEMA3A, respectively, and that these miRNAs could be therapeutic targets.

Comparing Effectiveness Rituximab (Mabthera®) to Other Second-line Biologics for Rheumatoid Arthritis Treatment in Patients Refractory to or Intolerant of First-line Anti-tumor Necrosis Factor Agent: An Observational Study

OBJECTIVE: Failure of first-line anti-tumor necrosis factor (TNF) agents in in rheumatoid arthritis patients leads to decisions among second-line biologic agents. To better inform these decisions, the therapeutic effectiveness of rituximab is compared with other second-line biologic agents in this observational study. METHODS: Between November 2011 and December 2014, study subjects were observed for 12 month periods. Patients with an inadequate response to initial anti-TNF agent received either rituximab or alternative anti-TNF agents (adalimumab/etanercept/infliximab) based on the preference of patients and physicians. The efficacy end point of this study was the change in 28-joint count Disease Activity Score (DAS28) at six and 12 months from baseline. Safety data were also collected. RESULTS: Ninety patients were enrolled in the study. DAS28 at six months did not change significantly whether the patients were treated with rituximab or alternative anti-TNF agents in intention-to-treat analysis (n=34, −1.63±0.30 vs. n=31, −2.05±0.34) and standard population set analysis (n=31, −1.51±0.29 vs. n=24, −2.21±0.34). Similarly, the change in DAS28 at 12 months did not reach statistical significance (−1.82±0.35 in the rituximab vs. −2.34±0.44 in the alternative anti-TNF agents, p=0.2390). Furthermore, the incidences of adverse events were similar between two groups (23.5% for rituximab group vs. 25.8% for alternative anti-TNF agents group, p=0.7851). CONCLUSION: Despite the limitations of our study, switching to rituximab or alternative anti-TNF agents after failure of the initial TNF antagonist showed no significant therapeutic difference in DAS28 reduction.

Identification of novel urinary biomarkers for assessing disease activity and prognosis of rheumatoid arthritis

To optimize treatment for rheumatoid arthritis (RA), it is ideal to monitor the disease activity on a daily basis because RA activity fluctuates over time. Urine can be collected routinely at home by patients. Recently, we identified four urinary biomarker candidates—gelsolin (GSN), orosomucoid (ORM)1, ORM2 and soluble CD14 (sCD14)—in RA patients through transcriptomic and proteomic studies. Here, we investigated the clinical significance of the aforementioned urinary biomarker candidates in a prospective manner. For the first time, we found that urinary ORM1, ORM2 and sCD14 levels, but not GSN, were elevated in RA patients and had a positive correlation with the status of the disease activity. In particular, urine tests for ORM 1, ORM 2 and sCD14 efficiently represented the presence of high RA activity without the need for measuring blood markers. In a parallel study, a more rapid radiographic progression over 3 years was observed in patients with higher ORM2 levels. Combined measurements of urinary ORM2 and serum C-reactive protein synergistically increased the predictability of the radiographic progression of RA (odds ratio: 46.5). Collectively, our data provide evidence that blood-free, urinary biomarkers are promising surrogates for assessing disease activity and prognosis of RA. We anticipate that our urinary biomarkers will provide novel candidates for patient-driven measurements of RA activity at home and can shift the paradigm from blood to urine testing in the assessment of RA activity and prognosis in hospitals.

Applications of systems approaches in the study of rheumatic diseases

The complex interaction of molecules within a biological system constitutes a functional module. These modules are then acted upon by both internal and external factors, such as genetic and environmental stresses, which under certain conditions can manifest as complex disease phenotypes. Recent advances in high-throughput biological analyses, in combination with improved computational methods for data enrichment, functional annotation, and network visualization, have enabled a much deeper understanding of the mechanisms underlying important biological processes by identifying functional modules that are temporally and spatially perturbed in the context of disease development. Systems biology approaches such as these have produced compelling observations that would be impossible to replicate using classical methodologies, with greater insights expected as both the technology and methods improve in the coming years. Here, we examine the use of systems biology and network analysis in the study of a wide range of rheumatic diseases to better understand the underlying molecular and clinical features.

