Precipitin to mite detected in asthmatic patients

Mite antigen from dermatophagoides farinae was labelled with 125I, and used for detection of precipitin to mite antigen in sera from asthmatic patients allergic to mite and house dust. By double gel diffusion using this labelled antigen, it was found that 16 out of 37 sera formed precipitin bands which were detected by radioautography. Only one serum formed a precipitin band when non-labelled mite antigen was used in double gel diffusion. The main immunogenic component in mite extract migrated to the beta region in immunoelectrophoresis. The intensity of the precipitin line did not correlate with the relative concentration of IgE antibodies as determined by RAST. IgG antibodies to mite were detected by radioimmunoelectrophoresis in three out of 37 sera.