Nodal generalised osteoarthritis is an autoimmune disease

Defining multiple joint osteoarthritis, its frequency and impact in a community-based cohort

BACKGROUND/PURPOSE

To update definitions of multiple joint osteoarthritis (MJOA), and to determine the frequency and impact of MJOA in a community-based cohort.

METHODS

Following PRISMA guidelines and with the help of a professional research librarian, we performed a systematic review in Medline using the terms osteoarthritis, generalized, polyarticular, multiple joint, and multi-joint among others, to obtain articles related to MJOA. A total of 42 articles were included for data extraction based on multiple criteria including the requirement for a clearly stated definition of OA assessed at more than one body site. We assessed frequency of these definitions in the Johnston County OA Project (JoCo OA) cohort as well as outcomes related to general health and physical function.

RESULTS

A total of 6 clearly stated definitions for MJOA were identified. These definitions were integrated with a list of 24 definitions from our previous systematic review and distilled down to produce 10 literature-derived, operationalized MJOA definitions. Based on these definitions, high frequencies of radiographic (4-74%) and symptomatic (2-52%) MJOA were found in the JoCo OA. Significant detrimental effects were seen on general health and physical function for most definitions.

CONCLUSIONS

We constructed a list of 10 summary MJOA definitions based in the literature that are frequent and associated with important clinical outcomes. These definitions capture some of the variability of MJOA phenotypes and provide a starting point for future analyses of both existing and newly initiated studies.

Immune Mediators in Osteoarthritis: Infrapatellar Fat Pad-Infiltrating CD8+ T Cells Are Increased in Osteoarthritic Patients with Higher Clinical Radiographic Grading

Osteoarthritis is a condition of joint failure characterized by many pathologic changes of joint-surrounding tissues. Many evidences suggest the role of both innate and adaptive immunity that interplay, resulting either in initiation or in progression of osteoarthritis. Adaptive immune cells, in particular T cells, have been demonstrated to play a role in the development of OA in animal models. However, the underlying mechanism is yet unclear. Our aim was to correlate the frequency and phenotype of tissue-infiltrating T cells in the synovial tissue and infrapatellar fat pad with radiographic grading. Our results show that CD8+ T cells are increased in osteoarthritic patients with higher radiographic grading. When peripheral blood CD8+ T cells were examined, we show that CD8+ T cells possess a significantly higher level of activation than its CD4+ T cell counterpart (P < 0.0001). Our results suggest a role for CD8+ T cells and recruitment of these activated circulating peripheral blood CD8+ T cells to the knee triggering local inflammation within the knee joint.

Increased Frequency of Hand Osteoarthritis in Patients with Primary Sjögren Syndrome Compared with Systemic Lupus Erythematosus

OBJECTIVE

In daily practice, we noticed that hand osteoarthritis (OA) was commonly associated with primary Sjögren syndrome (pSS). Therefore, we aimed to investigate its prevalence in patients with pSS in a controlled study.

METHODS

The study included patients with pSS and controls with systemic lupus erythematosus (SLE). Standard hand/wrist radiographs were obtained and classified according to the Kellgren-Lawrence system. "Erosive hand OA" was defined according to the Verbruggen-Veys classification.

RESULTS

There were 114 patients with pSS (110 women, 51.0 yrs) and 34 patients with SLE (33 women, 42.4 yrs). Among 114 patients with pSS, 42.7% had radiographic, 30.3% symptomatic, and 16.0% erosive hand OA. The prevalences of radiographic (45.5%) and erosive hand OA (14.4%) in 90 patients with pSS with age- and sex-matched patients with SLE were significantly higher than those in patients with SLE (14.7% and 0.0%, p = 0.007 and p = 0.012, respectively). Interobserver reliabilities for diagnosing radiographic and erosive OA were found to be good (ĸ = 0.780 and ĸ = 0.788, respectively). Intraobserver reliabilities for diagnosing radiographic and erosive OA were also good (ĸ = 0.784 and ĸ = 0.825 for FO, and ĸ = 0.722 and ĸ = 0.800 for AB, respectively). The frequency of hand OA in patients with pSS was found to be increased with increasing age (r = 0.513). The mean age of those with erosive hand OA was significantly higher than those without erosive OA (p < 0.001).

