Prevalence of IgG anti-Der p 2 antibodies in children from high and low antigen exposure groups: relationship of IgG and subclass antibody responses to exposure and allergic symptoms.

Serum IgG PAN, IgG1-4, and IgE antibodies (Ab) specific for the house dust mite Dermatophagoides antigen (Ag) Der p 2 were measured by enzyme-linked immunosorbent assay (ELISA) in two groups of school children, age 12-14, exposed to high (Charlottesville, VA) and low (Los Alamos, NM) mite Ag levels in their environment. More than 90% of the children were found to have Der p 2-specific IgG antibodies, although the levels of both IgG PAN and IgG 1-4 Ab were substantially higher in the high exposure group (P = 0.001). In addition, there was considerable overlap between these two groups in all Ab measurements. The presence of IgG anti-Der p 2 Ab in the Los Alamos children was unexpected and suggests continuing Ag exposure, although the source of such exposure is not apparent. There is no correlation between RAST (+) and RAST (-) subjects with respect to the level of IgG Ab measured by ELISA. These results suggest that the IgG Ab response to house dust mite has been underestimated in the RAST negative population. Two twin pairs were included in this study and the divergent and varied Ab responses in these individuals indicate that factors in addition to environmental exposure and genetic susceptibility require further investigation and provide evidence for the complexity of the pathogenesis of the allergic response.