C-reactive protein levels in patients with rheumatoid arthritis: the impact of therapy

Assessment for Septic Arthritis in Immunocompetent and Immunocompromised Patients: A Single-Institution Study

INTRODUCTION

Prompt diagnosis of septic arthritis is imperative to prevent irreversible joint damage. Immunocompromised patients are at an increased risk of septic arthritis as well as secondary systemic infection. Our aims were to identify features predictive of septic arthritis and to determine whether these features differed between immunocompetent and immunocompromised patients.

METHODS

A single institution retrospective cohort study was performed of 173 immunocompetent and 70 immunocompromised patients who underwent aspiration or arthrotomy for suspected septic arthritis from 2010 to 2018. Demographic data, symptoms, laboratory values, and imaging findings were recorded. Multiple variable logistic regression models were used to assess for predictive factors for septic arthritis in both cohorts. Results were reported as odds ratios, 95% confidence intervals, and P values.

RESULTS

In the regression analysis, independent predictive factors for septic arthritis in immunocompetent patients were younger age (P = 0.004), presence of radiographic abnormalities (P = 0.006), and C-reactive protein (CRP) (P < 0.001). For immunocompromised patients, only CRP was an independent continuous predictive factor (P = 0.008) for septic arthritis. A risk stratification tool for predicting septic arthritis in immunocompetent patients using age <55 years, CRP >100 mg/dL, and presence of radiographic abnormalities was developed. A similar tool was created using CRP >180 mg/dL and radiographic abnormalities in immunocompromised patients.

DISCUSSION

Differences in predictive factors for septic arthritis between immunocompromised and immunocompetent patients suggest dissimilar clinical presentations. The developed risk stratification tools allow one to predict the likelihood of septic arthritis in both groups. This may permit more accurate selection of patients for surgical intervention in the setting of insufficient data from synovial aspiration.

The Interleukin-1 Receptor-Associated Kinase 4 Inhibitor PF-06650833 Blocks Inflammation in Preclinical Models of Rheumatic Disease and in Humans Enrolled in a Randomized Clinical Trial

OBJECTIVE

To investigate the role of PF-06650833, a highly potent and selective small-molecule inhibitor of interleukin-1-associated kinase 4 (IRAK4), in autoimmune pathophysiology in vitro, in vivo, and in the clinical setting.

METHODS

Rheumatoid arthritis (RA) inflammatory pathophysiology was modeled in vitro through 1) stimulation of primary human macrophages with anti-citrullinated protein antibody immune complexes (ICs), 2) RA fibroblast-like synoviocyte (FLS) cultures stimulated with Toll-like receptor (TLR) ligands, as well as 3) additional human primary cell cocultures exposed to inflammatory stimuli. Systemic lupus erythematosus (SLE) pathophysiology was simulated in human neutrophils, dendritic cells, B cells, and peripheral blood mononuclear cells stimulated with TLR ligands and SLE patient ICs. PF-06650833 was evaluated in vivo in the rat collagen-induced arthritis (CIA) model and the mouse pristane-induced and MRL/lpr models of lupus. Finally, RNA sequencing data generated with whole blood samples from a phase I multiple-ascending-dose clinical trial of PF-06650833 were used to test in vivo human pharmacology.

RESULTS

In vitro, PF-06650833 inhibited human primary cell inflammatory responses to physiologically relevant stimuli generated with RA and SLE patient plasma. In vivo, PF-06650833 reduced circulating autoantibody levels in the pristane-induced and MRL/lpr murine models of lupus and protected against CIA in rats. In a phase I clinical trial (NCT02485769), PF-06650833 demonstrated in vivo pharmacologic action pertinent to SLE by reducing whole blood interferon gene signature expression in healthy volunteers.

CONCLUSION

These data demonstrate that inhibition of IRAK4 kinase activity can reduce levels of inflammation markers in humans and provide confidence in the rationale for clinical development of IRAK4 inhibitors for rheumatologic indications.

