Similar to our findings, Hu et al. [52] also demonstrated that infection with a virulent strain of C. burnetii in BALB/c mice elevated the serum levels of cytokines, including IL-1β, TNF-α, IFN-γ, and IL-12p70, suggesting an association between the expression of these pro-inflammatory cytokines and the virulence of C. burnetii. This evidence concerns the gene TNF and infection.