Exercise does not increase salivary lymphocytes, monocytes, or granulocytes, but does increase salivary lysozyme

An increase in salivary leukocytes may contribute to the exercise-induced increase in salivary antimicrobial proteins (AMPs). However, exercise-induced changes in salivary leukocytes have not been studied. The purpose of the study was to describe salivary leukocyte changes with exercise. Participants (n = 11, 20.3 ± 0.8 years, 57.2 ± 7.6 ml kg^-1 min^-1 peak oxygen uptake ((VO) ̇₂peak), 11.1 ± 3.9% body fat) ran for 45 min at 75% of VO_2peak. Stimulated saliva (12 mL) was collected pre- and immediately post exercise. Saliva was filtered through a 30 µm filter before analysis of leukocytes (CD45⁺), granulocytes (CD45⁺CD15⁺), monocytes (CD45⁺CD14⁺), T-cells (CD45⁺CD3⁺), and B-cells (CD45⁺CD20⁺) using flow cytometry. Saliva was analysed for Lysozyme (Lys) using ELISA. Exercise did not alter any leukocyte subset. The major constituent of leukocytes pre-exercise were granulocytes (57.9 ± 30.3% compared with monocytes: 5.1 ± 2.7%, T-cells: 17.1 ± 8.9%, B-cells: 12.1 ± 10.2%) (P < 0.05). In a subset of n = 6, Lys secretion rate increased after exercise (pre: 5,170 ± 5,215 ng/min; post: 7,639 ± 4,140 ng/min) (P < 0.05). Exercise does not result in increased granulocytes, but does increase Lys. Further, these data suggest that an increase in salivary leukocytes is not needed to increase Lys.