[The determination of IgG subclasses in healthy children by ELISA with monoclonal antibodies]

The age at which the different IgG subclasses reach stable values has not been uniformly established to date. In this study the concentration of IgG1, IgG2, IgG3 and IgG4 has been determined in the serum of 164 children (from 1 to 14 years of age) and 20 healthy adults, by using a monoclonal antibody enzyme immunoassay. The geometric mean, standard deviation and coefficient of correlation were obtained. Results showed a gradual increase in the levels of the different subclasses throughout age. The time at which the adult concentrations were obtained varied and these adult levels were not necessarily the highest values. During the first year of life, the level of IgG1 is already high and by 6-7 years its serum concentration represented 90% of the adult IgG concentration. IgG2, IgG3 and IgG4 were initially detected at low levels. IgG2 increased rapidly until it reached a stable value at 9-10 years of age. Adult values were obtained at 10-11 years of age for IgG3 and 7-8 years of age for IgG4.