S100B protein levels in saliva: correlation with gestational age in normal term and preterm newborns

Objectives: S100B is an acidic calcium-binding protein of the EF-hand family present in the central nervous system, where it is concentrated in glial cells. It has been suggested to act as a cytokine with neurotrophic effects at physiological concentrations. Design and methods: S100B concentration was assessed in saliva by western blot analysis and an immunoluminometric assay. A reference curve of the protein was established in 216 preterm and term newborns. Results: S100B levels were significantly higher in saliva taken from the preterm group, and the highest S100B levels were found in newborns who were delivered in the earlier weeks of gestation, exhibiting a progressive decrease nearer to term. S100B concentration in saliva was correlated with gestational age (r = −0.69; P< 0.001). Conclusions: The present study offers data consistent with the putative neurotrophic role of S100B and suggests the usefulness of saliva in the clinical monitoring of S100B levels.