SIgA and Upper Respiratory Syndrome During a College Cross Country Season

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PURPOSE: To examine changes in mucosal immunoglobulin A (SIgA) and the incidence of upper respiratory syndrome (URS) during a college cross country season. METHODS: Twenty-two cross country athletes (XC) (20.7 ± 1.4 years) and twenty-three matched controls (C) (20.4 ± 1.4 years) served as subjects in this investigation. Using standardized data collection procedures, all participants provided unstimulated resting saliva samples at four targeted time points (pre-season, two in-season, and post season) over a four-month study period. These samples were subsequently analyzed in one batch by an enzyme-linked immunosorbent assay (Salimetrics, Philadelphia, PA), to determine absolute SIgA (μg/ml) concentration and calculate the secretion rate of SIgA (μg/min). Throughout the study, subjects completed standard weekly logs indicating signs and symptoms of URS from which a total symptom score (TSS) was calculated according to the method of Gleeson, (2012). Differences between groups and across the duration of the study were examined using repeated measures ANOVA. RESULTS:Analysis of SIgA data revealed significant main effects for SIgA, F(1,43) = 15.617, p = .000 with a moderate effect size (.266) as well as a significant Group x Time interaction, F(3,41) = 6.386, p = .001 with a moderate effect size (.318). Analysis of the secretion rate of SIGA data revealed significant main effects for the secretion rate of IgA, F(1,43) = 15.617, p = .000 with a moderate effect size (.223) as well as a significant Group x Time interaction, F(3,41) = 5.998, p = .002 with a moderate effect size (.305). A Bonferroni adjusted multiple comparison test revealed that resting absolute SIgA concentration and secretory SIgA in XC decreased throughout the season but remained unchanged in C. There was no significant difference in the saliva flow rate, F(3,41) = 1.719, p = .178. There was also a group by time interaction for TSS F(1,42) = 5.8, p = .020. XC had both higher TSS scores during the season and a significant negative correlation of moderate strength between those scores and the secretion rate of SIgA (p<.05). CONCLUSIONS: These results indicate that a season of college cross country running is associated with a progressive reduction in mucosal SIgA levels and an increase in URS.