Evaluation of secretory IgA childhood respiratory diseases.

Secretory IgA salivary concentration was studied, in order to investigate its influence as a possible causative role in groups of children affected by different respiratory diseases. Allergic bronchial asthma (n = 37), recurrent pneumonias (n = 11), recurrent upper airway infectious (n = 12) and a control group of healthy children (n = 25) were included. The sIgA mean concentration plus S.D. were: 26.0 +/- 11.5, 15.5 +/- 16.7, 21.2 +/- 15.6, 16.2 +/- 12.7 and 30.8 +/- 10.1, respectively. A statistically significant association between decreased or absent levels of sIgA and disease was found, but no correlation between alterations in sIgA concentrations and any class of serum immunoglobulin levels, or with any other analyzed variables could be established. Among the group of diseases studied, a statistically significant difference (p less than 0.01) was found between infectious asthma and controls, recurrent upper airway infections and controls, and between allergic and infectious asthma. These findings support the conclusion that a decrease or absence of sIgA is an important factor to be considered in infectious asthma, as well as in recurrent upper airway infectious diseases affecting children.