Interestingly, two of the healthy women had increased levels of ACPA (88 U/mL and 96.4 U/mL, respectively) and rheumatoid factor (RF, 80 U/mL and 62 U/mL, respectively), but without any clinical signs of RA or other inflammatory/autoimmune diseases. This evidence concerns the gene PRTN3 and rheumatoid arthritis.