title: Resting plasma and salivary IL-6 concentrations are not correlated in distance runners.
abstract: Measurement of IL-6 has been widely undertaken to examine inflammatory and immune responses to exercise. Use of salivary IL-6 offers an alternative to the invasive collection procedures required for IL-6 measurement in plasma samples. Rarely, however, has the degree of association between plasma and salivary IL-6 been reported. The aim of the current study was to investigate the relationship between resting salivary and plasma IL-6 concentrations in 45 trained distance runners (36 males, 9 females; age: 35.1 +/- 8.0 y, mean +/- SD). Plasma and saliva samples were collected from athletes under resting conditions. Plasma IL-6 concentrations were determined using a Bioplex suspension array system and commercially available reagents. Salivary IL-6 concentrations were determined using a commercially available high-sensitivity ELISA kit. At rest, the mean (+/- SD) plasma IL-6 concentration was 3.43 +/- 3.75 pg mL(-1) compared to a mean salivary IL-6 concentration of 1.80 +/- 4.25 pg mL(-1). IL-6 concentrations in plasma and saliva samples were not correlated (r = -0.031, p = 0.85). At rest, salivary IL-6 concentrations do not reflect plasma IL-6 concentrations. The potential for salivary IL-6 to act as a surrogate marker for plasma IL-6 responses when examining inflammatory and immune responses to exercise, therefore, appears unlikely.
authors: Department of Physiology, Australian Institute of Sport, PO Box 176, Canberra, Belconnen, ACT 2616, Australia. amanda.cox@ausport.gov.au
authors: Amanda J
authors: AJ
authors: Cox
authors: David B
authors: DB
authors: Pyne
authors: Maree
authors: M
authors: Gleson
authors: Robin
authors: R
authors: Callister
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007107:Immune System / Q000378:metabolism; D015850:Interleukin-6 / Q000097:blood* / Q000378:metabolism; D008297:Male; D012146:Rest / Q000502:physiology; D012420:Running / Q000502:physiology*; D012463:Saliva / Q000378:metabolism*; D013177:Sports / Q000502:physiology
chemical_list: D015415:Biomarkers; D015850:Interleukin-6