High-resolution free-breathing automated quantitative myocardial perfusion by cardiovascular magnetic resonance for the detection of functionally significant coronary artery disease.

AIMS: Current assessment of myocardial ischaemia from stress perfusion cardiovascular magnetic resonance (SP-CMR) largely relies on visual interpretation. This study investigated the use of high-resolution free-breathing SP-CMR with automated quantitative mapping in the diagnosis of coronary artery disease (CAD). Diagnostic performance was evaluated against invasive coronary angiography (ICA) with fractional flow reserve (FFR) measurement. METHODS AND RESULTS: Seven hundred and three patients were recruited for SP-CMR using the research sequence at 3 Tesla. Of those receiving ICA within 6 months, 80 patients had either FFR measurement or identification of a chronic total occlusion (CTO) with inducible perfusion defects seen on SP-CMR. Myocardial blood flow (MBF) maps were automatically generated in-line on the scanner following image acquisition at hyperaemic stress and rest, allowing myocardial perfusion reserve (MPR) calculation. Seventy-five coronary vessels assessed by FFR and 28 vessels with CTO were evaluated at both segmental and coronary territory level. Coronary territory stress MBF and MPR were reduced in FFR-positive (≤0.80) regions [median stress MBF: 1.74 (0.90-2.17) mL/min/g; MPR: 1.67 (1.10-1.89)] compared with FFR-negative regions [stress MBF: 2.50 (2.15-2.95) mL/min/g; MPR 2.35 (2.06-2.54) P < 0.001 for both]. Stress MBF ≤ 1.94 mL/min/g and MPR ≤ 1.97 accurately detected FFR-positive CAD on a per-vessel basis (area under the curve: 0.85 and 0.96, respectively; P < 0.001 for both). CONCLUSION: A novel scanner-integrated high-resolution free-breathing SP-CMR sequence with automated in-line perfusion mapping is presented which accurately detects functionally significant CAD.

MMP expression in rheumatoid inflammation: the rs11568818 polymorphism is associated with MMP-7 expression at an extra-articular site.

Matrix metalloproteinases (MMPs) contribute to the joint damage in rheumatoid arthritis (RA). Less is known of the involvement of MMPs at extra-articular sites of rheumatoid inflammation. We assessed the relative contribution from MMP-1, MMP-3, MMP-7 and MMP-12 to joint and extra-articular tissue destruction and inflammation by comparing gene expression in joint synovia and subcutaneous rheumatoid nodules from RA patients. Expression of MMP-1 and MMP-3 predominated in synovia, whereas MMP-12 expression was significantly higher in rheumatoid nodules. Markedly higher MMP-7 expression distinguished a subgroup of nodules that featured infiltrating monocyte/macrophage-producing MMP-7 protein. The high MMP-7 expression in nodules was associated with the single-nucleotide polymorphism (SNP) rs11568818 (-181A>G, MMP-7 promoter) and more active inflammation within the nodule lesions. Patients with such nodules had significantly earlier age of RA onset. Our findings indicate that the expression of MMP-1 and MMP-3 occurs relatively independent of the tissue microenvironment with substantial expression also at extra-articular sites. MMP-12 expression reflects the involvement of monocyte/macrophages in rheumatoid inflammation. Evidence for the association between the rs11568818 SNP and increased MMP-7 expression is restricted to nodules, which indicates that consequences of the MMP-7 polymorphism are likely to manifest within aspects of immune/inflammatory activity that are monocyte/macrophage-mediated.

IL-23R rs11209026 polymorphism modulates IL-17A expression in patients with rheumatoid arthritis.

The interleukin (IL)-17/IL-23 axis is an important pro-inflammatory pathway in rheumatoid arthritis (RA). IL-23 maintains CD4(+) T-helper 17 (Th(17)) cells, whereas IL-12 negates IL-17A production by promoting Th(1)-cell differentiation. We sought evidence for any effect of polymorphisms within the interleukin-23 receptor (IL-23R), IL-12 or IL-21 genes on serum cytokine concentrations in 81 patients with RA. Serum cytokines were measured using bead-based multiplex assays. Targeted cytokines were detected in up to 66% of samples. A subgroup of 48 patients had detectable serum IL-17A. Within this subgroup, patients, homozygous for the IL-23R rs11209026 major allele had significantly higher serum IL-17A concentrations compared with patients with the minor allele (394.51 ± 529.72 pg ml(-1) vs 176.11 ± 277.32 pg ml(-1); P = 0.017). There was no significant difference in any of the cytokine concentrations examined in patients positive for the minor allele vs homozygosity for the major allele of IL-12B rs3213337, IL-12Bpro rs17860508 and IL-21 rs6822844. Our results suggest the IL-23R Arg381Gln substitution may influence serum IL-17A concentrations. In patients with the 381Gln allele higher IL-23 concentrations may be needed to produce similar IL-17A concentrations to those in patients with the 381Arg allele. This suggests altered IL-23R function in patients with the minor allele and warrants further functional studies.

