Salivary levels of cytokines in pre-term and fullterm infants

Objectives: Little is known about the ontogeny of the mucosal immune system in the first months of age especially in preterm newborn (less than 37 weeks of gestation). Specific cytokines play a major role in inducing immunoglobulin (Ig) A production by B cells in the humoral immune response. Thus, the aim of this study was to assess the salivary levels of interleukins in preterm and fullterm children early in life.

Methods: Twenty four fullterm [FT] and 24 preterm [PT] infants presenting similar levels of IgA were enrolled in this study. Unstimulated saliva samples (80-400 ul) were collected on the day of birth (T0) and after 3 months (T3). Levels of interleukins (IL)-6, IL-10, IL-12 and IFN-gama were measured in saliva supernatant using a multiplexed bead immunoassay (Luminex).

Results: Comparisons between PT and FT showed that IL-10 levels were significantly higher in the PT than FT (p<0.015, Kruskal Wallis ANOVA on ranks) in T0. Levels of interleukins in the FT group were not different from T0 to T3. Comparisons within groups showed that there were no significant differences in the levels of cytokines in the FT group between T0 to T3. But IL-10, IL-12 and IL-6 levels in the PT group at T3 were significantly lower than at T0 (p<0.05).

Conclusions: The data indicate that in PT groups showed salivary IL-10, IL-12 and IL-6 levels decline during the first three months of life to levels that are found in full term children that age. Even cytokines that were significantly different between the two groups at T0 (e.g., IL-10), are at similar levels after 3 months.