Lethal meningitis caused by S. pneumoniae requires the penetration of the blood-brain-barrier (BBB) by the bacteria (Iovino et al., 2016b): an interaction of RrgA with polymeric immunoglobulin receptor (pIgR) and platelet endothelial cell adhesion molecule 1 (PECAM-1), two BBB endothelial receptors, was found to promote the entry of bacteria into the brain and meningitis development (Iovino et al., 2017). This evidence concerns the gene PIGR and infectious meningitis.