Plasma haem oxygenase-1 may represent a first-in-class biomarker of oxidative stress in rheumatoid arthritis.

In eRA, plasma levels of HO-1 were increased and correlated with disease and radiographic progression. A baseline measurement of plasma HO-1 levels demonstrated superior performance to currently used clinical and serological disease markers in the prediction of radiographic progression. Plasma HO-1 may function as a first-in-class biomarker of synovial oxidative stress in RA.