IgG subclass deficiency in children with recurrent infections.

Serum IgG subclasses and IgG, IgA and IgM were measured in 35 patients with frequent infections and unusually severe infections, 45 normal children were compared. There is no significant difference between the geometric means of two age-matched groups (p greater than 0.05) and the proportion of low IgG subclass. We detected 9 cases with low IgG subclass in our selected patients, but we have 6 cases with low IgG subclass in our normal population without symptoms. For the low IgG subclass cases, total IgG level remain at normal age-related values, no IgA deficiency was found in our 78 cases. It is not uncommon to find low IgG subclass in Chinese children, but their significance is still questioned in our study. Larger number of cases should be collected and antibody response to antigen should be the goal for further study in Chinese children.