Cloxacillin sodium (1.6125 mg/kg; s.c.; 12-h intervals for 72 h) protects mice from S. aureus peritonitis in vivo when combines with Thioridazine and Tetracycline. Cloxacillin sodium (7.5 mg/per; i.p.; twice daily from day 3 for 3 days) develops less severe synovitis and reduces bone erosions when combines with anti-IL-15 antibodies.