SEB combined with IL-1ra could prolong the survival of the rat allografts in high-risk corneal transplantation

Abstract

Purpose To determine whether the superantigen Staphylococcal enterotoxin B (SEB) combined with interleukin-1 receptor antagonist (IL-1ra) prolong allograft survival better than individual agents in high-risk corneal transplantation in a rat model. Methods Fisher 344 donor corneas were transplanted into Lewis recipients. High-risk transplantation meant that the transplants were sutured into the recipient beds with corneal neovascularization induced by placing three interrupted sutures in the host cornea. All of the recipients were divided in blinded fashion into four groups. Group I was injected with saline buffer. Group II was injected intraperitoneally with 0.2 mL SEB (75 μg/kg) at 4-day intervals on three occasions before transplantation. Group III was injected with 0.1 mL IL-1ra (1 mg/mL) subconjunctivally from the first day after transplantation for 2 weeks. Group IV received both SEB and IL-1ra. All transplants were evaluated for signs of rejection for 4 weeks after surgery. Ten days after transplantation, two recipients in each group were sacrificed for histopathological and immunological evaluation. Results The mean survival time of the allografts in the control group was 5.89 ± 0.79 days; in SEB group, 10.70 ± 2.52 days; in IL-1ra group, 8.25 ± 0.71 days; in the SEB and IL-1ra group, 17.36 ± 2.39 days. CD4 + and CD8 + lymphocyte infiltration into the allografts and the percentage of the lymphocytes in the spleen and mandibular lymphatic nodes was significantly decreased among the treated groups with dampened lymphocyte reactivity. The SEB plus IL-1ra combination group showed the strongest inhibition. Conclusion SEB and IL-1ra are most effective in combination to treat high-risk corneal transplants.