Background A reduction in complement levels during anti-TNF treatment in patients with rheumatoid arthritis (RA) has been described. However, there are no reports regarding changes in complement levels with the use of Tocilizumab (TCZ).
Objectives In this study, we investigated changes in complement levels during TCZ treatment and compared them to those with anti-TNF treatment in patients with RA.
Methods We measured C3 and C4 levels in 25 patients treated with TCZ and 44 treated with anti-TNF. In addition, major disease activity indicators were monitored before and 1 year after the initiation of treatment.
Results Disease activities (DAS28-ESR) were significantly improved in both groups after 1 year. Furthermore, C3 and C4 concentrations were significantly reduced in both after 6 months and 1 year, though those effects were significantly more pronounced in the TCZ group than the anti-TNF group (graphs A and B, p<0.001). Notably, patients in the TCZ group who showed a reduction in C4 to under the lower limit had significantly lower disease activity than others (graph C).
Conclusions TCZ more effectively reduces complement C3 and C4 in patients with RA as compared with anti-TNF. Our results also indicate that C4 may be usable as a biomarker in RA patients undergoing TCZ treatment.
Di Mucio G, Perricone C, Ballanti E, et al. 2011. Complement system and rheumatoid arthritis: relationships with autoantibodies, serological, clinical features, and anti-TNF treatment. Int J Immunopathol Pharmacol; 24(2): 357-66.
Disclosure of Interest None declared