Evaluation of a novel particle-based assay for detection of autoantibodies in idiopathic inflammatory myopathies

Cavazzana, Ilaria; Richards, Michaelin; Bentow, Chelsea; Seaman, Andrea; Fredi, Micaela; Palterer, Boaz; Pratesi, Federico; Migliorini, Paola; Franceschini, Franco; Satoh, Minoru; Ceribelli, Angela; Mähler, Michael

doi:10.1016/j.jim.2019.112661

Cited by 24 publications

(31 citation statements)

References 22 publications

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“…Based on the promising performance characteristics of a novel PMAT system for the detection of MSA observed in previous studies [20][21][22], we aimed to validate those findings. In the current study, the prevalence of all MSA was within the expected range extracted from the published literature [37].…”

Section: Discussionmentioning

confidence: 85%

“…Consequently, the markers are not only relevant as an aid in the diagnosis, but also in the stratification to specific disease subsets . Most of the clinical associations of MSA and MAA have been established using IP and might be lost with newer methods [16][17][18][19][20][21][22][23][24][25][26][27][28].…”

Section: Discussionmentioning

confidence: 99%

“…All samples were tested using a novel fully automated particle-based multi-analyte technology (PMAT, Inova Diagnostics, research use only; Jo-1, PL-7, PL-12, EJ, Mi-2ß, TIF1γ, SAE, MDA5, NXP2, HMGCR, SRP) which utilizes paramagnetic particles with unique signatures and a digital interpretation system as described previously [ 20 , 21 , 22 ]. In brief: antigens are coupled to paramagnetic particles that carry unique signatures and incubated with diluted patient samples.…”

Section: Methodsmentioning

confidence: 99%

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Profiling of Myositis Specific Antibodies and Composite Scores as an Aid in the Differential Diagnosis of Autoimmune Myopathies

et al. 2021

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(1) Background: Myositis specific antibodies (MSA) represent important diagnostic and stratification tools in idiopathic inflammatory myositis (IIM) patients. Here we aimed to evaluate the clinical performance of MSA profiled by a novel particle based multi-analyte technology (PMAT) in IIM and subsets thereof. (2) Methods: 264 IIM patients and 200 controls were tested for MSA using PMAT (Inova Diagnostics, research use only). Diagnostic performance was analyzed and composite scores were generated. (3) Results: The sensitivity/specificity of the individual MSA were: 19.7%/100% (Jo-1), 7.2%/100.0% (Mi-2), 3.0%/99.0% (NXP2), 3.8%/100.0% (SAE), 2.7%/100.0% (PL-7), 1.9%/99.5 (PL-12), 1.1%/100.0% (EJ), 15.5%/99.5% (TIF1γ), 8.3%/98.5% (MDA5), 6.1%/99.0% (HMGCR) and 1.9%/98.5% (SRP). Of all IIM patients, 180/264 tested positive for at least one of the MSAs. In the individual control group, 12/200 (6.0%) tested positive for at least one MSA, most of which had levels close to the cut-off (except one SRP and one PL-12). Only 6/264 (2.3%) IIM patients were positive for more than one antibody (MDA5/HMGCR, EJ/PL-7, 2 x MDA5/TIF1γ, EJ/SAE, SAE/TIF1γ). The overall sensitivity was 68.2% paired with a specificity of 94.0%, leading to an odds ratio of 33.8. The composite scores showed good discrimination between subgroups (e.g., anti-synthetase syndrome). (4) Conclusion: MSA, especially when combined in composite scores (here measured by PMAT), provide value in stratification of patients with IIM.

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Section: Discussionmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Profiling of Myositis Specific Antibodies and Composite Scores as an Aid in the Differential Diagnosis of Autoimmune Myopathies

et al. 2021

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“…Limited validation, particularly for rarer autoantibodies, has been a growing concern among the myositis community [ 6 , 12 , 13 ]. Previous studies in this area have been small, with low numbers of sera containing individual MSAA specificities [ 6 , 14 , 15 ]. They have highlighted that the level of agreement of line blot with immunoprecipitation is highly dependent on autoantibody specificity [ 6 , 14 , 15 ].…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies in this area have been small, with low numbers of sera containing individual MSAA specificities [ 6 , 14 , 15 ]. They have highlighted that the level of agreement of line blot with immunoprecipitation is highly dependent on autoantibody specificity [ 6 , 14 , 15 ]. By selecting sera based on autoantibody specificity rather than analysing a cohort, where some MSAA specificities may be very low prevalence or absent, we have been able to clearly demonstrate that the two commercially available assays tested do not perform well for all MSAA specificities.…”

Section: Discussionmentioning

confidence: 99%

The reliability of immunoassays to detect autoantibodies in patients with myositis is dependent on autoantibody specificity

Tansley

Betteridge

et al. 2020

Rheumatology

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Objectives In order to address the reliability of commercial assays to identify myositis-specific and -associated autoantibodies, we aimed to compare the results of two commercial immunoassays with the results obtained by protein immunoprecipitation. Methods Autoantibody status was determined using radio-labelled protein immunoprecipitation for patients referred to our laboratory for myositis autoantibody characterization. For each autoantibody of interest, the sera from 25 different patients were analysed by line blot (Euroline Myositis Antigen Profile 4, EuroImmun, Lübeck, Germany) and dot blot (D-Tek BlueDiver, Diagnostic Technology, Belrose, NSW, Australia). Sera from 134 adult healthy controls were analysed. Results Overall commercial assays performed reasonably well, with high agreement (Cohen’s κ >0.8). Notable exceptions were the detection of rarer anti-synthetases with κ < 0.2 and detection of anti-TIF1γ, where κ was 0.70 for the line blot and 0.31 for dot blot. Further analysis suggested that the proportion of patients with anti-TIF1γ may recognize a conformational epitope, limiting the ability of blotting-based assays that utilize denatured antigen to detect this clinically important autoantibody. A false-positive result occurred in 13.7% of samples analysed by line blot and 12.1% analysed by dot blot. Conclusion The assays analysed do not perform well for all myositis-specific and -associated autoantibodies and overall false positives are relatively common. It is crucial that clinicians are aware of the limitations of the methods used by their local laboratory. Results must be interpreted within the clinical context and immunoprecipitation should still be considered in selected cases, such as apparently autoantibody-negative patients where anti-synthetase syndrome is suspected.

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Markers of Autoimmune Rheumatic Diseases

Baldovino,

Cecchi,

Radin

et al. 2024

Rare Diseases of the Immune System

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Evaluation of a novel particle-based assay for detection of autoantibodies in idiopathic inflammatory myopathies

Cited by 24 publications

References 22 publications

Profiling of Myositis Specific Antibodies and Composite Scores as an Aid in the Differential Diagnosis of Autoimmune Myopathies

Profiling of Myositis Specific Antibodies and Composite Scores as an Aid in the Differential Diagnosis of Autoimmune Myopathies

The reliability of immunoassays to detect autoantibodies in patients with myositis is dependent on autoantibody specificity

Markers of Autoimmune Rheumatic Diseases

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