To study the distribution of Tfh cells in TB infections, we examined Mtb antigen-specific induction Tfh cells subsets (defined as CD4+ CXCR5+ PD-1+ ICOS− or CD4+ CXCR5+ PD-1− ICOS+ or CD4+ CXCR5+ PD-1+ ICOS+) in PTB and LTB individuals in an area highly endemic for tuberculosis. This evidence concerns the gene ICOS and tuberculosis.