Objective.

To investigate the expression and function of Mohawk (MKX) in human adult anterior cruciate ligament (ACL) tissues and ligament cells from normal and osteoarthritis-affected knees. Methods. Knee joints were obtained at autopsy within 24-48 hours postmortem from 13 normal donors (age 36.9±11.0 years), 16 OA donors (age 79.7±11.4 years) and 8 old donors without OA (age 76.9±12.9 years). All cartilage surfaces were graded macroscopically. MKX expression was analyzed by immunohistochemistry and quantitative PCR. ACL-derived cells were used to study regulation of MKX expression by IL-1β. MKX was knocked down by siRNA to analyze function of MKX in extracellular matrix (ECM) production and differentiation in ACL-derived cells.

Results.

The expression of MKX was significantly decreased in ACL-derived cells from OA knees compared with normal knees. Consistent with this finding, immunohistochemistry showed that MKX positive cells were significantly reduced in ACL tissues from OA donors in particular in cells located in disorientated fibers. In ACL-derived cells, IL-1β strongly suppressed MKX gene expression and reduced ligament ECM genes, COL1A1 and TNXB. On the other hand, SOX9, chondrocyte master transcription factor, was up regulated by IL-1β treatment. Importantly, knock down of MKX expression by siRNA upregulated SOX9 expression in ACL-derived cells, whereas the expression of COL1A1 and TNXB were decreased.

Conclusion.

Reduced expression of MKX is a feature of degenerated ACL in OA-affected joints and this may be in part mediated by IL-1β. MKX appears necessary to maintain the tissue specific cellular differentiation status and ECM production in adult human tendons and ligaments. © 2013 American College of Rheumatology.

Objective:

To compare commonly-available tests for antibodies to citrullinated protein antigens (ACPAs) for diagnostic accuracy and assay agreement in established rheumatoid arthritis (RA) and subjects at elevated risk for RA.

Methods:

ELISA testing for anti-cyclic citrullinated peptide (anti-CCP) antibodies was performed using CCP2 (Axis-Shield) and CCP3.1 (IgA/IgG INOVA) in the following subjects: 1) probands with established RA (N=340) from the Studies of the Etiology of RA (SERA), 2) first degree relatives (FDRs) without RA (family members of SERA RA probands; N=681), 3) Department of Defense Serum Repository (DoDSR) RA cases with pre-diagnosis samples (N=83; 47/83 also had post-diagnosis samples), and 4) blood-donor and DoDSR controls (N=283).

Results:

In established RA, CCP2 was more specific (99.2% vs. 93.1%, p<0.01), but less sensitive (58.7% vs. 67.4%, p=0.01) than CCP3.1, with specificity of CCP3.1 increasing to 97.2% if levels ≥3 times the standard cut-off level were considered. In all subjects, at standard cut-off levels, CCP3.1 positivity was more prevalent. In DoDSR cases, CCP2 was more specific than CCP3.1 for a future diagnosis of RA, and higher CCP levels trended towards greater specificity for disease onset within 2 years. At standard cut-off levels, assay agreement was good in established RA (kappa=0.76), but poor in FDRs without inflammatory arthritis (kappa=0.25).

Conclusion:

Anti-CCP assays differ to an extent that may be meaningful in diagnosing RA in patients with inflammatory arthritis, and in evaluating the natural history of RA development in subjects at-risk for future RA. Mechanisms underlying these differences in test performance need further investigation. © 2013 American College of Rheumatology.

Background:

Sonography is a sensitive tool for evaluating synovitis in rheumatoid arthritis (RA) compared with clinical assessment. However, differences between these assessments may depend on how "joint activity" is defined. Therefore, we compared clinically vs. sonographically active joints in RA by different sonographic definitions.

Methods:

Sonographic assessment of finger and wrist joints (11 joints) of each hand was performed in RA patients in remission (n=60; CDAI ≤ 2.8). Grey scale (GS) and power Doppler (PD) signals were evaluated on a 4-point (0=no, 3=severe) scale. We investigated sensitivity and specificity of swollen joint counts using increasingly stringent sonographic definitions of "active joint" as reference. Sonographic findings were also correlated to other clinical variables, including HAQ. Follow-up analyses were performed after 6 to 12 months.

Results:

GS was positive in 67.2% of 1320 assessed joints and PD in 20.4%. Clinical joint swelling was 100% specific for sonographic activity independent of the stringency of definition; maximum sensitivity was 25% for the most stringent definition (i.e. GS=3 and PD=3). Further, patients with higher PD signals (PD=3) showed higher HAQ levels (HAQ 0.45±0.62) compared to patients with lower PD signals (HAQ 0.20±0.35). Higher grades of PD signals at baseline were found in joints which were clinically swollen at the consecutive visit.

Conclusion:

Low grade PD and GS signals may not necessarily reflect active synovitis, high grade PD correlates well with clinical joint swelling and clinical activity and high grade PD signals are associated with higher degrees of functional impairment. © 2013 American College of Rheumatology.