Evidence for association of an interleukin 23 receptor variant independent of the R381Q variant with rheumatoid arthritis.

OBJECTIVE: The rare allele of a non-synonymous interleukin 23 receptor (IL23R) single nucleotide polymorphism (SNP) rs11209026 (p.Arg381Gln) confers strong protection against Crohn disease (CD) and psoriasis. Other IL23R variants also exhibit association with CD, genetically independent of rs11209026. In rheumatoid arthritis (RA), IL23 is an important determinant of the production of IL17A, a cytokine of consequence in inflammation and bone destruction. While there is no previous support for strong association of IL23R with RA, the possibility of a weaker role for IL23R variants in the aetiology of RA cannot be eliminated. METHODS: A New Zealand RA cohort was tested for association with six IL23R SNPs and the resulting data combined with a reanalysis of the Wellcome Trust Case Control Consortium data and a previously published Spanish data set. The combined data set totals over 3000 Caucasian cases and 3800 controls, which has sufficient power to detect a risk of as low as odds ratio (OR) = 1.2. RESULTS: Our data emphasise the lack of association of rs11209026 with RA (OR 1.01, 95% confidence interval (CI) 0.88 to 1.16, p = 0.86). However there was some evidence for association of rs1343151 with RA (OR 1.14, 95% CI 1.06 to 1.22, p = <0.001). CONCLUSIONS: While requiring further replication, these data further support a role for the IL17A/IL23 pathway in RA. Understanding how different variants of IL23R associate, at varying levels of strength, with contrasting groups of immune-mediated diseases (CD, psoriasis, ankylosing spondylitis, RA) will enhance knowledge on the aetiology of these diseases.

Evidence for an influence of chemokine ligand 3-like 1 (CCL3L1) gene copy number on susceptibility to rheumatoid arthritis.

OBJECTIVE: There is increasing evidence that gene copy-number variation influences phenotypic variation. Chemokine ligand 3-like 1 (CCL3L1) is encoded by a variable copy-number gene, and binds to several pro-inflammatory cytokine receptors, including chemokine receptor 5 (CCR5). Considering lymphocyte recruitment by beta-chemokines is a feature of autoimmunity, and that the CCR5Delta32 variant is associated with protection to rheumatoid arthritis (RA), we hypothesised that CCL3L1 copy-number influences susceptibility to RA and type 1 diabetes (T1D). METHODS: We measured CCL3L1 copy-number in 1136 RA cases from New Zealand (NZ) and the UK, 252 NZ T1D cases and a total of 1470 controls. All subjects were ancestrally Caucasian. RESULTS: A copy-number higher than 2 (the most common copy number) was a risk factor for RA in the NZ cohort (odds ratio (OR) 1.34, 95% CI 1.08-1.66, p = 0.009) but not the smaller UK RA cohort (OR 1.09, 95% CI 0.75-1.60, p = 0.643). There was evidence for association in the T1D cohort (OR 1.46, 95% CI 0.98-2.20, p = 0.064) and in the combined RA/T1D cohort (OR 1.30, 95% CI 1.00-1.54, p = 0.003). Genetic interaction between CCL3L1 dosage and CCR5 genotype was found; the increased genetic risk conferred by higher CCL3L1 copy-number was ablated by a dysfunctional CCR5 (CCR5Delta32). CONCLUSIONS: These data suggest that increased CCL3L1 expression may enhance inflammatory responses and increase the chance of autoimmune disease. Genetic interaction data were consistent with a biologically plausible model; CCR5Delta32 protects against RA and T1D by blocking signalling through the CCR5 pathway, mitigating the pro-inflammatory effects of excess CCL3L1.

Disease Activity Score 28-ESR bears a similar relationship to treatment decisions across different rheumatologists, but misclassification is too frequent to replace physician judgement.

