Abstract

Objective. To evaluate serum interferon-alpha (interferon-a) activity in the context of autoantibody profiles in juvenile dermatomyositis (JDM) patients. Methods. Sera from 36 JDM patients were analyzed. Autoantibody profiles were determined by probing microarrays, fabricated with ~80 distinct autoantigens, with serum and a Cy3-conjugated secondary antibody. Arrays were scanned and analyzed to determine antigen reactivity. Serum interferon-a activity was measured using a functional reporter cell assay. Sera were assayed alone or in combination with cellular material released from necrotic U937 cells to stimulate peripheral blood mononuclear cells in vitro from healthy donors, and interferon-a production in culture was measured by a dissociation-enhanced lanthanide fluorescent immunoassay (DELFIA). Results. 75% of JDM sera reacted to at least one of forty-one autoantigens on the microarray, including Ro52, Ro60, La, Smith and ribonucleoprotein (RNP). Seven samples were positive in the reporter cell assay. There was a significant association between reactivity against Ro, La, Smith and proliferating cell nuclear antigen and serum interferon-a activity in this assay (p=0.005). Significance analysis of microarrays (SAM) identified increased reactivity against Smith, RNP, Ro52, U1-C and Mi-2 in these sera. Sixteen samples induced interferon-a production as measured by DELFIA. There was a significant association between reactivity against Ro, La, Smith and RNP and the induction of interferon-a with serum and necrotic cell material (p=0.035). SAM identified increased reactivity against Ro60 in these sera. Conclusion. These data support the hypothesis that nucleic-acid associated autoantibodies, including the Ro/La and Smith/RNP complexes, may stimulate the production of active interferon- a in children with JDM. © 2013 American College of Rheumatology.

View details for DOI 10.1002/art.38038

View details for Web of Science ID 000323481400025