NEW-ONSET JUVENILE DERMATOMYOSITIS - COMPARISONS WITH A HEALTHY COHORT AND CHILDREN WITH JUVENILE RHEUMATOID-ARTHRITIS

Objective. To determine, in a case-control study, if patients with new -onset juvenile dermatomyositis (juvenile DM) have increased symptoms prior to onset, exposure to certain environmental conditions, frequenc y of familial autoimmune diseases, or antibody titers, compared with 2 control groups. Methods. A structured interview with the families of 80 children with juvenile DM, 40 children with juvenile rheumatoid art hritis (JRA), or 23 healthy children, from the same geographic area as the children with juvenile DM, was conducted. All children's sera wer e tested for antibody to Toxoplasma gondii, herpes simplex virus (HSV) , or coxsackievirus B (CVB). Results. A high proportion of children wi th juvenile DM had constitutional symptoms 3 months before the disease -onset date (P = 0.013 versus control children). Children with JRA had more relatives with rheumatoid arthritis (P = 0.0001) and pernicious anemia (P = 0.003) than did children with juvenile DM or healthy child ren. Among children less than or equal to 7 years of age, elevated ent eroviral titers were more frequent in those with juvenile DM (81%) and in healthy controls (90%) than in those with JRA (64%), suggesting a common environmental exposure. Titers to T gondii, HSV, or CVB 1-6 wer e normal. Conclusion. Frequencies of familial autoimmune disease, expo sure to environmental factors, or elevated antibody titers to T gondii , HSV, or CVB are not increased in juvenile DM. Children with juvenile DM do have symptoms of illness 3 months before the disease-onset date , and young patients have elevated enteroviral titers, as do young geo graphic controls.