OBJECTIVES: To determine whether physician factors are associated with disease activity status in RA, independently of 28-joint disease activity score (DAS28)-ESR and to re-evaluate DAS28-ESR misclassification rates for identifying active disease in usual practice. METHODS: A prospective observational study of outpatients with RA seen by 17 rheumatologists across New Zealand. Active disease was defined by an increase in therapy together with a reason of 'active disease'; very low disease activity was defined by a decrease in therapy together with a reason of 'patient well'. The independent physician effect was assessed using logistic regression. Sensitivity and specificity of current DAS28-ESR thresholds were calculated. RESULTS: In 511 patients, 178 had active disease, 220 had low disease activity, 37 had very low disease activity and 76 had uncertain disease activity status. There was no independent effect of physician upon active disease status (P = 0.16) with DAS28-ESR [(OR) 3.7] explaining around 50% of the variability in active disease status. There was a trend towards an independent effect of physician upon very low disease activity status (P = 0.06) and greater variability in the distribution of DAS28-ESR for patients in very low disease activity. DAS28-ESR thresholds showed a significant risk of misclassification for active disease. CONCLUSIONS: DAS28-ESR discriminates satisfactorily between groups of patients with active and non-active disease, with no evidence of additional physician-specific factors to explain disease activity status. However, DAS28-ESR is not as good for discriminating remission from non-remission status. There are appreciable probabilities of misclassification error, which make DAS28-ESR inappropriate as a sole guide for treatment decisions.

A solid-phase enzyme immunoassay for C-reactive protein: clinical value and the effect of rheumatoid factor.

Measurement of serum C-reactive protein (CRP) concentration is useful in monitoring the progress of chronic inflammatory diseases. Rheumatoid factor, by its interaction with the Fc portion of IgG, has the potential to interfere with solid-phase immunoassays for CRP and other serum proteins. To determine the effect of RF on a solid-phase enzyme immunoassay for CRP we compared assays employing whole antisera or F(ab')2 fragments. In 92 sera with RF latex titres ranging from 1/80 to 1/81,920, no correlation was found between RF concentrations and CRP measurements. CRP concentrations measured by use of whole antisera (mean +/- standard error of the mean, 59.7 +/- 5.7 mg/l, n = 92) were lower than those measured with F(ab')2 fragments (62.5 +/- 5 mg/l), indicating that exaggeration of CRP measurements did not occur in RF containing sera under the conditions of the assay. Our results show that in the CRP-ELISA, interference from RF was precluded by the high serum dilutions employed. At lower serum dilutions RF binding was detected. Consequently, in solid-phase enzyme immunoassays at lower serum dilutions the presence of RF may lead to false positive results and exaggerated measurements.

Development of an enzyme immunoassay for the quantitation of cellular antigen expression.

An enzyme immunoassay is described which can be used to quantitate the cellular expression of antigens recognised by mouse monoclonal antibodies (mAb). To provide the sensitivity required, complexes of alkaline phosphatase and mouse monoclonal anti-alkaline phosphatase (APAAP) have been used. The speed and reproducibility of the assay was improved with the aid of immunofiltration methodology. Quantitative measurement of HLA-DR antigen expression by ELISA did not correlate directly with the number of mononuclear cells scored positive following immunohistochemical staining of cytocentrifuged preparations. In patients with rheumatoid arthritis, more HLA-DR was expressed on synovial fluid mononuclear cells than on the corresponding cells obtained from peripheral blood.

Development of the gout tophus. An hypothesis.

Sequential stages have been demonstrated in the development of individual focal deposits of crystalline urate and associated cell infiltrates within subcutaneous gout tophi. The findings suggest that acini of macrophages are formed and that active cellular transport of urate from the interstitial fluid into the central zones of these structures accounts for the focal nature of crystallization within the tophus. This process seems to account for the formation of focal urate deposits up to some 1.5-2 mm in diameter. The corona then commonly disappears and adjacent deposits may fuse. These events may lessen the consequences of hyperuricemia.

Differential relationships between stress and disease activity for immunologically distinct subgroups of people with rheumatoid arthritis.

Immunologically distinct subgroups of patients with rheumatoid arthritis (RA)--those with the autoantibody rheumatoid factor (seropositive RA) and those without (seronegative RA)--were compared on a variety of clinical and self-report measures in a consecutive series of women with disease of 7 years' or less duration. The groups were comparable on clinical, pain, functional, and psychosocial variables. However, the seronegative RA group reported elevated levels of preonset negative life event stress. Postonset life event stress and disease activity were significantly correlated for the seronegative RA group, but not for the seropositive RA group. Results suggest that stress factors may be more important in the etiology and maintenance of seronegative RA and that the seronegative RA group may possibly derive particular benefit from psychological techniques to enhance stress management skills.

