摘要With monoclonal antibodies serum immunoglobulin G(IgG) subclasses were measured in seventy children aged 2 to 13 years with recurrent respiratory tract infections including upper respiratory tract infections, otitis media, sinusitis, asthmatic bronchitis and pneumonia. 211 healthy, aged-matched children served as control. IgG subclass deficiency was found in 19 out of the 70 patients (27.1%, single IgG1 deficiency in 7, IgG2 deficiency in 4, combined IgG1-IgG3 deficiency in 5, IgG1-IgG2-IgG3-IgG4 deficiency, IgG1-IgG2-IgG4 deficiency and IgG2-IgG4 deficiency each in 1). The incidence of IgG subclass deficiencies was in the sequence as follows: IgG1, 20%; IgG2, 10%; IgG3, 8.6% and IgG4, 4.3%. The results suggest that IgG subclass deficiency indicate a common disorder in children with recurrent respiratory tract infections.