Clinical features of anti-TIF1-α antibody-positive dermatomyositis patients are closely associated with coexistent dermatomyositis-specific autoantibodies and anti-TIF1-γ or anti-Mi-2 autoantibodies

Rheumatology, 05/08/2012

Muro Y et al. – Although Myositis–specific autoantibodies (MSAs) have been regarded as mutually exclusive, anti–Mi–2 antibody–positive patients simultaneously have anti–TIF1–α antibodies. Anti–Mi–2 antibody–positive patients are associated with classical DM without cancer even with the simultaneous presence of anti–TIF1–α antibodies.

Methods

  • Sera from 202 Japanese patients with CTDs, including 108 with DM and 20 healthy controls, were screened for anti–TIF1–α antibodies by the novel ELISAs.
  • Positive sera were further examined by immunoprecipitation and also investigated for the detection of anti–TIF1–γ and anti–Mi–2 antibodies.

Results

  • Sera from 12 patients with DM were confirmed to be positive for anti–TIF1–α antibodies.
  • None of the patients with other CTDs and none of the healthy controls had the antibodies.
  • Seven anti–TIF1–α–positive patients simultaneously had anti–TIF1– γ antibodies and the other five had anti–Mi–2 antibodies, both of which are well known to be MSAs.
  • These double–positive patients with anti–TIF1–α and anti–γ antibodies included three JDM and two cancer–associated adult DM patients, whereas all the double–positive patients with anti–TIF1–α and anti–Mi–2 antibodies were classical adult DM.

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