IRF4 and infection: This included genes as CCL19, which expression was found to be increased in mouse lungs post-Mtb-infection to induce lymphoid structures25; FCMR, considered a target for host-directed therapies26, and the transcription factor IRF4, previously found to be required for the generation of Th1 and Th17 subsets of helper T cells and follicular helper T-like cellular responses27.