Abstract
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 ≤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 >0.58 g/l. On the other hand pneumococci were found 1.9 times as often in the group with IgG2 level >0.58 g/l, as in the group with IgG2 level ≤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.