[IgG subclasses in healthy children and in children with frequent respiratory tract infections].

A group of 130 children presenting with frequent respiratory tract infections was examined for serum levels of IgG-subclasses IgG1, IgG2, IgG3 and IgG4 using radial immunodiffusion according to Mancini. Additionally a control group of 175 children not prone to infections was investigated. Both, low and high levels compared to controls were observed for IgG3 and IgG4.