Characterization of P2X1 activation at the surface of PMNs. (A-B) Expression of CD11b (A), CD11b, CD18, and CD62L (B) at the surface of human PMNs (the gate of PMNs were based on their size (Side Scatter [SS]) and their granulometry (Forward Scatter [FS]) challenged with 10 μM ATP and 0.5 μM phorbol myristate acetate (PMA) (A) or 10 μM α, β-meATP, and 200 U/ml TNF-α (B), (n = 10, *P < .05).