[Secretory IgA and infantile respiratory pathology]

Secretory component of IgA is the major class of immunoglobulin in secretions and mucous membranes. Many causes have been involved in etiopathogenesis of respiratory tract disease in children, one of them the possible deficit of secretory component of IgA. Authors have studied 191 children with respiratory tract disease secondary to infections and/or allergy and a control group of 35 healthy children. In all of them the secretory IgA non stimulated sputum was measured. In the group with respiratory disease serum IgA, IgG, IgM and IgE were also measured. Levels of secretory IgA were greater in group with respiratory disease than in control; also serum level of IgA was above normal for their ages. Level of secretory IgA was greater in children with "wheezing respiratory disease". These findings do not agree with theory of existence of an IgA secretory deficit as a cause or respiratory tract disease in children.