Detection of myositis-specific antibodies

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

“…Similar to a previous study reporting variability between blot assays for anti-Jo-1 antibodies,6 the current letter also reports higher than expected variability for anti-Jo-1 antibodies which is related to the known limitation of IP for the detection of anti-Jo-1 antibodies, due to the relatively thin uncharacteristic band in IP (in contrast to other aminoacyl-tRNA synthetases) and to the co-migration with the IgG heavy chain 7…”

“…In these patients the clinical phenotype matches the co-occurring MSA, rather than having a separate phenotype. In this context, it should be noted that there is a large variation in anti-TIF1γ reactivity between different LIA methods, with, for example, the Euroimmun LIA detecting more anti-TIF1γ reactivity than the Alphadia DB 6…”

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

“…Another study that has opened Pandora’s box is Vulsteke’s10 which compared three different DIA/LIA assays showing significant differences in diagnostic performance which, however, varied according to the MSA considered. This great variability clearly demonstrates the urgent need to harmonise methods, and that their clinical validation against the reference IP method remains an issue 8 9.…”

Detection of myositis-specific antibodies: additional notes

“…With interest we read the recent article by Vulsteke et al 1 showing data derived from an evaluation of three immunoassay systems for the detection of autoantibodies associated with autoimmune inflammatory myopathies (AIM). As stated by the authors, careful evaluation of autoantibody assays for the detection of myositis-specific (MSA) and myositis-associated (MAA) antibodies is of utmost importance since some of these are included or being considered for the AIM classification criteria 2–4.…”