CYTOKINES IN SALIVA. BASAL CONCENTRATIONS AND THE EFFECT OF HIGH AMBIENT HEAT (SAUNA)

Abstract

The aim of this study is to investigate the presence of several interleukins in saliva and how their concentrations may be modified after physical stress. The effects of one kind of somatic stress (sauna heat) on the concentrations of salivary cytokines were studied using ELISA assay. In addition, saliva cortisol was assayed. Fourteen volunteers participated in this study. Each subject attended one control and one stress session which took place at the same hour on different days. Saliva was collected on the control day immediately after a 15-min rest period in a seated position (R1), and again after an additional 30-min seated period (R2). On the test day, saliva was collected after 15 min of sitting (S1) and 30 min later (S2) following exposure to the heat of a sauna (90°C, 10 min, 40 per cent humidity). We found that saliva contains the multifunctional polypeptide cytokines interleukin-1β, tumour necrosis factor alpha and the receptor for interleukin-2 with the basal mean concentrations (geometric mean; SD in parenthesis) of 172 (106; 148) ng/l, 46 (20; 67) ng/l and 9 (6; 7) pM, respectively. Interleukin-6 was detectable in only 60 per cent of the specimens investigated. Interleukin-2 and the receptor for interleukin-6 were not detectable. We examined the statistical differences between the ratio R2/R1 (the changes which occurred during the resting period) and S2/S1 (the changes during the exposure to heat). We observed a significantly higher S2/S1 ratio for the tumour necrosis factor alpha in males, compared to the control ratio (2.5±2.4 versus 0.7±0.7,N=6,p<0.05 using the Wilcoxon signed rank test). Our results indicate that a situation which induced an elevated body temperature was associated with a rise in the concentration of the salivary tumour necrosis factor alpha.