PRTN3 and rheumatoid arthritis: As such, we evaluated this subgroup and found the prevalence of self-reported chlamydial infection was significantly higher in women aged 30–50 with RF positivity as compared with those who were RF negative (5/20 [25.0%] vs 37/432 [8.6%], adjusted P = 0.010) although there were no significant associations between self-reported chlamydial infection and any RA-related antibodies (i.e. ACPA and/or RF), or ACPA positivity (Supplementary Table S3, available at Rheumatology online).