PRTN3 and rheumatoid arthritis: The median (interquartile range (IQR)) MRI inflammation scores in symptom-free controls, ACPA-negative arthralgia patients and ACPA-negative RA patients were 0 (0 to 1), 1 (1 to 3) and 10 (10 to 16), respectively (P < 0.001) (Figure 1).