By using real time PCR, the expression of ligands for the stimulatory receptor NKG2D as well as ligands for NK cell inhibitory receptors in dorsal root ganglia (DRG) were analyzed in vivo, after a peripheral nerve lesion, and in vitro, in DRG neuronal cultures exposed to interferon (IFN)-gamma or LPS, or infected with murine cytomegalovirus (MCMV) or a neurotropic influenza A virus strain, WSN/33.