Autoantibody to PL-12 (Anti-Alanyl-tRNA Synthetase) in an African American Girl with Juvenile Dermatomyositis and Resolution of Interstitial Lung Disease

To the Editor: Juvenile dermatomyositis (JDM) is an immune-mediated pediatric idiopathic inflammatory myopathy (IIM) characterized by muscle and skin inflammation1. Anti-PL-12 is a myositis-specific antibody (MSA), directed against alanine-tRNA synthetase2, often with debilitating interstitial lung disease (ILD), that is sporadically reported in childhood3. We describe a child with anti-PL-12 antibody who recovered lung function after therapy. A 14-year-old African American girl developed bilateral ankle stiffness associated with swelling and redness of the upper eyelid. One month later, she noticed proximal weakness of shoulder girdle and pelvic girdle. Four months later, she had fever to 102°F; an erythematous rash over upper chest, arms, and upper eyelids; difficulty walking and getting up from bed, with shortness of breath during exertion. After admission to intensive care unit for suspected aspiration pneumonia, she was diagnosed with JDM on the basis of a muscle biopsy. She received intravenous (IV) steroid (30 mg/kg/dose) for 5 days, followed by oral prednisone (1 mg/kg/day), and was lost to followup. Six months later, she was admitted to Children’s Memorial Hospital with fever, malaise, weakness, worsening rash, and bilateral knee arthritis. Laboratory data were elevated: creatine kinase 12,464 IU/l (normal 29–165 IU/l), aldolase 150 U/l (normal 3.4–8.6 U/l), alanine transaminase 156 IU/l (normal 2–30 IU/l), aspartate transaminase 257 … Address correspondence to Dr. L.M. Pachman, Children’s Memorial Research Center, 2300 Children’s Plaza, Box 212, Chicago, IL 60614. E-mail: pachman{at}northwestern.edu