Anti-Mi-2 dermatomyositis has immunohistochemical features distinct from non-Mi-2 dermatomyositis

Takeaway

  • Features of dermatomyositis associated with anti-Mi-2 antibodies that differentiate it from non-Mi-2 dermatomyositis include perifascicular necrosis, increased perimysial alkaline phosphatase activity, and sarcolemmal membrane attack complex deposition; these feature are akin to those of antisynthetase syndrome.

Why this matters

    Use of histochemical and immunohistochemical features may be useful for myositis classification; results also indicate a possible shared pathologic inflammatory mechanism for anti-Mi-2 dermatomyositis and antisynthetase syndrome, which could be investigated as a future treatment target.