Objectives: To understand the acute phase responses to surgical intervention in rheumatoid arthritis (RA) patients treated with the anti-IL-6 receptor antibody, tocilizumab.
Methods: In a retrospective 1:1 pair-matched case-control study, 22 tocilizumab-treated RA cases and 22 cases treated with conventional disease-modifying anti-rheumatic drugs (DMARDs) and matched in type of surgery, age, and sex were evaluated for body temperature everyday, blood CRP levels, WBC, neutrophil, and lymphocyte counts on days -1, 1, 3, and weeks 1 and 2 after joint surgery. Safety issues were also monitored.
Results: No complications of infection or delay of wound healing occurred in either patient group. Tocilizumab partially, but significantly, suppressed the increase in body temperature on post-operative days 1 and 2, compared with DMARD (average maximum increase in temperature was 0.45 + 0.1 degrees centigrade in the tocilizumab group and 0.78 + 0.1 degrees centigrade in the DMARD group; p<0.01). Tocilizumab completely suppressed the increase in CRP after surgery, whereas all cases treated with DMARDs showed a significant increase of CRP at post-operative day 1 (5.5 + 0.6 mg/dl; p<0.0001). WBC, neutrophil, and lymphocyte counts showed no remarkable change after surgery, and there was no significant difference in any cell counts between the patient groups.
Conclusions: Within this small number of cases, safe operations on patients were performed during tocilizumab treatment. Tocilizumab suppressed fever and increase of CRP after surgery, whereas tocilizumab had no influence on the transition in number of leukocytes. This characteristic post-operative response should be considered during tocilizumab treatment.