IgG subclass deficiency and recurrent respiratory infections in children.

The aim of this study was to investigate the humoral immunity of children with recurrent respiratory tract infections. Fifty-seven (17 female, 40 male) children, aged from 1.1 to 12.0 years were evaluated, after 1 month from the last infectious disease. The total number of children with IgG subclasses deficiency was 29/57 with the following IgG deficiency distribution: IgG1 = 2 children, IgG2 = 13 children, IgG3 = 4 children, IgG4 = 25 children. Moreover, 13 children with IgG4 deficiency showed low levels of other (one or more) IgG subclasses. It is probable that these low IgG subclasses levels are an important immunological abnormality of these children.