Research Update | July 2026
With support from a two-year Cure JM research grant, Dr. Rie Karasawa of St. Marianna University School of Medicine in Japan is studying how these antibody subtypes influence the cells lining the blood vessels. Blood vessel injury, known as vasculopathy, is an important feature of JDM and may contribute to differences in disease symptoms, severity, and treatment response.
Juvenile dermatomyositis does not affect every child in the same way. One reason may be the different myositis-specific autoantibodies, or MSAs, found in children with the disease.
Why was this study done?
Juvenile dermatomyositis (JDM) is a rare autoimmune disease that causes muscle weakness and inflammation in children. Different children develop different forms of the disease depending on which myositis-specific autoantibodies (MSAs)they have. These antibodies are known to affect disease severity, but it is not well understood how they influence damage to the small blood vessels (vasculopathy), which is a key feature of JDM.
This study aimed to identify proteins found in blood vessel cells (vascular endothelial cells) and in the blood (serum)that are associated with different antibody subtypes of JDM. By understanding these differences, researchers hope to find better biomarkers and develop more targeted treatments.
What did the researchers do?
The team used advanced protein analysis (proteomics) to examine blood samples from children with different JDM antibody subtypes, including anti-MDA5, anti-NXP2, anti-TIF1-γ, and children without detectable myositis-specific antibodies. They compared the proteins found in blood vessel cells with those found in the bloodstream to understand how each subtype affects the body.
What did they find?
The researchers found that each antibody subtype has its own unique pattern of proteins, suggesting that different forms of JDM may develop through different biological pathways.
Key findings included:
• Children with anti-MDA5 and anti-NXP2 antibodies showed strong activation of the type I interferon pathway, an immune pathway already known to play an important role in JDM.
• Children with anti-TIF1-γ antibodies showed a different pattern, with greater activation of the complement system, another part of the immune response.
• Children without detectable myositis-specific antibodies had protein patterns that were very different from those with antibodies, suggesting they may represent a biologically distinct group of JDM.
An important discovery
One of the most interesting findings was that, in children with anti-MDA5 antibodies, signs of interferon activity remained inside blood vessel cells even after treatment, despite interferon-related proteins decreasing in the bloodstream.
This suggests that blood vessels may continue to be affected even when standard blood tests suggest inflammation is improving. It may also help explain why some patients continue to have disease activity despite treatment.
Why does this matter?
These findings improve our understanding of why different children with JDM experience different disease patterns. They suggest that treatments may eventually need to be tailored to each antibody subtype rather than using the same approach for everyone.
The results also identify blood vessel cells as a potential therapeutic target, particularly in anti-MDA5 disease, and suggest that JAK inhibitors, which block interferon signalling, may be especially beneficial for this group.
What happens next?
The study is still ongoing. The researchers are now analysing samples collected before treatment and will compare them with samples collected during treatment. This will help them better understand how treatments change protein patterns over time and may lead to new biomarkers and more personalised therapies for children with JDM.
Your support makes research like this possible
Cure JM invests in research that addresses the most important unanswered questions in juvenile myositis. By supporting collaborations among researchers, clinicians, and institutions around the world, Cure JM is helping scientists better understand the disease and move toward more targeted treatments.
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