To investigate the effect of longterm infliximab therapy on serum levels of fluorescent antinuclear and anti-double and single-stranded DNA antibodies (FANA, anti-dsDNA, anti-ssDNA) in patients with rheumatoid arthritis (RA), and their possible association with clinical evolution.
Sera from 58 RA patients, treated for one to 3 years with infliximab, were retrospectively analyzed. Matched control groups were RA patients treated with corticosteroids or methotrexate. FANA were tested using HEp-2 cells, and anti-dsDNA and anti-ssDNA IgG by ELISA. After 28 months of infliximab therapy, clinical status was evaluated in 43/58 patients with uninterrupted therapy and associations with autoantibody levels were investigated. Data were documented for patients who discontinued infliximab.
Over the 3 year period, significant increases in FANA and anti-ssDNA IgG levels were observed in infliximab treated patients (p < 0.001 and p < 0.01, respectively). In 43 patients with an uninterrupted infliximab regimen, association was found between high FANA (>or= 1/1280) and lower age (p = 0.048) and patient's assessment of infliximab's efficacy (p = 0.014). Three patients developed anti-dsDNA IgG, preceded by high anti-ssDNA IgG levels, and one of them developed a lupus-like syndrome. Neither the initial presence of high FANA levels nor their increase >or= 1/1280 was significantly associated with discontinuation of infliximab. In contrast, at baseline (p = 0.0012) and at the time of infliximab discontinuation (p = 0.0078), anti-ssDNA IgG (>or= 500 arbitrary units) were more frequent in 7 patients who stopped infliximab due to skin or systemic anaphylactoid reactions.
Monitoring of serum FANA, anti-dsDNA, and anti-ssDNA IgG antibodies provided predictors of lupus-like symptoms and/or anaphylactoid reactions in patients with RA.