Patient global assessment and inflammatory markers in patients with idiopathic inflammatory myopathies - A longitudinal study

AIM

To explore if patient global assessment (PGA) is associated with inflammation over time and if associations are explained by other measures of disease activity and function in patients with idiopathic inflammatory myopathies (IIM).

METHODS

PGA and systemic inflammatory markers prospectively collected over five years were retrieved from the International MyoNet registry for 1200 patients with IIM. Associations between PGA, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and creatine kinase (CK) were analyzed using mixed models. Mediation analysis was used to test if the association between PGA and inflammatory markers during the first year of observation could be explained by measures of disease activity and function.

RESULTS

PGA improved, and inflammatory markers decreased during the first year of observation. In the mixed models, high levels of inflammatory markers were associated with worse PGA in both men and women across time points during five years of observation. In men, but not in women, the association between elevated ESR, CRP and poorer PGA was explained by measures of function and disease activity. With a few exceptions, the association between improved PGA and reduced inflammatory markers was partially mediated by improvements in all measures of function and disease activity.

CONCLUSION

Increased levels of systemic inflammation are associated with poorer PGA in patients with IIM. In addition to known benefits of lowered inflammation, these findings emphasize the need to reduce systemic inflammation to improve subjective health in patients with IIM. Furthermore, the results demonstrate the importance of incorporating PGA as an outcome measure in clinical practice and clinical trials.

Evaluation of a New Skeletal Troponin I Assay in Patients with Idiopathic Inflammatory Myopathies

BACKGROUND

The current biomarkers for diagnosis and monitoring of injured and diseased skeletal muscles, such as creatine kinase (CK), have limited tissue specificity and incapability to differentiate between pathological and physiological changes. Thus, new biomarkers with improved diagnostic accuracy are needed. Our aim was to develop and validate a novel assay for skeletal troponin I (skTnI), and to assess its clinical performance in patients with idiopathic inflammatory myopathies (IIM).

METHODS

A two-step fluoroimmunoassay was used to analyze samples from healthy reference individuals (n = 140), patients with trauma (n = 151), and patients with IIM (n = 61).

RESULTS

The limit of detection was 1.2 ng/mL, and the upper reference limit (90th percentile) was 5.2 ng/mL. The median skTnI concentrations were <limit of detection (LoD), 2.7 ng/mL, and 8.6 ng/mL in reference, trauma, and IIM cohorts, respectively. Differences in measured skTnI levels were statistically significant between all three study cohorts (Kruskal-Wallis P < 0.001; Mann-Whitney P < 0.001 for all). skTnI and CK had a strong positive correlation (Spearman's r = 0.771, P < 0.001), and the longitudinal changes in skTnI mirrored those observed with CK.

CONCLUSIONS

With the skTnI assay, patients with IIM were identified from healthy individuals and from patients with traumatic muscular injuries. When compared to CK, skTnI appeared to be more accurate in managing patients with low-grade IIM disease activities. The developed assay serves as a reliable analytical tool for the assessment of diagnostic accuracy of skTnI in the diagnosis and monitoring of myopathies.

THU0343 AUTOANTIBODIES CAN PARTLY PREDICT SEVERITY OF DAMAGE BUT NOT EXTENT IN PATIENTS WITH IDIOPATHIC INFLAMMATORY MYOSITIS

Background:

Patients with idiopathic inflammatory myopathies (IIM) might suffer from irreversible damage once inflammation has decreased. Autoantibodies are found in up to 80% of patients with IIM and are coupled with specific clinical features. Whether autoantibodies can be used as biomarkers to predict patterns of damage in IIM remains unknown.

Objectives:

To investigate the association between autoantibodies and organ damage in patients with IIM using longitudinal national register data.

Methods:

Data were retrieved from the electronic Swedish Rheumatology Quality Register (SRQ). Patients (n=302) with a clinical diagnosis of IIM (2017 EULAR/ACR criteria) were included. Autoantibody status was tested by either line blot or RNA- and protein immunoprecipitation; HMGCR and FHL-1 autoantibodies were tested by ELISA. Patients were grouped into six categories of autoantibodies (Table 1). TheMyositis Damage Index(MDI) score was applied to measure organ damage using both components (extentandseverity) as a continuous variable and were analyzed using generalized estimating equations (GEE). A categorical variable for each time point of MDI assessment since diagnosis was created to adjust for time (Table 2). A base model which included autoantibody group and time was fit. Other potential predictors included age at diagnosis, sex, disease duration from diagnosis to inclusion to SRQ, arthritis, Raynaud, mechanics’ hands and heart involvement at registry; core set measures at each MDI time point allowing multiple longitudinal observations were also tested.

Table 1.

Clinical diagnosis and autoantibody groups.

DiagnosisN (%)Polymyositis119 (38)Dermatomyositis (DM)99 (33)Inclusion body myositis35 (12)Amyopathic DM9 (3)Juvenile DM8 (3)Low probability myositis32 (11)Autoantibody286 (%)Antisynthetase (AS)74 (26)Necrotizing myopathy NM)20 (7)DM- specific44 (15)FHL-118 (6)Associated antibodies AA)50 (18)Negative to any80 (28)

AS: Jo1, PL7, PL12, EJ, OJ;NM: SRP, HMGCR;DM-specific: TIF1γ, Mi2, MDA5, SAE;AA: Ro52, PmScl, U1RNP, KU.

Table 2.

Predictors of damage severity and extent.