CONCLUSION

This study suggests that pSS, conversely to SLE, is more frequently associated with hand OA.

"Generalized osteoarthritis": a systematic review

OBJECTIVES

Given the conflicting definitions of "generalized osteoarthritis" (GOA) in the literature, we performed a systematic review of GOA definitions, risk factors, and outcomes.

METHODS

We searched the MEDLINE literature with the terms osteoarthritis, generalized, polyarticular, multiple joint, and multi-joint to obtain articles related to GOA, following evidence-based guidelines. Titles and abstracts of 948 articles were reviewed, with full-text review of 108. Data were extracted based on pre-specified criteria for 74 articles plus 24 identified through bibliographic review (n = 98).

RESULTS

Twenty-four large cohorts (n ~ 30,000) were represented along with numerous clinical series (n ~ 9000), across 22 countries and 60 years (1952-2012). No less than 15 definitions of GOA were given in 30 studies with a stated GOA definition; at least 6 groups used a summed score of joints or radiographic grades. Prevalence estimates based on these GOA definitions were 1-80%, although most were 5-25%. Increased risk and progression of GOA was associated with age, female sex, and genetic/familial factors. Associations with increased body mass index or bone mineral density were not consistent. A study estimated the heritability of GOA at 42%. Collagen biomarker levels increased with the number of involved joints. Increased OA burden was associated with increased mortality and disability, poorer health, and function.

CONCLUSION

While there remains no standard definition of GOA, this term is commonly used. The impact on health may be greater when OA is in more than one joint. A descriptive term, such as multi-joint or polyarticular OA, designating OA of multiple joints or joint groups is recommended.

Hand joint space narrowing and osteophytes are associated with magnetic resonance imaging-defined knee cartilage thickness and radiographic knee osteoarthritis: data from the Osteoarthritis Initiative

OBJECTIVE

To evaluate whether features of radiographic hand osteoarthritis (OA) are associated with quantitative magnetic resonance imaging (MRI)-defined knee cartilage thickness, radiographic knee OA, and 1-year structural progression.

METHODS

A total of 765 participants in Osteoarthritis Initiative (OAI; 455 women, mean age 62.5 yrs, SD 9.4) obtained hand radiographs (at baseline), knee radiographs (baseline and Year 1), and knee MRI (baseline and Year 1). Hand radiographs were scored for presence of osteophytes and joint space narrowing (JSN). Knee radiographs were scored according to the Kellgren-Lawrence (KL) scale. Cartilage thickness in the medial and lateral femorotibial compartments was measured quantitatively from coronal FLASHwe images. We examined the cross-sectional and longitudinal associations between features of hand OA (total osteophyte and JSN scores) and knee cartilage thickness, 1-year knee cartilage thinning (above smallest detectable change), presence of knee OA (KL grade ≥ 3), and progression of knee OA (KL change ≥ 1) by linear and logistic regression. Both hand OA features were included in a multivariate model (if p ≤ 0.25) adjusted for age, sex, and body mass index (BMI).

RESULTS

Hand JSN was associated with reduced knee cartilage thickness (ß = -0.02, 95% CI -0.03, -0.01) in the medial femorotibial compartment, while hand osteophytes were associated with the presence of radiographic knee OA (OR 1.10, 95% CI 1.03-1.18; multivariate models) with both hand OA features as independent variables adjusted for age, sex, and BMI). Radiographic features of hand OA were not associated with 1-year cartilage thinning or radiographic knee OA progression.

CONCLUSION

Our results support a systemic OA susceptibility and possibly different mechanisms for osteophyte formation and cartilage thinning.