Lipid peroxidation and malondialdehyde in the synovial fluid and plasma of patients with rheumatoid arthritis.

The concentration of lipid peroxides in the plasma and synovial fluid of 65 arthritic patients was determined using a new ion-pairing reverse phase HPLC technique. Patients with rheumatoid arthritis receiving only non-steroidal anti-inflammatory drugs, had a significantly higher mean concentration of lipid peroxides in synovial fluid samples (162 +/- 22.0 micrograms/l) than osteoarthritic patients (40.0 +/- 8.0 micrograms/l, p less than 0.0001). Mean concentrations in both groups correlated strongly with the level of beta-glucuronidase activity as a measure of lysosomal enzyme release (r = 0.71, p less than 0.0001). Contrary to previous reports by investigators using less specific methods, we were unable to demonstrate any increase in plasma levels of lipid peroxides in the rheumatoid patient. Treatment of rheumatoid arthritis with D-penicillamine was associated with a significant reduction of lipid peroxide levels (83.2 +/- 11.5 micrograms/ml, p less than 0.002), suggesting that this drug may function as an oxygen radical scavenger in the joint cavity. These results give further support to the concept of oxygen-free radicals playing an important role in the pathogenesis of chronic inflammatory disorders.

Non-steroidal anti-inflammatory drugs in combination. Experimental observations.

Diflunisal in combinations with oxaprozin, indomethacin and sodium meclofenamate produced significant synergistic suppression of carrageenan-induced oedema of the rat foot-pad. Oxaprozin, benoxaprofen, indomethacin, diflunisal, sodium meclofenamate and auranofin in some paired combinations but not in others were associated with a greater effect than the component drugs used alone. Antagonism was demonstrated with other combinations of these drugs.

A trial of clodronate-liposomes as anti-macrophage treatment in a sheep model of arthritis.

OBJECTIVE: Our previous research has concerned the role of macrophages in joint inflammation in rheumatoid arthritis. We have therefore been interested in liposomes containing clodronate as an antimacrophage treatment for arthritis. We have used the antigen-induced arthritis model in sheep to evaluate the effect of clodronate liposomes. METHODS: Arthritis was induced in the right hock joint (day 0). We were able to demonstrate uptake of liposomes into macrophages within the inflamed joint lining. On day 7, sheep were given a single intra-articular injection of clodronate liposomes (group 1, n = 10) or saline liposomes (group 2, n = 10). A further 6 sheep (group 3) had no arthritis and no treatment. RESULTS: No difference in joint diameter was observed between the sheep in group 1 (clodronate) and group 2 (saline treated). Both groups had joint swelling which persisted until the end of the trial (day 20). Histologic scoring was also similar in group 1 and group 2 animals, and both were worse than group 3. CONCLUSION: In vitro studies have shown that interaction of liposomes with neutrophils and monocytes stimulates a respiratory burst. Despite this possible pro-inflammatory effect we did not observe any increase in joint diameter following liposome injection. Thus we were unable to demonstrate a therapeutic effect of a single dose of clodronate liposomes in this large animal model of antigen-induced arthritis.

Antigen-induced (Dumonde Glynn) arthritis in the sheep: a large joint animal model of arthritis.

OBJECTIVE: To determine if the Dumonde Glynn model of arthritis can be established in sheep since a larger model would facilitate injection and the measurement of joints. METHODS: Three groups of sheep were immunised with ovalbumin in Freund's adjuvant. Arthritis was induced in group 1 (n = 10, by the injection of 5 mg ovalbumin in 0.5 ml to the right hock joint. Control groups received saline (n = 10) or no treatment (n = 6). RESULTS: Following joint injection the mean AP diameter increased so that there was a 32% difference between the right and left joints at 24 hr (p < 0.001) declining gradually to 12% (p < 0.01) 19 days after the induction of arthritis. The level of haptoglobin in group 1 prior to the induction of arthritis was 0.04 +/- 0.01. Haemoglobin binding capacity (mg/ml) peaked on day 3 at 0.33 +/- 0.13 (p < 0.01), and was 0.110 +/- 0.05 thirteen days after joint injection. Features observed included proliferation of the joint lining, fibrin deposition and early erosion of cartilage. Synovial membrane showed an infiltrate of inflammatory cells identified as monocytes/macrophages and lymphocytes. Synovial histology scores were 1.8 +/- 0.2 for the left joint and 9.3 +/- 0.73 for the arthritic right joint. CONCLUSION: We conclude that this is a model of mono-arthritis particularly useful when a larger joint is required for intra-articular injection or repeated joint measurements such as in a clinical trial.

