Reductions in secretory immunoglobulin A to cold pressor stress are not influenced by timing of saliva sampling

Acute psychological stress has been shown to alter secretory immunity, principally secretory immunoglobulin A (S-IgA). Most acute stress tasks result in increases in S-IgA, but decreases have been reported in response to the cold pressor. However, the evidence is mixed, with increases and no changes in S-IgA in response to the cold pressor also being reported. It was hypothesised that differences in the timing of saliva sampling may provide an explanation for these discrepant results. Participants completed two 4-min cold pressor tasks, each preceded by a rest period in which baseline S-IgA was measured. In one condition, S-IgA was assessed during the final 2 min of the cold pressor; in the other, it was measured immediately after completion of the task. S-IgA decreased from baseline to task, regardless of timing of saliva sampling. It was concluded that differences in timing of sampling do not account for the mixed reports in the literature.