B-CELLS IN SYSTEMIC AUTOIMMUNE-DISEASE - RECENT INSIGHTS FROM FAS-DEFICIENT MICE AND MEN

In mice functionally deficient for either Fas or Fas ligand expression , the failure of Fas-ligand-expressing cytotoxic T cells to eliminate autoreactive B cells can result in excessive autoantibody production. Recent in vitro studies have shown that B cells activated by CD40 liga nd become extremely sensitive to Fas-mediated apoptosis white IL-4 and /or surface IgM receptor engagement protects B cells from Fas ligand c ytolysis. Potential in vivo sites for Fas ligand regulation of self-re active B cells have been suggested and implications for human disease have been investigated.