[Immunoglobulin A in saliva of children: age dependence and effect of respiratory tract diseases].

Immunoglobulin A (IgA) plays an essential role in the local defence mechanism and is part of the immunologic system. It is transported to the endothelial surface either as a monomer or as a dimer of two molecules of IgA connected by a j-chain and attached to a secretory component. The aim of the present study was to assess the relation of salivary IgA to the age of children and to assess a possible influence by acute and chronic respiratory diseases. IgA was measured in the saliva of altogether 230 children by means of radial immunodiffusion (LC-IgA Partigen, Behring) following a standardised protocol. Relation to age was measured in 159 healthy children aged one month to 15 years. The median of IgA was 36 mg/l with a range of 3.5-291 mg/l. There was no statistically significant relationship between salivary IgA and the age of the children. Median IgA in the saliva of children without any respiratory disorders (n = 169) was 36 mg/l (3.5-291 mg/l), of children with acute respiratory diseases (n = 33) 51 mg/l (3.5-257 mg/l) and of children with chronic respiratory diseases (n = 28) 47 mg/l (3.5-165 mg/l). There was no statistically significant difference between these three groups. In conclusion, the results of this study show that IgA in the saliva of children may not be related to age or influenced by acute or chronic respiratory diseases.