The serum concentration of infliximab in cases of autologous blood donation for patients with rheumatoid arthritis

Our aim was to determine whether the use of infliximab for rheumatoid arthritis (RA) patients is associated with an increased rate of postoperative complications. In this study we evaluated the serum concentration of infliximab to study the influence of autologous blood donation (AB donation) in patients who were administered infliximab and underwent total knee replacement (TKR). We examined five RA patients. Infliximab combined with methotrexate was administered at 3 mg/kg every 8 weeks for all patients. We carried out the TKR operation in the middle of the 8-week interval in which infliximab was administered. The AB donation consisted of 400 ml pooled AB drawn at one point 2 weeks following the final administration of infliximab. Serum infliximab levels were measured using an enzyme-linked immunosorbent assay. Mean serum infliximab levels were 5.46 ± 5.62μg/ml 2 weeks after the final administration of infliximab, 2.02 ± 1.66 μg/ml just before the operation, and 1.48 ± 1.31μg/ml 1 day post operation. Moreover, the mean serum level in an autologous blood bag sampled just before AB donation was 5.02 ± 4.79 μg/ml. This study indicated the serum level of infliximab in the stored blood remained at almost the same level as the collected autologous blood. However, even after autotransfusion those levels were decreased compared with levels measured just before the operation. Therefore, we conclude that there is little influence of AB donation on the risks of infliximab.