What is the utility of routine ANA testing in predicting development of biological DMARD-induced lupus and vasculitis in patients with rheumatoid arthritis? Data from a single-centre cohort.

OBJECTIVE: To determine whether serial ANA testing predicts biological disease modifying antirheumatic drugs (bDMARD)-associated ANA/dsDNA production in patients with rheumatoid arthritis (RA). METHODS: Serial autoantibody profiles, bDMARD treatment sequences and clinical data were collected from patients identified from our database that since 2005 received (i) a first bDMARD (tumour necrosis factor inhibitor (TNFi)) and (ii) tocilizumab and/or abatacept. RESULTS: Of over 1000 patients, 454 RA patients received a first TNFi. Infliximab group demonstrated higher ANA seroconversion rates (31.2%) compared with etanercept (11.8%) and adalimumab (16.1%) (p<0.001). Median (range) treatment duration prior to ANA seroconversion was 10.9 (1.3-80.0) months. Positive anti-dsDNA titres of IgG class (median (range) of 77 IU/mL (65-109)) were noted in six (7.2%) patients, within a median (range) of 2.0 (0.8-4.2) years. Three patients developed classifiable lupus. 4 of 74 (5.4%) primary non-responders and 24 of 111 (21.6%) secondary non-responders developed positive ANA antibodies after TNFi initiation (p=0.003). Seven (9.5%) tocilizumab-treated patients changed to positive ANA; five (8.6%) abatacept-treated patients changed to positive ANA status. CONCLUSIONS: This study demonstrates no utility of serial ANA/dsDNA testing that could be used to predict onset of seroconversion and therefore the development of lupus/vasculitis. An association however between seroconversion and the development of a secondary non-response to bDMARD therapy is suggested.