Reduction in the incidence of rejection of heterotopic murine corneal transplants by pretreatment with ultraviolet radiation.

A reduction in the incidence of rejection of mouse heterotopic corneal allografts was achieved by in vitro pretreatment of the graft with ultraviolet light. By day 21, 68% of untreated BALB/c corneas transplanted into s.c. abdominal pouches of C57BL/6 recipients demonstrated rejection. In contrast, corneas pretreated with UV-A, -B, or -C at 150 mJ/cm2 showed an incidence of rejection at day 21 of 30%, 33%, and 18%, respectively. Experiments indicate a significant reduction in rejection with doses of UV-B radiation above 75 mJ/cm2. The mechanism of this reduction is unknown, but may be due to a depletion or alteration of ocular surface Langerhans cells residing in the corneal epithelium.