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Subgroups of early JIA patients produced different synovial proteins
Patients with polyarticular juvenile idiopathic arthritis had distinctly different synovial proteins compared with oligoarticular patients during an early stage of the disease, according to recent study results.
Researchers extracted protein from synovial membrane biopsies of 15 newly diagnosed, treatment-naive patients with juvenile idiopathic arthritis (JIA; 12 females). Proteins were separated by 2-D fluorescent difference in-gel electrophoresis, while matrix-assisted laser desorption ionization-time of flight mass spectrometry identified the proteins exhibiting a twofold or greater change in expression levels between the polyarticular (n=8) and oligoarticular (n=7) subgroups. Western blotting and immunohistochemistry also verified this expression.
In variance analysis, 25 protein spots with twofold or greater difference in expression levels were identified between patients with polyarticular JIA and oligoarticular JIA (P≤.05).
Two distinctive clusters of proteins were identified by Pearson ranked correlation, including one that was overexpressed in the polyarticular cohort and another overexpressed in oligoarticular patients. Integrin alpha 2b (P=.04), fibrinogen D fragment (P=.005), collagen type VI (P=.03), fibrinogen gamma chain (P=.04) and peroxiredoxin 2 (P=.02) were among the proteins differentially expressed. These proteins are involved in various processes, including platelet activation and coagulation, the researchers wrote.
Because understanding of JIA disease pathogenesis remains unclear, researchers said, “specific treatments have lagged behind the management of other adult arthritides.
“Proteomic analysis of synovial issue from early disease-stage JIA patients has revealed novel pathological protein expression patterns,” the investigators concluded. “With further work, molecular pathways, which discriminate JIA subtypes, could be exploited to develop new treatment strategies which suppress disease and reduce the risk of long-term joint damage.”
Disclosure: The researchers report no relevant financial disclosures.