King's College London

This breakthrough means that saliva could be used as a powerful, non-invasive tool to study how our bodies respond to infections and other diseases.

Published recently in the Journal of Cellular Immunology, the team identified over ten types of immune cells in saliva—including those involved in fighting viruses and regulating inflammation. Some of these cells were found in higher numbers in saliva than in blood, suggesting they play a unique role in protecting the mouth and other mucosal surfaces like the lungs and gut.

Importantly, the method used—called flow cytometry—proved to be reliable and consistent, even when samples were taken weeks apart. This opens up exciting possibilities for using saliva to monitor immune health over time, especially in conditions like COVID-19, allergies, and autoimmune diseases.

Why It Matters

• Non-invasive testing: Saliva collection is simple and painless, making it ideal for regular health monitoring.

• Understanding mucosal immunity: The mouth is a key entry point for many pathogens. Studying its immune cells helps us understand how the body defends itself.

• Broader applications: The technique could be adapted to study other body fluids, such as nasal or vaginal secretions, offering insights into a wide range of diseases.

This research marks a significant step toward making immune monitoring more accessible and could transform how we study and diagnose disease.