IL10 and tuberculosis: [34]. Recent studies indicate IL-10 dependent Treg cell mediated suppression of host immunity [5], [9] and higher expression of immune exhaustion marker PD-1 in tuberculosis [19], [20]. PD-1 is also known to be preferentially expressed on Treg cells [35]. However, precise role of Treg cells and PD-1 expressed on them in suppression of host T cells response against Mtb. among patients is yet to be unraveled.