Considering that some factors -as, for example, CXCL16- are regulated by microbiota through modulation of the quantity of iNKT cells in the gut and lung, leading to a higher tissue inflammatory response (46), these genetic variations could lead to a different expression of signaling proteins which could be, in turn, modified by the different microbiota patterns conferring more risk or protection against pneumococcal pneumonia. The gene discussed is CXCL16; the disease is pneumococcal pneumonia.