Secretory immunoglobulin A increases during relaxation in children with and without recurrent upper respiratory tract infections.

A diminished mucosal concentration of secretory immunoglobulin A (sIgA) in the upper respiratory tract may increase susceptibility to colds and flu. The aim of the present study was to determine whether sIgA increases during relaxation in children aged between 8 and 12 years with recurrent upper respiratory tract infections. Forty-five healthy children and 45 children with 10 or more upper respiratory tract infections in the previous year were randomly assigned to one of three experimental conditions: relaxation with suggestions to increase immune system proteins, relaxation alone, or a control condition. Samples of saliva were obtained before and after each condition. The concentration of sIgA in the saliva samples was later determined by measuring the rate of precipitation of antigen-antibody complexes to known concentration of sIgA antigen. The concentration of sIgA increased in the relaxation conditions but not in the control condition. The sIgA/albumin ratio (a more specific measure of local mucosal immunity than concentration) increased during the relaxation-suggestion condition but not during the relaxation or control conditions; however, both the concentration of sIgA and the sIgA/albumin ratio increased in proportion to subjective relaxation ratings. Neither response differed between healthy children and children with recurrent infections. The findings indicate that a disturbance in mucosal immunity in children with recurrent colds and flu does not limit increases in sIgA during relaxation. Higher preinfection levels of sIgA correlate with resistance to upper respiratory tract infection, so enhancing the sIgA concentration with relaxation techniques may help children with recurrent infection problems.