Immunology: Mechanisms of Rejection

Neural transplantation is a potential therapeutic strategy for treating neurological disorders such as Parkinson’s and Huntington’s diseases. Approx 200 patients with Parkinson’s disease have been transplanted with neural tissue into the brain. Of these, only a minority, approx 10%, have displayed graft function and survival, as demonstrated by positron emission tomography or histology (Lindvall et al., 1992 ; Sawle et al., 1992 ; Spencer et al., 1992 ; Widner et al., 1992 ; Freeman et al., 1994 ; Peschanski et al., 1994 ; Deacon et al., 1997 ). Motivated by these findings, many studies are now being carried out in experimental models that should provide a clearer understanding of the immunological issues that need to be considered when transplanting allogeneic or xenogeneic tissue into the brain (Kendall et al., 1998 ).