Considerations for the use of salivary IgA for monitoring mucosal immune function.
BACKGROUND
We aimed to make recommendations concerning the use of total IgA in saliva (s-IgA) as an aid for monitoring athletic and military training.


METHODS
Unstimulated whole saliva was collected from 16 subjects (11 women and 5 men ages 18-57) during nonconsecutive days of fasting and non-fasting. Seven samples were collected from each subject at 0700, 0900, 1200, 1400, 1600, 1800, and 2030 on each day and a further three samples were collected 30 min after three meals on the non-fasting day (at 0730, 1230, and 1830). Strenuous activity was avoided and subjects did not drink caffeine or alcohol-containing beverages. Albumin and s-IgA were measured by commercial nephelometric immunoassays with intra-analytical coefficient of variance (CVA) of 1.8% and 2.9%, respectively. Individual and group variations were determined. Diurnal variation was determined by use of repeated-measures analysis of variance.


RESULTS
CV-individual (CV(I)) was 48% for s-IgA concentration and 43% for s-IgA secretion and s-IgA:albumin. CV-group (CVG) for these same measures was 68%, 75%, and 68%, respectively. When measurements were adjusted for saliva flow rates there was no evidence that s-IgA is subject to diurnal variation. There was strong evidence for a postprandial decrease in s-IgA for all measures.


CONCLUSIONS
The high degree of individuality in s-IgA precludes the use of population reference ranges for identifying individual abnormal results. For the purpose of monitoring individuals we recommend using the individual's calculated biological variance (determined from previous serial measurements over a period of days to weeks). Individual abnormal results can then be identified.
Dwyer
Dan B
DB
Human Protection & Performance Division, Defence Science & Technology Organisation, Scottsdale, Tasmania, Australia.
Booth
Christine K
CK
Pacque
Paul F
PF
Ball
Madeleine J
MJ
D000293:Adolescent; D000328:Adult; D000418:Albumins / Q000032:analysis; D000704:Analysis of Variance; D001681:Biological Assay; D002940:Circadian Rhythm; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007118:Immunoassay; D007070:Immunoglobulin A / Q000032:analysis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000276:immunology*; D009391:Nephelometry and Turbidimetry; D012016:Reference Values; D012463:Saliva / Q000737:chemistry / Q000276:immunology*; D013997:Time Factors; D055815:Young Adult
D000418:Albumins; D007070:Immunoglobulin A