Use of saliva for assessment of stress and its effect on the immune system prior to gross anatomy practical examinations.

The objective of this study was to determine the longitudinal effects of a series of stressful gross anatomy tests on the immune system. Thirty-six freshman occupational therapy students completed a written stress evaluation survey, and saliva samples were obtained at baseline and prior to each of three timed-practical gross anatomy tests. Cortisol, secretory IgA (sIgA), and IL-12 concentrations were measured within the salivary samples by enzyme-linked immunosorbent assay. The total scores from the stress surveys were used as markers for environmental stress. Data were compiled for each student at baseline and prior to each examination and were compared by repeated-measures MANOVA and Pearson's correlation test. Following normalization for protein concentration and flow rate, the concentrations of IL-2, IL-6, IL-12, and sIgA progressively increased from baseline to the third test. Cortisol concentrations, following normalization for flow rate, were highest prior to the first test and became significantly reduced prior to second and third test. Prior to second and third test, salivary concentrations of IL-6, IL-2, IL-12, and sIgA were significantly correlated (P < 0.05). In contrast, prior to third test, there was a negative correlation between salivary concentrations of cortisol and IL-12 (P < 0.05). Progressive increases in salivary sIgA, IL-6, IL-2, and IL-12 concentrations from the first to the third test coincident to decreased salivary cortisol suggest that the initial examination stressors precede significant effects on the immune system. These data suggest that there may be latent effects of examination stress on the immune system and that saliva can be used to predict these effects.