In order to determine P2X7R secretome we analyzed the proteins present in cell-free supernatants from wild-type (P2rx7+/+) or P2rx7-/- bone marrow-derived macrophages (BMDMs) polarized either to M1 or M2 and subsequently treated with ATP. BMDMs were primed with LPS (M1) or IL-4 (M2) for 4 hours and the proteins secreted during this step were extensively washed with PBS before ATP was added in fresh buffer. The complex mixture of proteins obtained in the macrophages supernatants after ATP stimulation were fractionated using one dimension gel electrophoresis and 10 bands were selected for LC-MS/MS analysis based in their presence in higher intensity in P2rx7+/+ supernatant compared with P2rx7-/- supernatant.