Anti-HLA Class II Antibodies Correlate with C-Reactive Protein Levels in Patients with Rheumatoid Arthritis Associated with Interstitial Lung Disease

The pathogenesis of Rheumatoid Arthritis (RA) is not fully understood, probably influenced by genetic and environmental factors. Interstitial Lung Disease (ILD) is an extra-articular manifestation of RA, which contributes significantly to morbidity and mortality. The identification of anti-HLA antibodies has been useful in the transplantation field; however, its contribution to autoimmune diseases as RA has not been fully studied. We aimed to determine the presence of anti-HLA antibodies in RA patients with and without ILD and its possible association with clinical and biochemical markers. One-hundred and forty-seven RA patients, of which 65 had ILD (RA-ILD group), were included. Sera samples for Anti-HLA Class II LABScreen panel-reactive antibodies (PRA) were analyzed. In both groups, women predominated, and lung function was worse in patients with ILD. The anti-CCP+ (UI/mL) was higher in the RA group in comparison to RA-ILD (p < 0.001). Expositional risk factors (tobacco smoking and biomass-burning smoke) were higher in RA-ILD patients. PRA+ was identified in ~25% RA-ILD patients, while ~29% in the RA group. The CRP levels have a positive correlation with the percentage of reactivity (%PRA, p = 0.02, r2 = 0.60) in the RA-ILD group. In conclusion, anti-HLA antibodies correlate with C-reactive protein levels in RA patients with ILD.

Dissociation of C-Reactive Protein Localizes and Amplifies Inflammation: Evidence for a Direct Biological Role of C-Reactive Protein and Its Conformational Changes

C-reactive protein (CRP) is a member of the pentraxin superfamily that is widely recognized as a marker of inflammatory reactions and cardiovascular risk in humans. Recently, a growing body of data is emerging, which demonstrates that CRP is not only a marker of inflammation but also acts as a direct mediator of inflammatory reactions and the innate immune response. Here, we critically review the various lines of evidence supporting the concept of a pro-inflammatory “CRP system.” The CRP system consists of a functionally inert circulating pentameric form (pCRP), which is transformed to its highly pro-inflammatory structural isoforms, pCRP* and ultimately to monomeric CRP (mCRP). While retaining an overall pentameric structure, pCRP* is structurally more relaxed than pCRP, thus exposing neoepitopes important for immune activation and complement fixation. Thereby, pCRP* shares its pro-inflammatory properties with the fully dissociated structural isoform mCRP. The dissociation of pCRP into its pro-inflammatory structural isoforms and thus activation of the CRP system occur on necrotic, apoptotic, and ischemic cells, regular β-sheet structures such as β-amyloid, the membranes of activated cells (e.g., platelets, monocytes, and endothelial cells), and/or the surface of microparticles, the latter by binding to phosphocholine. Both pCRP* and mCRP can cause activation of platelets, leukocytes, endothelial cells, and complement. The localization and deposition of these pro-inflammatory structural isoforms of CRP in inflamed tissue appear to be important mediators for a range of clinical conditions, including ischemia/reperfusion (I/R) injury of various organs, cardiovascular disease, transplant rejection, Alzheimer’s disease, and age-related macular degeneration. These findings provide the impetus to tackle the vexing problem of innate immunity response by targeting CRP. Understanding the “activation process” of CRP will also likely allow the development of novel anti-inflammatory drugs, thereby providing potential new immunomodulatory therapeutics in a broad range of inflammatory diseases.

Disease-Drug Interaction of Sarilumab and Simvastatin in Patients with Rheumatoid Arthritis

Introduction

Elevated interleukin (IL)-6 occurs in patients with active rheumatoid arthritis (RA), which has been shown to lead to a decrease in cytochrome P450 (CYP) enzyme activity and alterations in drug concentrations metabolized by CYP. IL-6 signaling blockade by IL-6 receptor (IL-6R) antagonists may reverse this effect of IL-6 and restore CYP activity. This study evaluated the pharmacokinetic profile of simvastatin (a CYP3A4 substrate) before and 1 week after a single dose of sarilumab (a human monoclonal antibody [mAb] blocking the IL-6Rα) in patients with RA, to assess potential interaction.

