P2RX7 and infection: Some genetic factors that may account for the development of TB disease after infection include (list not exhaustive): chemokine(C-C motif) ligand 2 (CCL2, other designation: MCP-1), genes encoding human leukocyte antigen type, purinergic receptor (P2X7), the solute carrier family 11 member a1 protein (SLC11A1, formerly known as NRAMP1), and vitamin D3 receptor [4], [5], [6], [7], [8], [9], [10] although the data may vary among different ethnic groups.