Objectives:

CD8T cells lacking CD28 were originally reported by Wedderburn and colleagues as a characteristic feature of JIA, but the relevance of these unusual cells to JIA remains to be elucidated. Because of recent evidence that CD28 loss is typical of terminally differentiated lymphocytes, we examined for functional subsets of CD8T cells in JIA.

Methods:

Following informed consent/assent, blood and/or waste synovial fluid were collected from children with definite diagnosis of JIA (n = 98). De-identified blood (n = 33) and cord blood (n = 13) samples from healthy donors were also collected. CD8T and CD4T cells were screened for novel receptors, and where indicated, bioassays were performed to determine functional relevance of the identified receptor.

Results:

Patients had a naïve T cell compartment with shortened telomeres, and their entire T cell pool had reduced proliferative capacity. They had an over abundance of CD31(+) CD28(null) CD8T cells, which was a significant feature of oligoarticular JIA (n = 62) compared to polyarticular JIA (n = 36). CD31(+) CD28(null) CD8T cells had limited mitotic capacity, and expressed high levels of the senescence antigens γH2Ax and/or p16. Ligation of CD31, independent of the TCR, sufficiently induced tyrosine phosphorylation, vesicle exocytosis, and production of IFN-γ and IL-10.

Conclusion:

These data provide the first evidence for cell senescence, represented by CD31(+) CD28(null) CD8T cells, in the pathophysiology of JIA. Activation of these unusual cells in a TCR-independent manner suggests they are maladaptive, and could be potential targets for immunotherapy. © 2013 American College of Rheumatology.

Objective:

Methotrexate (MTX) monotherapy (MM) is recommended as the initial rheumatoid arthritis (RA) DMARD. We demonstrate for the first time in a blinded trial that initial MTX (IM) with the option to step-up to combination therapy results in similar outcomes to initial combination therapy (IC).

Methods:

The TEAR trial randomized 755 early poor prognosis RA participants to MTX (IM) versus IC (MTX+etanercept or MTX+sulfasalazine +hydroxychloroquine,). IM participants stepped-up to combinations at 24 weeks if DAS28 was > 3.2.

Results:

Attrition at 24 weeks was similar in IM and IC at 24 weeks. Of the 370 evaluable participants in the IM group, 28% achieved low disease activity and did not step-up to combination therapy (MM group). DAS28-ESR for participants remaining on MM at week 102 was 2.7±1.2, similar to participants treated with immediate combinations (2.9±1.2 ). Participants on MM had less radiographic progression at week 102 compared to participants who received immediate combination therapy (∆TSS 0.2±1.1 vs. 1.1±6.4). Participants assigned to IM requiring step-up at 24 weeks (72%, SU) demonstrated similar DAS28-ESR values (week 48: 3.5±1.3 vs. 3.2±1.3) and radiographic progression (week 102: ∆TSS1.2±4.1 vs. 1.1±6.4) as those treated with initial combination therapy. Results for either immediate combination approach, triple therapy or MTX+etanercept were similar.

Conclusions:

These results in early, poor prognosis RA validate the strategy of starting with MTX mono-therapy. Approximately 30% of patients will not need combination therapy and the 70% who need it are clinically and radiographically indistinguishable from those that received immediate combination therapy. © 2013 American College of Rheumatology.

OBJECTIVE:

Studies in human volunteers have shown that vitamin C reduces serum urate (SU). The aim of this study was to determine effects of vitamin C on SU in patients with gout.

METHODS:

Patients with gout and SU >0.36mmol/L were recruited. 20 patients already receiving allopurinol were randomised to an increase in allopurinol dose or commenced on vitamin C 500mg/d. 20 patients not receiving allopurinol were randomised to start allopurinol or vitamin C 500mg/d. Plasma ascorbate, creatinine, and SU were measured at day 0 and week 8.

RESULTS:

There was no significant difference in baseline SU or eGFR between those who received vitamin C and those who did not (SU 0.50±0.11mmol/l vs. 0.50±0.09mmol/l p=0.89; eGFR 65.5±15.7ml/min/1.73m(2) vs. 67.9±20.7 ml/min/1.73m(2) p=0.67). 30% in the vitamin C group and 25% in the no vitamin C group were receiving diuretics (p=0.72). In the patients receiving vitamin C there was a significant increase between week 0 and 8 in plasma ascorbate. The reduction in SU was significantly less in those patients receiving vitamin C compared to those who started or increased the dose of allopurinol (0.014mmol/l vs. 0.118mmol/l p<0.001).

CONCLUSION:

Modest dose vitamin C (500mg/d) for 8 weeks had no clinically significant urate lowering effect in patients with gout despite increasing plasma ascorbate. These results differ from findings in hyperuricaemic healthy controls. The uricosuric effect of modest dose vitamin C appears less in patients with gout both as monotherapy and in combination with allopurinol. © 2013 American College of Rheumatology.