TNF and infection: Other resistant Mtb strains showed a difference between 24 and 48 hr post-infection in the expression of IFN-γ (INHR [rank of difference: -1.0; P=0.1]; RifR [rank of difference: -0.66; P=0.3]; MDR [rank of difference: -0.66; P=0.2]; XDR [rank of difference: -0.66; P=0.3]) and TNF-α (INHR [rank of difference: -0.51; P=0.3]; RifR [rank of difference: -0.91; P=0.09]).