Methods

Nineteen patients with active RA received oral simvastatin 40 mg 1 day before and 7 days after subcutaneous injection of sarilumab 200 mg. The pharmacokinetic parameters of simvastatin and its primary metabolite, β-hydroxy-simvastatin acid, were calculated using noncompartmental analysis.

Results

Compared with simvastatin alone, single-dose simvastatin administration 7 days after single-dose sarilumab administration in patients with RA resulted in reduced simvastatin and β-hydroxy-simvastatin acid exposure in plasma. Mean effect ratios (90 % confidence interval) for simvastatin peak plasma concentration (C_max) and area under the concentration–time curve extrapolated to infinity (AUC_∞) were 54.1 % (42.2–69.4 %) and 54.7 % (47.2–63.3 %), respectively. No changes occurred in time to C_max or half-life for either simvastatin or β-hydroxy-simvastatin acid after sarilumab administration.

Conclusions

Sarilumab treatment resulted in a reduction in exposure of simvastatin, consistent with reversal of IL-6-mediated CYP3A4 suppression in patients with active RA, as was reported for tocilizumab with simvastatin and for sirukumab with midazolam.

Clinical trial registration number

NCT02017639.

Electronic supplementary material

The online version of this article (doi:10.1007/s40262-016-0462-8) contains supplementary material, which is available to authorized users.

Diagnostic accuracy of arthroscopic biopsy in periprosthetic infections of the hip

Background

Diagnosis of a low-grade periprosthetic joint infection (PJI) prior to revision surgery can be challenging, despite paramount importance for further treatment. Arthroscopic biopsy of synovial and periprosthetic tissue with subsequent microbiological and histological examination can be beneficial but its specific diagnostic value has not been clearly defined.

Methods

20 consecutive patients who underwent percutaneous synovial fluid aspiration as well as arthroscopic biopsy due to suspected PJI of the hip and subsequent one- or two-stage revision surgery at our institution between January 2012 and May 2015 were enrolled. Indication was based on the criteria (1) history of PJI and increased levels of erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP), (2) suspicious cell count and differential but negative bacterial culture in synovial aspirate, (3) early loosening (<less than 2 years), or (4) persisting pain without loosening but history of a PJI. At least two criteria had to be fulfilled in order to perform an arthroscopic biopsy.

Results

Best overall diagnostic value was identified for arthroscopic biopsy and a combination of bacteriological and histological analysis with a sensitivity of 87.5%, specificity of 100% and accuracy of 95%. Bacteriological assessment of synovial aspirate revealed a sensitivity of 50.0%, specificity of 91.7%, and accuracy of 75%. ESR and CRP yielded a sensitivity of 75.0% for either hematologic test and specificities of 87.5 and 66.7%, respectively.

Conclusions

In conclusion, our data indicate that arthroscopic biopsy is superior to ESR and CRP as well as joint aspiration and their combinations. Concurrent microbiological and histological examination of the biopsy specimens allows for identification of the causative pathogen and its susceptibility pattern in order to preoperatively plan the surgical strategy as well as the antibiotic regimen. Moreover, intraarticular mechanical failure can be detected during hip arthroscopy emphasizing its diagnostic value. Level II diagnostic study.

The effect of robenacoxib on the concentration of C-reactive protein in synovial fluid from dogs with osteoarthritis

Background

Robenacoxib is a novel and highly selective inhibitor of COX-2 in dogs and cats and because of its acidic nature is regarded as being tissue-selective. Thirty four dogs with stifle osteoarthritis secondary to failure of the cranial cruciate ligament were recruited into this study. Lameness, radiographic features, synovial cytology and C-reactive protein concentrations in serum and synovial fluid were assessed before and 28 days after commencing a course of Robenacoxib at a dose of 1 mg/kg SID.

