Objective: Oral and pharyngeal cavities harbor a commensal bacterial flora which is kept in check by several innate and acquired agents. In this study, we focused on the proportions in which some antibacterial moderators (lysozyme, lactoferrin, IgG and S-IgA) coat the tonsillar surface bacteria in healthy individuals, in patients with acute tonsillitis (AT) culture-positive for Streptococcus pyogenes, and in patients with infectious mononucleosis (IM) caused by Epstein-Barr virus (EBV).
Methods: Bacterial samples were collected for aerobic culturing and immunocytochemical evaluation from the tonsillar surfaces of eight healthy individuals (four males, four females; age range 16-22 years), eight patients with current AT (two males, six females; age range 16-29 years) and seven patients with IM (four males, three females; age range 15-21 years). The immunocytochemical assay was based on gold-labeled antiserum to human lysozyme, lactoferrin, IgG and S-IgA followed by gold particle tracing in the transmission electron microscope.
Results: During AT, a significant increase in lysozyme coating (P<0.05) and lactoferrin coating (P<0.0005) of the bacteria was noted, whereas the S-IgA coating was significantly reduced (P<0.0005). During IM infection, a significant increase in lactoferrin coating was noted (P<0.0005) whereas immunoglobulin coating was significantly reduced (IgG P<0.025; S-IgA P<0.0005) compared with healthy controls. During IM, all antibacterial moderators evaluated were significantly reduced compared with the situation during AT.
Conclusions: Noticeable changes in the local innate and acquired bacterial defence system were observed during tonsillar infections, particularly during IM.