LACK OF DETECTION OF ENTEROVIRAL RNA OR BACTERIAL-DNA IN MAGNETIC-RESONANCE IMAGING-DIRECTED MUSCLE BIOPSIES FROM 20 CHILDREN WITH ACTIVE UNTREATED JUVENILE DERMATOMYOSITIS

Objective, To investigate for the presence of increased titers of circ ulating antibody to putative infectious agents and for detectable vira l RNA or bacterial DNA in children with active recent-onset juvenile d ermatomyositis (DM), Methods, Magnetic resonance imaging-directed musc le biopsies were performed in 20 children with active, untreated, rece nt-onset juvenile DM and in age-matched children with neurologic disea se, Sera were tested for complement-fixing antibody to Coxsackievirus B (CVB), influenza A and B, parainfluenza 1 and 3, Mycoplasma pneumoni ae, mumps, respiratory syncytial virus, and Reovirus; and by immunoflu orescence for IgG antibody to Toxoplasma gondii cytomegalovirus and Ig M antibody to Epstein-Barr virus, Muscle from juvenile DM patients and control children, CD-1 Swiss mice with and without CVB1 infection, an d viral stock positive for CVB1-6 were tested using reverse-transcript ase polymerase chain reaction with 5 primer sets, 4 probes (1 Coxsacki evirus, 3 Enterovirus), and universal primers for DNA, Results, No inc reased antibody, viral RNA, or bacterial DNA was present in the juveni le DM patients or the control children, Conclusion. Juvenile DM may be triggered by unidentified agent(s) in the genetically susceptible hos t.