IL17A and Granuloma: Despite the decrease in Th17 cells (and IL-17 mRNA) in the lungs of IL-6-/- mice, H&E staining of lung sections indicated that there was still granuloma formation in the lungs similar to WT mice, indicating that Th1 cells are sufficient for granuloma formation and Th17 cells are not absolutely required (Figure 4A & B).