New‐onset juvenile dermatomyositis. Comparisons with a healthy cohort and children with juvenile rheumatoid arthritis

Abstract

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, frequency 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 arthritis (JRA), or 23 healthy children, from the same geographic area as the children with juvenile DM, was conducted. All children's sera were tested for antibody to Toxoplasma gondii, herpes simplex virus (HSV), or coxsackievirus B (CVB). Results. A high proportion of children with 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 children. Among children ⩽7 years of age, elevated enteroviral 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 were normal. Conclusion. Frequencies of familial autoimmune disease, exposure 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 geographic controls.

History of infection before the onset of juvenile dermatomyositis: Results from the National Institute of Arthritis and Musculoskeletal and Skin Diseases Research Registry

“…The infectious agents most frequently identified in JDM patients are CVB (4,35) or enterovirus (5,36), which often is associated with both upper respiratory and gastrointestinal symptoms (the most common complaints in this study). Neutralizing and complement-fixing antibody titers to coxsackievirus B2 and B4 were increased in JDM sera compared with titers from age-and geographicmatched control samples, suggesting previous exposure (4).…”

“…A previous national case-control investigation (1989 -1992) documented that age-and region-matched controls had fewer symptoms of infection in the 3 months prior to interview (44%) than the children who developed JDM (64%) in the 3 months before rash or weakness onset (P ϭ 0.03). However, the number of children in that study (n ϭ 80) was not sufficient to identify the type of infection, thus providing the incentive for this investigation (5).…”

“…More JDM children (63%) had symptoms of an illness in the 3 months before the recognition of definite symptoms of JDM compared with 41% of control children during the same time period (5). However, the type of specific illness, such as the association of fever with gastrointestinal or respiratory symptoms, was not characterized in that study (5). Studies of infectious agents, including group A beta hemolytic streptococci (6,7) and picornavirus (3,8), by testing tissue from newly diagnosed JDM patients have been inconclusive.…”

“…A national case-control study (1989 -1992) compared data from directed interview of the parents of children with newly diagnosed JDM with similar data from controls, who were age-matched playmates or children with juvenile rheumatoid arthritis residing in the same region during a comparable time period (5). More JDM children (63%) had symptoms of an illness in the 3 months before the recognition of definite symptoms of JDM compared with 41% of control children during the same time period (5). However, the type of specific illness, such as the association of fever with gastrointestinal or respiratory symptoms, was not characterized in that study (5).…”

“…Studies of infectious agents, including group A beta hemolytic streptococci (6,7) and picornavirus (3,8), by testing tissue from newly diagnosed JDM patients have been inconclusive. Studies of JDM sera for antibody to enterovirus, including coxsackievirus B (CVB), have been inconsistent as well (4,5,8). In contrast, gene expression profile data from untreated JDM muscle documented an intense interferon ␣/␤ (IFN-␣/␤)-induced response, compatible with an immune response to a microbial antigen (9).…”