FASLG and rheumatoid arthritis: A novel experimental system incorporating the grafting of RA synovial tissue into severe combined immunodeficiency (SCID) mice [20-22] has provided an in vivo model for the evaluation of our hypothesis; the repeated gene transfer of an apoptosis inducer such as FasL, mediated by an efficient vehicle, might function as a gene scalpel for the removal of inflammatory synovium in situ.