Determination of an appropriate collection method for analysis of human salivary lysozyme (s-Lys)

Lysozyme has been identified as a stress biomarker in addition to its function in local immunological defence. With the above in mind,
analysis of saliva lysozyme (s-Lys) in athletes may help in the evaluation of training stress and its possible effects on local immune protection following periods of heavy training. The objective of this study was to determine an appropriate saliva collection method for analysis of s-Lys
concentration. Following university ethical approval, six healthy
males were asked to produce 10 ml of whole unstimulated saliva via the passive drool [gold standard] method in a resting condition. Expectorated saliva was subsequently divided into preweighed vials corresponding to volumes 0.4, 0.7, 1, 2 and 3 ml. The remainder of saliva (3–4 ml) acted
as the study control (swab ‘‘free’’ sample). Preweighed cotton ‘‘salivette’’ swabs were immersed into each vial [2 min] and mixed [shaker 500 rpm]
before being removed and subsequently centrifuged (1500g 6 15 min). Samples were re-weighed to determine saliva release and stored at 7808C before analysis using a commercial sandwich Human Lysozyme EIA kit (Biomedical Technologies Inc., Stoughton, MA). Exposure of resting whole unstimulated saliva to the cotton-based salivette material profoundly affected s-Lys concentration (P ¼ 0.015). Mean s-Lys concentrations using the ‘‘salivette’’ swab method were 77% lower than corresponding values collected via the passive ‘‘drool’’ method. Furthermore, the
ability of the swab to release saliva for subsequent analysis was found to be diminished with smaller saliva volumes (Table I). In conclusion, collection of saliva for s-Lys determination using cotton based swabs significantly effects resultant s-Lys concentrations. Future use of
this collection method should be done so with caution.