Fig 1.
Flow diagram of the selection of patients in this study.
Patients were recruited among all patients diagnosed with rheumatoid arthritis and treated with a TNFi, with serum samples available at the research biobank at the Parker Institute, Copenhagen University Hospital at Frederiksberg and Bispebjerg, Denmark. A Only patients treated with adalimumab or infliximab were included, as we did not have access to a reliable detection method regarding antibodies towards etanercept. B Vials were adequate only if they had not been previously thawed. At baseline, one vial of ≥ 3μl was required, and at 6 months follow-up 2 vials of ≥ 3 μl were required. C Missing samples due to inclusion in project not requiring 6 months sampling, termination of current treatment, or lost to follow-up.
Fig 2.
Changes in levels of IL-6, sTNF-R1 and sTNF-R2 following 6 months of treatment with adalimumab or infliximab.
Level of IL-6 and sTNF-R1 and sTNF-R2 were determined in 26 patients with rheumatoid arthritis, 15 patients treated with adalimumab, and 11 patients treated with infliximab. Levels were determined prior to treatment (Baseline) and following 6 months of treatment (Follow-up). Levels of IL-6 (A) and sTNF-R2 (C) decreased significantly during treatment. *p < 0.05. Medians and interquartile ranges are shown.
Table 1.
Baseline characteristics of the 26 rheumatoid arthritis patients included in the study.
Table 2.
Clinical variables and biomarkers according to whether TNFi was detectable in the patients’ blood following 6 months of treatment with adalimumab or infliximab.
Fig 3.
Serum TNFi levels in relation to antibodies against adalimumab and infliximab following six months of treatment.
Antibodies towards the prescribed TNFi (anti-TNFi Abs) were measured in 26 patients with rheumatoid arthritis, using radioimmunoassay. Patients were treated with either adalimumab (A) or infliximab (B). Functional levels of TNFi were determined using reporter gene assays. Presence of anti-TNFi Abs correlated with lower levels of TNFi for both drugs *(p < 0.05). Medians and interquartile ranges are shown.
Table 3.
Variables according to development of anti-TNFi Ab production following 6 months of treatment with adalimumab or infliximab.