[Inflammatory middle ear diseases in children--sex differences].

We previously proposed that boys are more susceptible than girls to inflammatory middle ear diseases such as Acute Otitis Media (AOM) and cholesteatoma. This study attempts to describe the concentrations of three major immunoglobulins and IgG subclass-IgG2 in healthy children and "otitis-prone" children from 2 and 7 years of age divided into one-year interval age/sex categories. Also, we attempt to analyze how many attacks of AOM had occurred in these children. The statistical analysis of the results is described as below. The main effects of otitis-proneness, gender and age on the mean values of IgG, A, M and IgG2 as well as the joint effects of these factors were analyzed by a three-factor analysis of variance. The main effect of otitis-proneness was statistically significant for IgG2. It is assumed that the low levels of IgG2 in otitis-prone children are one cause of the high frequency of AOM. The main effect of gender was also statistically significant for IgG2. If OMA and cholesteatoma in children were considered a series of inflammatory middle ear diseases, this boy-dominant tendency could be associated with an insufficient IgG2 antibody production in boys. These children may represent extreme cases of delayed maturation of IgG2. We plan to observe our subjects over an extended period of time.