P2RX4 and systemic lupus erythematosus: We have studied the properties of the proinflammatory purinergic receptor P2X7, encoded by a gene within the human SLE locus SLEB4 [3] at 12q24 (Ensembl Genome Browser: ) and by the murine lbw3 region (Ensembl Genome Browser: ), and discuss its potential role in disease.