The Relationship between Anti-CCP Autoantibodies and ANA Status in RA
Orr C, Young F, Veale DJ.
Centre for Arthritis and Rheumatic Diseases, Dublin Academic Medical Centre, University College Dublin, Ireland
Anti-CCP auto-antibodies play a significant aetiological role in the pathogenesis of RA.1 ANA has been reported positive in 45% of RA patients,2,3 and there is a higher frequency of being ANA positive in those positive for RF.4 Furthermore, patients who are positive for RF and ANA have been shown to have a worse prognosis with respect to the development of erosive disease and pain.4 There have been no previous reports of how ANA in RA patients may relate to anti- CCP status.
In an RA cohort, we examined the relationship of anti-CCP, ANA and RF autoantibodies.
A cohort of consecutive RA patients were characterised for anti-CCP, RF, ANA. Those with symptoms potentially indicative of a connective tissue disease were excluded. The RF and anti- CCP status were recorded, as was the ANA dilution (if positive) and the ANA staining pattern. A positive ANA was determined as ≥1:100. Fisher’s Exact Test (2-tailed) was used to test for an association between both RF and anti-CCP, and ANA status.
ANA was positive in 86/171 (50.3%) of our cohort. In those positive for ANA the mean dilution was 1:744, mode 1:200. An association was observed for those positive for anti-CCP and those positive for ANA (p=0.0125), see fig.1. No association was observed for RF and ANA status (p=0.6471), or for concordant positive for RF and anti-CCP, and ANA (p=0.1044.)
To our knowledge, this is the first study in RA patients to report a significant association between anti-CCP and ANA status. Given that we found no association between RF and ANA as previously reported, it is especially important to define the characteristics of the anti-CCP/ANA concordant positive patients with respect to bone erosions and response to treatment.