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Gene expression differences could bring better classification and treatment of juvenile arthritis

May 05, 2017

In the second study, led by Thomas Griffin, M.D., Ph.D., also at Cincinnati Children's Hospital Medical Center, scientists looked more closely at patients from the study with one particular subtype of the disease - polyarticular JIA - to determine if that form was more complicated, or if there were more subgroups than originally thought. They included children with rheumatoid factor (RF) positive JIA, meaning their blood tested positive for an antibody commonly seen in adults with rheumatoid arthritis (RA). Surprisingly, the scientists found patterns of gene expression that indicated at least three subgroups of polyarthritis. There was an older subgroup (average age 11) that included both RF positive and negative children with an inflammatory gene expression signature bearing some resemblance to adult RA. A second older subgroup (RF negative) had less severe arthritis and an anti-inflammatory gene expression signature. A third subgroup was comprised mostly of younger patients (average age 7) who had no clearly defined gene expression signature and did have antinuclear antibodies (ANA). This third subgroup may be more similar to oligoarthritis patients, who frequently have a positive ANA, than to the other subgroups of polyarticular JIA.

Dr. Colbert says the new findings take pediatric rheumatologists a step closer to more precisely classifying JIA, and eventually developing individually tailored treatments that maximize the benefits, while minimizing the risks. "In pediatric rheumatology, we are at the early stages of improving our classification system for JIA. We expect that complementary studies designed to uncover the genetic differences that contribute to susceptibility will confirm the presence of several JIA subtypes, and add important information about what causes this group of diseases," he said. "We look forward to the day when we can use a combination of genetic and gene expression tests in the clinic to help us better diagnose and treat childhood arthritis."

In addition to NIAMS, funding for the studies was provided by the Cincinnati Children's Hospital Research Foundation and the Arthritis Foundation Ohio Valley Chapter.

For more information about juvenile arthritis, visit the NIAMS Web site at niams.nih/Health_Info/Juv_Arthritis/default.asp.

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