MX1 and pulmonary tuberculosis: MxA is a type 1 IFN-inducible gene that encodes an important mediator of the early innate immune defense against viruses.[23] Elevated MxA expression is part of the peripheral blood type 1 IFN signature in systemic autoimmune disease patients.[23] Yet in our study elevated MxA gene expression was not found in peripheral blood from patients with active pulmonary TB compared to healthy control subjects (S2 Fig).