Combining immunofluorescence with immunoblot assay improves the specificity of autoantibody testing for myositis

Infantino, María; Tampoia, Marilina; Fabris, Martina; Alessio, Maria Grazia; Previtali, Giulia; Pesce, Giampaola; Deleonardi, Gaia; Porcelli, Brunetta; Musso, Maura; Grossi,; Benucci, Maurizio; Manfredi, Mariangela; Bizzaro, Nicola

doi:10.1093/rheumatology/key451

Cited by 27 publications

(21 citation statements)

References 20 publications

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“…Considering only MSA/MAA positive patients with indirect immunofluorescence (IIF) pattern on HEp-2 cells compatible with the respective MSA/MAA (according to the International Consensus on Standardized Nomenclature of Antinuclear Antibody HEp-2 Cell Patterns - ICAP) decreased clinical sensitivity but did not enhance the clinical specificity (supplemental Table S1). 9,10 MSA/MAA levels and age or sex did not show any significant correlations. A clinical diagnosis of ILD was present in 9 MSA/MAA negative and in 12 MSA/MAA positive patients (Table 2).…”

Section: Resultsmentioning

confidence: 67%

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The use and diagnostic value of testing myositis-specific and myositis-associated autoantibodies by line immuno-assay: a retrospective study

Lackner

Tiefenthaler

Mirzayeva

et al. 2020

Therapeutic Advances in Musculoskeletal

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Aims: Line immune-assays (LIA) for the detection of myositis-specific antibodies (MSA) are used widely for characterization of idiopathic inflammatory myopathies (IIM). Their current use and significance for the diagnosis of IIM remains unclear. Methods: In this retrospective analysis, we retrieved clinical diagnoses of patients tested for MSA and myositis-associated antibodies (MAA) Jo-1, Mi-2α, Mi-2β, TIF1γ, SRP, MDA-5, NXP-2, SAE, PL-7, PL-12, EJ, OJ, PM-Scl100, PM-Scl75 and Ku. We calculated clinical specificity, clinical sensitivity, negative- and positive predictive values (PPV) as well as positive and negative likelihood ratios. Results: In total, we analyzed 3167 samples. After exclusion of repeated measurements and patients with insufficient clinical information, data of 1118 patients were available for analysis. A total of 242 patients tested positive for at least one antibody, of which 45 patients had a diagnosis of IIM; 25 IIM patients were negative for all MSA/MAA. Clinical specificity of MSA/MAA for the diagnosis of IIM ranged between 94.2% and 99.9%. Clinical sensitivity and PPV across all antibodies tested ranged from 0.0% to 12.9% and 0.0% to 72.7%, respectively. Conclusion: In clinical practice MSA/MAA are used widely for diagnostic work-up of IIM, resulting in a low pre-test probability. Clinicians should be aware that PPVs for most MSA/MAA are low.

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Section: Resultsmentioning

confidence: 67%

“…Infantino et al proposed to improve clinical specificity of MSA detection by additionally considering the corresponding HEp-2 IIF pattern. 9 Applying this approach to our cohort did not result in increased clinical specificity. The different assays used to detect MSA may explain the discrepant results.…”

Section: Discussionmentioning

confidence: 76%

The use and diagnostic value of testing myositis-specific and myositis-associated autoantibodies by line immuno-assay: a retrospective study

Lackner

Tiefenthaler

Mirzayeva

et al. 2020

Therapeutic Advances in Musculoskeletal

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“…Nevertheless, today some tools have emerged that may help to improve the specificity of MSA detection by DIA/LIA and to confirm the diagnosis of MSA-associated IIM (table 1). Among these tools, our group has observed the importance of the agreement between DIA/LIA results and a compatible HEp-2 IIF pattern, showing a concordance of around 50% in IIM patients 14. Recently, Piette et al have confirmed these data, suggesting caution in interpreting the results in case of low-positive MSA signal intensity 5.…”

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confidence: 64%

Correspondence on ‘Standardisation of myositis-specific antibodies: where are we today?’

2019

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“…Epitopes may therefore be modified leading to recognition by unspecific antibodies that can be present in patients with other autoimmune or inflammatory diseases, as it has been already reported. 12 In addition, the proteins used as targets for the detection of onconeural antibodies may not be the true antigens. For instance, cerebellar degeneration protein 2 (CDR2) was the first antigen described for anti-Yo antibodies in paraneoplastic cerebellar degeneration associated with breast and ovary cancer in women.…”

Section: Discussionmentioning

confidence: 99%

Diagnostic yield of commercial immunodots to diagnose paraneoplastic neurologic syndromes

Déchelotte

Muñiz‐Castrillo

Joubert

et al. 2020

Neurol Neuroimmunol Neuroinflamm

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ObjectiveTo investigate the diagnostic yield of commercial immunodots to detect onconeural antibodies associated with paraneoplastic neurologic syndromes (PNSs), we analyzed the proportion of confirmed positive results using alternative techniques.MethodsSera (n = 5,300) of patients with suspected PNS were tested by PNS+2 blot (Ravo Diagnostika; January 2016–May 2017) or EUROLINE PNS 12 Ag (Euroimmun; July 2017–November 2018). Positive samples were further explored by in-house indirect immunofluorescence and a third in-house technique (Western blot or cell-based assay) using recombinant protein. Those found negative by these 2 techniques were considered as nonconfirmed. We analyzed the relationship between band intensity and final confirmation. Clinical data were collected for all confirmed results and nonconfirmed EUROLINE immunodots.ResultsPNS+2 blot was positive in 128/1,658 (7.7%) sera and confirmed in 47/128 (36.7%). EUROLINE was positive in 186/3,626 (5.1%) and confirmed in 56/186 (30.1%). Confirmation was highly variable among the antibodies tested, from 7.2% (PNS+2 blot) and 5.8% (EUROLINE) for anti-Yo to 88.2% (PNS+2 blot) and 65.0% (EUROLINE) for anti-Hu. None of the 27 weak positive sera by EUROLINE was confirmed. Band intensity in confirmed cases was variable among the antibodies from strong positive for all anti-Yo (n = 3) and anti-Hu (n = 11) to positive (n = 19) or strong positive (n = 9) for anti-SOX1. Among patients with a nonconfirmed EUROLINE result and available clinical information, all had an alternative diagnosis, and only 6.7% had cancer.ConclusionsImmunodots may be useful for PNS screening, but a threshold should be established for each antibody, and clinical information and confirmation by other techniques are essential.Classification of evidenceThe study provides Class IV evidence that immunodot assays for onconeural antibodies accurately identify patients with paraneoplastic neurologic syndromes.

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Combining immunofluorescence with immunoblot assay improves the specificity of autoantibody testing for myositis

Cited by 27 publications

References 20 publications

The use and diagnostic value of testing myositis-specific and myositis-associated autoantibodies by line immuno-assay: a retrospective study

The use and diagnostic value of testing myositis-specific and myositis-associated autoantibodies by line immuno-assay: a retrospective study

Correspondence on ‘Standardisation of myositis-specific antibodies: where are we today?’

Diagnostic yield of commercial immunodots to diagnose paraneoplastic neurologic syndromes

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