P2RX7 and tuberculosis: In vivo, various cell populations can contribute to the deleterious role of P2X7 receptor in severe TB, as this receptor is expressed in many BM-derived cells (i.e., monocytes, macrophages, neutrophils, and T cells) and lung structural cells (i.e., alveolar epithelial type I cells, lung endothelial cells, and fibroblasts) (19, 22–25, 29, 30).