TRIM33 and dermatomyositis: Immunohistochemistry for myxovirus resistance A (MxA), one of type I interferon activity-associated molecules, revealed that epidermal keratinocytes express MxA in the skin samples of anti-MDA5 antibody-positive DM patients than in anti-TIF1γ antibody-positive DM patients, while few keratinocytes were expressed in anti-ARS antibody-positive DM patients [41].