TNF and bacterial infectious disease: We conducted a meta-analysis of previously published gene expression microarray data from mouse lungs exposed to multi-walled CNTs (MWCNTs), carbon black (CB), and nano-TiO2 of varying properties, and of publicly available gene expression microarray data of lung diseases induced by various exogenous agents including bleomycin, ovalbumin, TNFα, LPS, bacterial infection and welding fumes.