COMBINED TREATMENT OF AUTOIMMUNE MRL MP LPR/LPR MICE WITH A HERBAL MEDICINE, REN-SHEN-YANG-RONG-TANG (JAPANESE-NAME-NINJIN-YOUEI-TO) PLUS SUBOPTIMAL DOSAGE OF PREDNISOLONE/

Therapeutic effects of combined treatment with a Chinese medicine pres cription, Ren-shen-yang-rong-tang (Japanese name: Ninjin-youei-to, NYT ) and suboptimal doses of prednisolone (PSL) on pathological findings of autoimmune-prone MRL/lpr mice were examined. Six-week-old MRL/lpr m ice were treated orally with 1000 mg/kg of NYT, 0.5 or 2 mg/kg of PSL, 1000 mg/kg of NYT plus 0.5 or 2 mg/kg of PSL (combined treatment) or solvent only (control) six times per week. The rates of signs and symp toms of autoimmune disease (lymphadenopathy, proteinuria, dermatitis, loss of hair) were suppressed significantly in groups given PSL (2 mg/ kg) alone, NYT alone and combined treatment with PSL (2 mg/kg) plus NY T (1000 mg/kg) compared with control, respectively, whereas treatment with PSL (0.5 mg/kg) alone did not inhibit their occurrence. ConA resp onse and IL-2 production were also improved significantly in lymphocyt es of mice given the combined treatment. Interestingly, treatment with NYT alone enhanced further the augmented IFN-gamma production in MRL/ lpr mice but the combined treatment suppressed such an augmented produ ction. The combined treatment dramatically reduced the level of anti-D NA antibodies in serum of MRL/lpr mice. By contrast, NYT alone treatme nt had no effect on autoantibodies production. These results suggest t hat combined treatment with NYT plus a suboptimal dose of PSL could be effective for systemic lupus erythematosus without severe side-effect s.