Proteomics in Rheumatoid Arthritis Research

Although rheumatoid arthritis (RA) is the most common chronic inflammatory autoimmune disease, diagnosis of RA is currently based on clinical manifestations, and there is no simple, practical assessment tool in the clinical field to assess disease activity and severity. Recently, there has been increasing interest in the discovery of new diagnostic RA biomarkers that can assist in evaluating disease activity, severity, and treatment response. Proteomics, the large-scale study of the proteome, has emerged as a powerful technique for protein identification and characterization. For the past 10 years, proteomic techniques have been applied to different biological samples (synovial tissue/fluid, blood, and urine) from RA patients and experimental animal models. In this review, we summarize the current state of the application of proteomics in RA and its importance in identifying biomarkers and treatment targets.

Allopurinol hypersensitivity syndrome in patients with hematological malignancies: characteristics and clinical outcomes

BACKGROUND/AIMS: Allopurinol is a urate-lowering agent that is commonly used to prevent chemotherapy-related hyperuricemia. Allopurinol hypersensitivity syndrome (AHS) is a disorder involving multiple organs, which may be accompanied by cutaneous adverse reactions. We identified the characteristics and clinical outcomes of chemotherapy-associated AHS in patients with hematological malignancies. METHODS: This retrospective single-center study included 26 AHS patients (11 with and 15 without hematological malignancies) admitted to Seoul St. Mary's Hospital. AHS was defined using the criteria of Singer and Wallace. Comparisons were made using the Mann-Whitney U test and Fisher exact test as appropriate. RESULTS: In patients with a hematological malignancy and AHS, statistically significant differences were observed in terms of younger age at onset; shorter duration of exposure; higher starting and maintenance doses of allopurinol; lower incidence of eosinophilia, leukocytosis, and underlying renal insufficiency; and more frequent occurrence of fever compared to AHS patients without a hematological malignancy. Two AHS patients with a hematological malignancy were examined for human leukocyte antigen (HLA)-B typing, but neither patient harbored the HLA-B*5801 allele. All of the patients ceased allopurinol treatment, with most patients making a full recovery. Two patients in the study died; however, these deaths were unrelated to AHS. One patient developed serious sequelae of AHS that required hemodialysis. CONCLUSIONS: Physicians who prescribe allopurinol for the prevention of chemotherapy-related hyperuricemia should be aware of the unique risk of AHS, even in patients with hematological malignancies who do not have known risk factors for AHS. Novel urate-lowering agents should be considered alternative treatments.

A Case of Immunoglobulin G4-related Interstitial Nephritis with Bicytopenia

Immunoglobulin G4-related disease (IgG4-RD) is a systemic inflammatory disease found in many organs including biliary tract, salivary gland, kidney, and lung. Tubulointerstitial nephritis is the most common renal manifestation, but hematologic involvement of IgG4-RD is rare. Here, we report on a case of a 57-year-old male with IgG4-related interstitial nephritis with bicytopenia, which was initially thought to be systemic lupus erythematosus. He presented with proteinuria, anemia, thrombocytopenia, and low complement levels. Histological findings showed an increased number of IgG4-positive plasma cells (>200/high power field), and an elevated IgG4/IgG ratio (>90%). Serum levels of IgG and IgG4 were also increased. This case emphasized the importance of differential diagnosis of IgG4-RD and immune complex glomerulonephritis.

Role of Endoplasmic Reticulum Stress in Rheumatoid Arthritis Pathogenesis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by abnormal proliferation of synoviocytes, leukocyte infiltration, and angiogenesis. The endoplasmic reticulum (ER) is the site of biosynthesis for all secreted and membrane proteins. The accumulation of unfolded proteins in the ER leads to a condition known as ER stress. Failure of the ER's adaptive capacity results in abnormal activation of the unfolded protein response. Recently, we have demonstrated that ER stress-associated gene signatures are highly expressed in RA synovium and synovial cells. Mice with Grp78 haploinsufficiency exhibit the suppression of experimentally induced arthritis, suggesting that the ER chaperone GRP78 is crucial for RA pathogenesis. Moreover, increasing evidence has suggested that GRP78 participates in antibody generation, T cell proliferation, and pro-inflammatory cytokine production, and is therefore one of the potential therapeutic targets for RA. In this review, we discuss the putative, pathophysiological roles of ER stress and GRP78 in RA pathogenesis.