Two blood proteins could predict who will develop rare inflammatory disease

<p><strong>OBJECTIVE:</strong> To investigate the relation between biomarkers associated with metabolism and subsequent development of giant cell arteritis (GCA).</p><p><strong>METHOD:</strong> Participants in the population-based Malmö Diet Cancer Study (MDCS; N = 30447), who were subsequently diagnosed with GCA, were identified in a structured process. Matched GCA-free controls were selected from the study cohort. Baseline plasma samples were analyzed using the antibody-based OLINK proteomics metabolism panel (92 metabolic proteins). Analyses were pre-designated as hypothesis-driven or hypothesis-generating. In the latter, principal component analysis was used to identify groups of proteins that explain the variance in the proteome.</p><p><strong>RESULTS:</strong> There were 95 cases with a confirmed incident diagnosis of GCA (median 12.0 years after inclusion). Among biomarkers with a priori hypotheses, Adhesion G protein-coupled receptor E2 (ADGRE2) was positively associated (odds ratio (OR) per standard deviation (SD) 1.67; 95% CI 1.08-2.57), and Fructose-1,6-bisphosphatase 1 (FBP1) negatively associated (OR per SD 0.59; 95% CI 0.35-0.99) with GCA. In particular, ADGRE2 levels were associated with subsequent GCA in the subset sampled &lt;8.5 years before diagnosis. For meteorin-like protein (Metrnl), the highest impact on the risk of GCA was observed in those sampled closest to diagnosis with a decreasing trend with longer time to GCA (p= 0.03). In the hypothesis generating analyses, elevated levels of receptor tyrosine-like orphan receptor 1 (ROR1) were associated with subsequent GCA.</p><p><strong>CONCLUSION:</strong> Biomarkers identified years before clinical diagnosis indicated a protective role of gluconeogenesis (FBP1) and an association with macrophage activation (ADGRE2 and Metrnl) and proinflammatory signals (ROR1) for development of GCA.</p>