Early immune responses to Dermatophagoides pteronyssinus and atopic predisposition.

Responses to the house dust mite during infancy may be important determinants of asthma in susceptible individuals. This study assessed early IgG subclass antibody responses to Dermatophagoides pteronyssinus in children of atopic parents. Sixteen atopic and 15 non-atopic children were selected from a birth cohort, and atopic status was established according to follow up over the first two years. IgG1 and IgG4 antibodies to D pteronyssinus were measured by enzyme linked immunosorbent assay at 7 days and 3, 6, 12, and 24 months. In all children D pteronyssinus IgG1 fell at 3 months (indicating maternal antibody loss), rose progressively to 12 months, and waned at 24 months. D pteronyssinus IgG4 was only detectable at 7 days. Children who were atopic by 2 years and therefore at greater risk of asthma, tended to have higher D pteronyssinus IgG1 at 6 and 12 months. These data suggest greater exposure or responsiveness to dust mite during infancy than in the second year.