Results

There was a significant reduction in the lameness score (P < 0.01) and an increase in the radiographic score (P < 0.05) between pre- and post-treatment assessments. There was no difference between pre- (median 1.49 mg/l; Q1-Q3 0.56-4.24 mg/L) and post – (1.10 mg/L; 0.31-1.78 mg/L) treatment serum C-reactive protein levels although synovial fluid levels were significantly reduced (pre- : 0.44 mg/L; 0.23-1.62 mg/L; post- : 0.17 mg/L; 0.05-0.49 mg/L) (P < 0.05). There was no correlation between C-reactive protein concentrations in serum and matched synovial fluid samples.

Conclusions

Robenacoxib proved effective in reducing lameness in dogs with failure of the cranial cruciate ligament and osteoarthritis of the stifle joint. The drug also reduced levels of C-reactive protein in the synovial fluid taken from the affected stifle joint. Robenacoxib appears to reduce articular inflammation as assessed by C-reactive protein which supports the concept that Robenacoxib is a tissue-selective non-steroidal anti-inflammatory drug.

Statin or nonsteroidal anti-inflammatory drug use is associated with lower erythrocyte sedimentation rate in patients with giant cell arteritis

BACKGROUND

Previous studies have found that nonsteroidal anti-inflammatory drugs (NSAIDs) and statins may impact erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) levels in patients. The current study was performed to determine if NSAID or statin use is associated with lower ESR and CRP in patients with biopsy-proven giant cell arteritis (GCA).

METHODS

A retrospective cross-sectional study was conducted that included 161 patients via chart review. Charts of patients with GCA seen at the University of Iowa Hospitals and Clinics from 1960 to 2008 were reviewed. Inclusion criteria were adequate medication records, serum ESR and/or CRP on record, no prior corticosteroid use, and biopsy-positive GCA. Exclusion criteria were the presence of diseases known to elevate ESR or CRP. Main outcome measures included ESR and CRP values measured while evaluating patients for GCA but prior to receiving treatment.

RESULTS

Statin nonusers had an ESR of 85.0 mm per hour (interquartile range [IQR] = 60-110 mm per hour) and a CRP of 8.7 mg/dL (IQR = 2.7-16.2 mg/dL). Statin users had an ESR of 57.5 mm per hour (IQR = 35-85) and a CRP of 2.4 mg/dL (IQR = 0.8-15.9 mg/dL). Statin use was associated with a lower ESR (P = 0.005), while there was no significant association with a lower CRP (P = 0.127). NSAID nonusers had an ESR of 98.0 mm per hour (IQR = 64-116) and a CRP of 8.7 mg/dL (IQR = 2.1-16.2 mg/dL). NSAID users had an ESR of 75.0 mm per hour (IQR = 46-98.5 mm per hour) and CRP of 8.0 mg/dL (IQR. = 1.5-16.2 mg/dL). NSAID use was associated with a lower ESR (P = 0.004), but there was no significant association with a lower CRP (P = 0.522).

CONCLUSION

Statin use and NSAID use were associated with a lower ESR; however, they were not associated with lower CRP values. Clinicians should be aware that statin or NSAID use is associated with lower ESR in patients with GCA, and this test may therefore have lower sensitivity and specificity for recognizing patients with GCA, and CRP may be a superior test to evaluate patients for GCA.

Proteins of rat serum IV. Time-course of acute-phase protein expression and its modulation by indomethacine

Changes in the concentration of major serum proteins were monitored from day 0 to day 4 in three experimental groups: rats injected with turpentine, rats receiving the turpentine shot and daily doses of indomethacine, and rats given indomethacine alone. In inflamed animals, peak changes for acute-phase reactants, evaluated by two-dimensional electrophoresis (2-DE), were usually observed between 48 and 72 h after the phlogistic stimulus. By itself, indomethacine was found to affect the synthesis of most proteins (except one of the thiostatin variants and ceruloplasmin); the changes in serum levels, whether positive or negative, were the same as upon inflammation (except for kallikrein-binding protein), but their extent and/or timing usually differed. When inflamed animals were given indomethacine, a clear-cut difference in the concentration of some proteins was observed versus inflamed rats not given medication, at 24 h after the start of the treatments. Proteins mainly affected were alpha2-macroglobulin, alpha2-HS-glycoprotein, C-reactive protein and kallikrein-binding protein.

