IgG subclasses in children with recurrent respiratory tract infections in an allergy practice.

Isolated or combined deficiencies of immunoglobulin G (IgG) subclasses have been recognized in children with recurrent infections. In our allergy practice, there are a subset of children with recurrent respiratory tract infections. To investigate the presence of immunoglobulin G subclass deficiency (IgGSD), 60 children with atopy and 14 children without atopy suffering from recurrent respiratory tract infections were studied in an attempt to determine whether atopy is associated with a certain IgG subclass pattern. Ten atopic children were found to have isolated or combined IgG subclass deficiencies: one with IgG1, two with IgG2, four with IgG3 and three children had IgG2-IgG3. Neither IgG subclass concentration nor the frequency of children with high or low IgG subclasses showed any difference between atopic and non-atopic groups. Except for a week correlation with IgG3, no correlation existed between IgE and other IgG subclasses. It was concluded that childhood respiratory diseases complicated by recurrent respiratory tract infections may be associated with IgG subclass deficiencies. Although there have been reports noting some IgG subclass patterns in atopic disorders, in the present study, no distinctive feature between atopics and non-atopics with respect to IgG subclass concentrations and patterns was observed.