Background
The development of biologics has greatly increased the quality of life and the life expectancy of many patients with rheumatoid arthritis. However, a large number of these patients have an increased risk of developing serious infections. The
Conclusions
CTLA4-Ig therapy significantly increased the susceptibility to S. aureus septic arthritis in mice, whereas anti-TNF therapy deteriorated host bacterial clearance, resulting in more-severe weight loss and kidney abscesses.
Methods
Abatacept (CTLA4-Ig), etanercept (anti-TNF), or phosphate-buffered saline were given to NMRI mice intravenously inoculated with Staphylococcus aureus. The clinical course of septic arthritis and histopathological and radiological changes of joints were compared among the groups.
Results
Mice receiving CTLA4-Ig treatment had more-severe septic arthritis, compared with controls and mice receiving anti-TNF treatment. Anti-TNF treatment led to more-severe weight loss and kidney abscesses, as well as a higher bacterial burden in the kidneys. Mice receiving CTLA4-Ig therapy had lower serum levels of interleukin 4, whereas mice receiving anti-TNF therapy had higher levels of TNF-α. Both iNOS and arginase-1 expression were reduced in peritoneal macrophages from mice receiving CTLA4-Ig, compared with expression in the anti-TNF group. Conclusions: CTLA4-Ig therapy significantly increased the susceptibility to S. aureus septic arthritis in mice, whereas anti-TNF therapy deteriorated host bacterial clearance, resulting in more-severe weight loss and kidney abscesses.