Interestingly, we found that TD volunteers exposed to low doses of wild-type S. Typhi (103 CFU) had higher levels of CD8+ MAIT cells coexpressing CD38 and either CCR9, CCR6, or Ki67 during the development of typhoid fever than TD volunteers receiving a high dose of S. Typhi (104 CFU). This evidence concerns the gene CCR6 and typhoid fever.