EstimateP valueSeverityTime#0.20NSAutoantibody group1Negativereference--Antisynthetase-0.6NSIMNM1.6NSDM- specific-2.6**FHL-10.4NSAssociated0.7NSMMT score1-0.1***ExtentTime#0.33NSCK, mkat/L2-0.006*

#Time from diagnosis to MDI. *<0.05**<0.01***<0.001

1. Adjusted for gender + disease duration + time.

2. Adjusted for disease duration + time.

Results:

Mean age at diagnosis was 54 years (SD 16), 205 were female (68%), median disease duration was 4 months (IQR 1-39). Clinical diagnosis and the autoantibody groups are shown in Table 1. The median time from diagnosis to the first MDI assessment was 2.2 years (IQR 1.2 – 5.5), 227 patients had a second MDI assessment at median 4.5 years (3.3-8.6 years) and 114 patients had a third assessment at 7.8 (5.8-9.9) years.Severity of damage:Only the DM-specific autoantibodies (P = 0.01) and manual muscle test score (MMT) (P = 0.007) were independent negative predictors; disease duration was a positive predictor (P = 0.01).Extent of damage: Autoantibodies were not significant predictors; creatine kinase (CK) levels were negative predictors (P = 0.01) (Table 2).

Conclusion:

Presence of DM-specific autoantibodies, a high MMT score over time and short disease duration seem to predict less damage severity whereas high CK levels seem to predict of less extent of damage. These findings indicate that some myositis specific autoantibodies may serve as predictors of damage along with other clinical measures.

References:

[1]Sultan SM, et al. Interrater reliability and aspects of validity of the myositis damage index. Annals of the Rheumatic Diseases. 2011;70:1272-6.

Disclosure of Interests:

Fabricio Espinosa-Ortega: None declared, Marie Holmqvist: None declared, Maryam Dastmalchi: None declared, Andrew Mammen: None declared, Ingrid E. Lundberg Grant/research support from: Bristol Meyer Squibb, Corbus Pharmaceuticals, Inc and Astra Zeneca, Helene Alexanderson: None declared

Quantitative T cell subsets profile in peripheral blood from patients with idiopathic inflammatory myopathies: tilting the balance towards proinflammatory and pro-apoptotic subsets

The role of T cells in idiopathic inflammatory myopathies (IIM) is not yet clear. Some alterations in certain subsets have been reported in inflamed muscle cells. However, a broad quantitative assessment of peripheral T cell subsets has not been evaluated. The aim of this study was to address the quantitative profile of potential pathogenic T cell subsets, namely follicular helper T cells (Tfh), T helper type 17 (Th17), CD28(null) and regulatory T cells (Tregs ) in peripheral blood from IIM patients. Thirty IIM patients and 30 age- and gender-matched healthy donors were included. Peripheral blood mononuclear cells were isolated. T cell subsets were evaluated by flow cytometry, as follows: Tfh (CD4(+) CXCR5(+) ) and its subsets Tfh1 (CXCR3(+) CCR6(-) ), Tfh2 (CXCR3(-) CCR6(-) ), Tfh17 (CXCR3(-) CCR6(+) ), Th17 (CD4(+) IL17A(+) ), CD28(null) (CD4(+) CD28(-) CD244(+) ) and Tregs (CD4(+) CD25(high) forkhead box protein 3 (FoxP3(+) ); CD8(+) CD25(high) FoxP3(+) ). Percentage, absolute numbers and mean fluorescence intensity were analysed. We found increased numbers of total Tfh cells (28 ± 8.16 versus 6.64 ± 1.29, P=0.031) in IIM patients when compared to healthy controls. Moreover, this increment was dependent upon Tfh2 and Tfh17 (Tfh2:9.49 ± 2.19 versus 1.66 ± 0.46, P=0.005; Tfh17 9.48 ± 2.83 versus 1.18 ± 0.21, P=0.014). Also, IIM patients showed higher numbers of Th17 cells (30.25 ± 6.49 versus 13.46 ± 2.95, P=0.031) as well as decreased number of Tregs (5.98 ± 1.61 versus 30.82 ± 8.38, P=0.009). We also found an expansion of CD28(null) cells (162.88 ± 32.29 versus 64 ± 17.35, P=0.015). Our data suggest that IIM patients are characterized by an expansion of peripheral proinflammatory T cells, such as Tfh and Th17, as well as pro-apoptotic CD28 null cells and a deficiency of suppressor populations of Tregs (CD4(+) and CD8(+) ).

Cost-minimization study comparing annual infusion of zoledronic acid or weekly oral alendronate in women with low bone mineral density

Cost-minimization study to assess the annual direct costs of 2 antiresorptive strategies in postmenopausal women with low bone mineral densities (BMDs). Patients were randomly assigned to receive 70 mg of oral weekly alendronate or a 1-time 5mg of intravenous zoledronic acid. All medical and nonmedical direct costs were recorded for 1 yr. Student's t-test or the Chi-squared test was used. A total of 101 postmenopausal women were enrolled with a mean age of 58.3 ± 7.6 yr and a postmenopausal period of 13.5 ± 8.3 yr. A total of 50 patients completed 1 yr of alendronate and 51 patients received zoledronic acid. At baseline, no differences were seen between the 2 groups in anthropometric measures, comorbidities, and bone mineral density. The costs for medical attention for low bone mass were $81,532 (US Dollars) for the alendronate group and $69,251 for the zoledronic acid group; the cost per patient was $1631 in the alendronate group vs $1358 in the zoledronic acid group (p<0.0001). Therefore, zoledronic acid treatment provided an annual savings of 15% of the direct costs compared with oral alendronate treatment. Moreover, there was a significant increase in lumbar spine T-scores in the zoledronic acid group when compared with the alendronate group. Annual zoledronic acid infusion as an antiresorptive treatment in women with low BMD provides significant monetary savings when compared with weekly alendronate therapy for 1 yr. Zoledronic acid infusion is also linked to higher increase in BMD and compliance.