Aim To investigate the relationship between the serum concentration of infliximab, a chimeric monoclonal antibody to tumour necrosis factor-α (TNF-α), and its effectiveness in treating uveitis in Behçet disease.

Methods The authors studied 20 patients with Behçet disease who had been treated with infliximab (5 mg/kg). After informed consent was obtained, samples of the peripheral blood were taken. The authors began collecting blood samples after at least 4 months of infliximab infusions. The first sample was collected at 1 h after an infliximab infusion (Day 0), then after 4 weeks (Week 4), and finally at 1 h prior to the infliximab infusion 8 weeks later (Week 8). The clinical data on uveitis were collected from the clinical charts of the patients. The serum concentration of infliximab was measured by an enzyme-linked immunosorbent assay.

Results The mean serum concentration of infliximab in the 20 patients was 117.4±28.2 μg/ml on Day 0, 11.4±6.8 μg/ml on Week 4 and 6.3±4.8 μg/ml on Week 8. The serum concentration of infliximab in each patient was significantly correlated with its effectiveness in resolving the recurrent episodes of uveitis.

Conclusion Monitoring infliximab serum concentrations is useful in determining the effectiveness of infliximab treatments for uveitis in Behçet disease.