As a group, RA patients and ACPA+ FDR demonstrated significantly lower levels compared to the ACPA- FDR group (87.48 +/- 32.76 vs 87.98 +/- 59.06 vs 125.86 +/- 67.59 (mean +/- SD); P = 0.001). Here, PRTN3 is linked to rheumatoid arthritis.