Suppression of secondary herpes simplex uveitis by cyclosporine.

The authors studied the effect of an immunosuppressive agent, cyclosporine (CyA), on experimental secondary herpes simplex (HS) uveitis. Secondary HS uveitis was induced in a rabbit eye that had recovered from primary HS uveitis by challenging it with an intravitreal injection of herpes simplex virus (HSV) antigen. Daily intramuscular injections of CyA (25 mg/kg body weight) for 7 days prior to the intravitreal challenge with HSV antigen significantly suppressed the induction of secondary HS uveitis, but daily injections of CyA after the challenge with HSV antigen was ineffective. Intravitreal injections of CyA (5 mg) 7 days and 3 days prior to the HSV challenge were less effective, but the combined treatment with seven daily intramuscular CyA and two intravitreal CyA injections prior to the HSV challenge was most effective in the prevention of the uveitis. The daily intramuscular treatment with CyA resulted in a marked reduction of cell-mediated immunity while leaving the level of circulating HSV specific antibody high. No reactivation of latent HSV was detected in trigeminal and superior cervical ganglia of CyA-treated rabbits.