Peripheral nerve allografts. I. Distinctive histological features of nerve degeneration and immunological rejection.

Sequential sections were prepared from isografted or allografted sciatic nerves in adult female DBA/2 mice and were compared with the wallerian degeneration in the same inbred strain. Transverse sections were studied by qualitative and quantitative histology. Rejection was manifested by an important infiltration of mononuclear cells, including large pyroninophilic cells, around the grafted nerve, followed by the appearance of irregular infiltrates around the neovessels within the nerve. In parallel, the number of endoneural nuclei increased less rapidly in allografts than in isografts up to day 15 and diminished thereafter, in association with a possible reduction of neural vascularisation.