Salivary IgA subclasses and infection risk in elite swimmers

The concentrations of total IgA, IgA1 and IgA2 were measured in saliva coll ected from 25 elite swimmers in the early and late phases of a 7 month trai ning season and compared with the number of respiratory infections during t he season. The IgA1 concentrations in the early phase of the training seaso n were significantly associated (P = 0.01) with the number of respiratory i nfection episodes during the training season. The lower the concentration o f IgA1, the greater the number of infection episodes. Swimmers with four or more infections during the training season had significantly lower salivar y IgA1 concentrations than those with less than four infection episodes (P = 0.01). The proportion of IgA1 in the saliva of the elite swimmers (80%) w as higher than for normal non-exercising adults (60%). A small proportion o f athletes had salivary IgA2 concentrations below the detection limit of th e assay and the mean concentration of IgA2 was significantly lower than the concentrations for a normal adult population (P = 0.01). This study sugges ts that measurement of IgA subclasses, in particular IgA1, at the commencem ent of a training season may predict infection risk in elite swimmers.