Standardisation of myositis-specific antibodies: where are we today?

Abstract

Weak-Strong 95% CIs were reconstructed based on the given prevalence. DN, double negative; DP, double positive; IP, Immunoprecipitation positive; LP, line immunoassay positive; MSA, myositis specific antibody.on August 5, 2020 by guest. Protected by copyright.

Anti-Ku antibodies: important points to consider

“…Although known for decades, very little data are available on the standardisation of anti-Ku antibodies. In a recent study, a kappa agreement of 0.86 (95% CI 0.57 to 1.00) was found indicating weak-to-perfect agreement 6 7…”

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

“…Considering the controversial data between Espinosa-Ortega’s1 and Cavazzana’s7 8 studies, it is emblematic that there is still no concordance among LIA and IP even for anti-Jo1, the most common MSA and the first discovered in this group of diseases. The low agreement of IP versus other methods, evidenced by recent studies,2 6 7 9 raises the question of whether IP should still be considered the reference method for detecting MSA.…”

Dermatomyositis autoantibodies: how can we maximize utility?

“…ELISA is more affordable with advantages that include standardization, large-scale reproducibility, and quantitative results, but does not necessarily always provide the same set of antigenic epitopes as do IP assays (36). Similarly, bead-based assays have been employed to detect certain MSAs (145). Finally, assays to detect non-native denatured forms of the antigens are in wide use, in the form of lineblot or dot-blot assays (146).…”

“…One early study compared commercial line immunoblot assay (LIA) with IP for 208 patients, finding 100% specificity and comparable sensitivity for anti-Jo-1 (92). Several recent studies compared the Euroline line immunoassay with IP (145,151,152). Most of these studies find good test performance for anti-Jo-1 antibodies (145).…”

“…Several recent studies compared the Euroline line immunoassay with IP (145,151,152). Most of these studies find good test performance for anti-Jo-1 antibodies (145). These studies highlight a major issue that arises in these validation studies-that is, they include a large majority of seronegative patients, which can give falsely high concordance rates driven by the negative samples.…”