One limitation of our work was the missed experiment of Treg cells depletion since day 28 of infection with strain H37Rv, when the peak of these cells was seen and pneumonia started its formation, we suppose that the beneficial effect of Treg cells deletion should be more evident starting at this time, because there is in the pneumonic areas Treg cells in co-existence with macrophages that exhibited IDO and HO-1 strong immunostaining. Here, IDO1 is linked to susceptibility to pneumonia measurement.