Confirmation of two major polyarticular osteoarthritis (POA) phenotypes--differentiation on the basis of joint topography

OBJECTIVES

Previous studies of patients with primary hand and ankle osteoarthritis (OA) have suggested the presence of two major polyarticular OA (POA) phenotypes, designated Type 1 and Type 2. The former, characterised by sentinel distal interphalangeal (IP) (DIP) or proximal IP (PIP) joint OA resembles generalised OA (GOA), whereas the latter characterised by sentinel metacarpophalangeal (MCP)2,3 OA, resembles the arthropathy associated with hereditary haemochromatosis (HH). The aim of this study was to validate these putative phenotypes and to further investigate their clinical and genetic characteristics.

METHODS

Newly referred patients had X-rays if pre-determined clinical criteria for OA in hand and other joints were met. Subjects were assigned to the putative Type 1 POA (T1POA) or Type 2 POA (T2POA) phenotypes if radiological criteria were satisfied. Human haemochromatosis (HFE) gene mutations were determined in buffy-coat DNA by polymerase chain reaction amplification, followed by restriction enzyme cleavage and analysis on a 3% agarose gel. The significance of differences was determined by Chi-square test or by Fisher's exact test.

RESULTS

Sixty-seven patients fulfilled criteria for inclusion in this study; 39 (6M, 33F) for T1POA and 28 (18M, 10F) for T2POA. A statistically significant difference in gender was observed (64% male in the T2POA subset, P<0.0001). Heberden's nodes (HNs) were found in 34 of the 39 Type 1 subjects, but in only nine of the 28 Type 2 subjects (P<0.0001). HFE gene mutations were found in nine of the 39 Type 1 subjects (23%), whereas 21 of the 28 Type 2 subjects had a single HFE gene mutation (75%, P<0.0001).

CONCLUSIONS

These findings confirm the hitherto hypothetical proposition of a T1POA phenotype conforming to nodal GOA (NGOA) and a T2POA phenotype closely resembling the arthropathy described in haemochromatosis (HH).

The prevalence of autoantibodies against cartilage intermediate layer protein, YKL-39, osteopontin, and cyclic citrullinated peptide in patients with early-stage knee osteoarthritis: evidence of a variety of autoimmune processes

We studied arthritis-related autoantibodies in 136 patients with knee osteoarthritis (OA) and 67 age- and sex-matched healthy individuals in the Shanghai District of China. Serum antibody titers for recombinant fusion proteins of cartilage intermediate layer protein (CILP) and YKL-39 were analyzed using enzyme-linked immunosorbent assay (ELISA) and Western blot. Serum antibody titers against recombinant osteopontin (OPN) and cyclic citrullinated peptide (CCP) antibodies were measured also using ELISA. Anti-CILP antibodies were detected in 25/136 OA patients but only 1/67 controls. Anti-YKL-39, anti-OPN, and anti-CCP antibodies were detected in 9/136, 11/136, and 7/136 of the OA patients, respectively, and 0/67 controls. There was rarely overlap of these antibodies in a single patient, suggesting distinct antigen specificity in each case. The antibodies were detected in patients with OA of grades II and III but not grade IV. The prevalence of autoantibodies to various arthritis-related proteins in early-stage knee OA supports the involvement of a specific immune response in initial cartilage degeneration in OA.

The prevalence of autoantibodies against cartilage intermediate layer protein, YKL-39, osteopontin, and cyclic citrullinated peptide in patients with early-stage knee osteoarthritis: evidence of a variety of autoimmune processes

We studied arthritis-related autoantibodies in 136 patients with knee osteoarthritis (OA) and 67 age- and sex-matched healthy individuals in the Shanghai District of China. Serum antibody titers for recombinant fusion proteins of cartilage intermediate layer protein (CILP) and YKL-39 were analyzed using enzyme-linked immunosorbent assay (ELISA) and Western blot. Serum antibody titers against recombinant osteopontin (OPN) and cyclic citrullinated peptide (CCP) antibodies were measured also using ELISA. Anti-CILP antibodies were detected in 25/136 OA patients but only 1/67 controls. Anti-YKL-39, anti-OPN, and anti-CCP antibodies were detected in 9/136, 11/136, and 7/136 of the OA patients, respectively, and 0/67 controls. There was rarely overlap of these antibodies in a single patient, suggesting distinct antigen specificity in each case. The antibodies were detected in patients with OA of grades II and III but not grade IV. The prevalence of autoantibodies to various arthritis-related proteins in early-stage knee OA supports the involvement of a specific immune response in initial cartilage degeneration in OA.

