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.