Antipolysaccharide antibodies in 450 children with otitis media.

We have measured antibodies to pneumococcal and Haemophilus polysaccharides in a prospective study of 450 children aged 2–16 years with otitis media requiring grommets (ear tubes). Pneumococcal antibody levels were significantly higher in the 2–6 year (P < 0.004) and 7–10 year (P < 0.04) study groups in comparison with age-matched controls. There was no difference in Haemophilus antibody levels between the study and control group children for the age groups 2–6 years and 11–16 years. Haemophilus antibody levels were significantly lower in the 7–10 year (P < 0.003) group in comparison with age-matched controls. Eighty-eight out of 450 (19.6%) children had pneumococcal antibody levels below the 25th percentile. Nineteen out of 88 (21.6%) children with pneumococcal antibody levels below the 25th centile were test immunized with 23 valent Pneumococcal polysaccharide and unconjugated Haemophilus type b capsular polysaccharide. Of these 19 children (aged 4–11 years), five mounted suboptimal responses to both polysaccharide antigens, whilst one child failed to respond to Haemophilus polysaccharide alone. There was no significant difference in the prevalence of IgG subclass deficiency between the normal responders and poor responders to immunization (P= 0.12). We found no evidence of specific polysaccharide antibody deficiency in the vast majority of the 450 children studied. However, the significance of poor antibody responses to test immunization in a small minority of children with otitis media is unclear. Long-term follow up of these children is required to determine whether poor immunization responses herald the development of frank antibody deficiency.