PC and infection: At acute-phase presentation, we observed that mean IgG antibody levels for infected patients were significantly greater than those for the uninfected controls for LukS (P = 0.0027), LukE (P = 0.0002), HlgA (P = 0.0053), HlgC (P = 0.0022), LukF (P = 0.0028), LukD (P = 0.0002), HlgB (P = 0.0073), Hla (P = 0.0004), and Hla (H35L) (P = 0.0192) but not for the tetanus toxoid (P = 0.7741) or PC (P = 0.4326) antigens that are not produced during these infections (Fig. 1b).