Immune responses to cartilage link protein and the G1 domain of proteoglycan aggrecan in patients with osteoarthritis

OBJECTIVE

To determine whether patients with osteoarthritis (OA) express cellular immunity to cartilage link protein (LP) and the G1 globular domain of proteoglycan (PG) aggrecan, and whether immunity to the G1 domain is influenced by the removal of keratan sulfate (KS).

METHODS

LP and the G1 globular domain of PG were isolated from human and/or bovine cartilage and used in proliferation assays with peripheral blood lymphocytes (PBL) from 42 patients with OA and 40 healthy control subjects.

RESULTS

Patients with OA expressed a higher prevalence of cellular immunity to human cartilage LP (42.4%) compared with the control group (13.3%). The prevalence of immune reactivity to bovine LP in patients with OA was lower (35.7%) compared with the immunity to human LP, but remained similar in the control group (13.8%). PBL from patients with OA exhibited low reactivity to the native G1 domain of bovine PG. However, removal of KS chains from the G1 globular domain resulted in increased cellular immune responses to the G1 domain in OA patients (45.8%) compared with the control group (7.7%).

CONCLUSION

These results indicate the presence of immunity to cartilage-derived LP and the G1 globular domain of PG aggrecan in patients with OA and the inhibitory effect of KS chains on the G1 domain on the expression of this immunity in OA patients. This immune reactivity is commonly observed in patients with inflammatory joint disease and can experimentally induce arthritis. Thus, it may be involved in the pathogenesis of OA.

Osteoarthritis. A continuing challenge

Osteoarthritis is a disorder of cartilage that affects almost 85% of the population by age 75. A lack of rigorous clinical and radiographic criteria for defining the disorder makes precise determination of its prevalence impossible. The process of wear and tear explains many manifestations of osteoarthritis, but it does not account for some of the clinical findings or the biochemical changes in osteoarthritic cartilage. Thus, other factors such as heredity, hormones, and diet may play a role. Treatment consists of teaching patients about their disease, alleviating pain, and preserving joint function. Nonsteroidal anti-inflammatory drugs may be no more effective than simple analgesics in relieving the pain of this disorder. Moreover, some nonsteroidal anti-inflammatory drugs can adversely affect cartilage metabolism, and most are possibly dangerous in elderly patients. Drugs that inhibit the production or activity of chondrolytic enzymes can slow the degeneration of cartilage in some animals, but their effects on humans with osteoarthritis are unproved. The surgical repair of severely damaged joints can have gratifying results.

Erosive osteoarthritis

Erosive osteoarthritis is a disorder that most often involves the hands of postmenopausal women. It can begin abruptly with pain, swelling, and tenderness. Distal interphalangeal joints are involved most frequently, followed by proximal interphalangeal joints. Occasionally there is metacarpophalangeal, carpal, or large joint involvement. The female-to-male ratio is approximately 12:1. There are no known HLA associations. Laboratory studies generally are negative. A mild elevation of the sedimentation rate may occur. Radiologically, the disorder is characterized by central erosions and the "gull wing" deformity. Synovial pathology has shown changes consistent with both rheumatoid arthritis and osteoarthritis and manifests the stage of disease at the time of biopsy. The etiology remains obscure, but hormonal influences, metabolic disorders, and autoimmunity have been implicated. Treatment is largely supportive with physical therapy, nonsteroidal antiinflammatory drugs, and occasionally prednisone. Overall prognosis is good, although deformity and impairment of hand function may occur. For this reason, a reassessment of treatment strategies may be in order.