Autoantibodies to extractable nuclear antigens (ENAs) pattern in rheumatoid arthritis patients: Relevance and clinical implications

Objectives To study the frequency of different autoantibodies to extractable nuclear antigens (ENAs) in rheumatoid arthritis (RA) patients and to correlate findings with clinical manifestations, disease activity and radiological damage. Methods A total of 230 RA patients were included and 75 healthy controls. In all patients rheumatological assessment was done and routine laboratory investigations and immune profile were performed in both patients and controls, including: RF, ACPA, ANA and anti-ENAs (Ro/SSA, La/SSB, U1-RNP, anti-Jo-1 and anti-Sm). Radiological damage was scored using Sharp/van der Heijde, and disease activity was evaluated by DAS28-ESR and DAS28-CRP. Results RF was positive in 101 (43.9%), ACPA in 220 (95.7%), ANA in 58 (25.2%), anti Ro in 31 (13.5%), anti-La in 10 (4.3%), anti-Jo1 in 5 (2.2%) and anti-RNP in 2 (0.9%). Anti-Ro/SSA positively correlated with sicca symptoms (p = .02), RF titer (p < .001), ANA (p < .001), DAS28-ESR (p = .026), and DAS28-CRP (p = .003). Anti-La antibodies correlated positively with SJC (p = .001), TJC (p = .001), ANA (p < .001), DAS-28 ESR (p = .007). Anti-Jo-1 correlated positively with interstitial lung disease (ILD) (p ≤ .001), RF titer (p = .037) and ANA (p ≤ .001). Anti-RNP antibodies correlated positively with disease duration (p ≤ .001), ACPA titer (p ≤ .001) and ANA (p = .014). In the controls ANA was positive in two (2.7%), anti-Ro in three (4%), and none of the controls tested positive for other autoantibodies. Conclusions In RA patients, positive ANA is frequent and positively associated with anti-Ro, anti-La and anti-Jo1 autoantibodies. Screening for autoantibodies against other anti-ENAs seems mandatory in RA patients especially when ANA is positive. RA cases with positive Anti-Jo-1 may develop anti synthetase syndrome and ILD.