Schwann cells may play a role in the pathogenesis of autoimmune inflammatory diseases of peripheral nerve. They are the targets of autoimmune attack but may also act as antigen presenting cells. Here we investigate the possibility that Schwann cells may be able to modulate T-cell mediated immunity via prostanoid production. The results show that Lewis rat Schwann cells in vitro generate significant amounts of the pro-inflammatory and immunoregulatory mediators, prostaglandin E2 and thromboxane A2 and so may influence autoimmune inflammatory reactions within the peripheral nervous system.