Therapy with TNFa blocking agents has been associated with increased rate of anti-nuclear antibodies (ANA) and rare cases of lupus like syndromes. Our aim was to prospectively analyze a wide array of autoantibodies in rheumatoid arthritis (RA) patients before and 14 weeks after starting infliximab.
In this study, 26 consecutive active RA patients participated. All treated with infliximab at a dosage of 3 mg/kg on week 0, 2, 6 and every 8 weeks, along with weekly low dose methotrexate. Patients were evaluated at week 0 and 14. Clinical assessment included the number of tender and swollen joints, duration of morning stiffness, adverse events (AE) (including SLE-like) and ESR. Sera were collected before the 1st infusion of infliximab at week 0 and 14. The autoantibodies studied were: fluorescent ANA, anti-double-stranded-DNA (anti-ds-DNA), IgG and IgM anti-cardiolipin (ACA), anti-histone- H1 and C (H1, H2A, H2B, H3, H4), anti-SSA, -SSB, -ENA, -scleroderma 70, -thyroid peroxidase (TPO) and -neutrophilic cytoplasmatic (ANCA) antibodies.
Of 26 patients, 17 were women. A significant decrease in duration of morning stiffness, number of tender and swollen joints and ESR were observed between week 0 and 14. During follow up (mean of 20.5+/-7.3 months), 9 patients stopped infliximab due to inefficacy or AE (most of them after the 4th infusion). Two patients developed lupus-like phenomena. ANA was found positive at baseline in 7 out of 26 patients. In 5 of them, an increase in the titer of ANA was observed at week 14. ANA negative turned positive for 8 patients. A significant increase of anti-cardiolipin (ACA)-IgM levels was observed in 8 patients and of ACA-IgG in 6, in parallel with ANA seroconversion. The mean level of anti-double-stranded-DNA (anti-ds-DNA) -IgG significantly increased from 66+/-33 to 93+/-68 IU/ml, in 4 patients to pathological levels. Four patients demonstrated an increase in anti-histone H1. Levels of ANCA, anti-ENA, -SSA, -SSB, -RNP, -scleroderma70 and -thyroid peroxidase (TPO) were negative in all patients and remained unchanged during the study. Cessation of treatment with infliximab was found to be associated with the appearance of ANA.
An increased titer or a new appearance of ANA was observed in 12 out of 26 patients. The main autoantibodies found were anti-ds-DNA, ACA-IgM and -IgG and anti-histone. In our cohort, the appearance of some autoantibodies seemed to predict late cessation of treatment.