A Prospective Study Demonstrating an Association between Plasma IgG2 Concentrations and Susceptibility to Otitis Media in Children

Plasma IgG subclass levels of 20 children, 12 and 32 months of age, who were susceptible to acute purulent otitis media, were compared with those of 20 age-matched control children. The IgG2 levels were significantly lower in the otitis-prone group, with a mean of 0.58 +/- 0.30 g/l at 12 months of age (controls 0.85 +/- 0.39) and 0.82 +/- 0.30 at 32 months of age (controls 1.38 +/- 0.49). Otitis-prone children with IgG2 levels less than or equal to 0.58 g/l (at 12 months of age) were found to suffer from Haemophilus influenzae infections 2.6 times as often as those with IgG2 levels greater than 0.58 g/l. On the other hand pneumococci were found 1.9 times as often in the group with IgG2 level greater than 0.58 g/l, as in the group with IgG2 level less than or equal to 0.58 g/l. Otitis proneness seems partly to be due to an immunological incompetence of IgG2, which also influences the bacterial spectrum of the infections.