Assessment of Age-Related Changes of Salivary Immunoglobulin A Levels among Healthy Individuals

Background: Secretory immunoglobulin A (IgA) is the first line of defense against pathogens that invade mucosal surfaces. It has been reported that the immune system exhibits profound age-related changes. The aim of this study was to investigate the age-dependent changes of salivary IgA among healthy individuals. Materials and Methods: Saliva samples were collected from 120 healthy individuals (aged 11–70 years). The salivary IgA concentrations were measured by the use of a single radial immunodiffusion technique and analyzed using the Mann–Whitney U, Kruskal–Wallis, and Chi-square tests. Results: The mean salivary IgA levels were 81.11 ± 4.50 mg/dl at age 11–20 years, 92.71 ± 13.76 mg/dl at age 21–30 years, 96.50 ± 4.04 mg/dl at age 31–40 years, 104.96 ± 10.15 mg/dl at age 41–50 years, 113.22 ± 7.85 mg/dl at age 51–60 years, and 91.38 ± 4.77 mg/dl at age 61–70 years. There was a significant difference among the mean salivary IgA levels of different age groups (P < 0.001). Conclusion: These results showed that the salivary IgA levels exhibit age-related changes. Oral immunization may be considered to improve oral immunity when the salivary concentrations of IgA begin to decrease during lifetime.