For example, in a murine model of arthritis, P2X7 receptor–deficient animals showed a reduction in the incidence and severity of the disease compared with wild-type animals [23]; however, in a study of autoimmune encephalomyelitis, P2X7 receptor–deficient animals had exacerbated neuroinflammation compared with wild-type animals [24]. This evidence concerns the gene P2RX7 and arthritic joint disease.