Immunohistochemical analysis of synovial membranes from inflammatory and non-inflammatory arthritides: scarcity of CD5 positive B cells and IL2 receptor bearing T cells.

Rheumatoid Arthritis (RA) synovial membranes were examined by single and dual immunohistological techniques with a number of monoclonal antibodies against lymphocyte and macrophage related antigens. CD4 positive T lymphocytes frequently expressed MHC Class II antigens and were found in sublining collections in close association with activated macrophages as well as B lymphocytes. CD8 positive T cells surrounded these collections as well as being scattered throughout the membrane and also frequently expressed MHC Class II antigens. IL2 receptor (IL2r) expression on T cells and CD5 expression on B cells were rarely seen in these synovial membranes. Similar immunohistological architecture was found in synovial membranes from patients with psoriatic arthritis (PA) and Reiter's Syndrome (RS). Normal synovium contained few T cells, with few cells expressing MHC Class II antigens. Synovium from osteoarthritis (OA) patients also demonstrated similar immunohistological changes to those found in inflammatory arthritides, suggesting that there are only quantitative rather than qualitative differences between the synovial membrane immunohistological architecture from patients with inflammatory and noninflammatory arthritides.

Reactive arthritis: characteristics in southern New Zealand.

AIM: To review the clinical characteristics of patients with reactive arthritis and their associated triggering infections in a New Zealand community. METHOD: We reviewed the records of 60 patients with reactive arthritis. For comparison data was also collected on 30 randomly selected patients with psoriatic arthritis. RESULTS: Reactive arthritis affected a young age group. Half the episodes occurred in the age range 16-24 years and the mean age, (SD) of affected patients was 27(10) years cf psoriatic arthritis 40 (17) years, p<0.001. Almost half had a disease course longer than 2 yr and erosive joint damage in one quarter. Two thirds required treatment with sulphasalazine or methotrexate and patients with reactive arthritis were admitted to hospital frequently: 37% vs psoriatic arthritis 7%, p<0.001. Antecedent diarrhoea was documented in 23 episodes whereas a diagnosis of sexually acquired reactive arthritis was made in 11. CONCLUSION: Reactive arthritis has a significant impact on a young age group in this community. This provides a further reason for action to contain the rapidly increasing prevalence in the community of gastrointestinal infections known to trigger reactive arthritis.

Concurrent polyarteritis nodosa and temporal arteritis.

A patient is described in which features of both giant cell arteritis and polyarteritis nodosa were present simultaneously. The case emphasises our lack of an aetiologic classification for arteritis and that on occasions typical clinical presentations may be misleading.

A double blind comparison of tiaprofenic acid with placebo.

The results of a double blind crossover comparative trial of the nonsteroidal antiinflammatory drug tiaprofenic acid with placebo in the treatment of rheumatoid arthritis are reported. Tiaprofenic acid was confirmed as being an effective drug of this class and no untoward side effects were encountered. Individual response was varied and not related to disease activity.

Osteitis--an under-recognised association with seronegative spondyloarthropathy?

AIM: To emphasise osteitis as a feature of the spondyloarthritides. METHOD: We describe four cases spanning a spectrum of the spondyloarthritides in which osteitis was a feature. RESULTS: One patient had psoriatic arthritis with palmar-plantar pustular psoriasis and extensive osteitis involving the tibia and fibula. This case provides a link with two cases with SAPHO syndrome (synovitis, acne, pustulosis hyperostosis, osteitis) who had palmar-plantar pustulosis and osteitis. Many now argue that this syndrome is a form of spondyloarthritis. The fourth case, which was of particular interest to us, had enteric reactive arthritis and scintigraphic changes strongly suggesting the presence of osteitis of individual bones in the wrist. CONCLUSION: We propose that these four cases demonstrate that osteitis may be another feature common to the spondyloarthritides and SAPHO. Awareness of this may facilitate better documentation of this feature of the disease.