Immunoglobulin Concentrations in Plasma and Saliva during the Neonatal Period

Background Screening for infectious diseases in newborns using immunoglobulin (Ig)A-, IgM-, and IgE-specific antibodies is expensive and impractical. To determine if total levels of these Igs can be used for screening purposes, thus simplifying the process, their basic levels in the 1^st month of extrauterine life need to be determined. Additionally, the ability to simplify screening by using saliva also needs to be determined. The aim of this study was to determine IgA, IgM, and IgE concentrations in plasma and saliva in newborns, correlation between the samples, and relationship between Ig levels and newborn age. Methods We enrolled 53 apparently healthy newborns, paired samples of plasma and saliva were collected, and total IgA, IgM, and IgE concentrations determined by capture enzyme-linked immunosorbent assay. The correlation between plasma and saliva values was calculated by Spearman's rank correlation coefficient and the IgA, IgM, and IgE distributions were analyzed by the Shapiro-Wilk test. We also determined the level of each Ig concentration according to age. Results IgA and IgM levels in plasma and IgA levels in saliva increased significantly during 1^st month of life, especially in the 2^nd week and 3^rd week, with a good correlation of IgA between plasma and saliva. IgE levels in both plasma and saliva and IgM levels in saliva were very low or absent. Conclusion These results suggest that Igs in saliva could be good biomarkers for newborn screening programs during the 1^st week of life. This study established reference values for Igs according to age in the neonatal period.