Antimicrobial factors in whole saliva of human infants.

Antimicrobial factors were analyzed in samples of whole saliva from 31 children, aged 0.8 to 3.8 years. When compared with the adult reference group, the children displayed similar levels of lysozyme, salivary peroxidase, and hypothiocyanite (OSCN-), whereas the amounts of immunoglobulins (isotypes A, G, and M), lactoferrin, myeloperoxidase, thiocyanate (SCN-), amylase, and protein were significantly lower than the adult values. The child's behavior during the collection period noticeably influenced the composition of the saliva. Children who were restless and crying during the collection had significantly more immunoglobulins, lysozyme, lactoferrin, salivary peroxidase, myeloperoxidase, and protein in their saliva samples, obviously due to the contamination of saliva mixed with nasal or lacrimal secretions. Therefore, the normal values for saliva could be determined for the noncrying children only. These salivary defense systems did not show any relation to the length of breast-feeding or to the previous history of antibiotic treatment. Thus, with the exception of lactoferrin and myeloperoxidase, the nonimmunoglobulin antimicrobial saliva systems studied here seem to be already at the adult level during early childhood, when the protective antibody systems are still immature.