Even though the marked reduction of Treg cells in the peripheral blood of scrub typhus patients could be due to the migration and accumulation of suppressive cells to the inflamed tissues as observed in other chronic infections [26], the inverse correlation between a systemic decrease in Treg cells and an increase in proliferating CD8+ T cells (Figure 2B and 4B) along with increased CTL activity [48] strongly suggest a functional impairment of Treg cells in scrub typhus patients. This evidence concerns the gene CD8A and scrub typhus.