The highest expression levels were detected in samples of RA patients that showed significantly higher expression levels in comparison to samples of OA patients (P = 0.00001) and samples of RF/ACPA seronegative GZ patients (P < 0.001), while the difference was insignificant (P = 0.105) in comparison to expression levels in GZ patients who showed low RF/ACPA seropositivity. The gene discussed is PRTN3; the disease is rheumatoid arthritis.