O04 Serum nuclear magnetic resonance metabolomic signature can discriminate immunoglobulin G4-related sclerosing cholangitis and primary sclerosing cholangitis

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is often difficult to distinguish from primary (PSC) in clinical practice. Accurate, non-invasive biomarkers for discriminating IgG4-SC PSC are required, but the diagnostic utility of global serum nuclear magnetic resonance (NMR)-based metabolomics untested. We performed metabolomic profiling patients with and assess evidence a distinctive signature that could discriminate between these conditions, predict response therapy provide biomarker disease relapse. Stored samples collected prospectively IgG4-related (IgG4-RD; n=39 at diagnosis prior therapy), (n=100; 81 large duct; 19 small duct) healthy controls (HC; n=16) were prepared NMR spectroscopy using standardised protocol. Principal component analysis (PCA) orthogonal partial-least squares discriminatory (OPLS-DA) used identify metabolites. Clinical data was obtained review electronic databases correlation adjust confounders. The median (range) age gender proportion 65 (33–83) years 85% male IgG4-RD, 45 (12–84) 63% PSC. Lactate, glucose, glutamine increased IgG4-RD compared (p<0.0001), whereas -CH3 lipoprotein beta-hydroxybutyric acid resonances decreased (p<0.001). NMR-based discriminated greater accuracy (AUC 0.941, 95% CI 0.904–0.977) than upper limit normal IgG4 titre 0.865, 0.787–0.943). OPLS-DA modelling an optimised threshold diagnosed – as opposed 86%, sensitivity 96%, specificity 70% (figure 1), adjusted age, gender, comorbidities, level medications. Both independently distinguishable HC 96% 91%, respectively. When only (n=23) included large-duct (n=81), 88%. IBD excluded comorbid condition (IgG4-SC n=20, n=22), AUC 0.998 (0.991–1.000). determined by more specifically IgG4-SC, distinct our cohort. Metabolomic has potential be incorporated additional criterion improve help