ACE and latent syphilis: No significant differences of serum ACE levels revealed between AS and BD (p = 0.689), between AS and presumed latent TB (p = 1.000), between AS and presumed latent syphilis (p = 0.996), between BD and presumed latent TB (p = 1.000), between BD and presumed latent syphilis (p = 0.817), and between presumed latent TB and presumed latent syphilis (p = 0.504), (Table 4).