The value of C-reactive protein measurement in rheumatoid arthritis

Since 1973, assessment of serum concentrations of C-reactive protein (CRP) has been advocated as a objective measure of disease activity in rheumatoid arthritis (RA). Our review of clinical experience with CRP measurement suggests it has at least two important roles to play in the management of RA. First, persistently elevated CRP levels have prognostic value. In general, such elevated levels are found in those patients who are at greater risk for continuing joint deterioration and therefore may need more aggressive treatment and supportive care. Second, in general, improvement in CRP levels is an objective indication that a drug has produced a beneficial effect and thus may be useful to the physician for monitoring effects of therapy. Since CRP may be elevated in a number of conditions besides RA, a diagnosis of RA must be made before using CRP as a prognostic factor.

Clinical and laboratory outcomes during the treatment of rheumatoid arthritis with methotrexate

Ten clinical and three laboratory outcomes were evaluated in 86 patients completing a double-blind placebo-controlled trial of methotrexate in rheumatoid arthritis. The improvement in all measured outcomes was statistically significantly better in patients receiving methotrexate than in patients receiving placebo. The correlations of the changes in outcome measures were calculated to determine if improvement in one parameter was associated with improvement in other clinical parameters. Associations between different clinical outcomes were often statistically significant. Associations between laboratory outcomes were also often statistically significant. However, the association between clinical outcomes and laboratory outcomes was generally poor.

[C-reactive protein in inflammatory articular diseases: comparison of concentrations in blood and synovial fluid]

We evaluated the diagnostic value of measuring C-Reactive Protein (CRP) in blood and in synovial fluid for the detection of inflammatory articular diseases in 154 patients. High concentrations of CRP in blood were found in microcrystalin arthritis, polymyalgia rheumatica and Horton's disease. Our results show a good correlation between CRP and erythrocyte sedimentation rate for ankylosing spondylitis (p less than 0.01), systemic lupus erythematosus (p less than 0.01), rheumatoid arthritis (p less than 0.05), polymyalgia rheumatica and Horton's disease (p less than 0.05). The CRP measurement in blood did not separate seropositive versus seronegative rheumatoid arthritis, systemic lupus erythematosus versus rheumatoid arthritis and treated versus non-treated rheumatoid arthritis. There was a good correlation between CRP concentration in blood and in synovial fluid but the concentration was lower in synovial fluid than in blood (p less than 0.01). Then, the CRP measurement in synovial fluid does not have a higher diagnostic value than in blood.

The major leukocyte protein L1 as an indicator of inflammatory joint disease

L1 is a major protein in granulocytes and monocytes. It is released during activation of these cells, and the plasma level of L1 is therefore thought to reflect the turnover of leukocytes. Peripheral blood from 96 patients hospitalized in a rheumatological department, was analysed for L1, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). The total patient material was divided into groups depending on diagnosis: 47 patients with rheumatoid arthritis, 27 patients with arthritis of different etiologies, 15 patients with non-inflammatory diseases and 7 patients with arteritis. Correlation analysis were made between the different laboratory parameters. A high positive correlation was found between L1 and CRP in all the groups, and with a correlation coefficient of the total patient material of 0.68 (p less than 0.001). The correlation coefficient between L1 and ESR was 0.54 (p less than 0.001) in the total patient material, and between CRP and ESR it was 0.66 (p less than 0.001). The results indicate that the L1 protein could be a new laboratory marker of inflammation in rheumatic diseases.