Respiratory tract infections in children are one of the most common causes for medical consultations. When the
infections are of recurring nature, they are a major reason for the diagnostics for primary immunodeficiency that is in about 65% of cases underlain by disorders of humoral immunity. This study seeks to retrospectively evaluate the history of recurrent
respiratory tract infections in children with humoral disorders and the associations among deficiencies in the immune system components. We evaluated 394 children aged 3 months to 18 years. We found 49.5% (195 cases) of children with
IgG deficiencies, all of whom had normal
IgE levels. There were 8.4% (33 cases) of
IgA deficiency, 7.4% (29 cases) of
IgM insufficiency, and 4.1% (16 cases) of CD19+ cells deficiency. The elevated level of CD19+ cells was found in 27.7% (109 out of the 394 children).
Immunoglobulin deficiencies often coexisted with a deficiency in another
immunoglobulin class above outlined. There was an interdependence between
IgA abnormality and
IgG,
IgG3, and
IgG4 abnormalities as well as between
IgM abnormality and
IgG and
IgG1 abnormalities. We conclude that
respiratory tract infections in children are often underlain by a convergence of
IgG with both
IgA and
IgM abnormal states. The physiopathological meaning of this convergence for the
infection course and resulting functional respiratory changes remains elusive.